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Keywords: Integration, Aggregation, Switching, MPTCP, MPQUIC, GMA, 5G, LTE, Wi-Fi, Ethernet, Edge, Proxy

Independent Submission S. Kanugovi
Request for Comments: 8743 Nokia Bell Labs
Category: Informational F. Baboescu
ISSN: 2070-1721 Broadcom
J. Zhu
Intel
S. Seo
Korea Telecom
March 2020
Multi-Access Management Services (MAMS)
Abstract
In multiconnectivity scenarios, the clients can simultaneously
connect to multiple networks based on different access technologies
and network architectures like Wi-Fi, LTE, and DSL. Both the quality
of experience of the users and the overall network utilization and
efficiency may be improved through the smart selection and
combination of access and core network paths that can dynamically
adapt to changing network conditions.
This document presents a unified problem statement and introduces a
solution for managing multiconnectivity. The solution has been
developed by the authors based on their experiences in multiple
standards bodies, including the IETF and the 3GPP. However, this
document is not an Internet Standards Track specification, and it
does not represent the consensus opinion of the IETF.
This document describes requirements, solution principles, and the
architecture of the Multi-Access Management Services (MAMS)
framework. The MAMS framework aims to provide best performance while
being easy to implement in a wide variety of multiconnectivity
deployments. It specifies the protocol for (1) flexibly selecting
the best combination of access and core network paths for the uplink
and downlink, and (2) determining the user-plane treatment (e.g.,
tunneling, encryption) and traffic distribution over the selected
links, to ensure network efficiency and the best possible application
performance.
Status of This Memo
This document is not an Internet Standards Track specification; it is
published for informational purposes.
This is a contribution to the RFC Series, independently of any other
RFC stream. The RFC Editor has chosen to publish this document at
its discretion and makes no statement about its value for
implementation or deployment. Documents approved for publication by
the RFC Editor are not candidates for any level of Internet Standard;
see Section 2 of RFC 7841.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
https://www.rfc-editor.org/info/rfc8743.
Copyright Notice
Copyright (c) 2020 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(https://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document.
Table of Contents
1. Introduction
2. Terminology
3. Problem Statement
4. Requirements
4.1. Access-Technology-Agnostic Interworking
4.2. Support for Common Transport Deployments
4.3. Independent Access Path Selection for Uplink and Downlink
4.4. Core Selection Independent of Uplink and Downlink Access
4.5. Adaptive Access Network Path Selection
4.6. Multipath Support and Aggregation of Access Link Capacities
4.7. Scalable Mechanism Based on User-Plane Interworking
4.8. Separate Control-Plane and User-Plane Functions
4.9. Lossless Path (Connection) Switching
4.10. Concatenation and Fragmentation for Adaptation to MTU
Differences
4.11. Configuring Network Middleboxes Based on Negotiated
Protocols
4.12. Policy-Based Optimal Path Selection
4.13. Access-Technology-Agnostic Control Signaling
4.14. Service Discovery and Reachability
5. Solution Principles
6. MAMS Reference Architecture
7. MAMS Protocol Architecture
7.1. MAMS Control-Plane Protocol
7.2. MAMS User-Plane Protocol
8. MAMS Control-Plane Procedures
8.1. Overview
8.2. Common Fields in MAMS Control Messages
8.3. Common Procedures for MAMS Control Messages
8.3.1. Message Timeout
8.3.2. Keep-Alive Procedure
8.4. Discovery and Capability Exchange
8.5. User-Plane Configuration
8.6. MAMS Path Quality Estimation
8.6.1. MX Control PDU Definition
8.6.2. Keep-Alive Message
8.6.3. Probe-REQ/ACK Message
8.7. MAMS Traffic Steering
8.8. MAMS Application MADP Association
8.9. MAMS Network ID Indication
8.10. MAMS Client Measurement Configuration and Reporting
8.11. MAMS Session Termination Procedure
8.12. MAMS Network Analytics Request Procedure
9. Generic MAMS Signaling Flow
10. Relationship to IETF Technologies
11. Applying MAMS Control Procedures with MPTCP Proxy as User Plane
12. Applying MAMS Control Procedures for Network-Assisted Traffic
Steering When There Is No Convergence Layer
13. Coexistence of MX Adaptation and MX Convergence Layers
14. Security Considerations
14.1. MAMS Control-Plane Security
14.2. MAMS User-Plane Security
15. Implementation Considerations
16. Applicability to Multi-Access Edge Computing
17. Related Work in Other Industry and Standards Forums
18. IANA Considerations
19. References
19.1. Normative References
19.2. Informative References
Appendix A. MAMS Control-Plane Optimization over Secure
Connections
Appendix B. MAMS Application Interface
B.1. Overall Design
B.2. Notation
B.3. Error Indication
B.4. CCM APIs
B.4.1. GET Capabilities
B.4.2. Posting Application Requirements
B.4.3. Getting Predictive Link Parameters
Appendix C. MAMS Control-Plane Messages Described Using JSON
C.1. Protocol Specification: General Processing
C.1.1. Notation
C.1.2. Discovery Procedure
C.1.3. System Information Procedure
C.1.4. Capability Exchange Procedure
C.1.5. User-Plane Configuration Procedure
C.1.6. Reconfiguration Procedure
C.1.7. Path Estimation Procedure
C.1.8. Traffic-Steering Procedure
C.1.9. MAMS Application MADP Association
C.1.10. MX SSID Indication
C.1.11. Measurements
C.1.12. Keep-Alive
C.1.13. Session Termination Procedure
C.1.14. Network Analytics
C.2. Protocol Specification: Data Types
C.2.1. MXBase
C.2.2. Unique Session ID
C.2.3. NCM Connections
C.2.4. Connection Information
C.2.5. Features and Their Activation Status
C.2.6. Anchor Connections
C.2.7. Delivery Connections
C.2.8. Method Support
C.2.9. Convergence Methods
C.2.10. Adaptation Methods
C.2.11. Setup of Anchor Connections
C.2.12. Init Probe Results
C.2.13. Active Probe Results
C.2.14. Downlink Delivery
C.2.15. Uplink Delivery
C.2.16. Traffic Flow Template
C.2.17. Measurement Report Configuration
C.2.18. Measurement Report
C.3. Schemas in JSON
C.3.1. MX Base Schema
C.3.2. MX Definitions
C.3.3. MX Discover
C.3.4. MX System Info
C.3.5. MX Capability Request
C.3.6. MX Capability Response
C.3.7. MX Capability Acknowledge
C.3.8. MX Reconfiguration Request
C.3.9. MX Reconfiguration Response
C.3.10. MX UP Setup Configuration Request
C.3.11. MX UP Setup Confirmation
C.3.12. MX Traffic Steering Request
C.3.13. MX Traffic Steering Response
C.3.14. MX Application MADP Association Request
C.3.15. MX Application MADP Association Response
C.3.16. MX Path Estimation Request
C.3.17. MX Path Estimation Results
C.3.18. MX SSID Indication
C.3.19. MX Measurement Configuration
C.3.20. MX Measurement Report
C.3.21. MX Keep-Alive Request
C.3.22. MX Keep-Alive Response
C.3.23. MX Session Termination Request
C.3.24. MX Session Termination Response
C.3.25. MX Network Analytics Request
C.3.26. MX Network Analytics Response
C.4. Examples in JSON
C.4.1. MX Discover
C.4.2. MX System Info
C.4.3. MX Capability Request
C.4.4. MX Capability Response
C.4.5. MX Capability Acknowledge
C.4.6. MX Reconfiguration Request
C.4.7. MX Reconfiguration Response
C.4.8. MX UP Setup Configuration Request
C.4.9. MX UP Setup Confirmation
C.4.10. MX Traffic Steering Request
C.4.11. MX Traffic Steering Response
C.4.12. MX Application MADP Association Request
C.4.13. MX Application MADP Association Response
C.4.14. MX Path Estimation Request
C.4.15. MX Path Estimation Results
C.4.16. MX SSID Indication
C.4.17. MX Measurement Configuration
C.4.18. MX Measurement Report
C.4.19. MX Keep-Alive Request
C.4.20. MX Keep-Alive Response
C.4.21. MX Session Termination Request
C.4.22. MX Session Termination Response
C.4.23. MX Network Analytics Request
C.4.24. MX Network Analytics Response
Appendix D. Definition of APIs Provided by the CCM to the
Applications at the Client
Appendix E. Implementation Example Using Python for MAMS Client
and Server
E.1. Client-Side Implementation
E.2. Server-Side Implementation
Acknowledgments
Contributors
Authors' Addresses
1. Introduction
Multi-Access Management Services (MAMS) is a programmable framework
that provides mechanisms for the flexible selection of network paths
in a multi-access (MX) communication environment, based on the
application's needs. The MAMS framework leverages network
intelligence and policies to dynamically adapt traffic distribution
across selected paths and user-plane treatments (e.g., encryption
needed for transport over Wi-Fi, or tunneling needed to overcome a
NAT between client and multipath proxy) to changing network/link
conditions. The network path selection and configuration messages
are carried as user-plane data between the functional elements in the
network and the client, and thus without any impact on the control-
plane signaling schemes of the underlying access networks. For
example, in a multi-access network with LTE and Wi-Fi technologies,
existing LTE and Wi-Fi signaling procedures will be used to set up
the LTE and Wi-Fi connections, respectively, and MAMS-specific
control-plane messages are carried as LTE or Wi-Fi user-plane data.
The MAMS framework defined in this document provides the capability
to make a smart selection of a flexible combination of access paths
and core network paths, as well as to choose the user-plane treatment
when the traffic is distributed across the selected paths. Thus, it
is a broad programmable framework that provides functions beyond the
simple sharing of network policies such as those provided by the
Access Network Discovery and Selection Function (ANDSF) [ANDSF],
which offers policies and rules for assisting 3GPP clients to
discover and select available access networks. Further, it allows
the choice and configuration of user-plane treatment for the traffic
over the paths, depending on the application's needs.
The MAMS framework mechanisms are not dependent on any specific
access network types or user-plane protocols (e.g., TCP, UDP, Generic
Routing Encapsulation (GRE) [RFC2784] [RFC2890], Multipath TCP
(MPTCP) [RFC6824]). The MAMS framework coexists and complements the
existing protocols by providing a way to negotiate and configure
those protocols to match their use to a given multi-access scenario
based on client and network capabilities, and the specific needs of
each access network path. Further, the MAMS framework allows load
balancing of the traffic flows across the selected access network
paths, and the exchange of network state information to be used for
network intelligence to optimize the performance of such protocols.
This document presents the requirements, solution principles,
functional architecture, and protocols for realizing the MAMS
framework. An important goal for the MAMS framework is to ensure
that it requires either minimum dependency or (better) no dependency
on the actual access technologies of the participating links, beyond
the fact that MAMS functional elements form an IP overlay across the
multiple paths. This allows the scheme to be "future proof" by
allowing independent technology evolution of the existing access and
core networks as well as seamless integration of new access
technologies.
The solution described in this document has been developed by the
authors, based on their experiences in multiple standards bodies,
including the IETF and the 3GPP. However, this document is not an
Internet Standards Track specification, and it does not represent the
consensus opinion of the IETF.
2. Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
Client: An end-user device that supports connections with multiple
access nodes, possibly over different access technologies. Also
called a user device or user equipment (UE).
Multiconnectivity Client: A client with multiple network
connections.
Access Network: The segment in the network that delivers user data
packets to the client via an access link such as a Wi-Fi airlink,
an LTE airlink, or DSL.
Core: The functional element that anchors the client IP address used
for communication with applications via the network.
Network Connection Manager (NCM): A functional entity in the network
that handles MAMS control messages from the client and configures
the distribution of data packets over the available access and
core network paths, and manages the user-plane treatment (e.g.,
tunneling, encryption) of the traffic flows.
Client Connection Manager (CCM): A functional entity in the client
that exchanges MAMS signaling messages with the NCM, and which
configures the network paths at the client for the transport of
user data.
Network Multi-Access Data Proxy (N-MADP): A functional entity in the
network that handles the forwarding of user data traffic across
multiple network paths. The N-MADP is responsible for MAMS-
related user-plane functionalities in the network.
Client Multi-Access Data Proxy (C-MADP): A functional entity in the
client that handles the forwarding of user data traffic across
multiple network paths. The C-MADP is responsible for MAMS-
related user-plane functionalities in the client.
Anchor Connection: Refers to the network path from the N-MADP to the
user-plane gateway (IP anchor) that has assigned an IP address to
the client.
Delivery Connection: Refers to the network path from the N-MADP to
the client.
Uplink (also referred to as "UL" in this document): Refers to the
direction of a connection from a client toward the network.
Downlink (also referred to as "DL" in this document): Refers to the
direction of a connection from the network toward a client.
3. Problem Statement
Typically, a client has access to multiple communication networks
based on different technologies for accessing application services,
for example, LTE, Wi-Fi, DSL, or MulteFire. Different technologies
exhibit benefits and limitations in different scenarios. For
example, Wi-Fi provides high throughput for end users when their Wi-
Fi coverage is good, but the throughput degrades significantly as a
given user moves closer to the edge of its Wi-Fi coverage area
(typically in the range of a few tens of meters) or if the user
population is large (due to a contention-based Wi-Fi access scheme).
In LTE networks, the capacity is often constrained by the limited
availability of licensed spectrum. However, the quality of the
service is predictable even in multi-user scenarios, due to
controlled scheduling and licensed-spectrum usage.
Additionally, the use of a particular access network path is often
coupled with the use of its associated core network and the services
that are offered by that network. For example, in an enterprise that
has deployed both Wi-Fi and LTE networks, the enterprise services,
such as printers and corporate audio/video conferencing, are
accessible only via Wi-Fi access connected to the enterprise-hosted
(Wi-Fi) core, whereas the LTE access can be used to get operator
services, including access to the public Internet.
Thus, application performance in different scenarios becomes
dependent on the choice of access networks (e.g., Wi-Fi, LTE) and the
network and transport protocols used (e.g., VPN, MPTCP, GRE).
Therefore, to achieve the best possible application performance in a
wide range of scenarios, a framework is needed that allows the
selection and flexible combination of access and core network paths
as well as the protocols used for uplink and downlink data delivery.
For example, in uncongested scenarios and when the user's Wi-Fi
coverage is good, to ensure best performance for enterprise
applications at all times, it would be beneficial to use Wi-Fi access
for both the uplink and downlink for connecting to enterprise
applications. However, in congested scenarios or when the user is
getting close to the edge of its Wi-Fi coverage area, the use of Wi-
Fi in the uplink by multiple users can lead to degraded capacity and
increased delays due to contention. In this case, it would be
beneficial to at least use the LTE access for increased uplink
coverage, while Wi-Fi may still continue to be used for the downlink.
4. Requirements
The requirements set out in this section define the behavior of the
MAMS mechanism and the related functional elements.
4.1. Access-Technology-Agnostic Interworking
The access nodes MAY use different technology types (LTE, Wi-Fi,
etc.). The framework, however, MUST be agnostic about the type of
underlying technology used by the access network.
4.2. Support for Common Transport Deployments
The network path selection and user data distribution MUST work
transparently across various transport deployments that include end-
to-end IPsec, VPNs, and middleboxes like NATs and proxies.
4.3. Independent Access Path Selection for Uplink and Downlink
A client SHOULD be able to transmit on the uplink and receive on the
downlink, using one or more access networks. The selections of the
access paths for the uplink and downlink SHOULD happen independently.
4.4. Core Selection Independent of Uplink and Downlink Access
A client SHOULD flexibly select the core independently of the access
paths used to reach the core, depending on the application's needs,
local policies, and the result of MAMS control-plane negotiation.
4.5. Adaptive Access Network Path Selection
The framework MUST have the ability to determine the quality of each
of the network paths, e.g., access link delay and capacity. This
information regarding network path quality needs to be considered in
the logic for the selection of the combination of network paths to be
used for transporting user data. The path selection algorithm can
use the information regarding network path quality, in addition to
other considerations like network policies, for optimizing network
usage and enhancing the Quality of Experience (QoE) delivered to the
user.
4.6. Multipath Support and Aggregation of Access Link Capacities
The framework MUST support the distribution and aggregation of user
data across multiple network paths at the IP layer. The client
SHOULD be able to leverage the combined capacity of the multiple
network connections by enabling the simultaneous transport of user
data over multiple network paths. If required, packet reordering
needs to be done at the receiver. The framework MUST allow the
flexibility to choose the flow-steering and aggregation protocols
based on capabilities supported by the client and the network user-
plane entities. The multiconnection aggregation solution MUST
support existing transport and network-layer protocols like TCP, UDP,
and GRE. The framework MUST allow the use and configuration of
existing aggregation protocols such as MPTCP and SCTP [RFC4960].
4.7. Scalable Mechanism Based on User-Plane Interworking
The framework MUST leverage commonly available transport, routing,
and tunneling capabilities to provide user-plane interworking
functionality. The addition of functional elements in the user-plane
path between the client and the network MUST NOT impact the access-
technology-specific procedures. This makes the solution easy to
deploy and scale when different networks are added and removed.
4.8. Separate Control-Plane and User-Plane Functions
The client MUST use the control-plane protocol to negotiate the
following with the network: (1) the choice of access and core network
paths for both the uplink and downlink, and (2) the user-plane
protocol treatment. The control plane MUST configure the actual
user-plane data distribution function per this negotiation. A common
control protocol SHOULD allow the creation of multiple user-plane
function instances with potentially different user-plane (e.g.,
tunneling) protocol types. This enables maintaining a clear
separation between the control-plane and user-plane functions,
allowing the framework to be scalable and extensible, e.g., using
architectures and implementations based on Software-Defined
Networking (SDN).
4.9. Lossless Path (Connection) Switching
When switching data traffic from one path (connection) to another,
packets may be lost or delivered out of order; this will have
negative impact on the performance of higher-layer protocols, e.g.,
TCP. The framework SHOULD provide the necessary mechanisms to ensure
in-order delivery at the receiver, e.g., during path switching. The
framework MUST NOT cause any packet loss beyond losses that access
network mobility functions may cause.
4.10. Concatenation and Fragmentation for Adaptation to MTU Differences
Different network paths may have different security and middlebox
(e.g., NAT) configurations. These configurations will lead to the
use of different tunneling protocols for the transport of data
between the network user-plane function and the client. As a result,
different effective payload sizes per network path are possible
(e.g., due to variable encapsulation header overheads). Hence, the
MAMS framework SHOULD support the fragmentation of a single payload
across MTU-sized IP packets to avoid IP packet fragmentation when
aggregating packets from different paths. Further, the concatenation
of multiple IP packets into a single IP packet to improve efficiency
in packing the MTU size SHOULD also be supported.
4.11. Configuring Network Middleboxes Based on Negotiated Protocols
The framework SHOULD enable the identification of optimal settings,
like radio link dormancy timers, binding expiry times, and supported
MTUs, based on parameters negotiated between the client and the
network, that may be used to configure middleboxes for efficient
operation of user-plane protocols, e.g., configuring a NAT with a
longer binding expiry time when UDP versus TCP is used.
4.12. Policy-Based Optimal Path Selection
The framework MUST support both the implementation of policies at the
client and guidance from the network for network path selection that
will address different application requirements.
4.13. Access-Technology-Agnostic Control Signaling
The control-plane signaling MUST NOT be dependent on the underlying
access technology procedures, i.e., it is carried transparently, like
application data, on the user plane. The MAMS framework SHOULD
support the delivery of control-plane signaling over existing
Internet protocols, e.g., TCP or UDP.
4.14. Service Discovery and Reachability
There can be multiple instances of the control-plane and user-plane
functional elements of the framework, either collocated or hosted on
separate network elements and reachable via any of the available
user-plane paths. The client MUST have the flexibility to choose the
appropriate control-plane instance in the network and use the
control-plane signaling to choose the desired user-plane functional
element instances. The client's choice can be based on
considerations such as, but not limited to, the quality of the link
through which the network function is reachable, client preferences,
preconfiguration, etc.
5. Solution Principles
This document describes the Multi-Access Management Services (MAMS)
framework for dynamic selection of a flexible combination of access
and core network paths for the uplink and downlink, as well as the
user-plane treatment for the traffic spread across the selected
links. The user-plane paths, and access and core network
connections, can be selected independently for the uplink and
downlink. For example, the network paths chosen for the uplink do
not apply any constraints on the choice of paths for the downlink.
The uplink and downlink network paths can be chosen based on the
application needs and on the characteristics and available resources
on different network connections. For example, a Wi-Fi connection
can be chosen for the downlink for transporting high-bandwidth data
from the network to the client, whereas an LTE connection can be
chosen to carry the low-bandwidth feedback to the application server.
Also, depending on the characteristics of the access network link,
different processing would be needed on the user-plane packets on
different network paths. Encryption would be needed on a Wi-Fi link
to secure user-plane packets, but not on an LTE link. Tunneling
would be needed to ensure client and network end-point reachability
over NATs. Such differentiated user-plane treatment can be
accomplished by configuration of user plane-protocols (e.g., IPsec)
specific to each link.
The MAMS framework consists of clearly separated control- and user-
plane functions in the network and the client. The control-plane
protocol allows the configuration of the user-plane protocols and
desired network paths for the transport of application traffic. The
control-plane messages are carried as user-plane data over any of the
available network paths between the peer control-plane functional
elements in the client and the network. Multiple user-plane paths
are dynamically distributed across multiple access networks and
aggregated in the network (by the N-MADP). The access network's
diversity is not exposed to the application servers, but is kept
within the scope of the elements defined in this framework. This
reduces the burden placed on application servers that would otherwise
have to react to access link changes caused by mobility events or
changing link characteristics.
The selection of paths and user-plane treatment of the traffic is
based on (1) the negotiation of client and network capabilities, and
(2) link probing (i.e., checking the quality of links between the
user-plane functional elements at the client and the network). This
framework enables leveraging network intelligence to set up and
dynamically configure the best access network path combination based
on client and network capabilities, an application's needs, and
knowledge of the network state.
6. MAMS Reference Architecture
Figure 1 illustrates the MAMS architecture for the scenario where a
client is served by multiple (n) networks. It also introduces the
following functional elements:
* The NCM and the CCM in the control plane.
* The N-MADP and the C-MADP in the user plane.
+--------------------------------------------------------+
| +----------------+ +----------------+ |
| | | | | |
| |Core (IP anchor)| ..... |Core (IP anchor)| |
| |Network 1 | |Network "n" | |
| | | | | |
| +----------------+ +----------------+ |
| \ / |
| Anchor \ ...... Anchor |
| Connection 1 Connection "n" |
| \ / |
| +---------------+\+---+/+------+ |
| | +-----+ +----------+ | |
| +--------------| NCM | | N-MADP | | |
| | | +-----+ +----------+ | |
| | +------------------------------+ |
| | / \ |
| |Control-Plane Delivery ...... Delivery |
| |Path (over any Connection 1 Connection "n" |
| |access user plane) / \ |
| | / \ |
| | +------------------+ +---------------+ |
| | | Access | ...... | Access | |
| | | Network 1 | | Network "n" | |
| | +------------------+ +---------------+ |
+-----------------------------\----------------/---------+
| \ /
| +----------\------------/-+
| | +---+ \ +------+ / |
+--------------------+CCM| \|C-MADP|/ |
| +---+ +------+ |
| Client |
+-------------------------+
Figure 1: MAMS Reference Architecture
The NCM is the functional element in the network that handles the
MAMS control-plane procedures. It configures the network (N-MADP)
and client (C-MADP) user-plane functions, such as negotiating with
the client for the use of available access network paths, protocols,
and rules for processing the user-plane traffic, as well as link-
monitoring procedures. The control-plane messages between the NCM
and the CCM are transported as an overlay on the user plane, without
any impact on the underlying access networks.
The CCM is the peer functional element in the client for handling
MAMS control-plane procedures. It manages multiple network
connections at the client. The CCM exchanges MAMS signaling messages
with the NCM to support such functions as the configuration of the UL
and DL user network path for transporting user data packets and the
adaptive selection of network path by the NCM by reporting on the
results of link probing. In the downlink, for user data received by
the client, it configures the C-MADP such that application data
packets can be received over any access link so that the packets will
reach the appropriate application on the client. In the uplink, for
the data transmitted by the client, it configures the C-MADP to
determine the best access links to be used for uplink data based on a
combination of local and network policies delivered by the NCM.
The N-MADP is the functional element in the network that handles the
forwarding of user data traffic across multiple network paths, as
well as other user-plane functionalities (e.g., encapsulation,
fragmentation, concatenation, reordering, retransmission). The
N-MADP is the distribution node that routes (1) the uplink user-plane
traffic to the appropriate anchor connection toward the core network,
and (2) the downlink user traffic to the client over the appropriate
delivery connections. In the downlink, the NCM configures the use of
delivery connections and user-plane protocols at the N-MADP for
transporting user data traffic. The N-MADP SHOULD implement ECMP
support for the downlink traffic. Alternatively, it MAY be connected
to a router with ECMP functionality. The load-balancing algorithm at
the N-MADP is configured by the NCM, based on static and/or dynamic
network policies like assigning access and core paths for a specific
user data traffic type, user-volume-based percentage distribution,
and link availability and feedback information from the exchange of
MAMS signaling messages with the CCM at the client. The N-MADP can
be configured with appropriate user-plane protocols to support both
per-flow and per-packet traffic distribution across the delivery
connections. In the uplink, the N-MADP selects the appropriate
anchor connection over which to forward the user data traffic
received from the client (via the delivery connections). The
forwarding rules in the uplink at the N-MADP are configured by the
NCM based on application requirements, e.g., enterprise-hosted
application flows via a Wi-Fi anchor or mobile-operator-hosted
applications via the cellular core.
The C-MADP is the functional element in the client that handles the
MAMS user-plane data procedures. The C-MADP is configured by the
CCM, based on the signaling exchange with the NCM and local policies
at the client. The CCM configures the selection of delivery
connections and the user-plane protocols to be used for uplink user
data traffic based on the signaling messages exchanged with the NCM.
The C-MADP entity handles the forwarding of user-plane data across
multiple delivery connections and associated user-plane functions
(e.g., encapsulation, fragmentation, concatenation, reordering,
retransmissions).
The NCM and N-MADP can be either collocated or instantiated on
different network nodes. The NCM can set up multiple N-MADP
instances in the network. The NCM controls the selection of the
N-MADP instance by the client and the rules for the distribution of
user traffic across the N-MADP instances. This is beneficial in
multiple deployment scenarios, like the following examples:
* Different N-MADP instances to handle different sets of clients for
load balancing across clients.
* Network topologies where the N-MADP is hosted at the user-plane
node at the access edge or in the core network, while the NCM is
hosted at the access edge node.
* Access network technology architecture with an N-MADP instance at
the core network node to manage traffic distribution across LTE
and DSL networks, and an N-MADP instance at an access network node
to manage traffic distribution across LTE and Wi-Fi networks.
* A single client can be configured to use multiple N-MADP
instances. This is beneficial in addressing different application
requirements. For example, separate N-MADP instances to handle
traffic that is based on TCP and UDP transport.
Thus, the MAMS architecture flexibly addresses multiple network
deployments.
7. MAMS Protocol Architecture
This section describes the protocol structure for the MAMS user-plane
and control-plane functional elements.
7.1. MAMS Control-Plane Protocol
Figure 2 shows the default MAMS control-plane protocol stack.
WebSocket [RFC6455] is used for transporting management and control
messages between the NCM and the CCM.
+------------------------------------------+
| |
| Multi-Access (MX) Control Message |
| |
+------------------------------------------+
| |
| WebSocket |
| |
+------------------------------------------+
| |
| TCP/TLS |
| |
+------------------------------------------+
Figure 2: TCP-Based MAMS Control-Plane Protocol Stack
7.2. MAMS User-Plane Protocol
Figure 3 shows the MAMS user-plane protocol stack for transporting
the user payload, e.g., an IP Protocol Data Unit (PDU).
+-----------------------------------------------------+
| User Payload, e.g., IP Protocol Data Unit (PDU) |
+-----------------------------------------------------+
+-----------------------------------------------------------+
| +-----------------------------------------------------+ |
| | Multi-Access (MX) Convergence Layer | |
| +-----------------------------------------------------+ |
| +-----------------------------------------------------+ |
| | MX Adaptation | MX Adaptation | MX Adaptation | |
| | Layer | Layer | Layer | |
| | (optional) | (optional) | (optional) | |
| +-----------------+-----------------+-----------------+ |
| | Access #1 IP | Access #2 IP | Access #3 IP | |
| +-----------------------------------------------------+ |
| MAMS User-Plane Protocol Stack |
+-----------------------------------------------------------+
Figure 3: MAMS User-Plane Protocol Stack
The MAMS user-plane protocol consists of the following two layers:
* Multi-Access (MX) Convergence Layer: The MAMS framework configures
the Convergence Layer to perform multi-access-specific tasks in
the user plane. This layer performs such functions as access
(path) selection, multi-link (path) aggregation, splitting/
reordering, lossless switching, fragmentation, or concatenation.
The MX Convergence Layer can be implemented by using existing
user-plane protocols like MPTCP [RFC6824] or Multipath QUIC
(MPQUIC) [QUIC-MULTIPATH], or by adapting encapsulating header/
trailer schemes such as GRE [RFC2784] [RFC2890] or Generic Multi-
Access (GMA) [INTAREA-GMA].
* Multi-Access (MX) Adaptation Layer: The MAMS framework configures
the Adaptation Layer to address transport-network-related aspects
such as reachability and security in the user plane. This layer
performs functions to handle tunneling, network-layer security,
and NAT. The MX Adaptation Layer can be implemented using IPsec,
DTLS [RFC6347], or a Client NAT (Source NAT at the client with
inverse mapping at the N-MADP [INTAREA-MAMS]). The MX Adaptation
Layer is OPTIONAL and can be independently configured for each of
the access links. For example, in a deployment with LTE (assumed
secure) and Wi-Fi (assumed to not be secure), the MX Adaptation
Layer can be omitted for the LTE link, but is configured with
IPsec to secure the Wi-Fi link. Further details on the MAMS user
plane are provided in [INTAREA-MAMS].
8. MAMS Control-Plane Procedures
8.1. Overview
The CCM and NCM exchange signaling messages to configure the user-
plane functions via the C-MADP and the N-MADP at the client and the
network, respectively. The means for the CCM to obtain the NCM
credentials (Fully Qualified Domain Name (FQDN) or IP address) for
sending the initial discovery messages are out of scope for this
document. As an example, the client can obtain the NCM credentials
by using such methods as provisioning or DNS queries. Once the
discovery process is successful, the (initial) NCM can update and
assign additional NCM addresses, e.g., based on Mobile Country Code
(MCC) / Mobile Network Code (MNC) tuple information received in the
MX Discover message, for sending subsequent control-plane messages.
The CCM discovers and exchanges capabilities with the NCM. The NCM
provides the credentials of the N-MADP endpoint and negotiates the
parameters for the user plane with the CCM. The CCM configures the
C-MADP to set up the user-plane path (e.g., MPTCP/UDP Proxy
connection) with the N-MADP, based on the credentials (e.g.,
(MPTCP/UDP) Proxy IP address and port, associated core network path),
and the parameters exchanged with the NCM. Further, the NCM and CCM
exchange link status information to adapt traffic steering and user-
plane treatment to dynamic network conditions. The key procedures
are described in detail in the following subsections.
+-----+ +-----+
| CCM | | NCM |
+--+--+ +--+--+
| Discovery and |
| Capability |
| Exchange |
|<--------------------->|
| |
| Setup of |
| User-Plane |
| Protocols |
|<--------------------->|
| |
| Path Quality |
| Estimation |
|<--------------------->|
| |
| Network Capabilities |
| e.g., RNIS [ETSIRNIS] |
|<----------------------|
| |
| Network Policies |
|<----------------------|
+ +
"RNIS" stands for "Radio Network Information Service"
Figure 4: MAMS Control-Plane Procedures
8.2. Common Fields in MAMS Control Messages
Each MAMS control message consists of the following common fields:
* Version: Indicates the version of the MAMS control protocol.
* Message Type: Indicates the type of the message, e.g., MX
Discover, MX Capability Request (REQ) / Response (RSP).
* Sequence Number: Auto-incremented integer to uniquely identify a
particular message exchange, e.g., MX Capability Request/Response.
8.3. Common Procedures for MAMS Control Messages
This section describes the common procedures for MAMS control
messages.
8.3.1. Message Timeout
After sending a MAMS control message, the MAMS control-plane peer
(NCM or CCM) waits for a duration of MAMS_TIMEOUT ms before timing
out in cases where a response was expected. The sender of the
message will retransmit the message for MAMS_RETRY times before
declaring failure if no response is received. A failure implies that
the MAMS peer is dead or unreachable, and the sender reverts to
native non-multi-access / single-path mode. The CCM may initiate the
MAMS discovery procedure for re-establishing the MAMS session.
8.3.2. Keep-Alive Procedure
MAMS control-plane peers execute the keep-alive procedures to ensure
that the other peers are reachable and to recover from dead-peer
scenarios. Each MAMS control-plane endpoint maintains a Keep-Alive
timer that is set for a duration of MAMS_KEEP_ALIVE_TIMEOUT. The
Keep-Alive timer is reset whenever the peer receives a MAMS control
message. When the Keep-Alive timer expires, an MX Keep-Alive Request
is sent.
The values for MAMS_RETRY and MAMS_KEEP_ALIVE_TIMEOUT parameters used
in keep-alive procedures are deployment dependent, and the means for
obtaining them are out of scope for this document. As an example,
the client and network can obtain the values using provisioning. On
receipt of an MX Keep-Alive Request, the receiver responds with an MX
Keep-Alive Response. If the sender does not receive a MAMS control
message in response to MAMS_RETRY retries of the MX Keep-Alive
Request, the MAMS peer declares that the peer is dead or unreachable.
The CCM MAY initiate the MAMS discovery procedure for re-establishing
the MAMS session.
Additionally, the CCM SHALL immediately send an MX Keep-Alive Request
to the NCM whenever it detects a handover from one base station /
access point to another. During this time, the client SHALL stop
using MAMS user-plane functionality in the uplink direction until it
receives an MX Keep-Alive Response from the NCM.
The MX Keep-Alive Request includes the following information:
* Reason: Can be timeout or handover. Handover shall be used by the
CCM only on detection of a handover.
* Unique Session ID: See Section 8.4.
* Connection ID: If the reason is handover, the inclusion of this
field is mandatory.
* Delivery Node ID: Identity of the node to which the client is
attached. In the case of LTE, this is an E-UTRAN Cell Global
Identifier (ECGI). In the case of Wi-Fi, this is an AP ID or a
Media Access Control (MAC) address. If the reason is "Handover",
the inclusion of this field is mandatory.
8.4. Discovery and Capability Exchange
Figure 5 shows the MAMS discovery and capability exchange procedure.
CCM NCM
| |
|------- MX Discover Message ----------------------->|
| +-----------------+
| | Learn CCM |
| | IP address |
| | and port |
| +-----------------+
| |
|<----------------------------- MX System Info ------|
| |
|------------------------------ MX Capability REQ -->|
|<----- MX Capability RSP ---------------------------|
|------------------------------ MX Capability ACK -->|
| |
+ +
Figure 5: MAMS Control Procedure for Discovery and Capability
Exchange
This procedure consists of the following key steps:
Step 1 (discovery): The CCM periodically sends an MX Discover message
to a predefined (NCM) IP address/port until an MX System Info message
is received in acknowledgment.
* The MX Discover message includes the following information:
- MAMS Version.
- Mobile Country Code (MCC) / Mobile Network Code (MNC) Tuple:
Optional parameter to identify the operator network to which
the client is subscribed, in conformance with the format
specified in [ITU-E212].
* The MX System Info message includes the following information:
- Number of Anchor Connections.
For each anchor connection, the following parameters are
included:
o Connection ID: Unique identifier for the anchor connection.
o Connection Type (e.g., Wi-Fi, 5G NR, MulteFire, LTE).
o NCM Endpoint Address (for control-plane messages over this
connection):
+ IP Address or FQDN
+ Port Number
Step 2 (capability exchange): The CCM learns the IP address and port
from the MX System Info message. It then sends the MX Capability REQ
message, which includes the following parameters:
* MX Feature Activation List: Indicates whether the corresponding
feature is supported or not, e.g., lossless switching,
fragmentation, concatenation, uplink aggregation, downlink
aggregation, measurement, probing.
* Number of Anchor Connections (core networks).
For each anchor connection, the following parameters are included:
- Connection ID
- Connection Type (e.g., Wi-Fi, 5G NR, MulteFire, LTE)
* Number of Delivery Connections (access links).
For each delivery connection, the following parameters are
included:
- Connection ID
- Connection Type (e.g., Wi-Fi, 5G NR, MulteFire, LTE)
* MX Convergence Method Support List:
- GMA
- MPTCP Proxy
- GRE Aggregation Proxy
- MPQUIC
* MX Adaptation Method Support List:
- UDP without DTLS
- UDP with DTLS
- IPsec [RFC3948]
- Client NAT
In response, the NCM creates a unique identity for the CCM session
and sends the MX Capability Response, including the following
information:
* MX Feature Activation List: Indicates whether the corresponding
feature is enabled or not, e.g., lossless switching,
fragmentation, concatenation, uplink aggregation, downlink
aggregation, measurement, probing.
* Number of Anchor Connections (core networks):
For each anchor connection, the following parameters are included:
- Connection ID
- Connection Type (e.g., Wi-Fi, 5G NR, MulteFire, LTE)
* Number of Delivery Connections (access links):
For each delivery connection, the following parameters are
included:
- Connection ID
- Connection Type (e.g., Wi-Fi, 5G NR, MulteFire, LTE)
* MX Convergence Method Support List:
- GMA
- MPTCP Proxy
- GRE Aggregation Proxy
- MPQUIC
* MX Adaptation Method Support List:
- UDP without DTLS
- UDP with DTLS
- IPsec [RFC3948]
- Client NAT
* Unique Session ID: Unique session identifier for the CCM that set
up the connection. If the session already exists, then the
existing unique session identifier is returned.
- NCM ID: Unique identity of the NCM in the operator network.
- Session ID: Unique identity assigned to the CCM instance by
this NCM instance.
In response to the MX Capability Response, the CCM sends a
confirmation (or rejection) in the MX Capability Acknowledge. The MX
Capability Acknowledge includes the following parameters:
* Unique Session ID: Same identifier as the identifier provided in
the MX Capability Response.
* Acknowledgment: An indication of whether the client has accepted
or rejected the capability exchange phase.
- MX ACCEPT: The CCM accepts the capability set proposed by the
NCM.
- MX REJECT: The CCM rejects the capability set proposed by the
NCM.
If the NCM receives an MX_REJECT, the current MAMS session will be
terminated.
If the CCM can no longer continue with the current capabilities, it
SHOULD send an MX Session Termination Request to terminate the MAMS
session. In response, the NCM SHOULD send an MX Session Termination
Response to confirm the termination.
8.5. User-Plane Configuration
Figure 6 shows the user-plane (UP) configuration procedure.
CCM NCM
| |
|---- MX Reconfiguration REQ (setup) ----------->|
|<-------------------- MX Reconfiguration RSP ---|
| +-------------------------+
| | NCM prepares N-MADP for |
| | User-Plane Setup |
| +-------------------------+
|<-------------------- MX UP Setup Config -------|
|---- MX UP Setup Confirmation ----------------->|
+-------------------+ |
|Link "X" is up/down| |
+-------------------+ |
|---- MX Reconfiguration REQ (update/release) -->|
|<-------------------- MX Reconfiguration RSP ---|
Figure 6: MAMS Control Procedure for User-Plane Configuration
This procedure consists of the following two key steps:
* Reconfiguration: The CCM informs the NCM about the changes to the
client's connections - setup of a new connection, teardown of an
existing connection, or update of parameters related to an
existing connection. It consists of the client triggering the
procedure by requesting an update to the connection configuration,
and a response from the NCM.
* UP Setup: The NCM configures the user-plane protocols at the
client and the network. The NCM initiates the UP setup by sending
the MX UP Setup Configuration Request to the client, which
confirms the set of mutually acceptable parameters by using the
User Plane Setup Confirmation (CNF) message.
These steps are elaborated as follows.
Reconfiguration: When the client detects that the link is up/down or
the IP address changes (e.g., via APIs provided by the client OS),
the CCM sends an MX Reconfiguration Request to set up, update, or
release the connection. The message SHOULD include the following
information:
* Unique Session ID: Identity of the CCM at the NCM, created by the
NCM during the capability exchange phase.
* Reconfiguration Action: Indicates the reconfiguration action
(release, setup, or update).
* Connection ID: Identifies the connection for reconfiguration.
If the Reconfiguration Action is set to "setup" or "update", then the
message includes the following parameters:
* IP address of the connection.
* SSID (Service Set Identifier of the Wi-Fi connection).
* MTU of the connection: The MTU of the delivery path that is
calculated at the client for use by the NCM to configure
fragmentation and concatenation procedures [INTAREA-MAMS] at the
N-MADP.
* Delivery Node ID: Identity of the node to which the client is
attached. In the case of LTE, this is an ECGI. In the case of
Wi-Fi, this is an AP ID or a MAC address.
At the beginning of a connection setup, the CCM informs the NCM of
the connection status using the MX Reconfiguration Request with the
Reconfiguration Action set to "setup". The NCM acknowledges the
connection setup status and exchanges parameters with the CCM for
user-plane setup, as described below.
Setup of User-Plane Protocols: Based on the negotiated capabilities,
the NCM sets up the user-plane (Adaptation Layer and Convergence
Layer) protocols at the N-MADP and informs the CCM of the user-plane
protocols to be set up at the client (C-MADP) and the parameters for
the C-MADP to connect to the N-MADP.
The MX UP Setup Configuration Request is used to create one or more
MADP instances, with each anchor connection having one or more
configurations, namely MX Configurations. The MX UP Setup
Configuration Request consists of the following parameters:
* Number of Anchor Connections (core networks).
For each anchor connection, the following parameters are included:
- Anchor Connection ID
- Connection Type (e.g., Wi-Fi, 5G NR, MulteFire, LTE)
- Number of Active MX Configurations (included only if more than
one MX configuration is active for the anchor connection).
For each active MX configuration, the following parameters are
included:
o MX Configuration ID (included if more than one MX
configuration is present)
o MX Convergence Method. One of the following:
+ GMA
+ MPTCP Proxy
+ GRE Aggregation Proxy
+ MPQUIC
o MX Convergence Method Parameters:
+ Convergence Proxy IP Address
+ Convergence Proxy Port
+ Client Key
o MX Convergence Control Parameters (included if any MX
Control PDU types (e.g., Probe-REQ/ACK) are supported):
+ UDP port number for sending and receiving MX Control PDUs
(e.g., Probe-REQ/ACK, Keep-Alive)
+ Convergence Proxy Port
o Number of Delivery Connections.
For each delivery connection, include the following:
+ Delivery Connection ID
+ Connection Type (e.g., Wi-Fi, 5G NR, MulteFire, LTE)
+ MX Adaptation Method. One of the following:
* UDP without DTLS
* UDP with DTLS
* IPsec
* Client NAT
+ MX Adaptation Method Parameters:
* Tunnel Endpoint IP Address
* Tunnel Endpoint Port
* Shared Secret
* Header Optimization (included only if the MX
Convergence Method is GMA)
For example, when LTE and Wi-Fi are the two user-plane accesses, the
NCM conveys to the CCM that IPsec needs to be set up as the MX
Adaptation Layer over the Wi-Fi access, using the following
parameters: IPsec endpoint IP address, and Pre-Shared Key. No
Adaptation Layer is needed if it is considered secure with no NAT, or
a Client NAT may be used over the LTE access.
Similarly, as an example of the MX Convergence Method, the
configuration indicates the convergence method as the MPTCP proxy,
along with parameters for a connection to the MPTCP proxy: namely the
IP address and port of the MPTCP proxy for TCP applications.
Once the user-plane protocols are configured, the CCM informs the NCM
of the status via the MX UP Setup Confirmation. The MX UP Setup
Confirmation consists of the following parameters:
* Unique Session ID: Session identifier provided to the client in an
MX Capability Response.
* MX Convergence Control Parameters (included if any MX Control PDU
types (e.g., Probe-REQ/ACK, Keep-Alive) are supported):
- UDP port number for sending and receiving MX Control PDUs
(e.g., Probe-REQ/ACK, Keep-Alive)
- MX Configuration ID (if an MX Configuration ID is specified in
an MX UP Setup Configuration Request) to indicate the MX
Configuration that will be used for probing)
* Client Adaptation-Layer Parameters:
- Number of Delivery Connections.
For each delivery connection, include the following:
o Delivery Connection ID
o UDP port number: If UDP-based adaptation is in use, the UDP
port on the C-MADP side
8.6. MAMS Path Quality Estimation
Path quality estimations can be done either passively or actively.
Traffic measurements in the network can be performed passively by
comparing the real-time data throughput of the client with the
capacity available in the network. In special deployments where the
NCM has interfaces with access nodes, direct interfaces can be used
to gather information regarding path quality. For example, the
utilization of the LTE access node (also known as Evolved Node B), to
which the client is attached, could be used as data for the
estimation of path quality without creating any extra traffic
overhead. Active measurements by the client provide an alternative
way to estimate path quality.
CCM NCM
| |
|<-------------- MX Path Estimation Request ---------|
|------ MX Path Estimation Results ----------------->|
| |
Figure 7: MAMS Control-Plane Procedure for Path Quality Estimation
The NCM sends the following configuration parameters in the MX Path
Estimation Request to the CCM:
* Connection ID (of the delivery connection whose path quality needs
to be estimated)
* Init Probe Test Duration (ms)
* Init Probe Test Rate (Mbps)
* Init Probe Size (bytes)
* Init Probe-ACK Required (0 -> No / 1 -> Yes)
* Active Probe Frequency (ms)
* Active Probe Size (bytes)
* Active Probe Test Duration (ms)
* Active Probe-ACK Required (0 -> No / 1 -> Yes)
The CCM configures the C-MADP for probe receipt based on these
parameters and for collection of the statistics according to the
following configuration.
* Unique Session ID: Session identifier provided to the client in an
MX Capability Response.
* Init Probe Results Configuration:
- Lost Probes (percent)
- Probe Receiving Rate (packets per second)
* Active Probe Results Configuration:
- Average Throughput in the last Probe Duration
The user-plane probing is divided into two phases: the Initialization
phase and the Active phase.
* Initialization Phase: A network path that is not included by the
N-MADP for transmission of user data is deemed to be in the
Initialization phase. The user data may be transmitted over other
available network paths.
* Active Phase: A network path that is included by the N-MADP for
transmission of user data is deemed to be in the Active phase.
During the Initialization phase, the NCM configures the N-MADP to
send an Init Probe-REQ message. The CCM collects the Init Probe
statistics from the C-MADP and sends the MX Path Estimation Results
message to the NCM per the Initialization Probe Results
configuration.
During the Active phase, the NCM configures the N-MADP to send an
Active Probe-REQ message. The C-MADP calculates the metrics as
specified by the Active Probe Results configuration. The CCM
collects the Active Probe statistics from the C-MADP and sends the MX
Path Estimation Results message to the NCM per the Active Probe
Results configuration.
The following subsections define the control PDU encoding for Keep-
Alive and Probe-REQ/ACK messages to support path quality estimation.
8.6.1. MX Control PDU Definition
Control PDUs are sent as UDP messages between the C-MADP and the
N-MADP to exchange control messages for keep-alive or path quality
estimation. MX probe parameters are negotiated during the user-plane
setup phase (MX UP Setup Configuration Request and MX UP Setup
Confirmation). Figure 8 shows the MX Control PDU format with the
following fields:
* Type (1 byte): The type of the MX Control message.
- 0: Keep-Alive
- 1: Probe-REQ/ACK
- Others: Reserved
* CID (1 byte): The connection ID of the delivery connection for
sending the MX Control message.
* MX Control Message (variable): The payload of the MX Control
message.
The MX Control PDU is sent as a normal user-plane packet over the
desired delivery connection whose quality and reachability need to be
determined.
| |
|<--------- MX Control PDU Payload ------->|
| |
+-----------+-------------------+-----+-----------------------------+
| IP Header | UDP Header | Type | CID | MX Control Message |
+-----------+-------------------+-----+-----------------------------+
Figure 8: MX Control PDU Format
8.6.2. Keep-Alive Message
The "Type" field is set to "0" for Keep-Alive messages. The C-MADP
may periodically send a Keep-Alive message over one or multiple
delivery connections, especially if UDP tunneling is used as the
adaptation method for the delivery connection with a NAT function on
the path.
A Keep-Alive message is 2 bytes long and consists of the following
field:
* Keep-Alive Sequence Number (2 bytes): The sequence number of the
Keep-Alive message.
8.6.3. Probe-REQ/ACK Message
The "Type" field is set to "1" for Probe-REQ/ACK messages. The
N-MADP may send the Probe-REQ message for path quality estimation.
In response, the C-MADP may return the Probe-ACK message.
A Probe-REQ message consists of the following fields:
* Probing Sequence Number (2 bytes): The sequence number of the
Probe REQ message.
* Probing Flag (1 byte):
- Bit 0: A Probe-ACK flag to indicate whether the Probe-ACK
message is expected (1) or not (0).
- Bit 1: A Probe Type flag to indicate whether the Probe-REQ/ACK
message was sent during the Initialization phase (0) when the
network path is not included for transmission of user data, or
during the Active phase (1) when the network path is included
for transmission of user data.
- Bit 2: A bit flag to indicate the presence of the Reverse
Connection ID (R-CID) field.
- Bits 3-7: Reserved.
* Reverse Connection ID (R-CID) (1 byte): The connection ID of the
delivery connection for sending the Probe-ACK message on the
reverse path.
* Padding (variable).
The "R-CID" field is only present if both Bit 0 and Bit 2 of the
"Probing Flag" field are set to "1". Moreover, Bit 2 of the "Probing
Flag" field SHOULD be set to "0" if Bit 0 is "0", indicating that the
Probe-ACK message is not expected.
If the "R-CID" field is not present, but Bit 0 of the "Probing Flag"
field is set to "1", the Probe-ACK message SHOULD be sent over the
same delivery connection as the Probe-REQ message.
The "Padding" field is used to control the length of the Probe-REQ
message.
The C-MADP SHOULD send the Probe-ACK message in response to a Probe-
REQ message with the Probe-ACK flag set to "1".
A Probe-ACK message is 3 bytes long and consists of the following
field:
* Probing Acknowledgment Number (2 bytes): The sequence number of
the corresponding Probe-REQ message.
8.7. MAMS Traffic Steering
CCM NCM
| |
| +------------------------------+
| |Steer user traffic to Path "X"|
| +------------------------------+
|<----------------- MX Traffic Steering REQ ------|
|----- MX Traffic Steering RSP ------------------>|
Figure 9: MAMS Traffic-Steering Procedure
The NCM sends an MX Traffic Steering Request to steer data traffic.
It is also possible to send data traffic over multiple connections
simultaneously, i.e., aggregation. The message includes the
following information:
* Anchor Connection ID: Connection ID of the anchor connection.
* MX Configuration ID (if an MX Configuration ID is specified in an
MX UP Setup Configuration Request).
* DL Connection ID List: List of DL delivery connections, provided
as Connection IDs.
* UL Connection ID: Connection ID of the default UL delivery
connection.
* For the number of specific UL traffic templates, the message
includes the following:
- Traffic Flow Template for identifying the UL traffic.
- UL Connection ID List: List of UL delivery connections,
provided as Connection IDs, to be used for sending the UL
traffic.
* MX Feature Activation List. Each parameter indicates whether the
corresponding feature is enabled or not: lossless switching,
fragmentation, concatenation, uplink aggregation, downlink
aggregation, measurement, probing.
In response, the CCM sends an MX Traffic Steering Response, including
the following information:
* Unique Session ID: Session identifier provided to the client in an
MX Capability Response.
* MX Feature Activation List. Each parameter indicates whether the
corresponding feature is enabled or not: lossless switching,
fragmentation, concatenation, uplink aggregation, downlink
aggregation, measurement, probing.
8.8. MAMS Application MADP Association
CCM NCM
| |
| +-------------------------+
| | Associate MADP instance |
| | with application flow |
| +-------------------------+
|---------- MX App MADP ------------------->|
| Association REQ |
| |
|<----------------- MX App MADP ------------|
| Association RSP |
Figure 10: MAMS Application MADP Association Procedure
The CCM sends an MX Application MADP Association Request to request
the association of a specific application flow with a specific MADP
instance ID for the anchor connection with multiple active MX
configurations. The MADP Instance ID is a tuple (Anchor Connection
ID, MX Configuration ID). This provides the capability for the
client to indicate the user-plane processing that needs to be
associated with different application flows depending on the needs of
those flows. The application flow is identified by its associated
Traffic Flow Template.
The MX Application MADP Association Request includes the following
information:
* Number of Application Flows.
For each application flow, identified by the Traffic Flow
Templates:
- Anchor Connection ID
- MX Configuration ID (if more than one MX configuration is
associated with an anchor connection)
- Traffic Flow Template for identifying the UL traffic
- Traffic Flow Template for identifying the DL traffic
In response, the NCM sends an MX Application MADP Association
Response, including the following information:
* Number of Application Flows.
For each application flow, identified by the Traffic Flow
Templates:
- Status (Success or Failure)
8.9. MAMS Network ID Indication
CCM NCM
| |
| +---------------------------------+
| |NCM determines preferred networks|
| +---------------------------------+
| |
|<----------------- MX SSID Indication -----------|
| |
Figure 11: MAMS Network ID Indication Procedure
The NCM indicates the preferred network list to the CCM to guide the
client regarding networks that it should connect to. To indicate
preferred Wi-Fi networks, the NCM sends the list of WLANs, each
represented by an SSID (Service Set Identifier)/BSSID (Basic Service
Set Identifier)/HESSID (Homogeneous Extended Service Set Identifier)
as defined in [IEEE-80211]), available in the MX SSID Indication.
8.10. MAMS Client Measurement Configuration and Reporting
CCM NCM
| |
|<--------------- MX Measurement Config ----------|
| |
+---------------------------------+ |
|Client ready to send measurements| |
+---------------------------------+ |
| |
|----- MX Measurement Report -------------------->|
| |
Figure 12: MAMS Client Measurement Configuration and Reporting
Procedure
The NCM configures the CCM with the different parameters (e.g., radio
link information), with the associated thresholds to be reported by
the client. The MX Measurement Configuration message contains the
following parameters for each delivery connection:
* Delivery Connection ID.
* Connection Type (e.g., Wi-Fi, 5G NR, MulteFire, LTE).
* If the connection type is Wi-Fi:
- High and low thresholds for the sending of average Received
Signal Strength Indicator (RSSI) of the Wi-Fi link.
- Periodicity, in ms, for sending the average RSSI of the Wi-Fi
link.
- High and low thresholds for sending the loading of the WLAN
system.
- Periodicity, in ms, for sending the loading of the WLAN system.
- High and low thresholds for sending the reverse link throughput
on the Wi-Fi link.
- Periodicity, in ms, for sending the reverse link throughput on
the Wi-Fi link.
- High and low thresholds for sending the forward link throughput
on the Wi-Fi link.
- Periodicity, in ms, for sending the forward link throughput on
the Wi-Fi link.
- High and low thresholds for sending the reverse link throughput
(EstimatedThroughputOutbound as defined in [IEEE-80211]) on the
Wi-Fi link.
- Periodicity, in ms, for sending the reverse link throughput
(EstimatedThroughputOutbound as defined in [IEEE-80211]) on the
Wi-Fi link.
- High and low thresholds for sending the forward link throughput
(EstimatedThroughputInbound, as defined in [IEEE-80211]) on the
Wi-Fi link.
- Periodicity, in ms, for sending the forward link throughput
(EstimatedThroughputInbound, as defined in [IEEE-80211]) on the
Wi-Fi link.
* If the connection type is LTE:
- High and low thresholds for sending the Reference Signal
Received Power (RSRP) of the serving LTE link.
- Periodicity, in ms, for sending the RSRP of the serving LTE
link.
- High and low thresholds for sending the RSRQ (Reference Signal
Received Quality) of the serving LTE link.
- Periodicity, in ms, for sending the RSRP of the serving LTE
link.
- High and low thresholds for sending the reverse link throughput
on the serving LTE link.
- Periodicity, in ms, for sending the reverse link throughput on
the serving LTE link.
- High and low thresholds, for sending the forward link
throughput on the serving LTE link.
- Periodicity, in ms, for sending the forward link throughput on
the serving LTE link.
* If the connection type is 5G NR:
- High and low thresholds for sending the RSRP of the serving NR
link.
- Periodicity, in ms, for sending the RSRP of the serving NR
link.
- High and low thresholds for sending the RSRQ of the serving NR
link.
- Periodicity, in ms, for sending the RSRP of the serving NR
link.
- High and low thresholds for sending the reverse link throughput
on the serving NR link.
- Periodicity, in ms, for sending the reverse link throughput on
the serving NR link.
- High and low thresholds for sending the forward link throughput
on the serving NR link.
- Periodicity, in ms, for sending the forward link throughput on
the serving NR link.
The MX Measurement Report contains the following parameters:
* Unique Session ID: Session identifier provided to the client in an
MX Capability Response.
* For each delivery connection, include the following:
- Delivery Connection ID
- Connection Type (e.g., Wi-Fi, 5G NR, MulteFire, LTE)
- Delivery Node ID (ECGI in the case of LTE. In the case of Wi-
Fi, this is an AP ID or a MAC address.)
- If the connection type is Wi-Fi:
o Average RSSI of the Wi-Fi link.
o Loading of the WLAN system.
o Reverse link throughput on the Wi-Fi link.
o Forward link throughput on the Wi-Fi link.
o Estimated reverse link throughput on the Wi-Fi link
(EstimatedThroughputOutbound as defined in [IEEE-80211]).
o Estimated forward link throughput on the Wi-Fi link
(EstimatedThroughputInbound, as defined in [IEEE-80211]).
- If the connection type is LTE:
o RSRP of the serving LTE link.
o RSRQ of the serving LTE link.
o Reverse link throughput on the serving LTE link.
o Forward link throughput on the serving LTE link.
- If the connection type is 5G NR:
o RSRP of the serving NR link.
o RSRQ of the serving NR link.
o Reverse link throughput on the serving NR link.
o Forward link throughput on the serving NR link.
8.11. MAMS Session Termination Procedure
CCM NCM
| |
|---- MX Session Termination REQ --->|
| |
| |
|<--- MX Session Termination RSP ----|
| |
| +------------------+
| | Remove Resources |
| +------------------+
| |
Figure 13: MAMS Session Termination Procedure - Initiated by Client
CCM NCM
| |
|<--- MX Session Termination REQ ----|
| |
| |
|---- MX Session Termination RSP --->|
| |
+------------------+ |
| Remove Resources | |
+------------------+ |
| |
Figure 14: MAMS Session Termination Procedure - Initiated by Network
At any point in MAMS processing, if the CCM or NCM is no longer able
to support the MAMS functions, then either of them can initiate a
termination procedure by sending an MX Session Termination Request to
the peer. The peer SHALL acknowledge the termination by sending an
MX Session Termination Response message. After the session is
disconnected, the CCM SHALL start a new procedure with an MX Discover
message. An MX Session Termination Request shall contain a Unique
Session ID and the reason for the termination. Possible reasons for
termination are:
* Normal Release
* No Response from Peer
* Internal Error
8.12. MAMS Network Analytics Request Procedure
CCM NCM
| |
|----- MX Network Analytics REQ --->|
| |
| |
|<--- MX Network Analytics RSP -----|
| |
Figure 15: MAMS Network Analytics Request Procedure
The CCM sends the MX Network Analytics Request to the NCM to request
information related to such network parameters as bandwidth, latency,
jitter, and signal quality, based on the application of analytics at
the network (utilizing the received path measurements and client
measurement reporting).
The MX Network Analytics Request consists of the following
parameters:
* Link Quality Indicators. One or more of the following:
- Bandwidth
- Jitter
- Latency
- Signal Quality
The NCM sends the MX Network Analytics Response to convey analytics
information that might be of interest to the CCM. This message will
include network parameters with their predicted likelihoods.
The MX Network Analytics Response consists of the following
parameters:
* Number of Delivery Connections.
For each delivery connection, include the following:
- Access Link Identifier:
o Connection Type
o Connection ID
- Link Quality Indicator:
o Bandwidth:
+ Predicted Value (Mbps)
+ Likelihood (percent)
+ Prediction Validity (Validity Time, in seconds)
o Jitter:
+ Predicted Value (in seconds)
+ Likelihood (percent)
+ Prediction Validity (Validity Time, in seconds)
o Latency:
+ Predicted Value (in seconds)
+ Likelihood (percent)
+ Prediction Validity (Validity Time, in seconds)
o Signal Quality:
+ If delivery connection type is LTE, LTE_RSRP Predicted
Value in decibel-milliwatts (dBm)
+ If delivery connection type is LTE, LTE_RSRQ Predicted
Value (dBm)
+ If delivery connection type is 5G NR, NR_RSRP Predicted
Value (dBm)
+ If delivery connection type is 5G NR, NR_RSRQ Predicted
Value (dBm)
+ If delivery connection type is Wi-Fi, WLAN_RSSI Predicted
Value (dBm)
+ Likelihood (percent)
+ Prediction Validity (Validity Time, in seconds)
9. Generic MAMS Signaling Flow
Figure 16 illustrates the MAMS signaling mechanism for negotiation of
network paths and flow protocols between the client and the network.
In this example scenario, the client is connected to two networks
(LTE and Wi-Fi).
+--------------------------------------------+
| MAMS-enabled Network of Networks |
| +-------+ +-------+ +-----+ +------+ |
+------------------+ | | | | | | | | | |
| Client | | |Network| |Network| | | | | |
| +------+ +-----+ | | | 1 | | 2 | | NCM | |N-MADP| |
| |C-MADP| | CCM | | | | (LTE) | |(Wi-Fi)| | | | | |
| +------+ +-----+ | | +-------+ +-------+ +-----+ +------+ |
| | | | | | | | | |
++---+--------+----+ +-----+-----------+----------+----------+----+
| | | | | | |
| | | | | | |
| | 1. Setup Connection | | | |
|<-----------+------------->| | | |
| | | | | | |
| | | 2. MAMS Capabilities Exchange | |
| | |<-------------+-----------+--------->| |
| | | | | | |
| | 3. Setup Connection | | | |
|<--+---------------------------------->| | |
| | | | | | |
| 4c. Config | 4a. Negotiate network paths, |4b. Config|
| | C-MADP | Flow protocol, and parameters | N-MADP|
| |<------>|<-------------+-----------+--------->|<-------->|
| | | | | | |
| | | 5. Establish user-plane path according |
| | | to selected flow protocol | |
| |<----------------------+-----------+-------------------->|
| | | | | | |
+ + + + + + +
Figure 16: MAMS Call Flow
1. The client connects to Network 1 and gets an IP address assigned
by Network 1.
2. The CCM communicates with the NCM functional element via the
Network 1 connection and exchanges capabilities and parameters
for MAMS operation. Note: The NCM credentials (e.g., the NCM's
IP address) can be made known to the client by provisioning.
3. The client sets up the connection with Network 2 and gets an IP
address assigned by Network 2.
4. The CCM and NCM negotiate capabilities and parameters for
establishing network paths. The negotiated capabilities and
parameters are then used to configure user-plane functions, i.e.,
the N-MADP at the network and the C-MADP at the client.
4a. The CCM and NCM negotiate network paths, flow routing and
aggregation protocols, and related parameters.
4b. The NCM communicates with the N-MADP to exchange and
configure flow aggregation protocols, policies, and
parameters in alignment with those negotiated with the CCM.
4c. The CCM communicates with the C-MADP to exchange and
configure flow aggregation protocols, policies, and
parameters in alignment with those negotiated with the NCM.
5. The C-MADP and N-MADP establish the user-plane paths, e.g., using
Internet Key Exchange Protocol (IKE) [RFC7296] signaling, based
on the negotiated flow aggregation protocols and parameters
specified by the NCM.
The CCM and NCM can further exchange messages containing access link
measurements for link maintenance by the NCM. The NCM evaluates the
link conditions in the UL and DL across LTE and Wi-Fi, based on link
measurements reported by the CCM and/or link-probing techniques, and
determines the policy for UL and DL user data distribution. The NCM
and CCM also negotiate application-level policies for categorizing
applications, e.g., based on the Differentiated Services Code Point
(DSCP), destination IP address, and determination of which available
network path needs to be used for transporting data of that category
of applications. The NCM configures the N-MADP, and the CCM
configures the C-MADP, based on the negotiated application policies.
The CCM may apply local application policies, in addition to the
application policy conveyed by the NCM.
10. Relationship to IETF Technologies
The MAMS framework leverages technologies developed in the IETF (such
as MPTCP and GRE) and enables a control-plane framework to negotiate
the use of these protocols between the client and the network. It
also addresses the limitations in scope of other multihoming
protocols. For example, the IKEv2 Mobility and Multihoming Protocol
(MOBIKE [RFC4555]) scope indicates that it is limited to multihoming
between IPsec clients (tunnel mode IPsec Security Associations) and
does not support load balancing. To address this limitation
regarding how the multihoming scenario is handled, the MAMS framework
supports load balancing with the simultaneous use of multiple access
paths by negotiating the use of protocols like MPTCP. Unlike MOBIKE,
which only applies to endpoints connected with an IPsec tunnel mode
Security Association, the MAMS framework allows the flexibility to
use a wide range of tunneling protocols in the Adaptation Layer.
11. Applying MAMS Control Procedures with MPTCP Proxy as User Plane
If the NCM determines that the N-MADP is to be instantiated with
MPTCP as the MX Convergence Protocol, it exchanges the MPTCP
capability support in the discovery and capability exchange
procedures. An MPTCP proxy (e.g., see [TCPM-CONVERTERS]) is
configured to be the N-MADP instance. The NCM then provides the
credentials of the MPTCP Proxy instance, along with related
parameters, to the CCM. The CCM configures the C-MADP with these
parameters to connect to this MPTCP proxy instance.
Figure 17 illustrates the user-plane protocol layering when MPTCP is
configured to be the "MX Convergence Layer" protocol. MPTCP manages
traffic distribution and aggregation over multiple delivery
connections.
+-----------------------------------------------------+
| MPTCP |
+-----------------+-----------------+-----------------+
| TCP | TCP | TCP |
+-----------------------------------------------------+
| MX Adaptation | MX Adaptation | MX Adaptation |
| Layer | Layer | Layer |
| (optional) | (optional) | (optional) |
+-----------------------------------------------------+
| Access #1 IP | Access #2 IP | Access #3 IP |
+-----------------+-----------------+-----------------+
Figure 17: MAMS User-Plane Protocol Stack with MPTCP as MX
Convergence Layer
The client (C-MADP) sets up an MPTCP connection with the N-MADP to
begin with. The MAMS control procedures are then applied to do the
following:
* Connect to the appropriate MPTCP network endpoint, e.g., the MPTCP
proxy (illustrated in Figure 18).
* Control the addition of a second TCP subflow after the Wi-Fi
connection is established and is deemed good (illustrated in
Figure 19).
* Control the behavior of the MPTCP scheduler, e.g., by using only
the LTE subflow in the UL and both the LTE and Wi-Fi subflows in
the DL (illustrated in Figure 20).
* Provide faster response to Wi-Fi link degradation by proactively
deleting a TCP subflow over Wi-Fi when poor link conditions are
reported, maintaining optimum performance (illustrated in
Figure 21).
Figure 18 shows the call flow describing MAMS control procedures
applied to configure the user plane and dynamic optimal path
selection in a scenario with the MPTCP proxy as the convergence
protocol in the user plane.
+------+ +--------+ +--------+ +-------+ +-------+ +------+
| | | | | | | | | | | |
| CCM | | C-MADP | | Wi-Fi | | LTE | | NCM | |N-MADP|
| | | | | N/W | | N/W | | | | |
+------+ +--------+ +--------+ +-------+ +-------+ +------+
+------------------------------------------------------------------+
| 1. LTE Session Setup and IP Address Allocation |
+-----------------------------------------+-----------+------------+
| | | |
|2. MX Discover (MAMS Version, MCC/MNC) | | |
+----------------------------------------+---------->| |
|3. MX System Info (Serving NCM IP/Port Address) | |
|<------------+-------------+-------------+----------+ |
| | | | | |
|4. MX Capability REQ (Supported Anchor/Delivery | |
| | Links (Wi-Fi, LTE)) | |
+--------------------------------------------------->| |
|5. MX Capability RSP (Convergence/Adaptation Parameters) |
|<----------------------------------------+----------+ |
|6. MX Capability ACK (ACCEPT) | | |
+-------------+-------------+----------------------->| |
| | | | | |
|7. MX Meas Config (Wi-Fi/LTE Measurement Thresholds/Period) |
|<---------------------------------------------------+ |
|8. MX Meas Report (LTE RSRP, UL/DL TPUT) | | |
+-----------------------------------------+--------->| |
|9. MX SSID Indication (List of SSIDs) | | |
|<------------+-------------+------------------------+ |
| | | | | |
|10. MX Reconfiguration REQ (LTE IP) | | |
+--------------------------------------------------->| |
|11. MX Reconfiguration RSP | | |
|<----------------------------------------+----------+ |
|12. MX UP Setup REQ (MPTCP proxy IP/Port, Aggregation) |
|<--------------------------+-------------+----------+ |
|13. MX UP Setup RSP | | | |
+-------------+-------------+-------------+--------->| |
| | 14. MPTCP connection with designated | |
| | MPTCP proxy over LTE | |
| +-------------+-------------+----------+------->|
| | | | | |
+ + + + + +
Figure 18: MAMS-Assisted MPTCP Proxy as User Plane - Initial
Setup with LTE Leg
The salient steps described in the call flow are as follows. The
client connects to the LTE network and obtains an IP address (assume
that LTE is the first connection). It then initiates the NCM
discovery procedures and exchanges capabilities, including the
support for MPTCP as the convergence protocol at both the network and
the client.
The CCM provides the LTE connection parameters to the NCM. The NCM
provides the parameters like MPTCP proxy IP address/port, and MPTCP
Client Key for configuring the Convergence Layer. This is useful if
the N-MADP is reachable, via a different IP address or/and port, from
different access networks. The current MPTCP signaling can't
identify or differentiate the MPTCP proxy IP address and port from
multiple access networks. The client uses the MPTCP Client Key
during the subflow creation, and this enables the N-MADP to uniquely
identify the client, even if a NAT is present. The N-MADP can then
inform the NCM of the subflow creation and parameters related to
creating additional subflows. Since LTE is the only connection, the
user-plane traffic flows over the single TCP subflow over the LTE
connection. Optionally, the NCM provides assistance information to
the client on the neighboring/preferred Wi-Fi networks that it can
associate with.
Figure 19 describes the steps where the client establishes a Wi-Fi
connection. The CCM informs the NCM of the Wi-Fi connection, along
with such parameters as the Wi-Fi IP address or the SSID. The NCM
determines that the Wi-Fi connection needs to be secured, configures
the Adaptation Layer to use IPsec, and provides the required
parameters to the CCM. In addition, the NCM provides the information
for configuring the Convergence Layer (e.g., MPTCP proxy IP address)
and provides the MX Traffic Steering Request to indicate that the
client SHOULD use only the LTE access. The NCM may do this, for
example, on determining from the measurements that the Wi-Fi link is
not consistently good enough. As the Wi-Fi link conditions improve,
the NCM sends an MX Traffic Steering Request to use Wi-Fi access as
well. This triggers the client to establish the TCP subflow over the
Wi-Fi link with the MPTCP proxy.
+------+ +--------+ +--------+ +-------+ +-------+ +------+
| | | | | | | | | | | |
| CCM | | C-MADP | | Wi-Fi | | LTE | | NCM | |N-MADP|
| | | | | N/W | | N/W | | | | |
+------+ +--------+ +--------+ +-------+ +-------+ +------+
+-------------------------------------------------------------------+
| Traffic over LTE in UL and DL over MPTCP Connection |
+-------------------------------------------------------------------+
+-------------------------------------------------------------------+
| Wi-Fi Connection Establishment and IP Address Allocation |
+----------------------------------------------------------------+--+
| | | | | |
|15. MX Reconfiguration REQ (Wi-Fi IP) | | |
+--------------------------------------------------->| |
|16. MX Reconfiguration RSP | | |
|<----------------------------------------+----------+ |
|17. MX UP Setup REQ (MPTCP proxy IP/Port, Aggregation) |
|<--------------------------+-------------+----------+ |
|18. MX UP Setup RSP | | | |
+-------------+-------------+-------------+--------->| |
| |19. IPsec Tunnel Establishment over Wi-Fi Path |
| |<-------------------------------------+-------->|
| | | | | |
|20. MX Meas Report (Wi-Fi RSSI, | | |
| LTE RSRP, UL/DL TPUT) | |+------------+
+-------------+-------------+-------------+--------->||Wait for |
| | | | ||good reports|
| | | | |+------------+
|21. MX Traffic Steering REQ (UL/DL access, | |
| Traffic Flow Templates (TFTs)) | +----------+
|<----------------------------------------+----------+ |Allow use |
| | | | of |
|22. MX Traffic Steering RSP (...) | | |Wi-Fi link|
+-------------+-------------+----------------------->| +----------+
| | | | | |
| | 23. Add TCP subflow to the MPTCP connection |
| | over Wi-Fi link (IPsec Tunnel) |
| |<---------------------------------------------->|
| | | | | |
+----------------------------------------------------------------+
|| Aggregated Wi-Fi and LTE capacity for UL and DL ||
+----------------------------------------------------------------+
| |
| |
Figure 19: MAMS-Assisted MPTCP Proxy as User Plane - Add Wi-Fi Leg
Figure 20 describes the steps where the client reports that Wi-Fi
link conditions degrade in UL. The MAMS control plane is used to
continuously monitor the access link conditions on Wi-Fi and LTE
connections. The NCM may at some point determine an increase in UL
traffic on the Wi-Fi network, and trigger the client to use only LTE
in the UL via a MX Traffic Steering Request to improve UL
performance.
+------+ +--------+ +--------+ +-------+ +-------+ +------+
| | | | | | | | | | | |
| CCM | | C-MADP | | Wi-Fi | | LTE | | NCM | |N-MADP|
| | | | | N/W | | N/W | | | | |
+------+ +--------+ +--------+ +-------+ +-------+ +------+
+-------------------------------------------------------------------+
| Traffic over LTE and Wi-Fi in UL And DL over MPTCP |
++------------+-------------+-------------+------------+--------+---+
| | | | | |
|24. MX Meas Report (Wi-Fi RSSI, LTE RSRP, UL/DL TPUT)| +------+---+
+------------+-------------+-------------+----------->| |Reports of|
| | | | | |bad Wi-Fi |
| | | | | |UL tput |
| | | | | +----------+
|25. MX Traffic Steering REQ (UL/DL Access, TFTs) | +----------+
|<---------------------------------------+------------+ |Disallow |
| | | | | |use of |
|26. MX Traffic Steering RSP (...) | | |Wi-Fi UL |
|------------+-------------+------------------------->| +------+---+
| | | | | |
++------------+-------------+-------------+------------+--------+---+
| UL data to use TCP subflow over LTE link only, |
| aggregated Wi-Fi+LTE capacity for DL |
++------------+-------------+-------------+------------+--------+---+
| | | | | |
+ + + + + +
Figure 20: MAMS-Assisted MPTCP Proxy as User Plane - Wi-Fi UL
Degrades
Figure 21 describes the steps where the client reports that Wi-Fi
link conditions have degraded in both the UL and DL. As the Wi-Fi
link conditions deteriorate further, the NCM may decide to send a MX
Traffic Steering Request that instructs the client to stop using Wi-
Fi and to use only the LTE access in both the UL and DL. This
condition may be maintained until the NCM determines, based on
reported measurements, that the Wi-Fi link has again become usable.
+------+ +--------+ +--------+ +-------+ +-------+ +------+
| | | | | | | | | | | |
| CCM | | C-MADP | | Wi-Fi | | LTE | | NCM | |N-MADP|
| | | | | N/W | | N/W | | | | |
+------+ +--------+ +--------+ +-------+ +-------+ +------+
+------------------------------------------------------------------+
| UL data to use TCP subflow over LTE link only, |
| aggregated Wi-Fi+LTE capacity for DL |
++------------+-------------+-------------+----------+---------+---+
| | | | | |
| | | | | |
|27. MX Meas Report (Wi-Fi RSSI, | | |
| LTE RSRP, UL/DL TPUT) | | +-------+----+
+------------+-------------+-------------+--------->| | Reports of |
| | | | | | bad Wi-Fi |
| | | | | | UL/DL tput |
| | | | | +------------+
|28. MX Traffic Steering REQ (UL/DL Access, TFTs) | +------------+
|<---------------------------------------+----------+ | Disallow |
| | | | | | use of |
|29. MX Traffic Steering RSP (...) | | | Wi-Fi |
+----------------------------------------+--------->| +------------+
| |30. Delete TCP subflow from MPTCP | |
| | connection over Wi-Fi link | |
| |<---------------------------------------------->|
| | | | | |
+--------------------------------------------------------------+
|| Traffic over LTE link only for DL and UL |
|| (until client reports better Wi-Fi link conditions) |
+--------------------------------------------------------------+
| | | | | |
+ + + + + +
Figure 21: MAMS-Assisted MPTCP Proxy as User Plane - Part 4
12. Applying MAMS Control Procedures for Network-Assisted Traffic
Steering When There Is No Convergence Layer
Figure 22 shows the call flow describing MAMS control procedures
applied for dynamic optimal path selection in a scenario where
Convergence and Adaptation Layer protocols are omitted. This
scenario indicates the applicability of a solution for only the MAMS
control plane.
In the capability exchange messages, the NCM and CCM negotiate that
Convergence-Layer and Adaptation-Layer protocols are not needed (or
supported). The CCM informs the NCM of the availability of the LTE
and Wi-Fi links. The NCM dynamically determines the access links
(Wi-Fi or LTE) to be used based on the reported measurements of link
quality.
+------+ +--------+ +--------+ +-------+ +-------+ +------+
| | | | | | | | | | | |
| CCM | | C-MADP | | Wi-Fi | | LTE | | NCM | |N-MADP|
| | | | | N/W | | N/W | | | | |
+------+ +--------+ +--------+ +-------+ +-------+ +------+
+------------------------------------------------------------------+
| 1. LTE Session Setup and IP Address Allocation |
+---------------------------------------+-------------+----------+-+
|2. MX Discover (MAMS Version, MCC/MNC ) | |
+--------------------------------------+------------>| |
|3. MX System Info (Serving NCM IP/Port address) | |
|<------------+-------------+----------+-------------| |
| | | | | |
|4. MX Capability REQ (Supported | | |
| Anchor/Delivery Links (Wi-Fi, LTE))| | |
+--------------------------------------------------->| |
|5. MX Capability RSP (No Convergence/Adaptation parameters) |
|<-------------------------------------+-------------+ |
|6. MX Capability ACK (ACCEPT) | | |
+-------------+-------------+----------------------->| |
| | | | | |
|7. MX Meas Config (Wi-Fi/LTE Measurement Thresholds/Period) |
|<---------------------------------------------------| |
|8. MX Meas Report (LTE RSRP, UL/DL TPUT) | |
|--------------------------------------+------------>| |
|9. MX SSID Ind (List of SSIDs) | | |
|<---------------------------------------------------| |
+-----------------------------------------------------------------++
| 10. Wi-Fi Connection Setup and IP Address Allocation |
+-+-------------+-------------+----------+-------------+----------++
| | | | | |
|11. MX Reconfiguration REQ (LTE IP, Wi-Fi IP) | |
|--------------------------------------+------------>| |
|12. MX Reconfiguration RSP | | |
|<---------------------------------------------------| |
+-----------------------------------------------------------------++
| Initial Condition, Data over LTE link only, Wi-Fi link is poor |
+------------------------------------------------------+----------++
| | | | | |
|13. MX Meas Report (Wi-Fi RSSI, | | |
| LTE RSRP, UL/DL TPUT)| | |+----------+
|--------------------------------------------------->||Wi-Fi link|
| | | | ||conditions|
| | | | ||reported |
| | | | ||good |
| | | | |+----------+
| | | | | |
|14. MX Traffic Steering REQ (UL/DL Access, TFTs) |+----------+
|<------------+-------------+----------+-------------||Steer |
| | | | ||traffic to|
|15. MX Traffic Steering RSP (...) | ||use Wi-Fi |
|<------------+-------------+----------+-------------||link |
| | | | |+----------+
| | | | | |
+-----------------------------------------------------------------++
| Use Wi-Fi link for Data |
+------------------------------------------------------+----------++
| | | | | |
+ + + + + +
Figure 22: MAMS with No Convergence Layer
13. Coexistence of MX Adaptation and MX Convergence Layers
The MAMS user plane supports multiple instances and combinations of
protocols to be used at the MX Adaptation and the Convergence Layer.
For example, one instance of the MX Convergence Layer can be MPTCP
Proxy and another instance can be GMA. The MX Adaptation for each
can be either a UDP tunnel or IPsec. IPsec may be set up when the
network path needs to be secured, e.g., to protect the TCP subflow
traversing the network path between the client and the MPTCP proxy.
Each instance of the MAMS user plane, i.e., the combination of MX
Convergence-Layer and MX Adaptation-Layer protocols, can coexist
simultaneously and independently handle different traffic types.
14. Security Considerations
14.1. MAMS Control-Plane Security
The NCM functional element is hosted on a network node that is
assumed to be within a secure network, e.g., within the operator's
network, and is assumed to be protected against hijack attacks.
For deployment scenarios where the client is configured (e.g., by the
network operator) to use a specific network path for exchanging
control-plane messages, and if the network path is assumed to be
secure, MAMS control messages will rely on security provided by the
underlying network.
For deployment scenarios where the security of the network path
cannot be assumed, NCM and CCM implementations MUST support the "wss"
URI scheme [RFC6455] and Transport Layer Security (TLS) [RFC8446] to
secure the exchange of control-plane messages between the NCM and the
CCM.
For deployment scenarios where client authentication is desired, the
WebSocket server can use any client authentication mechanisms
available to a generic HTTP server, such as cookies, HTTP
authentication, or TLS authentication.
14.2. MAMS User-Plane Security
User data in the MAMS framework relies on the security of the
underlying network transport paths. When this security cannot be
assumed, the NCM configures the use of protocols (e.g., IPsec
[RFC4301] [RFC3948]) in the MX Adaptation Layer, for security.
15. Implementation Considerations
The MAMS architecture builds on commonly available functions in
clients that can be used to deliver software updates over popular
client operating systems, thereby enabling rapid deployment and
addressing the large base of deployed clients.
16. Applicability to Multi-Access Edge Computing
Multi-access Edge Computing (MEC), previously known as Mobile Edge
Computing, is an access-edge cloud platform being considered at the
European Telecommunications Standards Institute (ETSI) [ETSIMEC],
whose initial focus was to improve the QoE by leveraging intelligence
at the cellular (e.g., 3GPP technologies like LTE) access edge, and
the scope is now being extended to support access technologies beyond
3GPP. The applicability of the framework described in this document
to the MEC platform has been evaluated and tested in different
network configurations by the authors.
The NCM can be hosted on a MEC cloud server that is located in the
user-plane path at the edge of the multi-technology access network.
The NCM and CCM can negotiate the network path combinations based on
an application's needs and the necessary user-plane protocols to be
used across the multiple paths. The network conditions reported by
the CCM to the NCM can be complemented by a Radio Analytics
application [ETSIRNIS] residing at the MEC cloud server to configure
the uplink and downlink access paths according to changing radio and
congestion conditions.
The user-plane functional element, N-MADP, can either be collocated
with the NCM at the MEC cloud server (e.g., MEC-hosted applications)
or placed at a separate network element like a common user-plane
gateway across the multiple networks.
Also, even in scenarios where an N-MADP is not deployed, the NCM can
be used to augment the traffic-steering decisions at the client.
The aim of these enhancements is to improve the end user's QoE by
leveraging the best network path based on an application's needs and
network conditions, and building on the advantages of significantly
reduced latency and the dynamic and real-time exposure of radio
network information available at the MEC.
17. Related Work in Other Industry and Standards Forums
The MAMS framework described in this document has been incorporated
or is proposed for incorporation as a solution to address multi-
access integration in multiple industry forums and standards. This
section describes the related work in other industry forums and the
standards organizations.
Wireless Broadband Alliance industry partners have published a white
paper that describes the applicability of different technologies for
multi-access integration to different deployments as part of their
"Unlicensed Integration with 5G Networks" project [WBAUnl5G]. The
white paper includes the MAMS framework described in this document as
a technology for integrating unlicensed (Wi-Fi) networks with 5G
networks above the 5G core network.
The 3GPP is developing a technical report as part of its work item
Study on Access Traffic Steering, Switching, and Splitting (ATSSS).
That report, TR 23.793 [ATSSS], contains a number of potential
solutions; Solution 1 in [ATSSS] utilizes a separate control plane
for the flexible negotiation of user-plane protocols and path
measurements in a way that is similar to the MAMS architecture
described in this document.
The Small Cell Forum (SCF) [SCFTECH5G] plans to develop a white paper
as part of its work item on LTE/5G and Wi-Fi. There is a proposal to
include MAMS in this white paper.
The ETSI Multi-access Edge Computing Phase 2 technical work is
examining many aspects of this work, including use cases for
optimizing QoE and resource utilization. The MAMS architecture and
procedures outlined in this document are included in the ETSI's use
cases and requirements document [ETSIMAMS].
18. IANA Considerations
This document has no IANA actions.
19. References
19.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC4301] Kent, S. and K. Seo, "Security Architecture for the
Internet Protocol", RFC 4301, DOI 10.17487/RFC4301,
December 2005, <https://www.rfc-editor.org/info/rfc4301>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
19.2. Informative References
[ANDSF] 3rd Generation Partnership Project, "Access Network
Discovery and Selection Function (ANDSF) Management Object
(MO)", 3GPP TS 24.312 version 15.0.0, Technical
Specification Group Core Network and Terminals, June 2018,
<https://www.3gpp.org/ftp//Specs/
archive/24_series/24.312/24312-f00.zip>.
[ATSSS] 3rd Generation Partnership Project, "Study on access
traffic steering, switch and splitting support in the 5G
System (5GS) architecture", Work in Progress, 3GPP TR
23.793 v16.0.0, December 2018,
<https://www.3gpp.org/ftp/Specs/
archive/23_series/23.793/>.
[ETSIMAMS] European Telecommunications Standards Institute, "Multi-
access Edge Computing (MEC); Phase 2: Use Cases and
Requirements", ETSI GS MEC 002 v2.1.1, October 2018,
<https://www.etsi.org/deliver/etsi_gs/
MEC/001_099/002/02.01.01_60/gs_MEC002v020101p.pdf>.
[ETSIMEC] European Telecommunications Standards Institute, "Multi-
access Edge Computing (MEC)",
<https://www.etsi.org/technologies/multi-access-edge-
computing>.
[ETSIRNIS] European Telecommunications Standards Institute, "Mobile
Edge Computing (MEC) Radio Network Information API", ETSI
GS MEC 012 v1.1.1, July 2017,
<https://www.etsi.org/deliver/etsi_gs/
MEC/001_099/012/01.01.01_60/gs_MEC012v010101p.pdf>.
[IEEE-80211]
IEEE, "IEEE Standard for Information technology-
Telecommunications and information exchange between
systems - Local and metropolitan area networks-Specific
requirements - Part 11: Wireless LAN Medium Access Control
(MAC) and Physical Layer (PHY) Specifications",
IEEE 802.11-2016,
<https://ieeexplore.ieee.org/document/7786995>.
[INTAREA-GMA]
Zhu, J. and S. Kanugovi, "Generic Multi-Access (GMA)
Convergence Encapsulation Protocols", Work in Progress,
Internet-Draft, draft-zhu-intarea-gma-05, 16 December
2019,
<https://tools.ietf.org/html/draft-zhu-intarea-gma-05>.
[INTAREA-MAMS]
Zhu, J., Seo, S., Kanugovi, S., and S. Peng, "User-Plane
Protocols for Multiple Access Management Service", Work in
Progress, Internet-Draft, draft-zhu-intarea-mams-user-
protocol-09, 4 March 2020, <https://tools.ietf.org/html/
draft-zhu-intarea-mams-user-protocol-09>.
[ITU-E212] International Telecommunication Union, "The international
identification plan for public networks and
subscriptions", ITU-T Recommendation E.212, September
2016, <https://www.itu.int/rec/T-REC-E.212-201609-I/en>.
[QUIC-MULTIPATH]
Coninck, Q. and O. Bonaventure, "Multipath Extensions for
QUIC (MP-QUIC)", Work in Progress, Internet-Draft, draft-
deconinck-quic-multipath-04, 5 March 2020,
<https://tools.ietf.org/html/draft-deconinck-quic-
multipath-04>.
[RFC2784] Farinacci, D., Li, T., Hanks, S., Meyer, D., and P.
Traina, "Generic Routing Encapsulation (GRE)", RFC 2784,
DOI 10.17487/RFC2784, March 2000,
<https://www.rfc-editor.org/info/rfc2784>.
[RFC2890] Dommety, G., "Key and Sequence Number Extensions to GRE",
RFC 2890, DOI 10.17487/RFC2890, September 2000,
<https://www.rfc-editor.org/info/rfc2890>.
[RFC3948] Huttunen, A., Swander, B., Volpe, V., DiBurro, L., and M.
Stenberg, "UDP Encapsulation of IPsec ESP Packets",
RFC 3948, DOI 10.17487/RFC3948, January 2005,
<https://www.rfc-editor.org/info/rfc3948>.
[RFC4555] Eronen, P., "IKEv2 Mobility and Multihoming Protocol
(MOBIKE)", RFC 4555, DOI 10.17487/RFC4555, June 2006,
<https://www.rfc-editor.org/info/rfc4555>.
[RFC4960] Stewart, R., Ed., "Stream Control Transmission Protocol",
RFC 4960, DOI 10.17487/RFC4960, September 2007,
<https://www.rfc-editor.org/info/rfc4960>.
[RFC6347] Rescorla, E. and N. Modadugu, "Datagram Transport Layer
Security Version 1.2", RFC 6347, DOI 10.17487/RFC6347,
January 2012, <https://www.rfc-editor.org/info/rfc6347>.
[RFC6455] Fette, I. and A. Melnikov, "The WebSocket Protocol",
RFC 6455, DOI 10.17487/RFC6455, December 2011,
<https://www.rfc-editor.org/info/rfc6455>.
[RFC6824] Ford, A., Raiciu, C., Handley, M., and O. Bonaventure,
"TCP Extensions for Multipath Operation with Multiple
Addresses", RFC 6824, DOI 10.17487/RFC6824, January 2013,
<https://www.rfc-editor.org/info/rfc6824>.
[RFC7231] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer
Protocol (HTTP/1.1): Semantics and Content", RFC 7231,
DOI 10.17487/RFC7231, June 2014,
<https://www.rfc-editor.org/info/rfc7231>.
[RFC7296] Kaufman, C., Hoffman, P., Nir, Y., Eronen, P., and T.
Kivinen, "Internet Key Exchange Protocol Version 2
(IKEv2)", STD 79, RFC 7296, DOI 10.17487/RFC7296, October
2014, <https://www.rfc-editor.org/info/rfc7296>.
[RFC8259] Bray, T., Ed., "The JavaScript Object Notation (JSON) Data
Interchange Format", STD 90, RFC 8259,
DOI 10.17487/RFC8259, December 2017,
<https://www.rfc-editor.org/info/rfc8259>.
[RFC8446] Rescorla, E., "The Transport Layer Security (TLS) Protocol
Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018,
<https://www.rfc-editor.org/info/rfc8446>.
[SCFTECH5G]
Small Cell Forum, "Small Cell Forum", <https://scf.io/>.
[ServDesc3GPP]
3rd Generation Partnership Project, "General Packet Radio
Service (GPRS); Service description; Stage 2", 3GPP TS
23.060 version 16.0.0, Technical Specification Group
Services and System Aspects, March 2019,
<https://www.3gpp.org/ftp/Specs/
archive/23_series/23.060/23060-g00.zip>.
[TCPM-CONVERTERS]
Bonaventure, O., Boucadair, M., Gundavelli, S., Seo, S.,
and B. Hesmans, "0-RTT TCP Convert Protocol", Work in
Progress, Internet-Draft, draft-ietf-tcpm-converters-19,
22 March 2020, <https://tools.ietf.org/html/draft-ietf-
tcpm-converters-19>.
[WBAUnl5G] Wireless Broadband Alliance, "Unlicensed Integration with
5G Networks", <https://wballiance.com/resource/unlicensed-
integration-with-5g-networks/>.
Appendix A. MAMS Control-Plane Optimization over Secure Connections
This appendix is informative, and provides indicative information
about how MAMS operates.
If the connection between the CCM and the NCM over which the MAMS
control-plane messages are transported is assumed to be secure, UDP
is used as the transport for management and control messages between
the NCM and the CCM (see Figure 23).
+-------------------------------------------------+
| Multi-Access (MX) Control Message |
|-------------------------------------------------|
| UDP |
|-------------------------------------------------|
Figure 23: UDP-Based MAMS Control-Plane Protocol Stack
Appendix B. MAMS Application Interface
This appendix describes the MAMS Application Interface. It does not
provide normative text for the definition of the MAMS framework or
protocols, but offers additional information that may be used to
construct a system based on the MAMS framework.
B.1. Overall Design
The CCM hosts an HTTPS server for applications to communicate and
request services. This document assumes, from a security point of
view, that all CCMs and the communicating application instances are
hosted in a single administrative domain.
The content of messages is described in JavaScript Object Notation
(JSON) format. They offer RESTful APIs for communication.
The exact mechanism regarding how the application knows about the
endpoint of the CCM is out of scope for this document. This
mechanism may instead be provided as part of the application
settings.
B.2. Notation
The documentation of APIs is provided in the OpenAPI format, using
Swagger v2.0. See Appendix D.
B.3. Error Indication
For every API, there could be an error response if the objective of
the API could not be met; see [RFC7231].
B.4. CCM APIs
The following subsections describe the APIs exposed by the CCM to the
applications.
B.4.1. GET Capabilities
The CCM provides an HTTPS GET interface as "/ccm/v1.0/capabilities"
for the application to query the capabilities supported by the CCM
instance.
+---------+ +-----------+
| | | |
| App |--------- HTTPS GET / Capabilities -------->| CCM |
| | | |
+---------+ +-----------+
Figure 24: CCM API - GET Procedures
The CCM shall provide information regarding its capabilities as
follows:
* Supported Features: One or more of the "Feature Name" values, as
defined in the MX Feature Activation List parameter of the MX
Capability Request (Appendix C.2.5).
* Supported Connections: Supported connection types and connection
IDs.
* Supported MX Adaptation Layers: List of MX Adaptation Layer
protocols supported by the N-MADP instance, along with the
connection types where these are supported and their respective
parameters.
* Supported MX Convergence Layers: List of supported MX Convergence
Layer protocols, along with the parameters associated with the
respective convergence technique.
B.4.2. Posting Application Requirements
The CCM provides an HTTPS POST interface as "/ccm/v1.0/
app_requirements" for the application to post the needs of the
application data streams to the CCM instance.
+---------+ +-----------+
| | | |
| App |-------- HTTPS POST / App Requirements ---->| CCM |
| | | |
+---------+ +-----------+
Figure 25: CCM API - POST Procedures
The CCM shall provide for the application to post the following
requirements for its different data streams:
* Number of Data Stream Types.
* For each data stream type, specify the following parameters for
the link, which are preferred by the application:
- Protocol Type: Transport-layer protocol associated with the
application data stream packets.
- Port Range: Supported connection types and connection IDs.
- Traffic QoS: Quality of service parameters, as follows:
o Bandwidth
o Latency
o Jitter
B.4.3. Getting Predictive Link Parameters
The CCM provides an HTTPS GET interface as "/ccm/v1.0/
predictive_link_params" for the application to get the predicted link
parameters from the CCM instance.
+---------+ +-----------+
| | | |
| App |----- HTTPS GET / Predictive Link Params --->| CCM |
| | | |
+---------+ +-----------+
Figure 26: CCM API - Getting Predictive Link Parameters
The CCM asks the NCM for link parameters via the MAMS Network
Analytics Request Procedure (Section 8.12) and includes the
information in response to the API invocation.
* Number of Delivery Connections.
For each delivery connection, include the following:
- Access Link Identifier:
o Connection Type
o Connection ID
- Link Quality Indicator
o Bandwidth:
+ Predicted Value (Mbps)
+ Likelihood (percent)
+ Prediction Validity (Validity Time, in seconds)
o Jitter:
+ Predicted Value (in seconds)
+ Likelihood (percent)
+ Prediction Validity (Validity Time, in seconds)
o Latency:
+ Predicted Value (in seconds)
+ Likelihood (percent)
+ Prediction Validity (Validity Time, in seconds)
o Signal Quality
+ If delivery connection type is LTE, LTE_RSRP Predicted
Value (dBm)
+ If delivery connection type is LTE, LTE_RSRQ Predicted
Value (dBm)
+ If delivery connection type is 5G NR, NR_RSRP Predicted
Value (dBm)
+ If delivery connection type is 5G NR, NR_RSRQ Predicted
Value (dBm)
+ If delivery connection type is Wi-Fi, WLAN_RSSI Predicted
Value (dBm)
+ Likelihood (percent)
+ Prediction Validity (Validity Time, in seconds)
Appendix C. MAMS Control-Plane Messages Described Using JSON
MAMS control-plane messages are exchanged between the CCM and the
NCM. This non-normative appendix describes the format and content of
messages using JSON [RFC8259].
C.1. Protocol Specification: General Processing
C.1.1. Notation
This document uses JSONString, JSONNumber, and JSONBool to indicate
the JSON string, number, and boolean types, respectively.
This document uses an adaptation of the C-style struct notation to
describe JSON objects. A JSON object consists of name/value pairs.
This document refers to each pair as a field. In some contexts, this
document also refers to a field as an attribute. The name of a
field/attribute may be referred to as the key. An optional field is
enclosed by "[ ]". In the definitions, the JSON names of the fields
are case sensitive. An array is indicated by two numbers in angle
brackets, <m..n>, where m indicates the minimal number of values and
n is the maximum. When this document uses * for n, it means no upper
bound.
For example, the text below describes a new type Type4, with three
fields: "name1", "name2", and "name3", respectively. The "name3"
field is optional, and the "name2" field is an array of at least one
value.
object { Type1 name1; Type2 name2 <1..*>; [Type3 name3;] } Type4;
This document uses subtyping to denote that one type is derived from
another type. The example below denotes that TypeDerived is derived
from TypeBase. TypeDerived includes all fields defined in TypeBase.
If TypeBase does not have a "name1" field, TypeDerived will have a
new field called "name1". If TypeBase already has a field called
"name1" but with a different type, TypeDerived will have a field
called "name1" with the type defined in TypeDerived (i.e., Type1 in
the example).
object { Type1 name1; } TypeDerived : TypeBase;
Note that, despite the notation, no standard, machine-readable
interface definition or schema is provided in this document.
Extension documents may describe these as necessary.
For compatibility with publishing requirements, line breaks have been
inserted inside long JSON strings, with the following continuation
lines indented. To form the valid JSON example, any line breaks
inside a string must be replaced with a space and any other white
space after the line break removed.
C.1.2. Discovery Procedure
C.1.2.1. MX Discover Message
This message is the first message sent by the CCM to discover the
presence of NCM in the network. It contains only the base
information as described in Appendix C.2.1 with message_type set as
mx_discover.
The representation of the message is as follows:
object {
[JSONString MCC_MNC_Tuple;]
} MXDiscover : MXBase;
C.1.3. System Information Procedure
C.1.3.1. MX System Info Message
This message is sent by the NCM to the CCM to inform the endpoints
that the NCM supports MAMS functionality. In addition to the base
information (Appendix C.2.1), it contains the following information:
(a) NCM Connections (Appendix C.2.3).
The representation of the message is as follows:
object {
NCMConnections ncm_connections;
} MXSystemInfo : MXBase;
C.1.4. Capability Exchange Procedure
C.1.4.1. MX Capability Request
This message is sent by the CCM to the NCM to indicate the
capabilities of the CCM instance available to the NCM indicated in
the System Info message earlier. In addition to the base information
(Appendix C.2.1), it contains the following information:
(a) Features and their activation status: See Appendix C.2.5.
(b) Number of Anchor Connections: The number of anchor connections
(toward the core) supported by the NCM.
(c) Anchor connections: See Appendix C.2.6.
(d) Number of Delivery Connections: The number of delivery
connections (toward the access) supported by the NCM.
(e) Delivery connections: See Appendix C.2.7.
(f) Convergence methods: See Appendix C.2.9.
(g) Adaptation methods: See Appendix C.2.10.
The representation of the message is as follows:
object {
FeaturesActive feature_active;
JSONNumber num_anchor_connections;
AnchorConnections anchor_connections;
JSONNumber num_delivery_connections;
DeliveryConnections delivery_connections;
ConvergenceMethods convergence_methods;
AdaptationMethods adaptation_methods
} MXCapabilityReq : MXBase;
C.1.4.2. MX Capability Response
This message is sent by the NCM to the CCM to indicate the
capabilities of the NCM instance and unique session identifier for
the CCM. In addition to the base information (Appendix C.2.1), it
contains the following information:
(a) Features and their activation status: See Appendix C.2.5.
(b) Number of Anchor Connections: The number of anchor connections
(toward the core) supported by the NCM.
(c) Anchor connections: See Appendix C.2.6.
(d) Number of Delivery Connections: The number of delivery
connections (toward the access) supported by the NCM.
(e) Delivery connections: See Appendix C.2.7.
(f) Convergence methods: See Appendix C.2.9.
(g) Adaptation methods: See Appendix C.2.10.
(h) Unique Session ID: This uniquely identifies the session between
the CCM and the NCM in a network. See Appendix C.2.2.
The representation of the message is as follows:
object {
FeaturesActive feature_active;
JSONNumber num_anchor_connections;
AnchorConnections anchor_connections;
JSONNumber num_delivery_connections;
DeliveryConnections delivery_connections;
ConvergenceMethods convergence_methods;
AdaptationMethods adaptation_methods
UniqueSessionId unique_session_id;
} MXCapabilityRsp : MXBase;
C.1.4.3. MX Capability Acknowledge
This message is sent by the CCM to the NCM to indicate acceptance of
capabilities advertised by the NCM in an earlier MX Capability
Response message. In addition to the base information
(Appendix C.2.1), it contains the following information:
(a) Unique Session ID: Same identifier as the identifier provided in
the MX Capability Response. See Appendix C.2.2.
(b) Capability Acknowledgment: Indicates either acceptance or
rejection of the capabilities sent by the CCM. Can use either
"MX_ACCEPT" or "MX_REJECT" as acceptable values.
The representation of the message is as follows:
object {
UniqueSessionId unique_session_id;
JSONString capability_ack;
} MXCapabilityAck : MXBase;
C.1.5. User-Plane Configuration Procedure
C.1.5.1. MX User-Plane Configuration Request
This message is sent by the NCM to the CCM to configure the user
plane for MAMS. In addition to the base information
(Appendix C.2.1), it contains the following information:
(a) Number of Anchor Connections: The number of anchor connections
supported by the NCM.
(b) Setup of anchor connections: See Appendix C.2.11.
The representation of the message is as follows:
object {
JSONNumber num_anchor_connections;
SetupAnchorConns anchor_connections;
} MXUPSetupConfigReq : MXBase;
C.1.5.2. MX User-Plane Configuration Confirmation
This message is the confirmation of the user-plane setup message sent
from the CCM after successfully configuring the user plane on the
client. This message contains the following information:
(a) Unique Session ID: Same identifier as the identifier provided in
the MX Capability Response. See Appendix C.2.2.
(b) MX probe parameters (included if probing is supported).
(1) Probe Port: UDP port for accepting probe message.
(2) Anchor connection ID: Identifier of the anchor connection
to be used for probe function. Provided in the MX UP Setup
Configuration Request.
(3) MX Configuration ID: This parameter is included only if the
MX Configuration ID parameter is available from the user-
plane setup configuration. It indicates the MX
configuration ID of the anchor connection to be used for
probe function.
(c) The following information is required for each delivery
connection:
(1) Connection ID: Delivery connection ID supported by the
client.
(2) Client Adaptation-Layer Parameters: If the UDP Adaptation
Layer is in use, then the UDP port to be used on the C-MADP
side.
The representation of the message is as follows:
object {
UniqueSessionId unique_session_id;
[ProbeParam probe_param;]
JSONNumber num_delivery_conn;
ClientParam client_params <1...*>;
} MXUPSetupConfigCnf : MXBase;
Where ProbeParam is defined as follows:
object {
JSONNumber probe_port;
JSONNumber anchor_conn_id;
[JSONNumber mx_configuration_id;]
} ProbeParam;
Where ClientParam is defined as follows:
object {
JSONNumber connection_id;
[AdaptationParam adapt_param;]
} ClientParam;
Where AdaptationParam is defined as follows:
object {
JSONNumber udp_adapt_port;
} AdaptationParam;
C.1.6. Reconfiguration Procedure
C.1.6.1. MX Reconfiguration Request
This message is sent by the CCM to the NCM in the case of
reconfiguration of any of the connections from the client's side. In
addition to the base information (Appendix C.2.1), it contains the
following information:
(a) Unique Session ID: Identifier for the CCM-NCM association
Appendix C.2.2.
(b) Reconfiguration Action: The reconfiguration action type can be
one of "setup", "release", or "update".
(c) Connection ID: Connection ID for which the reconfiguration is
taking place.
(d) IP address: Included if Reconfiguration Action is either "setup"
or "update".
(e) SSID: If the connection type is Wi-Fi, then this parameter
contains the SSID to which the client has attached.
(f) MTU of the connection: The MTU of the delivery path that is
calculated at the client for use by the NCM to configure
fragmentation and concatenation procedures at the N-MADP.
(g) Connection Status: This parameter indicates whether the
connection is currently "disabled", "enabled", or "connected".
Default: "connected".
(h) Delivery Node ID: Identity of the node to which the client is
attached. In the case of LTE, this is an ECGI. In the case of
Wi-Fi, this is an AP ID or a MAC address.
The representation of the message is as follows:
object {
UniqueSessionId unique_session_id;
JSONString reconf_action;
JSONNumber connection_id;
JSONString ip_address;
JSONString ssid;
JSONNumber mtu_size;
JSONString connection_status;
[JSONString delivery_node_id;]
} MXReconfReq : MXBase;
C.1.6.2. MX Reconfiguration Response
This message is sent by the NCM to the CCM as a confirmation of the
received MX Reconfiguration Request and contains only the base
information (as defined in Appendix C.2.1).
The representation of the message is as follows:
object {
} MXReconfRsp : MXBase;
C.1.7. Path Estimation Procedure
C.1.7.1. MX Path Estimation Request
This message is sent by the NCM toward the CCM to configure the CCM
to send MX Path Estimation Results. In addition to the base
information (Appendix C.2.1), it contains the following information:
(a) Connection ID: ID of the connection for which the path
estimation report is required.
(b) Init Probe Test Duration: Duration of initial probe test, in
milliseconds.
(c) Init Probe Test Rate: Initial testing rate, in megabits per
second.
(d) Init Probe Size: Size of each packet for initial probe, in
bytes.
(e) Init Probe-ACK: If an acknowledgment for probe is required.
(Possible values: "yes", "no")
(f) Active Probe Frequency: Frequency, in milliseconds, at which the
active probes shall be sent.
(g) Active Probe Size: Size of the active probe, in bytes.
(h) Active Probe Duration: Duration, in seconds, for which the
active probe shall be performed.
(i) Active Probe-ACK: If an acknowledgment for probe is required.
(Possible values: "yes", "no")
The representation of the message is as follows:
object {
JSONNumber connection_id;
JSONNumber init_probe_test_duration_ms;
JSONNumber init_probe_test_rate_Mbps;
JSONNumber init_probe_size_bytes;
JSONString init_probe_ack_req;
JSONNumber active_probe_freq_ms;
JSONNumber active_probe_size_bytes;
JSONNumber active_probe_duration_sec;
JSONString active_probe_ack_req;
} MXPathEstReq : MXBase;
C.1.7.2. MX Path Estimation Results
This message is sent by the CCM to the NCM to report on the probe
estimation configured by the NCM. In addition to the base
information (Appendix C.2.1), it contains the following information:
(a) Unique Session ID: Same identifier as the identifier provided in
the MX Capability Response. See Appendix C.2.2.
(b) Connection ID: ID of the connection for which the MX Path
Estimation Results message is required.
(c) Init Probe Results: See Appendix C.2.12.
(d) Active Probe Results: See Appendix C.2.13.
The representation of the message is as follows:
object {
JSONNumber connection_id;
UniqueSessionId unique_session_id;
[InitProbeResults init_probe_results;]
[ActiveProbeResults active_probe_results;]
} MXPathEstResults : MXBase;
C.1.8. Traffic-Steering Procedure
C.1.8.1. MX Traffic Steering Request
This message is sent by the NCM to the CCM to enable traffic steering
on the delivery side in uplink and downlink configurations. In
addition to the base information (Appendix C.2.1), it contains the
following information:
(a) Connection ID: Anchor connection number for which the traffic
steering is being defined.
(b) MX Configuration ID: MX configuration for which the traffic
steering is being defined.
(c) Downlink Delivery: See Appendix C.2.14.
(d) Default UL Delivery: The default delivery connection for the
uplink. All traffic should be delivered on this connection in
the uplink direction, and the Traffic Flow Template (TFT) filter
should be applied only for the traffic mentioned in Uplink
Delivery.
(e) Uplink Delivery: See Appendix C.2.15.
(f) Features and their activation status: See Appendix C.2.5.
The representation of the message is as follows:
object {
JSONNumber connection_id;
[JSONNumber mx_configuration_id;]
DLDelivery downlink_delivery;
JSONNumber default_uplink_delivery;
ULDelivery uplink_delivery;
FeaturesActive feature_active;
} MXTrafficSteeringReq : MXBase;
C.1.8.2. MX Traffic Steering Response
This message is a response to an MX Traffic Steering Request from the
CCM to the NCM. In addition to the base information
(Appendix C.2.1), it contains the following information:
(a) Unique Session ID: Same identifier as the identifier provided in
the MX Capability Response. See Appendix C.2.2.
(b) Features and their activation status: See Appendix C.2.5.
The representation of the message is as follows:
object {
UniqueSessionId unique_session_id;
FeaturesActive feature_active;
} MXTrafficSteeringResp : MXBase;
C.1.9. MAMS Application MADP Association
C.1.9.1. MX Application MADP Association Request
This message is sent by the CCM to the NCM to select MADP instances
provided earlier in the MX UP Setup Configuration Request, based on
requirements for the applications.
In addition to the base information (Appendix C.2.1), it contains the
following:
(a) Unique Session ID: This uniquely identifies the session between
the CCM and the NCM in a network. See Appendix C.2.2.
(b) A list of MX Application MADP Associations, with each entry as
follows:
(1) Connection ID: Represents the anchor connection number of
the MADP instance.
(2) MX Configuration ID: Identifies the MX configuration of the
MADP instance.
(3) Traffic Flow Template Uplink: Traffic Flow Template, as
defined in Appendix C.2.16, to be used in the uplink
direction.
(4) Traffic Flow Template Downlink: Traffic Flow Template, as
defined in Appendix C.2.16, to be used in the downlink
direction.
The representation of the message is as follows:
object {
UniqueSessionId unique_session_id;
MXAppMADPAssoc app_madp_assoc_list <1..*>;
} MXAppMADPAssocReq : MXBase;
Where each measurement MXAppMADPAssoc is represented by the
following:
object {
JSONNumber connection_id;
JSONNumber mx_configuration_id
TrafficFlowTemplate tft_ul_list <1..*>;
TrafficFlowTemplate tft_dl_list <1..*>;
} MXAppMADPAssoc;
C.1.9.2. MX Application MADP Association Response
This message is sent by the NCM to the CCM to confirm the selected
MADP instances provided in the MX Application MADP Association
Request by the CCM.
In addition to the base information (Appendix C.2.1), it contains
information if the request has been successful.
The representation of the message is as follows:
object {
JSONBool is_success;
} MXAppMADPAssocResp : MXBase;
C.1.10. MX SSID Indication
This message is sent by the NCM to the CCM to indicate the list of
allowed SSIDs that are supported by the MAMS entity on the network
side. It contains the list of SSIDs.
Each SSID consists of the type of SSID (which can be one of the
following: SSID, BSSID, or HESSID) and the SSID itself.
The representation of the message is as follows:
object {
SSID ssid_list <1..*>;
} MXSSIDIndication : MXBase;
Where each SSID is defined as follows:
object {
JSONString ssid_type;
JSONString ssid;
} SSID;
C.1.11. Measurements
C.1.11.1. MX Measurement Configuration
This message is sent from the NCM to the CCM to configure the period
measurement reporting at the CCM. The message contains a list of
measurement configurations, with each element containing the
following information:
(a) Connection ID: Connection ID of the delivery connection for
which the reporting is being configured.
(b) Connection Type: Connection type for which the reporting is
being configured. Can be "LTE", "Wi-Fi", "5G_NR".
(c) Measurement Report Configuration: Actual report configuration
based on the Connection Type, as defined in Appendix C.2.17.
The representation of the message is as follows:
object {
MeasReportConf measurement_configuration <1..*>;
} MXMeasReportConf : MXBase;
Where each measurement MeasReportConf is represented by the
following:
object {
JSONNumber connection_id;
JSONString connection_type;
MeasReportConfs meas_rep_conf <1..*>;
} MeasReportConf;
C.1.11.2. MX Measurement Report
This message is periodically sent by the CCM to the NCM after
measurement configuration. In addition to the base information, it
contains the following information:
(a) Unique Session ID: Same identifier as the identifier provided in
the MX Capability Response. Described in Appendix C.2.2.
(b) Measurement report for each delivery connection is measured by
the client as defined in Appendix C.2.18.
The representation of the message is as follows:
object {
UniqueSessionId unique_session_id;
MXMeasRep measurement_reports <1..*>;
} MXMeasurementReport : MXBase;
C.1.12. Keep-Alive
C.1.12.1. MX Keep-Alive Request
An MX Keep-Alive Request can be sent from either the NCM or the CCM
on expiry of the Keep-Alive timer or a handover event. The peer
shall respond to this request with an MX Keep-Alive Response. In the
case of no response from the peer, the MAMS connection shall be
assumed to be broken, and the CCM shall establish a new connection by
sending MX Discover messages.
In addition to the base information, it contains the following
information:
(a) Keep-Alive Reason: Reason for sending this message, can be
"Timeout" or "Handover".
(b) Unique Session ID: Identifier for the CCM-NCM association
Appendix C.2.2.
(c) Connection ID: Connection ID for which handover is detected, if
the reason is "Handover".
(d) Delivery Node ID: The target delivery node ID (ECGI or Wi-Fi AP
ID/MAC address) to which the handover is executed.
The representation of the message is as follows:
object {
JSONString keep_alive_reason;
UniqueSessionId unique_session_id;
JSONNumber connection_id;
JSONString delivery_node_id;
} MXKeepAliveReq : MXBase;
C.1.12.2. MX Keep-Alive Response
On receiving an MX Keep-Alive Request from a peer, the NCM/CCM shall
immediately respond with an MX Keep-Alive Response on the same
delivery path from where the request arrived. In addition to the
base information, it contains the unique session identifier for the
CCM-NCM association (defined in Appendix C.2.2)
The representation of the message is as follows:
object {
UniqueSessionId unique_session_id;
} MXKeepAliveResp : MXBase;
C.1.13. Session Termination Procedure
C.1.13.1. MX Session Termination Request
In the event where the NCM or CCM can no longer handle MAMS for any
reason, it can send an MX Session Termination Request to the peer.
In addition to the base information, it contains a Unique Session ID
and the reason for the termination; this can be "MX_NORMAL_RELEASE",
"MX_NO_RESPONSE", or "INTERNAL_ERROR".
The representation of the message is as follows:
object {
UniqueSessionId unique_session_id;
JSONString reason;
} MXSessionTerminationReq : MXBase;
C.1.13.2. MX Session Termination Response
On receipt of an MX Session Termination Request from a peer, the NCM/
CCM shall respond with MX Session Termination Response on the same
delivery path where the request arrived and clean up the MAMS-related
resources and settings. The CCM shall reinitiate a new session with
MX Discover messages.
The representation of the message is as follows:
object {
UniqueSessionId unique_session_id;
} MXSessionTerminationResp : MXBase;
C.1.14. Network Analytics
C.1.14.1. MX Network Analytics Request
This message is sent by the CCM to the NCM to request parameters like
bandwidth, jitter, latency, and signal quality predicted by the
network analytics function. In addition to the base information, it
contains the following parameter:
(a) Unique Session ID: Same identifier as the identifier provided in
the MX Capability Response. Described in Appendix C.2.2.
(b) Parameter List: List of parameters in which the CCM is
interested: one or more of "bandwidth", "jitter", "latency", and
"signal_quality".
The representation of the message is as follows:
object {
UniqueSessionId unique_session_id;
JSONString params <1..*>;
} MXNetAnalyticsReq : MXBase;
Where the params object can take one or more of the following values:
"bandwidth"
"jitter"
"latency"
"signal_quality"
C.1.14.2. MX Network Analytics Response
This message is sent by the NCM to the CCM in response to the MX
Network Analytics Request. For each delivery connection that the
client has, the NCM reports the requested parameter predictions and
their respective likelihoods (between 1 and 100 percent).
In addition to the base information, it contains the following
parameters:
(a) Number of Delivery Connections: The number of delivery
connections that are currently configured for the client.
(b) The following information is provided for each delivery
connection:
(1) Connection ID: Connection ID of the delivery connection for
which the parameters are being predicted.
(2) Connection Type: Type of connection. Can be "Wi-Fi",
"5G_NR", "MulteFire", or "LTE".
(3) List of Parameters for which Prediction is requested, where
each of the predicted parameters consists of the following:
(a) Parameter Name: Name of the parameter being predicted.
Can be one of "bandwidth", "jitter", "latency", or
"signal_quality".
(b) Additional Parameter: If Parameter name is
"signal_quality", then this qualifies the quality
parameter like "lte_rsrp", "lte_rsrq", "nr_rsrp",
"nr_rsrq", or "wifi_rssi".
(c) Predicted Value: Provides the predicted value of the
parameter and, if applicable, the additional
parameter.
(d) Likelihood: Provides a stochastic likelihood of the
predicted value.
(e) Validity Time: The time duration for which the
predictions are valid.
The representation of the message is as follows:
object {
MXAnalyticsList param_list <1..*>;
} MXNetAnalyticsResp : MXBase;
Where MXAnalyticsList is defined as follows:
object {
JSONNumber connection_id;
JSONString connection_type;
ParamPredictions predictions <1..*>;
} MXAnalyticsList;
Where each ParamPredictions item is defined as:
object {
JSONString param_name;
[JSONString additional_param;]
JSONNumber prediction;
JSONNumber likelihood;
JSONNumber validity_time;
} ParamPredictions;
C.2. Protocol Specification: Data Types
C.2.1. MXBase
This is the base information that every message between the CCM and
NCM exchanges shall have as mandatory information. It contains the
following information:
(a) Version: Version of MAMS used.
(b) Message Type: Message type being sent, where the following are
considered valid values:
"mx_discover"
"mx_system_info"
"mx_capability_req"
"mx_capability_rsp"
"mx_capability_ack"
"mx_up_setup_conf_req"
"mx_up_setup_cnf"
"mx_reconf_req"
"mx_reconf_rsp"
"mx_path_est_req"
"mx_path_est_results"
"mx_traffic_steering_req"
"mx_traffic_steering_rsp"
"mx_ssid_indication"
"mx_keep_alive_req"
"mx_keep_alive_rsp"
"mx_measurement_conf"
"mx_measurement_report"
"mx_session_termination_req"
"mx_session_termination_rsp"
"mx_app_madp_assoc_req"
"mx_app_madp_assoc_rsp"
"mx_network_analytics_req"
"mx_network_analytics_rsp"
(c) Sequence Number: Sequence number to uniquely identify a
particular message exchange, e.g., MX Capability
Request/Response/Acknowledge.
The representation of this data type is as follows:
object {
JSONString version;
JSONString message_type;
JSONNumber sequence_num;
} MXBase;
C.2.2. Unique Session ID
This data type represents the unique session ID between a CCM and NCM
entity. It contains an NCM ID that is unique in the network and a
session ID that is allocated by the NCM for that session. On receipt
of the MX Discover message, if the session exists, then the old
session ID is returned in the MX System Info message; otherwise, the
NCM allocates a new session ID for the CCM and sends the new ID in
the MX System Info message.
The representation of this data type is as follows:
object {
JSONNumber ncm_id;
JSONNumber session_id;
} UniqueSessionId;
C.2.3. NCM Connections
This data type represents the connection available at the NCM for
MAMS connectivity toward the client. It contains a list of NCM
connections available, where each connection has the following
information:
(a) Connection Information: See Appendix C.2.4.
(b) NCM Endpoint Information: Contains the IP address and port
exposed by the NCM endpoint for the CCM.
The representation of this data type is as follows:
object {
NCMConnection items <1..*>;
} NCMConnections;
where NCMConnection is defined as:
object {
NCMEndPoint ncm_end_point;
} NCMConnection : ConnectionInfo;
where NCMEndPoint is defined as:
object {
JSONString ip_address;
JSONNumber port;
} NCMEndPoint;
C.2.4. Connection Information
This data type provides the mapping of connection ID and connection
type. It contains the following information:
(a) Connection ID: Unique number identifying the connection.
(b) Connection Type: Type of connection can be "Wi-Fi", "5G_NR",
"MulteFire", or "LTE".
The representation of this data type is as follows:
object {
JSONNumber connection_id;
JSONString connection_type;
} ConnectionInfo;
C.2.5. Features and Their Activation Status
This data type provides the list of all features with their
activation status. Each feature status contains the following:
(a) Feature Name: The name of the feature can be one of the
following:
"lossless_switching"
"fragmentation"
"concatenation"
"uplink_aggregation"
"downlink_aggregation"
"measurement"
(b) Active status: Activation status of the feature: "true" means
that the feature is active, and "false" means that the feature
is inactive.
The representation of this data type is as follows:
object {
FeatureInfo items <1..*>;
} FeaturesActive;
where FeatureInfo is defined as:
object {
JSONString feature_name;
JSONBool active;
} FeatureInfo;
C.2.6. Anchor Connections
This data type contains the list of Connection Information items
(Appendix C.2.4) that are supported on the anchor (core) side.
The representation of this data type is as follows:
object {
ConnectionInfo items <1..*>;
} AnchorConnections;
C.2.7. Delivery Connections
This data type contains the list of Connection Information
(Appendix C.2.4) that are supported on the delivery (access) side.
The representation of this data type is as follows:
object {
ConnectionInfo items <1..*>;
} DeliveryConnections;
C.2.8. Method Support
This data type provides the support for a particular convergence or
adaptation method. It consists of the following:
(a) Method: Name of the method.
(b) Supported: Whether the method listed above is supported or not.
Possible values are "true" and "false".
The representation of this data type is as follows:
object {
JSONString method;
JSONBool supported;
} MethodSupport;
C.2.9. Convergence Methods
This data type contains the list of all convergence methods and their
support status. The possible convergence methods are:
"GMA"
"MPTCP_Proxy"
"GRE_Aggregation_Proxy"
"MPQUIC"
The representation of this data type is as follows:
object {
MethodSupport items <1..*>;
} ConvergenceMethods;
C.2.10. Adaptation Methods
This data type contains the list of all adaptation methods and their
support status. The possible adaptation methods are:
"UDP_without_DTLS"
"UDP_with_DTLS"
"IPsec"
"Client_NAT"
The representation of this data type is as follows:
object {
MethodSupport items <1..*>;
} AdaptationMethods;
C.2.11. Setup of Anchor Connections
This data type represents the setup configuration for each anchor
connection that is required on the client's side. It contains the
following information, in addition to the connection ID and type of
the anchor connection:
(a) Number of Active MX Configurations: If more than one active
configuration is present for this anchor, then this identifies
the number of such connections.
(b) The following convergence parameters are provided for each
active configuration:
(1) MX Configuration ID: Present if there are multiple active
configurations. Identifies the configuration for this MADP
instance ID.
(2) Convergence Method: Convergence method selected. Has to be
one of the supported convergence methods listed in
Appendix C.2.9.
(3) Convergence Method Parameters: Described in
Appendix C.2.11.1
(4) Number of Delivery Connections: The number of delivery
connections (access side) that are supported for this
anchor connection.
(5) Setup of delivery connections: Described in
Appendix C.2.11.2.
The representation of this data type is as follows:
object {
SetupAnchorConn items <1..*>;
} SetupAnchorConns;
Where each anchor connection configuration is defined as follows:
object {
[JSONNumber num_active_mx_conf;]
ConvergenceConfig convergence_config
} SetupAnchorConn : ConnectionInfo;
where each Convergence configuration is defined as follows:
object {
[JSONNumber mx_configuration_id;]
JSONString convergence_method;
ConvergenceMethodParam convergence_method_params;
JSONNumber num_delivery_connections;
SetupDeliveryConns delivery_connections;
} ConvergenceConfig;
C.2.11.1. Convergence Method Parameters
This data type represents the parameters used for the convergence
method and contains the following:
(a) Proxy IP: IP address of the proxy that is provided by the
selected convergence method.
(b) Proxy Port: Port of the proxy that is provided by the selected
convergence method.
The representation of this data type is as follows:
object {
JSONString proxy_ip;
JSONString proxy_port;
JSONString client_key;
} ConvergenceMethodParam;
C.2.11.2. Setup Delivery Connections
This is the list of delivery connections and their parameters to be
configured on the client. Each delivery connection defined by its
connection information (Appendix C.2.4) optionally contains the
following:
(a) Adaptation Method: Selected adaptation method name. This shall
be one of the methods listed in Appendix C.2.10.
(b) Adaptation Method Parameters: Depending on the adaptation
method, one or more of the following parameters shall be
provided.
(1) Tunnel IP address
(2) Tunnel Port number
(3) Shared Secret
(4) MX header optimization: If the adaptation method is
UDP_without_DTLS or UDP_with_DTLS, and convergence is GMA,
then this flag represents whether or not the checksum field
and the length field in the IP header of an MX PDU should
be recalculated by the MX Convergence Layer. The possible
values are "true" and "false". If it is "true", both
fields remain unchanged; otherwise, both fields should be
recalculated. If this field is not present, then the
default of "false" should be considered.
The representation of this data type is as follows:
object {
SetupDeliveryConn items <1..*>;
} SetupDeliveryConns;
where each "SetupDeliveryConn" consists of the following:
object {
[JSONString adaptation_method;]
[AdaptationMethodParam adaptation_method_param;]
} SetupDeliveryConn : ConnectionInfo;
where AdaptationMethodParam is defined as:
object {
JSONString tunnel_ip_addr;
JSONString tunnel_end_port;
JSONString shared_secret;
[JSONBool mx_header_optimization;]
} AdaptationMethodParam;
C.2.12. Init Probe Results
This data type provides the results of the init probe request made by
the NCM. It consists of the following information:
(a) Lost Probes: Percentage of probes lost.
(b) Probe Delay: Average delay of probe message, in microseconds.
(c) Probe Rate: Probe rate achieved, in megabits per second.
The representation of this data type is as follows:
object {
JSONNumber lost_probes_percentage;
JSONNumber probe_rate_Mbps;
} InitProbeResults;
C.2.13. Active Probe Results
This data type provides the results of the active probe request made
by the NCM. It consists of the following information:
(a) Average Probe Throughput: Average active probe throughput
achieved, in megabits per second.
The representation of this data type is as follows:
object {
JSONNumber avg_tput_last_probe_duration_Mbps;
} ActiveProbeResults;
C.2.14. Downlink Delivery
This data type represents the list of connections that are enabled on
the delivery side to be used in the downlink direction.
The representation of this data type is as follows:
object {
JSONNumber connection_id <1..*>;
} DLDelivery;
C.2.15. Uplink Delivery
This data type represents the list of connections and parameters
enabled for the delivery side to be used in the uplink direction.
The uplink delivery consists of multiple uplink delivery entities,
where each entity consists of a Traffic Flow Template (TFT)
(Appendix C.2.16) and a list of connection IDs in the uplink, where
traffic qualifying for such a Traffic Flow Template can be
redirected.
The representation of this data type is as follows:
object {
ULDeliveryEntity ul_del <1..*>;
} ULDelivery;
Where each uplink delivery entity consists of the following data
type:
object {
TrafficFlowTemplate ul_tft <1..*>;
JSONNumber connection_id <1..*>;
} ULDeliveryEntity;
C.2.16. Traffic Flow Template
The Traffic Flow Template generally follows the guidelines specified
in [ServDesc3GPP].
The Traffic Flow Template in MAMS consists of one or more of the
following:
(a) Remote Address and Mask: IP address and subnet for remote
addresses represented in Classless Inter-Domain Routing (CIDR)
notation. Default: "0.0.0.0/0".
(b) Local Address and Mask: IP address and subnet for local
addresses represented in CIDR notation. Default: "0.0.0.0/0"
(c) Protocol Type: IP protocol number of the payload being carried
by an IP packet (e.g., UDP, TCP). Default: 255.
(d) Local Port Range: Range of ports for local ports for which the
Traffic Flow Template is applicable. Default: Start=0,
End=65535.
(e) Remote Port Range: Range of ports for remote ports for which the
Traffic Flow Template is applicable. Default: Start=0,
End=65535.
(f) Traffic Class: Represented by Type of Service in IPv4 and
Traffic Class in IPv6. Default: 255
(g) Flow Label: Flow label for IPv6, applicable only for IPv6
protocol type. Default: 0.
The representation of this data type is as follows:
object {
JSONString remote_addr_mask;
JSONString local_addr_mask;
JSONNumber protocol_type;
PortRange local_port_range;
PortRange remote_port_range;
JSONNumber traffic_class;
JSONNumber flow_label;
} TrafficFlowTemplate;
Where the port range is defined as follows:
object {
JSONNumber start;
JSONNumber end;
} PortRange;
C.2.17. Measurement Report Configuration
This data type represents the configuration done by the NCM toward
the CCM for reporting measurement events.
(a) Measurement Report Parameter: Parameter that shall be measured
and reported. This is dependent on the connection type:
(1) For the connection type of "Wi-Fi", the allowed measurement
type parameters are "WLAN_RSSI", "WLAN_LOAD", "UL_TPUT",
"DL_TPUT", "EST_UL_TPUT", and "EST_DL_TPUT".
(2) For the connection type of "LTE", the allowed measurement
type parameters are "LTE_RSRP", "LTE_RSRQ", "UL_TPUT", and
"DL_TPUT".
(3) For the connection type of "5G_NR", the allowed measurement
type parameters are "NR_RSRP", "NR_RSRQ", "UL_TPUT", and
"DL_TPUT".
(b) Threshold: High and low threshold for reporting.
(c) Period: Period for reporting, in milliseconds.
The representation of this data type is as follows:
object {
JSONString meas_rep_param;
Threshold meas_threshold;
JSONNumber meas_period;
} MeasReportConfs;
Where "Threshold" is defined as follows:
object {
JSONNumber high;
JSONNumber low;
} Threshold;
C.2.18. Measurement Report
This data type represents the measurements reported by the CCM for
each access network measured. This type contains the connection
information, the Delivery Node ID that identifies either the cell
(ECGI) or the Wi-Fi Access Point ID or MAC address (or equivalent
identifier in other technologies), and the actual measurement
performed by the CCM in the last measurement period.
The representation of this data type is as follows:
object {
JSONNumber connection_id;
JSONString connection_type;
JSONString delivery_node_id;
Measurement measurements <1..*>;
} MXMeasRep;
Where Measurement is defined as the key-value pair of the measurement
type and value. The exact measurement type parameter reported for a
given connection depends on its Connection Type. The measurement
type parameters, for each Connection Type, are specified in
Appendix C.2.17.
object {
JSONString measurement_type;
JSONNumber measurement_value;
} Measurement;
C.3. Schemas in JSON
C.3.1. MX Base Schema
{
"$schema": "https://json-schema.org/draft-04/schema#",
"definitions": {
"message_type_def": {
"enum": [
"mx_discover",
"mx_system_info",
"mx_capability_req",
"mx_capability_rsp",
"mx_capability_ack",
"mx_up_setup_conf_req",
"mx_up_setup_cnf",
"mx_reconf_req",
"mx_reconf_rsp",
"mx_path_est_req",
"mx_path_est_results",
"mx_traffic_steering_req",
"mx_traffic_steering_rsp",
"mx_ssid_indication",
"mx_keep_alive_req",
"mx_keep_alive_rsp",
"mx_measurement_conf",
"mx_measurement_report",
"mx_session_termination_req",
"mx_session_termination_rsp",
"mx_app_madp_assoc_req",
"mx_app_madp_assoc_rsp",
"mx_network_analytics_req",
"mx_network_analytics_rsp"
],
"type": "string"
},
"sequence_num_def": {
"minimum": 1,
"type": "integer"
},
"version_def": {
"type": "string"
}
},
"id": "https://example.com/mams/mx_base_def.json"
}
C.3.2. MX Definitions
{
"$schema": "https://json-schema.org/draft-04/schema#",
"definitions": {
"adapt_method": {
"enum": [
"UDP_without_DTLS",
"UDP_with_DTLS",
"IPsec",
"Client_NAT"
],
"type": "string"
},
"conv_method": {
"enum": [
"GMA",
"MPTCP_Proxy",
"GRE_Aggregation_Proxy",
"MPQUIC"
],
"type": "string"
},
"supported": {
"type": "boolean"
},
"active": {
"type": "boolean"
},
"connection_id": {
"type": "integer"
},
"feature_name": {
"enum": [
"lossless_switching",
"fragmentation",
"concatenation",
"uplink_aggregation",
"downlink_aggregation",
"measurement"
"probing"
],
"type": "string"
},
"connection_type": {
"enum": [
"Wi-Fi",
"5G_NR",
"MulteFire",
"LTE"
],
"type": "string"
},
"ip_address": {
"type": "string"
},
"port": {
"maximum": 65535,
"minimum": 1,
"type": "integer"
},
"adaptation_method": {
"allOf" : [
{ "$ref": "#/definitions/adapt_method" },
{ "$ref": "#/definitions/supported" }
]
},
"connection": {
"allOf" : [
{ "$ref": "#/definitions/connection_id" },
{ "$ref": "#/definitions/connection_type" }
]
},
"convergence_method": {
"allOf": [
{ "$ref": "#/definitions/conv_method" },
{ "$ref": "#/definitions/supported" }
]
},
"feature_status": {
"allOf": [
{ "$ref": "#/definitions/feature_name" },
{ "$ref": "#/definitions/active" }
]
},
"ncm_end_point": {
"allOf" : [
{ "$ref" : "#/definitions/ip_address" },
{ "$ref" : "#/definitions/port" }
]
},
"capability_acknowledgment" : {
"enum" : [
"MX_ACCEPT",
"MX_REJECT"
],
"type" : "string"
},
"threshold" : {
"high" : {
"type" : "integer"
},
"low" : {
"type" : "integer"
},
"type" : "object"
},
"meas_report_param" : {
"enum" : [
"WLAN_RSSI",
"WLAN_LOAD",
"LTE_RSRP",
"LTE_RSRQ",
"UL_TPUT",
"DL_TPUT",
"EST_UL_TPUT",
"EST_DL_TPUT",
"NR_RSRP",
"NR_RSRQ"
],
"type" : "string"
},
"meas_report_conf" : {
"meas_rep_param" : {
"$ref" : "#definitions/meas_report_param"
},
"meas_threshold" : {
"$ref" : "#definitions/threshold"
},
"meas_period_ms" : {
"type" : "integer"
},
"type" : "object"
},
"ssid_types" : {
"enum" : [
"ssid",
"bssid",
"hessid"
],
"type" : "string"
},
"ip_addr_mask" : {
"type" : "string",
"default" : "0.0.0.0/0"
},
"port_range" : {
"start" : {
"type" : "integer",
"default" : 0
},
"end" : {
"type" : "integer",
"default" : 65535
}
},
"traffic_flow_template" : {
"remote_addr_mask" : {
"$ref" : "#definitions/ip_addr_mask" },
"local_addr_mask" : {
"$ref" : "#definitions/ip_addr_mask" },
"protocol_type" : {
"type" : "integer",
"minimum" : 0,
"maximum" : 255
},
"local_port_range" : {
"$ref" : "#definitions/port_range" },
"remote_port_range" : {
"$ref" : "#definitions/port_range" },
"traffic_class" : {
"type" : "integer",
"default" : 255
},
"flow_label" : {
"type" : "integer",
"default" : 0
}
},
"delivery_node_id" : {
"type" : "string"
},
"unique_session_id" : {
"type" : "object",
"ncm_id" : {
"type" : "integer"
},
"session_id" : {
"type" : "integer"
}
},
"keep_alive_reason" : {
"enum" : [
"Timeout",
"Handover"
],
"type" : "string"
},
"connection_status" : {
"enum" : [
"disabled",
"enabled",
"connected"
],
"type" : "string",
"default" : "connected"
},
"adaptation_param" : {
"udp_adapt_port" : {
"type" : "integer"
}
},
"probe_param" : {
"probe_port" : {
"type" : "integer"
},
"anchor_conn_id" : {
"type" : "integer"
},
"mx_configuration_id" : {
"type" : "integer"
}
},
"client_param" : {
"connection_id" : {
"type" : "integer"
},
"adapt_param" : {
"type" : {"$ref" : "#definitions/adaptation_param" }
}
}
},
"adapt_param": {
"tunnel_ip_addr": {
"type": "string"
},
"tunnel_end_port": {
"type": "integer"
},
"shared_secret": {
"type": "string"
},
"mx_header_optimization": {
"type": "boolean",
"default": false
}
},
"delivery_connection": {
"connection_id": {
"$ref": "#definitions/connection_id"
},
"connection_type": {
"$ref": "#definitions/connection_type"
},
"adaptation_method": {
"$ref": "#definitions/adapt_method"
},
"adaptation_method_param": {
"$ref": "#definitions/adapt_param"
}
},
"app_madp_assoc": {
"anchor_conn_id" : {
"type" : "integer"
},
"mx_configuration_id" : {
"type" : "integer"
}
"ul_tft_list": {
"items": {
"$ref": "#definitions/traffic_flow_template"
},
"type": "array"
},
"dl_tft_list": {
"items": {
"$ref": "#definitions/traffic_flow_template"
},
"type": "array"
}
},
"predict_param_name": {
"enum": [
"validity_time",
"bandwidth",
"jitter",
"latency",
"signal_quality"
],
"type": "string"
},
"predict_add_param_name": {
"enum": [
"WLAN_RSSI",
"WLAN_LOAD",
"LTE_RSRP",
"LTE_RSRQ",
"NR_RSRP",
"NR_RSRQ"
],
"type": "string"
},
"id": "https://example.com/mams/definitions.json"
}
C.3.3. MX Discover
{
"$schema": "https://json-schema.org/draft-04/schema#",
"additionalProperties": false,
"id": "https://example.com/mams/mx_discover.json",
"properties": {
"message_type": {"$ref": "mx_base_def.json#/message_type_def"},
"sequence_num": {"$ref": "mx_base_def.json#/sequence_num_def"},
"version": {"$ref": "mx_base_def.json#/version_def"}
},
"type": "object"
}
C.3.4. MX System Info
{
"$schema": "https://json-schema.org/draft-04/schema#",
"additionalProperties": false,
"id": "https://example.com/mams/mx_system_info.json",
"properties": {
"message_type": {"$ref": "mx_base_def.json#/message_type_def"},
"sequence_num": {"$ref": "mx_base_def.json#/sequence_num_def"},
"version": {"$ref": "mx_base_def.json#/version_def"},
"ncm_connections": {
"type": "array",
"items": [
{"$ref": "definitions.json#/connection"},
{"$ref": "definitions.json#/ncm_end_point"}
]
}
},
"type": "object"
}
C.3.5. MX Capability Request
{
"$schema": "https://json-schema.org/draft-04/schema#",
"additionalProperties": false,
"id": "https://example.com/mams/mx_capability_req.json",
"properties": {
"message_type": {"$ref": "mx_base_def.json#/message_type_def"},
"sequence_num": {"$ref": "mx_base_def.json#/sequence_num_def"},
"version": {"$ref": "mx_base_def.json#/version_def"},
"adaptation_methods": {
"items": {"$ref": "definitions.json#/adaptation_method"},
"type": "array"
},
"anchor_connections": {
"items": {"$ref": "definitions.json#/connection"},
"type": "array"
},
"convergence_methods": {
"items": {"$ref": "definitions.json#/convergence_method"},
"type": "array"
},
"delivery_connections": {
"items": {"$ref": "definitions.json#/connection"},
"type": "array"
},
"feature_active": {
"items": {"$ref": "definitions.json#/feature_status"},
"type": "array"
},
"num_anchor_connections": {
"type": "integer"
},
"num_delivery_connections": {
"type": "integer"
}
},
"type": "object"
}
C.3.6. MX Capability Response
{
"$schema": "https://json-schema.org/draft-04/schema#",
"additionalProperties": false,
"id": "https://example.com/mams/mx_capability_rsp.json",
"properties": {
"message_type": {"$ref": "mx_base_def.json#/message_type_def"},
"sequence_num": {"$ref": "mx_base_def.json#/sequence_num_def"},
"version": {"$ref": "mx_base_def.json#/version_def"},
"adaptation_methods": {
"items": {"$ref": "definitions.json#/adaptation_method"},
"type": "array"
},
"anchor_connections": {
"items": {"$ref": "definitions.json#/connection"},
"type": "array"
},
"convergence_methods": {
"items": {"$ref": "definitions.json#/convergence_method"},
"type": "array"
},
"delivery_connections": {
"items": {"$ref": "definitions.json#/connection"},
"type": "array"
},
"feature_active": {
"items": {"$ref": "definitions.json#/feature_status"},
"type": "array"
},
"num_anchor_connections": {
"type": "integer"
},
"num_delivery_connections": {
"type": "integer"
},
"unique_session_id": {
"$ref": "definitions.json#/unique_session_id"
}
},
"type": "object"
}
C.3.7. MX Capability Acknowledge
{
"$schema": "https://json-schema.org/draft-04/schema#",
"definitions": {},
"id": "https://example.com/mams/mx_capability_ack.json",
"properties": {
"message_type": {"$ref": "mx_base_def.json#/message_type_def"},
"sequence_num": {"$ref": "mx_base_def.json#/sequence_num_def"},
"version": {"$ref": "mx_base_def.json#/version_def"},
"unique_session_id": {
"$ref": "definitions.json#/unique_session_id"},
"capability_ack": {
"$ref": "definitions.json#/capability_acknowledgment"}
},
"type": "object"
}
C.3.8. MX Reconfiguration Request
{
"$schema": "https://json-schema.org/draft-04/schema#",
"definitions": {},
"id": "https://example.com/mams/mx_reconf_req.json",
"properties": {
"message_type": {"$ref": "mx_base_def.json#/message_type_def"},
"sequence_num": {"$ref": "mx_base_def.json#/sequence_num_def"},
"version": {"$ref": "mx_base_def.json#/version_def"},
"unique_session_id": {
"$ref": "definitions.json#/unique_session_id"
},
"connection_id": {"$ref": "definitions.json#/connection_id"},
"ip_address": {"$ref": "definitions.json#/ip_address"},
"mtu_size": {
"maximum": 65535,
"minimum": 1,
"type": "integer"
},
"ssid": {
"type": "string"
},
"reconf_action": {
"enum": [
"release",
"setup",
"update"
],
"id": "/properties/reconf_action",
"type": "string"
},
"connection_status": {
"$ref": "definitions.json#/connection_status"},
"delivery_node_id": {
"$ref": "definitions.json#/delivery_node_id"}
},
"type": "object"
}
C.3.9. MX Reconfiguration Response
{
"$schema": "https://json-schema.org/draft-04/schema#",
"definitions": {},
"id": "https://example.com/mams/mx_reconf_rsp.json",
"properties": {
"message_type": {"$ref": "mx_base_def.json#/message_type_def"},
"sequence_num": {"$ref": "mx_base_def.json#/sequence_num_def"},
"version": {"$ref": "mx_base_def.json#/version_def"}
},
"type": "object"
}
C.3.10. MX UP Setup Configuration Request
{
"$schema": "https://json-schema.org/draft-04/schema#",
"additionalProperties": false,
"definitions": {
"convergence_configuration": {
"mx_configuration_id": {"type": "integer"},
"convergence_method": {
"$ref": "definitions.json#/conv_method"},
"convergence_method_params": {
"properties": {
"proxy_ip": {"$ref": "definitions.json#/ip_address"},
"proxy_port": {"$ref": "definitions.json#/port"},
"client_key": {"$ref": "definitions.json#/client_key"}
},
"type": "object"
},
"num_delivery_connections": {
"type": "integer"
},
"delivery_connections": {
"items": {"$ref": "definitions.json#/delivery_connection"},
"type": "array"
}
}
},
"id": "https://example.com/mams/mx_up_setup_conf_req.json",
"properties": {
"message_type": {"$ref": "mx_base_def.json#/message_type_def"},
"sequence_num": {"$ref": "mx_base_def.json#/sequence_num_def"},
"version": {"$ref": "mx_base_def.json#/version_def"},
"num_anchor_connections": {
"type": "integer"
},
"anchor_connections": {
"items": {
"properties": {
"connection_id": {
"$ref": "definitions.json#/connection_id"},
"connection_type": {
"$ref": "definitions.json#/connection_type"},
"num_active_mx_conf": {"type": "integer"},
"convergence_config": {
"items": {
"$ref": "definitions/convergence_configuration"},
"type": "array"
}
},
"type": "object"
},
"type": "array"
}
},
"type": "object"
}
C.3.11. MX UP Setup Confirmation
{
"$schema": "https://json-schema.org/draft-04/schema#",
"definitions": {},
"id": "https://example.com/mams/mx_up_setup_cnf.json",
"properties": {
"message_type": {"$ref": "mx_base_def.json#/message_type_def"},
"sequence_num": {"$ref": "mx_base_def.json#/sequence_num_def"},
"version": {"$ref": "mx_base_def.json#/version_def"},
"unique_session_id": {
"$ref": "definitions.json#/unique_session_id"},
"probe_param": {"$ref": "definitions.json#/probe_param"},
"num_delivery_conn": {
"type": "integer"
},
"client_params": {
"type": "array",
"items": [
{"$ref": "definitions.json#/client_param"}
]
}
},
"type": "object"
}
C.3.12. MX Traffic Steering Request
{
"$schema": "https://json-schema.org/draft-04/schema#",
"definitions": {
"conn_list": {
"items": {"$ref": "definitions.json#/connection_id"},
"type": "array"
},
"ul_delivery": {
"ul_tft": {
"$ref": "definitions.json#/traffic_flow_template"},
"connection_list": {"$ref": "#definitions/conn_list"}
}
},
"id": "https://example.com/mams/mx_traffic_steering_req.json",
"properties": {
"message_type": {"$ref": "mx_base_def.json#/message_type_def"},
"sequence_num": {"$ref": "mx_base_def.json#/sequence_num_def"},
"version": {"$ref": "mx_base_def.json#/version_def"},
"connection_id": {"$ref": "definitions.json#/connection_id"},
"mx_configuration_id": {"type": "integer"},
"downlink_delivery": {
"items": {"$ref": "definitions.json#/connection_id"},
"type": "array"
},
"feature_active": {
"items": {"$ref": "definitions.json#/feature_status"},
"type": "array"
},
"default_uplink_delivery": {
"type": "integer"
},
"uplink_delivery": {
"items": {"$ref": "#definitions/ul_delivery"},
"type": "array"
}
},
"type": "object"
}
C.3.13. MX Traffic Steering Response
{
"$schema": "https://json-schema.org/draft-04/schema#",
"definitions": {},
"id": "https://example.com/example.json",
"properties": {
"message_type": {"$ref": "mx_base_def.json#/message_type_def"},
"sequence_num": {"$ref": "mx_base_def.json#/sequence_num_def"},
"version": {"$ref": "mx_base_def.json#/version_def"},
"unique_session_id": {
"$ref": "definitions.json#/unique_session_id"},
"feature_active": {
"items": {"$ref": "definitions.json#/feature_status"},
"type": "array"
}
},
"type": "object"
}
C.3.14. MX Application MADP Association Request
{
"$schema": "https://json-schema.org/draft-04/schema#",
"definitions": {},
"id": "https://example.com/example.json",
"properties": {
"message_type": {"$ref": "mx_base_def.json#/message_type_def"},
"sequence_num": {"$ref": "mx_base_def.json#/sequence_num_def"},
"version": {"$ref": "mx_base_def.json#/version_def"},
"unique_session_id": {
"$ref": "definitions.json#/unique_session_id"},
"app_madp_assoc_list": {
"items": {
"$ref": "definitions.json#/app_madp_assoc"
},
"type": "array"
}
},
"type": "object"
}
C.3.15. MX Application MADP Association Response
{
"$schema": "https://json-schema.org/draft-04/schema#",
"definitions": {},
"id": "https://example.com/example.json",
"properties": {
"message_type": {"$ref": "mx_base_def.json#/message_type_def"},
"sequence_num": {"$ref": "mx_base_def.json#/sequence_num_def"},
"version": {"$ref": "mx_base_def.json#/version_def"},
"unique_session_id": {
"$ref": "definitions.json#/unique_session_id"},
"is_success": {
"type": "boolean"
}
},
"type": "object"
}
C.3.16. MX Path Estimation Request
{
"$schema": "https://json-schema.org/draft-04/schema#",
"definitions": {},
"id": "https://example.com/mams/mx_path_est_req.json",
"properties": {
"message_type": {"$ref": "mx_base_def.json#/message_type_def"},
"sequence_num": {"$ref": "mx_base_def.json#/sequence_num_def"},
"version": {"$ref": "mx_base_def.json#/version_def"},
"active_probe_ack_req": {
"enum": [
"no",
"yes"
],
"type": "string"
},
"active_probe_freq_ms": {
"maximum": 10000,
"minimum": 100,
"type": "integer"
},
"active_probe_size_bytes": {
"maximum": 1500,
"minimum": 100,
"type": "integer"
},
"active_probe_duration_sec": {
"maximum": 100,
"minimum": 10,
"type": "integer"
},
"connection_id": {"$ref": "definitions#/connection_id"},
"init_probe_ack_req": {
"enum": [
"no",
"yes"
],
"type": "string"
},
"init_probe_size_bytes": {
"maximum": 1500,
"minimum": 100,
"type": "integer"
},
"init_probe_test_duration_ms": {
"maximum": 10000,
"minimum": 100,
"type": "integer"
},
"init_probe_test_rate_Mbps": {
"maximum": 100,
"minimum": 1,
"type": "integer"
}
},
"type": "object"
}
C.3.17. MX Path Estimation Results
{
"$schema": "https://json-schema.org/draft-04/schema#",
"definitions": {},
"id": "https://example.com/mams/mx_path_est_results.json",
"properties": {
"message_type": {"$ref": "mx_base_def.json#/message_type_def"},
"sequence_num": {"$ref": "mx_base_def.json#/sequence_num_def"},
"version": {"$ref": "mx_base_def.json#/version_def"},
"unique_session_id": {
"$ref": "definitions.json#/unique_session_id"},
"active_probe_results": {
"properties": {
"avg_tput_last_probe_duration_Mbps": {
"maximum":100,
"minimum": 1,
"type": "number"
}
},
"type": "object"
},
"connection_id": {"$ref": "definitions.json#/connection_id"},
"init_probe_results": {
"properties": {
"lost_probes_percentage": {
"maximum": 100,
"minimum": 1,
"type": "integer"
},
"probe_rate_Mbps": {
"maximum": 100,
"minimum": 1,
"type": "number"
}
},
"type": "object"
}
},
"type": "object"
}
C.3.18. MX SSID Indication
{
"$schema": "https://json-schema.org/draft-04/schema#",
"definitions": {},
"id": "https://example.com/mams/mx_ssid_indication.json",
"properties": {
"message_type": {"$ref": "mx_base_def.json#/message_type_def"},
"sequence_num": {"$ref": "mx_base_def.json#/sequence_num_def"},
"version": {"$ref": "mx_base_def.json#/version_def"},
"ssid_list": {
"items": {
"properties": {
"ssid_type": {
"$ref": "definitions.json#/ssid_types"},
"ssid_id": {
"type": "integer"
}
}
},
"type": "array"
}
},
"type": "object"
}
C.3.19. MX Measurement Configuration
{
"$schema": "https://json-schema.org/draft-04/schema#",
"additionalProperties": false,
"definitions": {
"meas_conf": {
"connection_id" : {
"$ref": "definitions.json#/connection_id"},
"connection_type": {
"$ref": "definitions.json#/connection_type"},
"meas_rep_conf": {
"items": {
"$ref": "definitions.json#/meas_report_conf"},
"type": "array"
}
}
},
"id": "https://example.com/mams/mx_measurement_conf.json",
"properties": {
"message_type": {"$ref": "mx_base_def.json#/message_type_def"},
"sequence_num": {"$ref": "mx_base_def.json#/sequence_num_def"},
"version": {"$ref": "mx_base_def.json#/version_def"},
"measurement_configuration": {
"items": {"$ref": "#definitions/meas_conf"},
"type": "array"
}
},
"type": "object"
}
C.3.20. MX Measurement Report
{
"$schema": "https://json-schema.org/draft-04/schema#",
"definitions": {},
"id": "https://example.com/mams/mx_measurement_report.json",
"properties": {
"message_type": {"$ref": "mx_base_def.json#/message_type_def"},
"sequence_num": {"$ref": "mx_base_def.json#/sequence_num_def"},
"version": {"$ref": "mx_base_def.json#/version_def"},
"unique_session_id": {
"$ref": "definitions.json#/unique_session_id"},
"measurement_reports": {
"items": {
"properties": {
"connection_id": {
"$ref": "definitions.json#/connection_id"},
"connection_type": {
"$ref": "definitions.json#/connection_type"},
"delivery_node_id": {
"$ref": "definitions.json#/delivery_node_id"},
"measurements": {
"items": {
"properties": {
"measurement_type": {
"$ref": "definitions.json#/meas_report_param"},
"measurement_value": {
"type": "integer"
}
},
"type": "object"
},
"type": "array"
}
},
"type": "object"
},
"type": "array"
}
},
"type": "object"
}
C.3.21. MX Keep-Alive Request
{
"$schema": "https://json-schema.org/draft-04/schema#",
"additionalProperties": false,
"id": "https://example.com/mams/mx_keep_alive_req.json",
"properties": {
"message_type": {"$ref": "mx_base_def.json#/message_type_def"},
"sequence_num": {"$ref": "mx_base_def.json#/sequence_num_def"},
"version": {"$ref": "mx_base_def.json#/version_def"},
"keep_alive_reason": {
"$ref": "definitions.json#/keep_alive_reason"},
"unique_session_id": {
"$ref": "definitions.json#/unique_session_id"},
"connection_id": {
"$ref": "definitions.json#/connection_id"},
"delivery_node_id": {
"$ref": "definitions.json#/connection_id"}
},
"type": "object"
}
C.3.22. MX Keep-Alive Response
{
"$schema": "https://json-schema.org/draft-04/schema#",
"additionalProperties": false,
"id": "https://example.com/mams/mx_keep_alive_rsp.json",
"properties": {
"message_type": {"$ref": "mx_base_def.json#/message_type_def"},
"sequence_num": {"$ref": "mx_base_def.json#/sequence_num_def"},
"version": {"$ref": "mx_base_def.json#/version_def"},
"unique_session_id": {
"$ref": "definitions.json#/unique_session_id"}
},
"type": "object"
}
C.3.23. MX Session Termination Request
{
"$schema": "https://json-schema.org/draft-04/schema#",
"additionalProperties": false,
"id": "https://example.com/mams/mx_keep_alive_req.json",
"properties": {
"message_type": {"$ref": "mx_base_def.json#/message_type_def"},
"sequence_num": {"$ref": "mx_base_def.json#/sequence_num_def"},
"version": {"$ref": "mx_base_def.json#/version_def"},
"unique_session_id": {
"$ref": "definitions.json#/unique_session_id"},
"reason": {
"enum": [
"MX_NORMAL_RELEASE",
"MX_NO_RESPONSE",
"INTERNAL_ERROR"
],
"type": "string"
}
},
"type": "object"
}
C.3.24. MX Session Termination Response
{
"$schema": "https://json-schema.org/draft-04/schema#",
"additionalProperties": false,
"id": "https://example.com/mams/mx_session_termination_rsp.json",
"properties": {
"message_type": {"$ref": "mx_base_def.json#/message_type_def"},
"sequence_num": {"$ref": "mx_base_def.json#/sequence_num_def"},
"version": {"$ref": "mx_base_def.json#/version_def"},
"unique_session_id": {
"$ref": "definitions.json#/unique_session_id"}
},
"type": "object"
}
C.3.25. MX Network Analytics Request
{
"$schema": "https://json-schema.org/draft-04/schema#",
"additionalProperties": false,
"id": "https://example.com/mams/mx_network_analytics_req.json",
"properties": {
"message_type": {"$ref": "mx_base_def.json#/message_type_def"},
"sequence_num": {"$ref": "mx_base_def.json#/sequence_num_def"},
"version": {"$ref": "mx_base_def.json#/version_def"},
"unique_session_id": {
"$ref": "definitions.json#/unique_session_id"},
"params": {
"items": {
"$ref": "definitions.json#/predict_param_name"},
"type": "array"
}
},
"type": "object"
}
C.3.26. MX Network Analytics Response
{
"$schema": "https://json-schema.org/draft-04/schema#",
"additionalProperties": false,
"definitions": {
"ParamPredictions": {
"param_name": {
"$ref": "definitions.json#/predict_param_name"},
"additional_param": {
"$ref": "definitions.json#/predict_add_param_name"},
"prediction": {"type": "integer"},
"likelihood": {"type": "integer"},
"validity_time": {"type": "integer"}
},
"MXAnalyticsList": {
"connection_id": {
"$ref": "definitions.json#/connection_id"},
"connection_type": {
"$ref": "definitions.json#/connection_type"},
"predictions": {
"items": {
"$ref": "#definitions/ParamPredictions"},
"type": "array"
}
}
},
"id": "https://example.com/mams/mx_network_analytics_rsp.json",
"properties": {
"message_type": {"$ref": "mx_base_def.json#/message_type_def"},
"sequence_num": {"$ref": "mx_base_def.json#/sequence_num_def"},
"version": {"$ref": "mx_base_def.json#/version_def"},
"param_list": {
"items": {
"$ref": "#definitions/MXAnalyticsList"},
"type": "array"}
},
"type": "object"
}
C.4. Examples in JSON
C.4.1. MX Discover
{
"version" : "1.0",
"message_type" : "mx_discover",
"sequence_num" : 1
}
C.4.2. MX System Info
{
"version" : "1.0",
"message_type" : "mx_system_info",
"sequence_num" : 2,
"ncm_connections" : [
{
"connection_id" : 0,
"connection_type" : "LTE",
"ncm_end_point" : {
"ip_address" : "192.168.1.10",
"port" : 1234
}
},
{
"connection_id" : 1,
"connection_type" : "Wi-Fi",
"ncm_end_point" : {
"ip_address" : "192.168.1.10",
"port" : 1234
}
}
]
}
C.4.3. MX Capability Request
{
"version" : "1.0",
"message_type" : "mx_capability_req",
"sequence_num" : 3,
"feature_active" : [
{
"feature_name" : "lossless_switching",
"active" : true
},
{
"feature_name" : "fragmentation",
"active" : false
}
],
"num_anchor_connections" : 2,
"anchor_connections" : [
{
"connection_id" : 0,
"connection_type" : "LTE"
},
{
"connection_id" : 1,
"connection_type" : "Wi-Fi"
}
],
"num_delivery_connections" : 2,
"delivery_connections" : [
{
"connection_id" : 0,
"connection_type" : "LTE"
},
{
"connection_id" : 1,
"connection_type" : "Wi-Fi"
}
],
"convergence_methods" : [
{
"method" : "GMA",
"supported" : true
},
{
"method" : "MPTCP_Proxy",
"supported" : false
}
],
"adaptation_methods" : [
{
"method" : "UDP_without_DTLS",
"supported" : false
},
{
"method" : "UDP_with_DTLS",
"supported" : false
},
{
"method" : "IPsec",
"supported" : true
},
{
"method" : "Client_NAT",
"supported" : false
}
]
}
C.4.4. MX Capability Response
{
"version" : "1.0",
"message_type" : "mx_capability_rsp",
"sequence_num" : 3,
"feature_active" : [
{
"feature_name" : "lossless_switching",
"active" : true
},
{
"feature_name" : "fragmentation",
"active" : false
}
],
"num_anchor_connections" : 2,
"anchor_connections" : [
{
"connection_id" : 0,
"connection_type" : "LTE"
},
{
"connection_id" : 1,
"connection_type" : "Wi-Fi"
}
],
"num_delivery_connections" : 2,
"delivery_connections" : [
{
"connection_id" : 0,
"connection_type" : "LTE"
},
{
"connection_id" : 1,
"connection_type" : "Wi-Fi"
}
],
"convergence_methods" : [
{
"method" : "GMA",
"supported" : true
},
{
"method" : "MPTCP_Proxy",
"supported" : false
}
],
"adaptation_methods" : [
{
"method" : "UDP_without_DTLS",
"supported" : false
},
{
"method" : "UDP_with_DTLS",
"supported" : false
},
{
"method" : "IPsec",
"supported" : true
},
{
"method" : "Client_NAT",
"supported" : false
}
],
"unique_session_id" : {
"ncm_id" : 110,
"session_id" : 1111
}
}
C.4.5. MX Capability Acknowledge
{
"version" : "1.0",
"message_type" : "mx_capability_ack",
"sequence_num" : 3,
"unique_session_id" : {
"ncm_id" : 110,
"session_id" : 1111
},
"capability_ack" : "MX_ACCEPT"
}
C.4.6. MX Reconfiguration Request
{
"version" : "1.0",
"message_type" : "mx_reconf_req",
"sequence_num" : 4,
"unique_session_id" : {
"ncm_id" : 110,
"session_id" : 1111
},
"reconf_action" : "setup",
"connection_id" : 0,
"ip_address" : "192.168.110.1",
"ssid" : "SSID_1",
"mtu_size" : 1300,
"connection_status" : "connected",
"delivery_node_id" : "2A12C"
}
C.4.7. MX Reconfiguration Response
{
"version" : "1.0",
"message_type" : "mx_reconf_rsp",
"sequence_num" : 4
}
C.4.8. MX UP Setup Configuration Request
{
"version": "1.0",
"message_type": "mx_up_setup_conf_req",
"sequence_num": 5,
"num_anchor_connections": 2,
"anchor_connections": [{
"connection_id": 1,
"connection_type": "Wi-Fi",
"num_active_mx_conf" : 2,
"convergence_config" : [
{
"mx_configuration_id" : 1,
"convergence_method": "GMA",
"convergence_method_params": {},
"num_delivery_connections": 2,
"delivery_connections": [{
"connection_id": 0,
"connection_type": "LTE",
"adaptation_method": "UDP_without_DTLS",
"adaptation_method_param": {
"tunnel_ip_addr": "6.6.6.6",
"tunnel_end_port": 9999,
"mx_header_optimization": true
}
},
{
"connection_id": 1,
"connection_type": "Wi-Fi"
}
]
},
{
"mx_configuration_id" : 2,
"convergence_method": "GMA",
"convergence_method_params": {},
"num_delivery_connections": 1,
"delivery_connections": [{
"connection_id": 0,
"connection_type": "LTE",
"adaptation_method": "UDP_without_DTLS",
"adaptation_method_param": {
"tunnel_ip_addr": "6.6.6.6",
"tunnel_end_port": 8877
}
}
]
}
]
},
{
"connection_id": 0,
"connection_type": "LTE",
"udp_port": 8888,
"num_delivery_connections": 2,
"delivery_connections": [{
"connection_id": 0,
"connection_type": "LTE"
},
{
"connection_id": 1,
"connection_type": "Wi-Fi",
"adaptation_method": "UDP_without_DTLS",
"adaptation_method_param": {
"tunnel_ip_addr": "192.168.3.3",
"tunnel_end_port": "6000"
}
}
]
}
]
}
C.4.9. MX UP Setup Confirmation
{
"version" : "1.0",
"message_type" : "mx_up_setup_cnf",
"sequence_num" : 5,
"unique_session_id" : {
"ncm_id" : 110,
"session_id" : 1111
},
"probe_param" : {
"probe_port" : 48700,
"anchor_conn_id" : 0,
"mx_configuration_id" : 1
},
"num_delivery_conn" : 2,
"client_params" : [
{
"connection_id" : 0,
"adapt_param" : {
"udp_adapt_port" : 51000
}
},
{
"connection_id" : 1,
"adapt_param" : {
"udp_adapt_port" : 52000
}
}
]
}
C.4.10. MX Traffic Steering Request
{
"version" : "1.0",
"message_type" : "mx_traffic_steering_req",
"sequence_num" : 6,
"connection_id" : 0,
"mx_configuration_id" : 1,
"downlink_delivery" : [
{
"connection_id" : 0
},
{
"connection_id" : 1
}
],
"default_uplink_delivery" : 0,
"uplink_delivery" : [
{
"ul_tft" : {
"remote_addr_mask" : "10.10.0.0/24",
"local_addr_mask" : "192.168.0.0/24",
"protocol_type" : 6,
"local_port_range" : {
"start" : 100,
"end" : 1000
},
"remote_port_range" : {
"start" : 100,
"end" : 1000
},
"traffic_class" : 20,
"flow_label" : 100
},
"conn_list" : [
{
"connection_id" : 1
}
]
},
{
"ul_tft" : {
"remote_addr_mask" : "10.10.0.0/24",
"local_addr_mask" : "192.168.0.0/24",
"protocol_type" : 6,
"local_port_range" : {
"start" : 2000,
"end" : 2000
},
"remote_port_range" : {
"start" : 100,
"end" : 1000
},
"traffic_class" : 20,
"flow_label" : 50
},
"conn_list" : [
{
"connection_id" : 1
}
]
}
],
"feature_active" : [
{
"feature_name" : "dl_aggregation",
"active" : true
},
{
"feature_name" : "ul_aggregation",
"active" : false
}
]
}
C.4.11. MX Traffic Steering Response
{
"version": "1.0",
"message_type": "mx_traffic_steering_rsp",
"sequence_num": 6,
"unique_session_id": {
"ncm_id": 110,
"session_id": 1111
},
"feature_active": [{
"feature_name": "lossless_switching",
"active": true
},
{
"feature_name": "fragmentation",
"active": false
}
]
}
C.4.12. MX Application MADP Association Request
{
"version": "1.0",
"message_type": "mx_app_madp_assoc_req",
"sequence_num": 6,
"unique_session_id": {
"ncm_id": 110,
"session_id": 1111
},
"app_madp_assoc_list": [{
"connection_id" : 0,
"mx_configuration_id" : 1,
"ul_tft_list": [{
"protocol_type": 17,
"local_port_range": {
"start": 8888,
"end": 8888
}
}],
"dl_tft_list": [{
"protocol_type": 17,
"remote_port_range": {
"start": 8888,
"end": 8888
}
}]
}
]
}
C.4.13. MX Application MADP Association Response
{
"version": "1.0",
"message_type": "mx_app_madp_assoc_rsp",
"sequence_num": 6,
"is_success": true
}
C.4.14. MX Path Estimation Request
{
"version" : "1.0",
"message_type" : "mx_path_est_req",
"sequence_num" : 7,
"connection_id" : 0,
"init_probe_test_duration_ms" : 100,
"init_probe_test_rate_Mbps" : 10,
"init_probe_size_bytes" : 1000,
"init_probe_ack_req" : "yes",
"active_probe_freq_ms" : 10000,
"active_probe_size_bytes" : 1000,
"active_probe_duration_sec" : 10,
"active_probe_ack_req" : "no"
}
C.4.15. MX Path Estimation Results
{
"version" : "1.0",
"message_type" : "mx_path_est_results",
"sequence_num" : 8,
"unique_session_id" : {
"ncm_id" : 110,
"session_id" : 1111
},
"connection_id" : 0,
"init_probe_results" : {
"lost_probes_percentage" : 1,
"probe_rate_Mbps" : 9.9
},
"active_probe_results" : {
"avg_tput_last_probe_duration_Mbps" : 9.8
}
}
C.4.16. MX SSID Indication
{
"version" : "1.0",
"message_type" : "mx_ssid_indication",
"sequence_num" : 9,
"ssid_list" : [
{
"ssid_type" : "ssid",
"ssid_id" : "SSID_1"
},
{
"ssid_type" : "bssid",
"ssid_id" : "xxx-yyy"
}
]
}
C.4.17. MX Measurement Configuration
{
"version" : "1.0",
"message_type" : "mx_measurement_conf",
"sequence_num" : 10,
"measurement_configuration" : [
{
"connection_id" : 0,
"connection_type" : "Wi-Fi",
"meas_rep_conf" : [
{
"meas_rep_param" : "WLAN_RSSI",
"meas_threshold" : {
"high" : -10,
"low" : -15
},
"meas_period_ms" : 500
},
{
"meas_rep_param" : "WLAN_LOAD",
"meas_threshold" : {
"high" : -10,
"low" : -15
},
"meas_period_ms" : 500
},
{
"meas_rep_param" : "EST_UL_TPUT",
"meas_threshold" : {
"high" : 100,
"low" : 30
},
"meas_period_ms" : 500
}
]
},
{
"connection_id" : 1,
"connection_type" : "LTE",
"meas_rep_conf" : [
{
"meas_rep_param" : "LTE_RSRP",
"meas_threshold" : {
"high" : -10,
"low" : -15
},
"meas_period_ms" : 500
},
{
"meas_rep_param" : "LTE_RSRQ",
"meas_threshold" : {
"high" : -10,
"low" : -15
},
"meas_period_ms" : 500
}
]
}
]
}
C.4.18. MX Measurement Report
{
"version" : "1.0",
"message_type" : "mx_measurement_report",
"sequence_num" : 11,
"unique_session_id" : {
"ncm_id" : 110,
"session_id" : 1111
},
"measurement_reports" : [
{
"connection_id" : 0,
"connection_type" : "Wi-Fi",
"delivery_node_id" : "2021A",
"measurements" : [
{
"measurement_type" : "WLAN_RSSI",
"measurement_value" : -12
},
{
"measurement_type" : "UL_TPUT",
"measurement_value" : 10
},
{
"measurement_type" : "EST_UL_TPUT",
"measurement_value" : 20
}
]
},
{
"connection_id" : 1,
"connection_type" : "LTE",
"delivery_node_id" : "12323",
"measurements" : [
{
"measurement_type" : "LTE_RSRP",
"measurement_value" : -12
},
{
"measurement_type" : "LTE_RSRQ",
"measurement_value" : -12
}
]
}
]
}
C.4.19. MX Keep-Alive Request
{
"version" : "1.0",
"message_type" : "mx_keep_alive_req",
"sequence_num" : 12,
"keep_alive_reason" : "Handover",
"unique_session_id" : {
"ncm_id" : 110,
"session_id" : 1111
},
"connection_id" : 0,
"delivery_node_id" : "2021A"
}
C.4.20. MX Keep-Alive Response
{
"version" : "1.0",
"message_type" : "mx_keep_alive_rsp",
"sequence_num" : 12,
"unique_session_id" : {
"ncm_id" : 110,
"session_id" : 1111
}
}
C.4.21. MX Session Termination Request
{
"version" : "1.0",
"message_type" : "mx_session_termination_req",
"sequence_num" : 13,
"unique_session_id" : {
"ncm_id" : 110,
"session_id" : 1111
},
"reason" : "MX_NORMAL_RELEASE"
}
C.4.22. MX Session Termination Response
{
"version" : "1.0",
"message_type" : "mx_session_termination_rsp",
"sequence_num" : 13,
"unique_session_id" : {
"ncm_id" : 110,
"session_id" : 1111
}
}
C.4.23. MX Network Analytics Request
{
"version" : "1.0",
"message_type" : "mx_network_analytics_req",
"sequence_num" : 20,
"unique_session_id" : {
"ncm_id" : 110,
"session_id" : 1111
},
"params" : [
"jitter",
"latency"
]
}
C.4.24. MX Network Analytics Response
{
"version": "1.0",
"message_type": "mx_network_analytics_rsp",
"sequence_num": 20,
"param_list": [{
"connection_id": 1,
"connection_type": "Wi-Fi",
"predictions": [{
"param_name": "jitter",
"prediction": 100,
"likelihood": 50,
"validity_time": 10
},
{
"param_name": "latency",
"prediction": 19,
"likelihood": 40,
"validity_time": 10
}
]
},
{
"connection_id": 2,
"connection_type": "LTE",
"predictions": [{
"param_name": "jitter",
"prediction": 10,
"likelihood": 80,
"validity_time": 10
},
{
"param_name": "latency",
"prediction": 4,
"likelihood": 60,
"validity_time": 10
}
]
}
]
}
Appendix D. Definition of APIs Provided by the CCM to the Applications
at the Client
This section provides an example implementation of the APIs exposed
by the CCM to the applications on the client, documented with OpenAPI
using Swagger 2.0.
{
"swagger": "2.0",
"info": {
"version": "1.0.0",
"title": "Client Connection Manager (CCM)",
"description": "API provided by the CCM towards the application
on a MAMS client."
},
"host": "MAMS.ietf.org",
"basePath": "/ccm/v1.0",
"schemes": [
"https"
],
"consumes": [
"application/json"
],
"produces": [
"application/json"
],
"paths": {
"/capabilities": {
"get": {
"description": "This API can be used by an application to
request the capabilities of the CCM.",
"produces": [
"application/json",
"text/html"
],
"responses": {
"200": {
"description": "OK",
"schema": {
"$ref": "#/definitions/capability"
}
},
"default": {
"description": "unexpected error",
"schema": {
"$ref": "#/definitions/errorModel"
}
}
}
}
},
"/app_requirements": {
"post": {
"description": "This API is used by the N-MADP to report
any types of MAMS user-specific errors to
the NCM.",
"produces": [
"application/json",
"text/html"
],
"parameters": [
{
"name": "app-requirements",
"in": "body",
"required": true,
"schema": {
"$ref": "#/definitions/app-requirements"
}
}
],
"responses": {
"200": {
"description": "OK"
},
"default": {
"description": "unexpected error",
"schema": {
"$ref": "#/definitions/errorModel"
}
}
}
}
},
"/predictive_link_params": {
"get": {
"description": "This API is used by applications to get the
information about predicted parameters for
each delivery connection.",
"produces": [
"application/json",
"text/html"
],
"responses": {
"200": {
"description": "OK",
"schema": {
"$ref": "#/definitions/link-params"
}
},
"default": {
"description": "unexpected error",
"schema": {
"$ref": "#/definitions/errorModel"
}
}
}
}
}
},
"definitions": {
"connection-id": {
"type": "integer",
"format": "uint8"
},
"connection-type": {
"enum": [
"Wi-Fi",
"5G_NR",
"MulteFire",
"LTE"
],
"type": "string"
},
"features": {
"enum": [
"lossless_switching",
"fragmentation",
"concatenation",
"uplink_aggregation",
"downlink_aggregation",
"measurement"
"probing"
],
"type": "string"
},
"adaptation-methods": {
"enum": [
"UDP_without_DTLS",
"UDP_with_DTLS",
"IPsec",
"Client_NAT"
],
"type": "string"
},
"convergence-methods": {
"enum": [
"GMA",
"MPTCP_Proxy",
"GRE_Aggregation_Proxy",
"MPQUIC"
],
"type": "string"
},
"connection": {
"type": "object",
"properties": {
"conn-id": {
"$ref": "#/definitions/connection-id"
},
"conn-type": {
"$ref": "#/definitions/connection-type"
}
}
},
"convergence-parameters": {
"type": "object",
"properties": {
"conv-param-name": {
"type": "string"
},
"conv-param-value": {
"type": "string"
}
}
},
"convergence-details": {
"type": "object",
"properties": {
"conv-method": {
"$ref": "#/definitions/convergence-methods"
},
"conv-params": {
"type": "array",
"items": {
"$ref": "#/definitions/convergence-parameters"
}
}
}
},
"capability": {
"type": "object",
"properties": {
"connections": {
"type": "array",
"items": {
"$ref": "#/definitions/connection"
}
},
"features": {
"type": "array",
"items": {
"$ref": "#/definitions/features"
}
},
"adapt-methods": {
"type": "array",
"items": {
"$ref": "#/definitions/adaptation-methods"
}
},
"conv-methods": {
"type": "array",
"items": {
"$ref": "#/definitions/convergence-details"
}
}
}
},
"qos-param-name": {
"enum": [
"jitter",
"latency",
"bandwidth"
],
"type": "string"
},
"qos-param": {
"type": "object",
"properties": {
"qos-param-name": {
"$ref": "#/definitions/qos-param-name"
},
"qos-param-value": {
"type": "integer"
}
}
},
"port-range": {
"type": "object",
"properties": {
"start": {
"type": "integer"
},
"end": {
"type": "integer"
}
}
},
"protocol-type": {
"type": "integer"
},
"stream-features": {
"type": "object",
"properties": {
"proto": {
"$ref": "#/definitions/protocol-type"
},
"port-range": {
"$ref": "#/definitions/port-range"
},
"traffic-qos": {
"$ref": "#/definitions/qos-param"
}
}
},
"app-requirements": {
"type": "object",
"properties": {
"num-streams": {
"type": "integer"
},
"stream-feature": {
"type": "array",
"items": {
"$ref": "#/definitions/stream-features"
}
}
}
},
"param-name": {
"enum": [
"bandwidth",
"jitter",
"latency",
"signal_quality"
],
"type": "string"
},
"additional-param-name": {
"enum": [
"lte-rsrp",
"lte-rsrq",
"nr-rsrp",
"nr-rsrq",
"wifi-rssi"
],
"type": "string"
},
"link-parameter": {
"type": "object",
"properties": {
"connection": {
"$ref": "#/definitions/connection"
},
"param": {
"$ref": "#/definitions/param-name"
},
"additional-param": {
"$ref": "#/definitions/additional-param-name"
},
"prediction": {
"type": "integer"
},
"likelihood": {
"type": "integer"
},
"validity_time": {
"type": "integer"
}
}
},
"link-params": {
"type": "array",
"items": {
"$ref": "#/definitions/link-parameter"
}
},
"errorModel": {
"type": "object",
"description": "Error indication containing the error code and
message.",
"required": [
"code",
"message"
],
"properties": {
"code": {
"type": "integer",
"format": "int32"
},
"message": {
"type": "string"
}
}
}
}
}
Appendix E. Implementation Example Using Python for MAMS Client and
Server
E.1. Client-Side Implementation
A simple client-side implementation using Python can be as follows:
#!/usr/bin/env python
import asyncio
import websockets
import json
import ssl
import time
import sys
context = ssl.SSLContext(ssl.PROTOCOL_TLS)
context.verify_mode = ssl.CERT_REQUIRED
context.set_ciphers("RSA")
context.check_hostname = False
context.load_verify_locations("/home/mecadmin/certs/rootca.pem")
discoverMsg = {'version':'1.0',
'message_type':'mx_discover'}
MXCapabilityRes = {'version':'1.0',
'message_type':'mx_capability_res',
'FeatureActive':[{'feature_name':'fragmentation', 'active':'yes'},
{'feature_name':'lossless_switching', 'active':'yes'}],
'num_anchor_connections':1,
'anchor_connections':[{'connection_id':0, 'connection_type':'LTE'}],
'num_delivery_connections':1,
'delivery_connections':[{'connection_id':1,
'connection_type':"Wi-Fi"}],
'convergence_methods':[{'method':'GMA', 'supported':'true'}],
'adaptation_methods':[{'method':'client_nat', 'supported':'false'}]
}
async def hello():
async with websockets.connect('wss://localhost:8765',
ssl=context) as websocket:
try:
loopFlag=False
while True:
await websocket.send(json.dumps(discoverMsg))
json_message = await websocket.recv()
message = json.loads(json_message)
if "message_type" in message.keys():
print("Received message:{}".format(
message["message_type"]),
"version:{}".format(message["version"]))
if message["message_type"] == "mx_capability_req" :
await websocket.send(json.dumps(MXCapabilityRes))
loopFlag=True
while(loopFlag==True):
pass
except:
print("Client stopped")
asyncio.get_event_loop().run_until_complete(hello())
E.2. Server-Side Implementation
A server-side implementation using Python can be as follows:
#!/usr/bin/env python
import asyncio
import websockets
import json
import ssl
ctx = ssl.SSLContext(ssl.PROTOCOL_TLS)
#ctx.set_ciphers("RSA-AES256-SHA")
ctx.load_verify_locations("/home/mecadmin/certs/rootca.pem")
certfile = "/home/mecadmin/certs/server.pem"
keyfile = "/home/mecadmin/certs/serverkey.pem"
ctx.load_cert_chain(certfile, keyfile, password=None)
MXCapabilityReq = {'version':'1.0',
'message_type':'mx_capability_req',
'FeatureActive':[{'feature_name':'fragmentation', 'active':'yes'},
{'feature_name':'lossless_switching', 'active':'yes'}],
'num_anchor_connections':1,
'anchor_connections':[{'connection_id':0, 'connection_type':'LTE'}],
'num_delivery_connections':1,
'delivery_connections':[{'connection_id':1,
'connection_type':"Wi-Fi"}],
'convergence_methods':[{'method':'GMA', 'supported':'true'}],
'adaptation_methods':[{'method':'client_nat', 'supported':'false'}]
}
async def hello(websocket, path):
try:
while True:
name = await websocket.recv()
msg = json.loads(name)
if "message_type" in msg.keys():
print("Received message:{}".format(msg["message_type"]),
"version:{}".format(msg["version"]))
if msg['message_type'] == 'mx_discover':
await websocket.send(json.dumps(MXCapabilityReq))
except:
print("Client disconnected")
try:
start_server = websockets.serve(hello, 'localhost', 8765,ssl=ctx)
asyncio.get_event_loop().run_until_complete(start_server)
asyncio.get_event_loop().run_forever()
except:
print("Server stopped")
Acknowledgments
This protocol is the outcome of work by many engineers, not just the
authors of this document. The people who contributed to this
project, listed in alphabetical order by first name, are Barbara
Orlandi, Bongho Kim, David Lopez-Perez, Doru Calin, Jonathan Ling,
Lohith Nayak, and Michael Scharf.
Contributors
The authors gratefully acknowledge the following additional
contributors, in alphabetical order by first name: A Krishna Pramod/
Nokia Bell Labs, Hannu Flinck/Nokia Bell Labs, Hema Pentakota/Nokia,
Julius Mueller/AT&T, Nurit Sprecher/Nokia, Salil Agarwal/Nokia,
Shuping Peng/Huawei, and Subramanian Vasudevan/Nokia Bell Labs.
Subramanian Vasudevan has been instrumental in conceptualization and
development of solution principles for the MAMS framework. Shuping
Peng has been a key contributor in refining the framework and
control-plane protocol aspects.
Authors' Addresses
Satish Kanugovi
Nokia Bell Labs
Email: satish.k@nokia-bell-labs.com
Florin Baboescu
Broadcom
Email: florin.baboescu@broadcom.com
Jing Zhu
Intel
Email: jing.z.zhu@intel.com
SungHoon Seo
Korea Telecom
Email: sh.seo@kt.com