Network Working Group K. Tesink Request for Comments: 2558 Telcordia Technologies Obsoletes: 1595 March 1999 Category: Standards Track Definitions of Managed Objects for the SONET/SDH Interface Type Status of this Memo This document specifies an Internet standards track protocol for the Internet community, and requests discussion and suggestions for improvements. Please refer to the current edition of the "Internet Official Protocol Standards" (STD 1) for the standardization state and status of this protocol. Distribution of this memo is unlimited. Copyright Notice Copyright (C) The Internet Society (1999). All Rights Reserved. 1. Abstract This memo defines a portion of the Management Information Base (MIB) for use with network management protocols in TCP/IP-based internets. In particular, it defines objects for managing Synchronous Optical Network/Synchronous Digital Hierarchy (SONET/SDH) interfaces. This document is a companion to the documents that define Managed Objects for the DS1/E1/DS2/E2 and DS3/E3 Interface Types [24][25]. Textual Conventions used in this MIB are defined in [6] and [36]. This memo replaces RFC 1595 [30]. Changes relative to RFC 1595 are summarized in the MIB module's REVISION clause. Table of Contents 1 Abstract .............................................. 1 2 The SNMP Network Management Framework ................. 2 3 Overview .............................................. 3 3.1 Use of the ifTable .................................. 4 3.2 Use of ifTable for SONET/SDH Medium/Section/Line Layer ............................................... 5 3.3 Use of ifTable for SONET/SDH Paths .................. 6 3.4 Use of ifTable for SONET/SDH VTs/VCs ................ 7 3.5 SONET/SDH Terminology ............................... 8 4 Object Definitions .................................... 16 4.1 The SONET/SDH Medium Group .......................... 19 Tesink Standards Track [Page 1] RFC 2558 SONET/SDH Objects March 1999 4.2 The SONET/SDH Section Group ......................... 23 4.2.1 The SONET/SDH Section Current Group ............... 23 4.2.2 The SONET/SDH Section Interval Group .............. 26 4.3 The SONET/SDH Line Group ............................ 28 4.3.1 The SONET/SDH Line Current Group .................. 28 4.3.2 The SONET/SDH Line Interval Group ................. 30 4.4 The SONET/SDH Far End Line Group .................... 32 4.4.1 The SONET/SDH Far End Line Current Group .......... 33 4.4.2 The SONET/SDH Far End Line Interval Group ......... 34 4.5 The SONET/SDH Path Group ............................ 37 4.5.1 The SONET/SDH Path Current Group .................. 37 4.5.2 The SONET/SDH Path Interval Group ................. 39 4.6 The SONET/SDH Far End Path Group .................... 42 4.6.1 The SONET/SDH Far End Path Current Group .......... 42 4.6.2 The SONET/SDH Far End Path Interval Group ......... 44 4.7 The SONET/SDH Virtual Tributary Group ............... 46 4.7.1 The SONET/SDH VT Current Group .................... 46 4.7.2 The SONET/SDH VT Interval Group ................... 49 4.8 The SONET/SDH Far End VT Group ...................... 51 4.8.1 The SONET/SDH Far End VT Current Group ............ 51 4.8.2 The SONET/SDH Far End VT Interval Group ........... 53 4.9 Conformance Information ............................. 55 4.10 Compliance Statements .............................. 56 5 Acknowledgments ....................................... 65 6 Security Considerations ............................... 65 7 References ............................................ 66 8 Author's Address ...................................... 69 9 Intellectual Property ................................. 69 Appendix A .............................................. 70 Appendix B .............................................. 72 Full Copyright Statement ................................ 74 2. The SNMP Network Management Framework The SNMP Management Framework presently consists of five major components: 0 An overall architecture, described in RFC 2271 [1]. 0 Mechanisms for describing and naming objects and events for the purpose of management. The first version of this Structure of Management Information (SMI) is called SMIv1 and described in STD 16, RFC 1155 [2], STD 16, RFC 1212 [3] and RFC 1215 [4]. The second version, called SMIv2, is described in RFC 1902 [5], RFC 1903 [6] and RFC 1904 [7]. Tesink Standards Track [Page 2] RFC 2558 SONET/SDH Objects March 1999 0 Message protocols for transferring management information. The first version of the SNMP message protocol is called SNMPv1 and described in STD 15, RFC 1157 [8]. A second version of the SNMP message protocol, which is not an Internet standards track protocol, is called SNMPv2c and described in RFC 1901 [9] and RFC 1906 [10]. The third version of the message protocol is called SNMPv3 and described in RFC 1906 [10], RFC 2272 [11] and RFC 2274 [12]. 0 Protocol operations for accessing management information. The first set of protocol operations and associated PDU formats is described in STD 15, RFC 1157 [8]. A second set of protocol operations and associated PDU formats is described in RFC 1905 [13]. 0 A set of fundamental applications described in RFC 2273 [14] and the view-based access control mechanism described in RFC 2275 [15]. Managed objects are accessed via a virtual information store, termed the Management Information Base or MIB. Objects in the MIB are defined using the mechanisms defined in the SMI. This memo specifies a MIB module that is compliant to the SMIv2. A MIB conforming to the SMIv1 can be produced through the appropriate translations. The resulting translated MIB must be semantically equivalent, except where objects or events are omitted because no translation is possible (e.g., use of Counter64). Some machine readable information in SMIv2 will be converted into textual descriptions in SMIv1 during the translation process. However, this loss of machine readable information is not considered to change the semantics of the MIB. 3. Overview These objects are used when the particular media being used to realize an interface is a SONET/SDH interface. At present, this applies to these values of the ifType variable in the Internet- standard MIB: sonet (39), sonetPath (50), sonetVT (51) The definitions contained herein are based on the SONET/SDH specifications in ANSI T1.105 and T1.106-1988 [19][20][21] and CCITT G.707, 708, 709, and G.783 [26][27][28][29]. Tesink Standards Track [Page 3] RFC 2558 SONET/SDH Objects March 1999 3.1. Use of the ifTable This section specifies how the MIB II interfaces group, as defined in [23], is used for SONET/SDH interfaces. The SONET/SDH layers support several multiplexing possibilities. For example in SONET, an Synchronous Transport Signal 3 (STS-3) has 3 SONET Paths, and a STS-3c has 1 SONET Path. Another example could be a STS-12 having 4 SONET STS-3c Paths. Similarly, a SONET Synchronous Payload Envelope (SPE) can carry many Virtual Tributaries (VTs), for example, one SONET SPE can carry 28 VT1.5s. It is important to note that an SPE and a VT in SONET is collectively referred to as a Virtual Container (VC) in SDH. Also, an STS is called Synchronous Transport Module (STM) in SDH. Not all SONET/SDH equipment terminates all SONET/SDH layers. For example, a SONET/SDH STE regenerator terminates SONET/SDH Sections only, and is transparent for all layers above that. SONET/SDH Add- Drop multiplexers and Digital Cross Connect Systems terminate SONET/SDH Lines. SONET/SDH Terminal Multiplexers may also terminate SONET/SDH Paths and VTs/VCs. MIB II [16], as extended by [23], accommodates these cases by appropriate use of the MIB II system group, and the interfaces group. The system group can name and describe the type of managed resource. The interfaces group defines which SONET/SDH layers apply, how these layers are configured and multiplexed. This is achieved by proper representation of SONET/SDH Layers by ifEntries as defined in [23], as follows: Tesink Standards Track [Page 4] RFC 2558 SONET/SDH Objects March 1999 _____________________________ | | | | > | | | | | | VT 1 |..........|VT K| > K ifEntries | | | | | |_____________|__________|____| > | | | | > | | | | | | Path 1 |......|Path L| > L ifEntries | | | | | |_______________|______|______| > | | > | | | | Line | | | | | |_____________________________| | | | | | | | | Section Layer | > 1 ifEntry | | | |_____________________________| | | | | | | | | Physical Medium Layer | | | | | |_____________________________| > Use of ifTable for a SONET/SDH port The exact configuration and multiplexing of the layers is maintained in the ifStackTable [23]. 3.2. Use of ifTable for SONET/SDH Medium/Section/Line Layer Only the ifGeneralInformationGroup needs to be supported. ifTable Object Use for combined SONET/SDH Medium/Section/Line Layer ====================================================================== ifIndex Interface index. ifDescr SONET/SDH Medium/Section/Line ifType sonet(39) ifSpeed Speed of line rate for SONET/SDH, (e.g., 155520000 bps). Tesink Standards Track [Page 5] RFC 2558 SONET/SDH Objects March 1999 ifPhysAddress The value of the Circuit Identifier. If no Circuit Identifier has been assigned this object should have an octet string with zero length. ifAdminStatus Supports read-only access. The desired administrative status of the interface. ifOperStatus The value testing(3) is not used. This object assumes the value down(2), if the objects sonetSectionCurrentStatus and sonetLineCurrentStatus have any other value than sonetSectionNoDefect(1) and sonetLineNoDefect(1), respectively. ifLastChange sysUpTime at the last change in ifOperStatus. ifName Textual name of the interface or an OCTET STRING of zero length. ifLinkUpDownTrapEnable Default value is enabled(1). Just read-only access may be supported. ifHighSpeed Speed of line in Mega-bits per second (e.g., 155 Mbps) ifConnectorPresent Set to true(1). ifAlias The (non-volatile) alias name for this interface as assigned by the network manager. 3.3. Use of ifTable for SONET/SDH Paths Only the ifGeneralInformationGroup needs to be supported. ifTable Object Use for SONET/SDH Paths ========================================= ifIndex Interface index. ifDescr SONET/SDH Path ifType sonetPath(50) ifSpeed set to speed of SONET/SDH path (e.g., an STS-1 path has a rate of 50112000 bps.) Tesink Standards Track [Page 6] RFC 2558 SONET/SDH Objects March 1999 ifPhysAddress Circuit Identifier or OCTET STRING of zero length. ifAdminStatus Supports read-only access. The desired administrative status of the interface. ifOperStatus This object assumes the value down(2), if the object sonetPathCurrentStatus has any other value than sonetPathNoDefect(1). ifLastChange sysUpTime at the last change in ifOperStatus. ifName Textual name of the interface or an OCTET STRING of zero length. ifLinkUpDownTrapEnable Default value is disabled(2). Just read-only access may be supported. ifHighSpeed Set to rate of SONET/SDH path in Mega-bits per second. ifConnectorPresent Set to false(2). ifAlias The (non-volatile) alias name for this interface as assigned by the network manager. 3.4. Use of ifTable for SONET/SDH VTs/VCs Only the ifGeneralInformationGroup needs to be supported. ifTable Object Use for SONET/SDH VTs/VCs =========================================== ifIndex Interface index. ifDescr SONET/SDH VT/VC ifType sonetVT(51) ifSpeed Set to speed of VT/VC (e.g., a VT1.5 has a rate of 1728000 bps.) ifPhysAddress Circuit Identifier or OCTET STRING of zero length. ifAdminStatus Supports read-only access. The desired administrative status of the interface. Tesink Standards Track [Page 7] RFC 2558 SONET/SDH Objects March 1999 ifOperStatus This object assumes the value down(2), if the object sonetVTCurrentStatus has any other value than sonetVTNoDefect(1). ifLastChange sysUpTime at the last change in ifOperStatus. ifName Textual name of the interface or an OCTET STRING of zero length. ifLinkUpDownTrapEnable Default value is disabled(2). Just read-only access may be supported. ifHighSpeed Set to rate of VT in Mega-bits per second. ifConnectorPresent Set to false(2). ifAlias The (non-volatile) alias name for this interface as assigned by the network manager. 3.5. SONET/SDH Terminology The terminology used in this document to describe error conditions on a SONET circuit as monitored by a SONET system are from the T1.231 [22][31][35]. The terminology used in this document to describe error conditions on a SDH circuit as monitored by a SDH system are from the CCITT G.783 [29]. Only the SONET Performance Monitoring terminology is defined in this document. The definitions for SDH Performance Monitoring terms are similar but not identical, and they can be found in [29]. If the definition in this document does not match the definition in the T1.231 document, the implementer should follow the definition described in this document. In some cases other or additional references are used as compared with the ones cited above. This will be indicated in the text. Section Loss Of Frame Failure (Out of Frame Event, Severely Errored Frame Defect) An Out of Frame (OOF) event (or Severely Errored Frame defect) is the occurrence of four contiguous errored frame alignment words. A frame alignment word occupies the A1 and A2 bytes of an STS frame, and is defined in T1.105. The SEF defect is terminated when two contiguous error-free frame words are detected. Any implementation of the frame recovery circuitry which achieves realignment following an OOF within the 250 microsecond (two frames) interval implied by this definition is acceptable. Tesink Standards Track [Page 8] RFC 2558 SONET/SDH Objects March 1999 A Loss of Frame (LOF) defect is declared when an OOF/SEF defect persists for a period of 3 milliseconds. The LOF defect is terminated when the incoming signal remains continuously in- frame for a period of 1 ms to 3 ms. A LOF failure is declared when the LOF defect persists for a period of 2.5 +/- 0.5 seconds, except when an LOS defect or failure is present. The LOF failure is cleared when the LOS failure is declared, or when the LOF defect is absent for 10 +/- 0.5 seconds. Loss of Signal The Loss of Signal (LOS) defect is declared when no transitions are detected on the incoming signal (before descrambling). The LOS defect is detected upon observing 2.3 to 100 microseconds of no transitions. The LOS defect is cleared after a 125 microsecond interval (one frame) during which no LOS defect is detected. The LOS failure is declared when the LOS defect persists for a period of 2.5 +/- 0.5 seconds, or if LOS defect is present when the criteria for LOF failure declaration have been met. The LOS failure is cleared when the LOS defect is absent for a period of 10 +/- 0.5 seconds. Declaration of LOS failure clears any existing LOF failure. Clearing the LOS failure allows immediate declaration of the LOF failure if conditions warrant. STS-Path Loss of Pointer A Loss of Pointer (LOP) defect is declared when either a valid pointer is not detected in eight consecutive frames, or when eight consecutive frames are detected with the New Data Flag (NDF) set to "1001" without a valid concatenation indicator (see ANSI T1.105). A LOP defect is terminated when either a valid pointer with a normal NDF set to "0110", or a valid concatenation indicator is detected for three contiguous frames. Incoming STS-Path AIS shall not result in the declaration of a LOP defect. An STS-Path LOP failure is declared when the STS-Path LOP defect persists for a period of 2.5 +/- 0.5 seconds. A STS-Path LOP failure is cleared when the STS-Path LOP defect is absent for 10 +/- 0.5 seconds. VT Loss of Pointer A VT LOP defect is declared when either a valid pointer is not detected in eight consecutive VT superframes, or when eight consecutive VT superframes are detected with the NDF set to "1001" without a valid concatenation indicator. A VT LOP defect Tesink Standards Track [Page 9] RFC 2558 SONET/SDH Objects March 1999 is terminated when either a valid pointer with a normal NDF set to "0110", or a valid concatenation indicator is detected for three contiguous VT superframes. Incoming VT-Path AIS shall not result in declaring a VT LOP defect. A VT LOP failure is declared when the VT LOP defect persists for 2.5 +/- 0.5 seconds. A VT LOP failure is cleared when the VT LOP defect is absent for 10 +/- 0.5 seconds. Line Alarm Indication Signal A Line Alarm Indication Signal (L-AIS) is defined in ANSI T1.105. The following criteria are specific to the L-AIS defect: -- Line AIS defect is detected as a "111" pattern in bits 6, 7, and 8 of the K2 byte in five consecutive frames. -- Line AIS defect is terminated when bits 6, 7, and 8 of the K2 byte do not contain the code "111" for five consecutive frames. A Line AIS failure is declared when the Line AIS defect persists for a period of 20.5 +/- 0.5 seconds. A Line AIS failure is cleared when the Line AIS defect is absent for 10 +/- 0.5 seconds. STS-Path Alarm Indication Signal The STS-Path Alarm Indication Signal (AIS) is defined in ANSI T1.105 as all ones in bytes H1, H2, and H3 as well as all ones in the entire STS SPE. The following criteria are specific to the STS-Path AIS defect: -- STS-Path AIS defect is detected as all ones in bytes H1 and H2 in three contiguous frames. -- The STS-Path AIS defect is terminated when a valid STS Pointer is detected with the NDF set to "1001" (inverted) for one frame, or "0110" (normal) for three contiguous frames. An STS-Path AIS failure is declared when the STS-Path AIS defect persists for 2.5 +/- 0.5 seconds. An STS-Path AIS failure is cleared when the STS-Path AIS defect is absent for 10 +/- 0.5 seconds. VT-Path Alarm Indication Signal The VT-Path Alarm Indication Signal (AIS) is only applicable for VTs in the floating mode of operation. VT-Path AIS is used to alert the downstream VT Path Terminating Entity (PTE) of an Tesink Standards Track [Page 10] RFC 2558 SONET/SDH Objects March 1999 upstream failure. Upon detection of a failure, Line AIS, or STS-Path AIS, an STS PTE will generate downstream VT-Path AIS if the STS Synchronous Payload Envelope (SPE) is carrying floating VTs. VT-Path AIS is specified in ANSI T1.105 as all ones in bytes V1, V2, V3, and V4, as well as all ones in the entire VT SPE. The following criteria are specific to VT-Path AIS defect: -- VT-Path AIS defect is detected by a VT PTE as all ones in bytes V1 and V2 in three contiguous VT superframes. -- VT-Path AIS defect is terminated when valid VT pointer with a valid VT size is detected with the NDF set to "1001" (inverted) for one VT superframe, or "0110" (normal) for three contiguous VT superframes are detected. A VT-Path AIS failure is declared when the VT-Path AIS defect persists for 2.5 +/- 0.5 seconds. A VT-Path AIS failure is cleared when the VT-Path AIS defect is absent for 10 +/- 0.5 seconds. Line Remote Defect Indication Line Remote Defect Indication (RDI) (aka Line FERF) signal is the occurrence of a "110" pattern in bit positions 6, 7, and 8 of the K2 byte in STS-1 #1 of the STS-N signal. Line RDI is defined in ANSI T1.105. The following criteria are specific to Line RDI defect: -- Line RDI defect is a "110" code in bits 6, 7, and 8 of the K2 byte of in STS-1 #1 in x consecutive frames, where x = 5 [31][35] or 10 [35]. -- Line RDI defect is terminated when any code other than "110" is detected in bits 6, 7, and 8 of the K2 byte in x consecutive frames, where x = 5 [31][35] or 10 [35]. A Line Remote Failure Indication (RFI) failure is declared when the incoming Line RDI defects lasts for 2.5 +/- 0.5 seconds. The Line RFI failure is cleared when no Line RDI defects are detected for 10 +/- 0.5 seconds. STS-Path Remote Defect Indication STS-Path RDI (aka STS-Path FERF) signal shall be generated within 100 milliseconds by the STS PTE upon detection of an AIS or LOP defect. Transmission of the STS-Path RDI signal shall cease within 100 milliseconds when the STS PTE no longer detects STS-Path AIS or STS-Path LOP defect. The STS-Path RDI shall accurately report the presence or absence of STS-Path AIS or STS-Path LOP defects. STS-Path RDI defect is defined in ANSI Tesink Standards Track [Page 11] RFC 2558 SONET/SDH Objects March 1999 T1.105. The following requirements are specific to the STS-Path RDI defect: -- STS-Path RDI is detected by all STS PTEs. STS-Path RDI is detected by the upstream STS PTE as a "1" in bit five of the Path Status byte (G1) for x consecutive frames, where x = 5 [31] or 10 [35]. -- Removal of STS-Path Remote Defect Indication is detected by a "0" in bit 5 of the G1 byte in x consecutive frames, where x = 5 [31] or 10 [35]. An STS-Path Remote Failure Indication (RFI) failure is declared when the incoming STS-Path RDI defects lasts for 2.5 +/- 0.5 seconds. The STS-Path RFI failure is cleared when no STS-Path RDI defects are detected for 10 +/- 0.5 seconds. VT-Path Remote Defect Indication VT Path RDI (aka VT Path FERF) signal shall be generated within 100 milliseconds by the VT PTE upon detection of a VT-Path AIS or LOP defect. Transmission of the VT-Path RDI signal shall cease within 100 milliseconds when the VT PTE no longer detects VT-Path AIS or VT-Path LOP defect. The VT-Path RDI shall accurately report the presence or absence of VT-Path AIS or VT- Path LOP defects. VT-Path RDI defect is defined in ANSI T1.105. The following requirements are specific to VT-Path RDI defect: -- VT-Path RDI defect is the occurrence of a "1" in bit 4 of the VT-Path Overhead byte (V5) in x consecutive frames, where x = 5 [31] or 10 [35]. -- VT-Path RDI defect is terminated when a "0" is detected in bit 4 of the VT-Path Overhead byte (V5) for x consecutive frames, where x = 5 [31] or 10 [35]. A VT-Path Remote Failure Indication (RFI) (derived) failure is declared when the incoming VT-Path RDI defects lasts for 2.5 +/- 0.5 seconds. The VT-Path RFI failure is cleared when no VT-Path RDI defects are detected for 10 +/- 0.5 seconds. VT-Path Remote Failure Indication The VT-Path RFI signal is only required for the case of byte synch mapped DS1s where the DS1 frame bit is not mapped. The VT-Path RFI is specified in ANSI T1.105, where it is currently called VT path yellow. When provided, the VT-Path RFI signal is used to indicate the occurrence of far-end failures. When the VT-Path RFI is not provided, far-end failures are derived from local timing of the VT-Path RDI defect. The VT-Path RFI failure Tesink Standards Track [Page 12] RFC 2558 SONET/SDH Objects March 1999 is declared within 5 ms of detecting the incoming VT-Path RFI Signal. The VT-Path Remote Failure Indication (RFI) failure is cleared within 50 ms of detecting the removal of the incoming VT-Path RFI signal. Coding Violation Coding Violations (CV) are Bit Interleaved Parity (BIP) errors that are detected in the incoming signal. CV counters are incremented for each BIP error detected. That is, each BIP-8 can detect up to eight errors per STS-N frame, with each error incrementing the CV counter. Section CVs shall be collected using the BIP-8 in the B1 byte located in the Section Overhead of STS-1 #1. Line CVs shall be collected using the BIP-8s in B2 bytes located in the Line Overhead of each STS-1 (since all CVs on an STS-N line are counted together, this is equivalent to counting each error in the BIP-8*N contained in the B2 bytes of the STS-N Line Overhead). Thus, on an STS-N signal, up to 8 x N CVs may occur in each frame. Path CVs shall be collected using the BIP-8 in the B3 byte of the STS-Path Overhead of the STS SPE. VT CVs shall be collected using the BIP-2 in the V5 overhead byte of the floating VT. Errored Seconds At each layer, an Errored Second (ES) is a second with one or more Coding Violations at that layer OR one or more incoming defects (e.g., SEF, LOS, AIS, LOP) at that layer has occurred. Severely Errored Seconds According to [22][31][32][34][35] at each layer, an Severely Errored Second (SES) is a second with x or more CVs at that layer, or a second during which at least one or more incoming defects at that layer has occurred. The values of x in RFC1595[30] were based on [22] and [32] (see Appendix B). These values have subsequently been relaxed in [31][34][35]. In addition, according to G.826 [33] SESs are measured as a percentage of errored blocks. To deal with these sets of definitions this memo defines an object sonetSESThresholdSet that determines the correct interpretation of SES. For backward compatibility, if this object is not implemented the interpretation of Appendix B shall apply. Otherwise, a more recent interpretation is suggested. An agent is not required to support all sets of definitions. Note that if a manager changes the value of this object all SES statistics collected prior to this change shall be invalidated. Tesink Standards Track [Page 13] RFC 2558 SONET/SDH Objects March 1999 Severely Errored Framing Seconds A Severely Errored Framing Second (SEFS) is a second containing one or more SEF events. This counter is only counted at the Section Layer. Unavailable Seconds At the Line, Path, and VT layers, an unavailable second is calculated by counting the number of seconds that the interface is unavailable. At each layer, the SONET/SDH interface is said to be unavailable at the onset of 10 contiguous SESs. The 10 SESs are included in unavailable time. Once unavailable, the SONET/SDH interface becomes available at the onset of 10 contiguous seconds with no SESs. The 10 seconds with no SESs are excluded from unavailable time. With respect to the SONET/SDH error counts at each layer, all counters at that layer are incremented while the SONET/SDH interface is deemed available at that layer. While the interface is deemed unavailable at that layer, the only count that is incremented is UASs at that layer. Note that this definition implies that the agent cannot determine until after a ten second interval has passed whether a given one-second interval belongs to available or unavailable time. If the agent chooses to update the various performance statistics in real time then it must be prepared to retroactively reduce the ES, SES, and SEFS counts by 10 and increase the UAS count by 10 when it determines that available time has been entered. It must also be prepared to reduce the CV count by the number of violations counted since the onset of unavailable time. The agent must be similarly prepared to retroactively decrease the UAS count by 10 and increase the ES and CV counts as necessary upon entering available time. A special case exists when the 10 second period leading to available or unavailable time crosses a 900 second statistics window boundary, as the foregoing description implies that the CV, ES, SES, SEFS, and UAS counts the PREVIOUS interval must be adjusted. In this case successive GETs of the affected sonetPathIntervalSES and sonetPathIntervalUAS objects (and the analogous Line and VT objects also) objects will return differing values if the first GET occurs during the first few seconds of the window. According to ANSI T1.231 unavailable time begins at the _onset_ of 10 contiguous severely errored seconds -- that is, unavailable time starts with the _first_ of the 10 contiguous SESs. Also, while an interface is deemed unavailable all counters for that interface are frozen except for the UAS count. It follows that an implementation which strictly complies with Tesink Standards Track [Page 14] RFC 2558 SONET/SDH Objects March 1999 this standard must _not_ increment any counters other than the UAS count -- even temporarily -- as a result of anything that happens during those 10 seconds. Since changes in the signal state lag the data to which they apply by 10 seconds, an ANSI- compliant implementation must pass the one-second statistics through a 10-second delay line prior to updating any counters. That can be done by performing the following steps at the end of each one second interval. i) Read near/far end CV counter and alarm status flags from the hardware. ii) Accumulate the CV counts for the preceding second and compare them to the ES and SES threshold for the layer in question. Update the signal state and shift the one-second CV counts and ES/SES flags into the 10-element delay line. Note that far-end one-second statistics are to be flagged as "absent" during any second in which there is an incoming defect at the layer in question or at any lower layer. iii) Update the current interval statistics using the signal state from the _previous_ update cycle and the one-second CV counts and ES/SES flags shifted out of the 10-element delay line. This approach is further described in Appendix A. An agent may choose to use this approach in lieu of retroactive adjustments to the counters. In any case, a linkDown trap shall be sent only after the agent has determined for certain that the unavailable state has been entered, but the time on the trap will be that of the first UAS (i.e., 10 seconds earlier). A linkUp trap shall be handled similarly. Unequipped If a Path or VT connection is not provisioned (idle) the SONET equipment will signal this state by transmitting the Path or VT Signal Label as follows: - byte C2 of the STS Path Overhead equal to 0 for an unequipped Path, - byte V5 of the VT Path Overhead equal to 0 for an unequipped VT. Signal Label Mismatch A Path or VT connection is not correctly provisioned if a received Path or VT Signal Label mismatch occurs. A received Signal Label is considered mismatched if it does not equal either the locally provisioned value or the value 'equipped Tesink Standards Track [Page 15] RFC 2558 SONET/SDH Objects March 1999 non-specific' (1 hex). Note that any received non-zero Signal Label is considered a locally provisioned value of 'equipped non-specific'. Only in-service, provisioned Path Terminating equipment can detect mismatched Signal labels. It is considered provisioned if it has been configured for a mapping and has been assigned signals to and from which the mapping takes place. While a Path is unequipped or has mismatched signal labels ES/SES counts continue, but these conditions do not themselves contribute to ES/SES. Circuit Identifier This is a character string specified by the circuit vendor, and is useful when communicating with the vendor during the troubleshooting process. 4. Object Definitions SONET-MIB DEFINITIONS ::= BEGIN IMPORTS MODULE-IDENTITY, OBJECT-TYPE, Integer32, transmission FROM SNMPv2-SMI DisplayString, TruthValue FROM SNMPv2-TC MODULE-COMPLIANCE, OBJECT-GROUP FROM SNMPv2-CONF ifIndex FROM IF-MIB PerfCurrentCount, PerfIntervalCount FROM PerfHist-TC-MIB; -- This is the MIB module for the SONET/SDH Interface objects. sonetMIB MODULE-IDENTITY LAST-UPDATED "9810190000Z" ORGANIZATION "IETF AToM MIB Working Group" CONTACT-INFO "Kaj Tesink Telcordia Technologies Tel: (732) 758-5254 Fax: (732) 758-2269 E-mail: kaj@research.telcordia.com." DESCRIPTION "The MIB module to describe SONET/SDH interfaces objects." Tesink Standards Track [Page 16] RFC 2558 SONET/SDH Objects March 1999 REVISION "9810190000Z" DESCRIPTION "The key changes made to this MIB module since its initial publication in RFC 1595 are as follows. (1) The MODULE-IDENTITY has been updated to reflect the changes to the MIB. (2) Where applicable, the textual conventions PerfCurrentCount and PerfIntervalCount from PerfHist-TC-MIB have been used in place of Gauge32. (3) An agent now has the option to delay updates to the various performance counts in lieu of performing retroactive adjustments upon entering into or exiting from unavailable time. This implementation option is described in Appendix A of this memo. (4) In order to make the SONET-MIB more useful for circuit provisioning, the formerly read-only objects sonetMediumType, sonetMediumLineCoding, sonetMediumLineType, and sonetMediumCircuitIdentifier have been given a MAX-ACCESS of read-write. The MIN-ACCESS remains read-only. (5) The DESCRIPTION clause for sonetMediumTimeElapsed has been updated to describe its behaviour if the duration of the current interval exceeds the maximum value. (6) The DESCRIPTION clause for sonetMediumValidIntervals has been updated to describe its behaviour when some intervals may be unavailable, and the object sonetMediumInvalidIntervals has been added to keep count of the number of missing intervals (if any). (7) The object sonetMediumLoopbackConfig has been added to enable or disable loopback configurations. (8) Because the error count thresholds for declaring severely errored seconds that are specified in ANSI T1.231-1993, ITU-T G.826-1995, and ANSI T1.231-1997 are all different from each other and from the thresholds specified in RFC 1595, an enumerated INTEGER object sonetSESthresholdSet has been added to allow an agent to specify which threshold set is in use. Text has been added to Section 3 stating that if this object is not implemented the thresholds specified in RFC 1595 Tesink Standards Track [Page 17] RFC 2558 SONET/SDH Objects March 1999 should be assumed, and the table containing those thresholds has been moved to Appendix B of this memo. (9) A column with SYNTAX TruthValue has been added to each interval table. The purpose of the additional column is to indicate, for each interval, whether the data is valid in the sense intended by ANSI T1.231 clause 9.1.2.2 [31][35]. The objects in question are: sonetSectionIntervalValidData sonetLineIntervalValidData sonetFarEndLineIntervalValidData sonetPathIntervalValidData sonetFarEndPathIntervalValidData sonetVTIntervalValidData sonetFarEndVTIntervalValidData (10) The ranges for sonetPathCurrentStatus and sonetVTCurrentStatus have been made consistent with the DESCRIPTION clauses. (11) The conformance information has been updated. Previous conformance information from RFC 1595 has been deprecated. Some typographical errors in the deprecated section have been corrected in order to prevent MIB compilation errors." REVISION "9401030000Z" DESCRIPTION "The RFC1595 version of this MIB module." ::= { transmission 39 } -- This is the MIB module for the SONET/SDH objects sonetObjects OBJECT IDENTIFIER ::= { sonetMIB 1 } sonetObjectsPath OBJECT IDENTIFIER ::= { sonetMIB 2 } sonetObjectsVT OBJECT IDENTIFIER ::= { sonetMIB 3 } -- groups in the SONET/SDH MIB module sonetMedium OBJECT IDENTIFIER ::= { sonetObjects 1 } sonetSection OBJECT IDENTIFIER ::= { sonetObjects 2 } Tesink Standards Track [Page 18] RFC 2558 SONET/SDH Objects March 1999 sonetLine OBJECT IDENTIFIER ::= { sonetObjects 3 } sonetFarEndLine OBJECT IDENTIFIER ::= { sonetObjects 4 } sonetPath OBJECT IDENTIFIER ::= { sonetObjectsPath 1 } sonetFarEndPath OBJECT IDENTIFIER ::= { sonetObjectsPath 2 } sonetVT OBJECT IDENTIFIER ::= { sonetObjectsVT 1 } sonetFarEndVT OBJECT IDENTIFIER ::= { sonetObjectsVT 2 } -- the SONET/SDH Medium group -- SONET/SDH interfaces for some applications may be electrical -- interfaces and not optical interfaces. This group handles -- the configuration information for both optical SONET/SDH -- interfaces and electrical SONET/SDH interfaces. sonetMediumTable OBJECT-TYPE SYNTAX SEQUENCE OF SonetMediumEntry MAX-ACCESS not-accessible STATUS current DESCRIPTION "The SONET/SDH Medium table." ::= { sonetMedium 1 } sonetMediumEntry OBJECT-TYPE SYNTAX SonetMediumEntry MAX-ACCESS not-accessible STATUS current DESCRIPTION "An entry in the SONET/SDH Medium table." INDEX { ifIndex } ::= { sonetMediumTable 1 } SonetMediumEntry ::= SEQUENCE { sonetMediumType INTEGER, sonetMediumTimeElapsed Integer32, sonetMediumValidIntervals Integer32, sonetMediumLineCoding INTEGER, sonetMediumLineType INTEGER, sonetMediumCircuitIdentifier DisplayString, sonetMediumInvalidIntervals Integer32, sonetMediumLoopbackConfig BITS } Tesink Standards Track [Page 19] RFC 2558 SONET/SDH Objects March 1999 sonetMediumType OBJECT-TYPE SYNTAX INTEGER { sonet(1), sdh(2) } MAX-ACCESS read-write STATUS current DESCRIPTION "This variable identifies whether a SONET or a SDH signal is used across this interface." ::= { sonetMediumEntry 1 } sonetMediumTimeElapsed OBJECT-TYPE SYNTAX Integer32 (1..900) MAX-ACCESS read-only STATUS current DESCRIPTION "The number of seconds, including partial seconds, that have elapsed since the beginning of the current measurement period. If, for some reason, such as an adjustment in the system's time-of-day clock, the current interval exceeds the maximum value, the agent will return the maximum value." ::= { sonetMediumEntry 2 } sonetMediumValidIntervals OBJECT-TYPE SYNTAX Integer32 (0..96) MAX-ACCESS read-only STATUS current DESCRIPTION "The number of previous 15-minute intervals for which data was collected. A SONET/SDH interface must be capable of supporting at least n intervals. The minimum value of n is 4. The default of n is 32. The maximum value of n is 96. The value will be unless the measurement was (re-)started within the last (*15) minutes, in which case the value will be the number of complete 15 minute intervals for which the agent has at least some data. In certain cases (e.g., in the case where the agent is a proxy) it is possible that some intervals are unavailable. In this case, this interval is the maximum interval number for which data is available. " ::= { sonetMediumEntry 3 } Tesink Standards Track [Page 20] RFC 2558 SONET/SDH Objects March 1999 sonetMediumLineCoding OBJECT-TYPE SYNTAX INTEGER { sonetMediumOther(1), sonetMediumB3ZS(2), sonetMediumCMI(3), sonetMediumNRZ(4), sonetMediumRZ(5) } MAX-ACCESS read-write STATUS current DESCRIPTION "This variable describes the line coding for this interface. The B3ZS and CMI are used for electrical SONET/SDH signals (STS-1 and STS-3). The Non-Return to Zero (NRZ) and the Return to Zero are used for optical SONET/SDH signals." ::= { sonetMediumEntry 4 } sonetMediumLineType OBJECT-TYPE SYNTAX INTEGER { sonetOther(1), sonetShortSingleMode(2), sonetLongSingleMode(3), sonetMultiMode(4), sonetCoax(5), sonetUTP(6) } MAX-ACCESS read-write STATUS current DESCRIPTION "This variable describes the line type for this interface. The line types are Short and Long Range Single Mode fiber or Multi-Mode fiber interfaces, and coax and UTP for electrical interfaces. The value sonetOther should be used when the Line Type is not one of the listed values." ::= { sonetMediumEntry 5 } sonetMediumCircuitIdentifier OBJECT-TYPE SYNTAX DisplayString (SIZE (0..255)) MAX-ACCESS read-write STATUS current DESCRIPTION "This variable contains the transmission vendor's circuit identifier, for the purpose of facilitating troubleshooting. Note that the circuit identifier, if available, Tesink Standards Track [Page 21] RFC 2558 SONET/SDH Objects March 1999 is also represented by ifPhysAddress." ::= { sonetMediumEntry 6 } sonetMediumInvalidIntervals OBJECT-TYPE SYNTAX Integer32 (0..96) MAX-ACCESS read-only STATUS current DESCRIPTION "The number of intervals in the range from 0 to sonetMediumValidIntervals for which no data is available. This object will typically be zero except in cases where the data for some intervals are not available (e.g., in proxy situations)." ::= { sonetMediumEntry 7 } sonetMediumLoopbackConfig OBJECT-TYPE SYNTAX BITS { sonetNoLoop(0), sonetFacilityLoop(1), sonetTerminalLoop(2), sonetOtherLoop(3) } MAX-ACCESS read-write STATUS current DESCRIPTION "The current loopback state of the SONET/SDH interface. The values mean: sonetNoLoop Not in the loopback state. A device that is not capable of performing a loopback on this interface shall always return this value. sonetFacilityLoop The received signal at this interface is looped back out through the corresponding transmitter in the return direction.