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Internet Engineering Task Force (IETF) M. Boucadair
Request for Comments: 9284 Orange
Category: Informational T. Reddy.K
ISSN: 2070-1721 Nokia
W. Pan
Huawei Technologies
August 2022
Multihoming Deployment Considerations for DDoS Open Threat Signaling
(DOTS)
Abstract
This document discusses multihoming considerations for DDoS Open
Threat Signaling (DOTS). The goal is to provide some guidance for
DOTS clients and client-domain DOTS gateways when multihomed.
Status of This Memo
This document is not an Internet Standards Track specification; it is
published for informational purposes.
This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Not all documents
approved by the IESG are 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/rfc9284.
Copyright Notice
Copyright (c) 2022 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. Code Components extracted from this document must
include Revised BSD License text as described in Section 4.e of the
Trust Legal Provisions and are provided without warranty as described
in the Revised BSD License.
Table of Contents
1. Introduction
2. Requirements Language
3. Terminology
4. Multihoming Scenarios
4.1. Multihomed Residential: Single CPE
4.2. Multihomed Enterprise: Single CPE, Multiple Upstream ISPs
4.3. Multihomed Enterprise: Multiple CPEs, Multiple Upstream
ISPs
4.4. Multihomed Enterprise with the Same ISP
5. DOTS Multihoming Deployment Considerations
5.1. Residential CPE
5.2. Multihomed Enterprise: Single CPE, Multiple Upstream ISPs
5.3. Multihomed Enterprise: Multiple CPEs, Multiple Upstream
ISPs
5.4. Multihomed Enterprise: Single ISP
6. Security Considerations
7. IANA Considerations
8. References
8.1. Normative References
8.2. Informative References
Acknowledgements
Authors' Addresses
1. Introduction
In many deployments, it may not be possible for a network to
determine the cause of a DDoS attack [RFC4732]. Rather, the network
may just realize that some resources appear to be under attack. To
help with such situations, the IETF has specified the DDoS Open
Threat Signaling (DOTS) architecture [RFC8811], where a DOTS client
can inform an upstream DOTS server that its network is under a
potential attack and that appropriate mitigation actions are
required. The DOTS protocols can be used to coordinate real-time
mitigation efforts that can evolve as the attacks mutate, thereby
reducing the impact of an attack and leading to more-efficient
responsive actions. [RFC8903] identifies a set of scenarios for
DOTS; most of these scenarios involve a Customer Premises Equipment
(CPE).
The high-level base DOTS architecture is illustrated in Figure 1
(repeated from Section 2 of [RFC8811]):
+-----------+ +-------------+
| Mitigator | ~~~~~~~~~~ | DOTS Server |
+-----------+ +-------------+
|
|
|
+---------------+ +-------------+
| Attack Target | ~~~~~~ | DOTS Client |
+---------------+ +-------------+
Figure 1: Basic DOTS Architecture
[RFC8811] specifies that the DOTS client may be provided with a list
of DOTS servers; each of these servers is associated with one or more
IP addresses. These addresses may or may not be of the same address
family. The DOTS client establishes one or more DOTS sessions by
connecting to the provided addresses for the DOTS server or servers
[RFC8973].
DOTS may be deployed within networks that are connected to one single
upstream provider. DOTS can also be enabled within networks that are
multihomed. The reader may refer to [RFC3582] for an overview of
multihoming goals and motivations. This document discusses DOTS
multihoming considerations. Specifically, the document aims to:
1. Complete the base DOTS architecture with multihoming specifics.
Those specifics need to be taken into account because:
* Sending a DOTS mitigation request to an arbitrary DOTS server
will not necessarily help in mitigating a DDoS attack.
* Randomly replicating all DOTS mitigation requests among all
available DOTS servers is suboptimal.
* Sequentially contacting DOTS servers may increase the delay
before a mitigation plan is enforced.
2. Identify DOTS deployment schemes in a multihoming context, where
DOTS services can be offered by all or a subset of upstream
providers.
3. Provide guidelines and recommendations for placing DOTS requests
in multihomed networks, for example:
* Select the appropriate DOTS server(s).
* Identify cases where anycast is not recommended for DOTS.
This document adopts the following methodology:
* Identify and extract viable deployment candidates from [RFC8903].
* Augment the description with multihoming technicalities, for
example:
- One vs. multiple upstream network providers
- One vs. multiple interconnect routers
- Provider-Independent (PI) vs. Provider-Aggregatable (PA) IP
addresses
* Describe the recommended behavior of DOTS clients and client-
domain DOTS gateways for each case.
Multihomed DOTS agents are assumed to make use of the protocols
defined in [RFC9132] and [RFC8783]. This document does not require
any specific extension to the base DOTS protocols for deploying DOTS
in a multihomed context.
2. Requirements Language
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.
3. Terminology
This document makes use of the terms defined in [RFC8811], [RFC8612],
and [RFC4116]. In particular:
Provider-Aggregatable (PA) addresses: globally unique addresses
assigned by a transit provider to a customer. The addresses are
considered "aggregatable" because the set of routes corresponding
to the PA addresses are usually covered by an aggregate route set
corresponding to the address space operated by the transit
provider, from which the assignment was made (Section 2 of
[RFC4116]).
Provider-Independent (PI) addresses: globally unique addresses that
are not assigned by a transit provider, but are provided by some
other organization, usually a Regional Internet Registry (RIR)
(Section 2 of [RFC4116]).
IP indifferently refers to IPv4 or IPv6.
4. Multihoming Scenarios
This section describes some multihoming scenarios that are relevant
to DOTS. In the following subsections, only the connections of
border routers are shown; internal network topologies are not
elaborated.
A multihomed network may enable DOTS for all or a subset of its
upstream interconnection links. In such a case, DOTS servers can be
explicitly configured or dynamically discovered by a DOTS client
using means such as those discussed in [RFC8973]. These DOTS servers
can be owned by the upstream provider, managed by a third-party
(e.g., mitigation service provider), or a combination thereof.
If a DOTS server is explicitly configured, it is assumed that an
interface is also provided to bind the DOTS service to an
interconnection link. If no interface is provided, the DOTS server
can be reached via any active interface.
This section distinguishes between residential CPEs and enterprise
CPEs because PI addresses may be used for enterprises, which is not
the current practice for residential CPEs.
In the following subsections, all or a subset of interconnection
links are associated with DOTS servers.
4.1. Multihomed Residential: Single CPE
The scenario shown in Figure 2 is characterized as follows:
* The home network is connected to the Internet using one single
CPE.
* The CPE is connected to multiple provisioning domains (i.e., both
fixed and mobile networks). Provisioning Domain (PvD) is
explained in [RFC7556].
In a typical deployment scenario, these provisioning domains are
owned by the same provider (Section 1 of [RFC8803]). Such a
deployment is meant to seamlessly use both fixed and cellular
networks for bonding, faster handovers, or better resiliency
purposes.
* Each of these provisioning domains assigns IP addresses or
prefixes to the CPE and provides additional configuration
information such as a list of DNS servers, DNS suffixes associated
with the network, the default gateway address, and the DOTS
server's name [RFC8973]. These addresses or prefixes are assumed
to be Provider-Aggregatable (PA).
* Because of ingress filtering, packets forwarded by the CPE towards
a given provisioning domain must be sent with a source IP address
that was assigned by that domain [RFC8043].
+-------+ +-------+
|Fixed | |Mobile |
|Network| |Network|
+---+---+ +---+---+
| | Service Providers
............|....................|.......................
+---------++---------+ Home Network
||
+--++-+
| CPE |
+-----+
... (Internal Network)
Figure 2: Typical Multihomed Residential CPE
4.2. Multihomed Enterprise: Single CPE, Multiple Upstream ISPs
The scenario shown in Figure 3 is characterized as follows:
* The enterprise network is connected to the Internet using a single
router.
* That router is connected to multiple provisioning domains managed
by distinct administrative entities.
Unlike the previous scenario, two sub-cases can be considered for an
enterprise network with regard to assigned addresses:
1. PI addresses or prefixes: The enterprise is the owner of the IP
addresses or prefixes; the same address or prefix is then used
when establishing communications over any of the provisioning
domains.
2. PA addresses or prefixes: Each of the provisioning domains
assigns IP addresses or prefixes to the enterprise network.
These addresses or prefixes are used when communicating over the
provisioning domain that assigned them.
+------+ +------+
| ISP1 | | ISP2 |
+---+--+ +--+---+
| | Service Providers
............|....................|.......................
+---------++---------+ Enterprise Network
||
+--++-+
| CPE |
+-----+
... (Internal Network)
Figure 3: Multihomed Enterprise Network (Single CPE Connected to
Multiple Networks)
4.3. Multihomed Enterprise: Multiple CPEs, Multiple Upstream ISPs
This scenario is similar to the one described in Section 4.2; the
main difference is that dedicated routers (CPE1 and CPE2) are used to
connect to each provisioning domain.
+------+ +------+
| ISP1 | | ISP2 |
+---+--+ +--+---+
| | Service Providers
......................|..........|.......................
| | Enterprise Network
+---+--+ +--+---+
| CPE1 | | CPE2 |
+------+ +------+
... (Internal Network)
Figure 4: Multihomed Enterprise Network (Multiple CPEs, Multiple
ISPs)
4.4. Multihomed Enterprise with the Same ISP
This scenario is a variant of Sections 4.2 and 4.3 in which
multihoming is supported by the same ISP (i.e., same provisioning
domain).
5. DOTS Multihoming Deployment Considerations
Table 1 provides some sample, non-exhaustive deployment schemes to
illustrate how DOTS agents may be deployed for each of the scenarios
introduced in Section 4.
+=========================+=======================+===============+
| Scenario | DOTS Client | Client-Domain |
| | | DOTS Gateway |
+=========================+=======================+===============+
| Residential CPE | CPE | N/A |
+-------------------------+-----------------------+---------------+
| Single CPE, multiple | Internal hosts or CPE | CPE |
| provisioning domains | | |
+-------------------------+-----------------------+---------------+
| Multiple CPEs, multiple | Internal hosts or all | CPEs (CPE1 |
| provisioning domains | CPEs (CPE1 and CPE2) | and CPE2) |
+-------------------------+-----------------------+---------------+
| Multihomed enterprise, | Internal hosts or all | CPEs (CPE1 |
| single provisioning | CPEs (CPE1 and CPE2) | and CPE2) |
| domain | | |
+-------------------------+-----------------------+---------------+
Table 1: Sample Deployment Cases
These deployment schemes are further discussed in the following
subsections.
5.1. Residential CPE
Figure 5 depicts DOTS sessions that need to be established between a
DOTS client (C) and two DOTS servers (S1, S2) within the context of
the scenario described in Section 4.1. As listed in Table 1, the
DOTS client is hosted by the residential CPE.
+--+
----------|S1|
/ +--+
/ DOTS Server Domain #1
/
+---+/
| C |
+---+\
CPE \
\
\ +--+
----------|S2|
+--+
DOTS Server Domain #2
Figure 5: DOTS Associations for a Multihomed Residential CPE
The DOTS client MUST resolve the DOTS server's name provided by each
provisioning domain using the DNS servers either learned from the
respective provisioning domain or associated with the interface(s)
for which a DOTS server was explicitly configured (Section 4).
IPv6-capable DOTS clients MUST use the source address selection
algorithm defined in [RFC6724] to select the candidate source
addresses to contact each of these DOTS servers. DOTS sessions MUST
be established and MUST be maintained with each of the DOTS servers
because the mitigation scope of each of these servers is restricted.
The DOTS client MUST use the security credentials (a certificate,
typically) provided by a provisioning domain to authenticate itself
to the DOTS server(s) provided by the same provisioning domain. How
such security credentials are provided to the DOTS client is out of
the scope of this document. The reader may refer to Section 7.1 of
[RFC9132] for more details about DOTS authentication methods.
When conveying a mitigation request to protect the attack target(s),
the DOTS client MUST select an available DOTS server whose network
has assigned the IP prefixes from which target addresses or prefixes
are derived. This implies that if no appropriate DOTS server is
found, the DOTS client MUST NOT send the mitigation request to any
other available DOTS server.
For example, a mitigation request to protect target resources bound
to a PA IP address or prefix cannot be satisfied by a provisioning
domain other than the one that owns those addresses or prefixes.
Consequently, if a CPE detects a DDoS attack that spreads over all
its network attachments, it MUST contact all DOTS servers for
mitigation purposes.
The DOTS client MUST be able to associate a DOTS server with each
provisioning domain it serves. For example, if the DOTS client is
provisioned with S1 using DHCP when attaching to a first network and
with S2 using Protocol Configuration Option (PCO) [TS.24008] when
attaching to a second network, the DOTS client must record the
interface from which a DOTS server was provisioned. A DOTS signaling
session to a given DOTS server must be established using the
interface from which the DOTS server was provisioned. If a DOTS
server is explicitly configured, DOTS signaling with that server must
be established via the interfaces that are indicated in the explicit
configuration or via any active interface if no interface is
configured.
5.2. Multihomed Enterprise: Single CPE, Multiple Upstream ISPs
Figure 6 illustrates the DOTS sessions that can be established with a
client-domain DOTS gateway (hosted within the CPE as per Table 1)
that is enabled within the context of the scenario described in
Section 4.2. This deployment is characterized as follows:
* One or more DOTS clients are enabled in hosts located in the
internal network.
* A client-domain DOTS gateway is enabled to aggregate and then
relay the requests towards upstream DOTS servers.
+--+
.................... ----------|S1|
. +---+ . / +--+
. | C1|----+ ./ DOTS Server Domain #1
. +---+ | .
. | /.
.+---+ +-+-+/ .
.| C3|------| G | .
.+---+ +-+-+\ .
. CPE \.
. +---+ | .
. | C2|----+ .\
. +---+ . \ +--+
'..................' ----------|S2|
+--+
DOTS Client Domain DOTS Server Domain #2
Figure 6: Multiple DOTS Clients, Single DOTS Gateway, Multiple
DOTS Servers
When PA addresses or prefixes are in use, the same considerations
discussed in Section 5.1 need to be followed by the client-domain
DOTS gateway to contact its DOTS server(s). The client-domain DOTS
gateways can be reachable from DOTS clients by using a unicast
address or an anycast address (Section 3.2.4 of [RFC8811]).
Nevertheless, when PI addresses or prefixes are assigned, and absent
any policy, the client-domain DOTS gateway SHOULD send mitigation
requests to all its DOTS servers. Otherwise, the attack traffic may
still be delivered via the ISP that hasn't received the mitigation
request.
An alternate deployment model is depicted in Figure 7. This
deployment assumes that:
* One or more DOTS clients are enabled in hosts located in the
internal network. These DOTS clients may use [RFC8973] to
discover their DOTS server(s).
* These DOTS clients communicate directly with upstream DOTS
servers.
..........
. +--+ .
+--------|C1|--------+
| . +--+ . |
| . . |
+--+ . +--+ . +--+
|S2|------|C3|------|S1|
+--+ . +--+ . +--+
| . . |
| . +--+ . |
+--------|C2|--------+
. +--+ .
'........'
DOTS Client
Domain
Figure 7: Multiple DOTS Clients, Multiple DOTS Servers
If PI addresses or prefixes are in use, the DOTS client MUST send a
mitigation request to all the DOTS servers. The use of the same
anycast addresses to reach these DOTS servers is NOT RECOMMENDED. If
a well-known anycast address is used to reach multiple DOTS servers,
the CPE may not be able to select the appropriate provisioning domain
to which the mitigation request should be forwarded. As a
consequence, the request may not be forwarded to the appropriate DOTS
server.
If PA addresses or prefixes are used, the same considerations
discussed in Section 5.1 need to be followed by the DOTS clients.
Because DOTS clients are not embedded in the CPE and multiple
addresses or prefixes may not be assigned to the DOTS client
(typically in an IPv4 context), some issues may arise in how to steer
traffic towards the appropriate DOTS server by using the appropriate
source IP address. These complications discussed in [RFC4116] are
not specific to DOTS.
Another deployment approach is to enable many DOTS clients; each of
them is responsible for handling communications with a specific DOTS
server (see Figure 8).
..........
. +--+ .
+--------|C1| .
| . +--+ .
+--+ . +--+ . +--+
|S2| . |C2|------|S1|
+--+ . +--+ . +--+
'........'
DOTS Client
Domain
Figure 8: Single-Homed DOTS Clients
For both deployments depicted in Figures 7 and 8, each DOTS client
SHOULD be provided with policies (e.g., a prefix filter that is used
to filter DDoS detection alarms) that will trigger DOTS
communications with the DOTS servers. Such policies will help the
DOTS client to select the appropriate destination DOTS server. The
CPE MUST select the appropriate source IP address when forwarding
DOTS messages received from an internal DOTS client.
5.3. Multihomed Enterprise: Multiple CPEs, Multiple Upstream ISPs
The deployments depicted in Figures 7 and 8 also apply to the
scenario described in Section 4.3. One specific problem for this
scenario is to select the appropriate exit router when contacting a
given DOTS server.
An alternative deployment scheme is shown in Figure 9:
* DOTS clients are enabled in hosts located in the internal network.
* A client-domain DOTS gateway is enabled in each CPE (CPE1 and CPE2
per Table 1).
* Each of these client-domain DOTS gateways communicates with the
DOTS server of the provisioning domain.
.................................
. +---+ .
. +------------| C1|----+ .
. | +---+ | .
. | | .
+--+ . +-+-+ +---+ +-+-+ . +--+
|S2|------|G2 |------| C3|------|G1 |------|S1|
+--+ . +-+-+ +---+ +-+-+ . +--+
. CPE2 CPE1 .
. | +---+ | .
. +------------| C2|----+ .
. +---+ .
'...............................'
DOTS Client Domain
Figure 9: Multiple DOTS Clients, Multiple DOTS Gateways, Multiple
DOTS Servers
When PI addresses or prefixes are used, DOTS clients MUST contact all
the client-domain DOTS gateways to send a DOTS message. Client-
domain DOTS gateways will then relay the request to the DOTS servers
as a function of local policy. Note that (same) anycast addresses
cannot be used to establish DOTS sessions between DOTS clients and
client-domain DOTS gateways because only one DOTS gateway will
receive the mitigation request.
When PA addresses/prefixes are used, but no filter rules are provided
to DOTS clients, the DOTS clients MUST contact all client-domain DOTS
gateways simultaneously to send a DOTS message. Client-domain DOTS
gateways MUST check whether a received request is to be forwarded
upstream (if the target IP prefix is managed by the upstream server)
or rejected.
When PA addresses or prefixes are used, but specific filter rules are
provided to DOTS clients using some means that are out of scope of
this document, the clients MUST select the appropriate client-domain
DOTS gateway to reach. The use of the same anycast addresses is NOT
RECOMMENDED to reach client-domain DOTS gateways.
5.4. Multihomed Enterprise: Single ISP
The key difference between the scenario described in Section 4.4 and
the other scenarios is that multihoming is provided by the same ISP.
Concretely, that ISP can decide to provision the enterprise network
with:
* The same DOTS server for all network attachments.
* Distinct DOTS servers for each network attachment. These DOTS
servers need to coordinate when a mitigation action is received
from the enterprise network.
In both cases, DOTS agents enabled within the enterprise network MAY
decide to select one or all network attachments to send DOTS
mitigation requests.
6. Security Considerations
A set of security threats related to multihoming is discussed in
[RFC4218].
DOTS-related security considerations are discussed in Section 5 of
[RFC8811].
DOTS clients should control the information that they share with peer
DOTS servers. In particular, if a DOTS client maintains DOTS
sessions with specific DOTS servers per interconnection link, the
DOTS client SHOULD NOT leak information specific to a given link to
DOTS servers on different interconnection links that are not
authorized to mitigate attacks for that given link. Whether this
constraint is relaxed is deployment specific and must be subject to
explicit consent from the DOTS client domain administrator. How to
seek such consent is implementation and deployment specific.
7. IANA Considerations
This document has no IANA actions.
8. References
8.1. 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>.
[RFC6724] Thaler, D., Ed., Draves, R., Matsumoto, A., and T. Chown,
"Default Address Selection for Internet Protocol Version 6
(IPv6)", RFC 6724, DOI 10.17487/RFC6724, September 2012,
<https://www.rfc-editor.org/info/rfc6724>.
[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>.
[RFC8811] Mortensen, A., Ed., Reddy.K, T., Ed., Andreasen, F.,
Teague, N., and R. Compton, "DDoS Open Threat Signaling
(DOTS) Architecture", RFC 8811, DOI 10.17487/RFC8811,
August 2020, <https://www.rfc-editor.org/info/rfc8811>.
8.2. Informative References
[RFC3582] Abley, J., Black, B., and V. Gill, "Goals for IPv6 Site-
Multihoming Architectures", RFC 3582,
DOI 10.17487/RFC3582, August 2003,
<https://www.rfc-editor.org/info/rfc3582>.
[RFC4116] Abley, J., Lindqvist, K., Davies, E., Black, B., and V.
Gill, "IPv4 Multihoming Practices and Limitations",
RFC 4116, DOI 10.17487/RFC4116, July 2005,
<https://www.rfc-editor.org/info/rfc4116>.
[RFC4218] Nordmark, E. and T. Li, "Threats Relating to IPv6
Multihoming Solutions", RFC 4218, DOI 10.17487/RFC4218,
October 2005, <https://www.rfc-editor.org/info/rfc4218>.
[RFC4732] Handley, M., Ed., Rescorla, E., Ed., and IAB, "Internet
Denial-of-Service Considerations", RFC 4732,
DOI 10.17487/RFC4732, December 2006,
<https://www.rfc-editor.org/info/rfc4732>.
[RFC7556] Anipko, D., Ed., "Multiple Provisioning Domain
Architecture", RFC 7556, DOI 10.17487/RFC7556, June 2015,
<https://www.rfc-editor.org/info/rfc7556>.
[RFC8043] Sarikaya, B. and M. Boucadair, "Source-Address-Dependent
Routing and Source Address Selection for IPv6 Hosts:
Overview of the Problem Space", RFC 8043,
DOI 10.17487/RFC8043, January 2017,
<https://www.rfc-editor.org/info/rfc8043>.
[RFC8612] Mortensen, A., Reddy, T., and R. Moskowitz, "DDoS Open
Threat Signaling (DOTS) Requirements", RFC 8612,
DOI 10.17487/RFC8612, May 2019,
<https://www.rfc-editor.org/info/rfc8612>.
[RFC8783] Boucadair, M., Ed. and T. Reddy.K, Ed., "Distributed
Denial-of-Service Open Threat Signaling (DOTS) Data
Channel Specification", RFC 8783, DOI 10.17487/RFC8783,
May 2020, <https://www.rfc-editor.org/info/rfc8783>.
[RFC8803] Bonaventure, O., Ed., Boucadair, M., Ed., Gundavelli, S.,
Seo, S., and B. Hesmans, "0-RTT TCP Convert Protocol",
RFC 8803, DOI 10.17487/RFC8803, July 2020,
<https://www.rfc-editor.org/info/rfc8803>.
[RFC8903] Dobbins, R., Migault, D., Moskowitz, R., Teague, N., Xia,
L., and K. Nishizuka, "Use Cases for DDoS Open Threat
Signaling", RFC 8903, DOI 10.17487/RFC8903, May 2021,
<https://www.rfc-editor.org/info/rfc8903>.
[RFC8973] Boucadair, M. and T. Reddy.K, "DDoS Open Threat Signaling
(DOTS) Agent Discovery", RFC 8973, DOI 10.17487/RFC8973,
January 2021, <https://www.rfc-editor.org/info/rfc8973>.
[RFC9132] Boucadair, M., Ed., Shallow, J., and T. Reddy.K,
"Distributed Denial-of-Service Open Threat Signaling
(DOTS) Signal Channel Specification", RFC 9132,
DOI 10.17487/RFC9132, September 2021,
<https://www.rfc-editor.org/info/rfc9132>.
[TS.24008] 3GPP, "Mobile radio interface Layer 3 specification; Core
network protocols; Stage 3", 3GPP TS 24.008 16.3.0,
December 2019,
<https://www.3gpp.org/DynaReport/24008.htm>.
Acknowledgements
Thanks to Roland Dobbins, Nik Teague, Jon Shallow, Dan Wing, and
Christian Jacquenet for sharing their comments on the mailing list.
Thanks to Kirill Kasavchenko for the comments.
Thanks to Kathleen Moriarty for the secdir review, Joel Jaeggli for
the opsdir review, Mirja Kühlewind for the tsvart review, and Dave
Thaler for the intdir review.
Many thanks to Roman Danyliw for the careful AD review.
Thanks to Lars Eggert, Robert Wilton, Paul Wouters, Erik Kline, and
Éric Vyncke for the IESG review.
Authors' Addresses
Mohamed Boucadair
Orange
35000 Rennes
France
Email: mohamed.boucadair@orange.com
Tirumaleswar Reddy.K
Nokia
Email: kondtir@gmail.com
Wei Pan
Huawei Technologies
Email: william.panwei@huawei.com