Pseudowire (PW) Management Information Base (MIB)
RFC 5601
| Document | Type | RFC - Proposed Standard (July 2009) Errata | |
|---|---|---|---|
| Authors | Thomas Nadeau , David Zelig | ||
| Last updated | 2020-01-21 | ||
| RFC stream | Internet Engineering Task Force (IETF) | ||
| Formats | |||
| Additional resources | Mailing list discussion | ||
| IESG | Responsible AD | Mark Townsley | |
| Send notices to | (None) |
RFC 5601
RFC 5601 PW MIB July 2009 GROUP pwAttachmentGroup DESCRIPTION "This group is only mandatory for implementations that support attachment of two PWs (PW stitching)." GROUP pwPeformance1DayIntervalGroup DESCRIPTION "This group is only mandatory for implementations that support PW performance gathering in 1-day intervals." GROUP pwPerformanceIntervalGeneralGroup DESCRIPTION "This group is only mandatory for implementations that support PW performance gathering in 15- minute intervals." GROUP pwPeformanceIntervalGroup DESCRIPTION "This group is only mandatory for implementations that support PW performance gathering in 15- minute intervals." GROUP pwHCPeformanceIntervalGroup DESCRIPTION "This group is only mandatory for implementations where at least one of the interval performance counters wraps around too quickly based on the criteria specified in RFC 2863 for high-capacity counters." GROUP pwMappingTablesGroup DESCRIPTION "This group is only mandatory for implementations that support reverse mapping of PW indexes to the pwIndex and the peer mapping table." GROUP pwSignalingGroup DESCRIPTION "This group is only mandatory for implementations that support the PW signaling." GROUP pwNotificationControlGroup DESCRIPTION "This group is only mandatory for implementations that support the PW notifications." OBJECT pwAdminStatus SYNTAX INTEGER { up(1), down(2) } DESCRIPTION "Support of the value testing(3) is not required." OBJECT pwOperStatus SYNTAX INTEGER { up(1), down(2), notPresent(5), lowerLayerDown(6) } DESCRIPTION "Support of the values testing(3) and dormant(4) Nadeau & Zelig Standards Track [Page 50] RFC 5601 PW MIB July 2009 is not required." OBJECT pwRowStatus SYNTAX RowStatus { active(1), notInService(2), notReady(3) } WRITE-SYNTAX RowStatus { active(1), notInService(2), createAndGo(4), destroy(6) } DESCRIPTION "Support for createAndWait is not required. Support of notReady is not required for implementations that do not support signaling, or if it is guaranteed that the conceptual row has all the required information to create the PW when the row has been created by the agent or written by the operator." OBJECT pwPeerAddrType SYNTAX InetAddressType { unknown(0), ipv4(1) } MIN-ACCESS read-only DESCRIPTION "Only unknown(0) and ipv4(1) are required. Implementations that support only IPv4 MAY support read-only access." OBJECT pwPeerAddr SYNTAX InetAddress (SIZE(0|4)) DESCRIPTION "An implementation is only required to support 0, 4 address sizes." OBJECT pwStorageType MIN-ACCESS read-only DESCRIPTION "Write access is not required." OBJECT pwNotifRate MIN-ACCESS read-only DESCRIPTION "Write access is not required." ::= { pwCompliances 1 } -- Compliance requirement for read-only compliant implementations pwModuleReadOnlyCompliance MODULE-COMPLIANCE STATUS current DESCRIPTION "The compliance statement for agents that provide read- only support for the PW MIB module. Such devices can then be monitored but cannot be configured using this MIB module." Nadeau & Zelig Standards Track [Page 51] RFC 5601 PW MIB July 2009 MODULE -- this module MANDATORY-GROUPS { pwBasicGroup } GROUP pwNotificationGroup DESCRIPTION "This group is only mandatory for implementations that can efficiently implement the notifications contained in this group." GROUP pwPwIdGroup DESCRIPTION "This group is only mandatory for implementations that support the PW ID FEC. " GROUP pwGeneralizedFecGroup DESCRIPTION "This group is only mandatory for implementations that support the generalized PW FEC. " GROUP pwFcsGroup DESCRIPTION "This group is only mandatory for implementations that support FCS retention." GROUP pwFragGroup DESCRIPTION "This group is only mandatory for implementations that support PW fragmentation. " GROUP pwPwStatusGroup DESCRIPTION "This group is only mandatory for implementations that support PW status notification. " GROUP pwGetNextGroup DESCRIPTION "This group is only mandatory for implementations where the pwIndex may be any arbitrary value and the EMS would require retrieval of the next free index." GROUP pwPriorityGroup DESCRIPTION "This group is only mandatory for implementations that support the controlling the PW setup and holding priority." GROUP pwAttachmentGroup DESCRIPTION "This group is only mandatory for implementations that support attachment of two PWs (PW stitching)." Nadeau & Zelig Standards Track [Page 52] RFC 5601 PW MIB July 2009 GROUP pwPeformance1DayIntervalGroup DESCRIPTION "This group is only mandatory for implementations that support PW performance gathering in 1-day intervals." GROUP pwPerformanceIntervalGeneralGroup DESCRIPTION "This group is only mandatory for implementations that support PW performance gathering in 15- minute intervals." GROUP pwPeformanceIntervalGroup DESCRIPTION "This group is only mandatory for implementations that support PW performance gathering in 15- minute intervals." GROUP pwHCPeformanceIntervalGroup DESCRIPTION "This group is only mandatory for implementations where at least one of the interval performance counters wraps around too quickly based on the criteria specified in RFC 2863 for high-capacity counters." GROUP pwMappingTablesGroup DESCRIPTION "This group is only mandatory for implementations that support reverse mapping of PW indexes to the pwIndex and the peer mapping table." GROUP pwSignalingGroup DESCRIPTION "This group is only mandatory for implementations that support the PW signaling." GROUP pwNotificationControlGroup DESCRIPTION "This group is only mandatory for implementations that support the PW notifications." OBJECT pwType MIN-ACCESS read-only DESCRIPTION "Write access is not required." OBJECT pwOwner MIN-ACCESS read-only DESCRIPTION "Write access is not required." OBJECT pwPsnType MIN-ACCESS read-only DESCRIPTION "Write access is not required." OBJECT pwSetUpPriority Nadeau & Zelig Standards Track [Page 53] RFC 5601 PW MIB July 2009 MIN-ACCESS read-only DESCRIPTION "Write access is not required." OBJECT pwHoldingPriority MIN-ACCESS read-only DESCRIPTION "Write access is not required." OBJECT pwPeerAddrType SYNTAX InetAddressType { unknown(0), ipv4(1) } MIN-ACCESS read-only DESCRIPTION "Write access is not required. Only unknown(0) and ipv4(1) are required." OBJECT pwPeerAddr SYNTAX InetAddress (SIZE(0|4)) MIN-ACCESS read-only DESCRIPTION "Write access is not required. An implementation is only required to support 0, 4 address sizes." OBJECT pwAttachedPwIndex MIN-ACCESS read-only DESCRIPTION "Write access is not required." OBJECT pwIfIndex MIN-ACCESS read-only DESCRIPTION "Write access is not required." OBJECT pwID MIN-ACCESS read-only DESCRIPTION "Write access is not required." OBJECT pwLocalGroupID MIN-ACCESS read-only DESCRIPTION "Write access is not required." OBJECT pwGroupAttachmentID MIN-ACCESS read-only DESCRIPTION "Write access is not required." OBJECT pwLocalAttachmentID MIN-ACCESS read-only DESCRIPTION "Write access is not required." OBJECT pwRemoteAttachmentID MIN-ACCESS read-only DESCRIPTION "Write access is not required." OBJECT pwCwPreference Nadeau & Zelig Standards Track [Page 54] RFC 5601 PW MIB July 2009 MIN-ACCESS read-only DESCRIPTION "Write access is not required." OBJECT pwLocalIfMtu MIN-ACCESS read-only DESCRIPTION "Write access is not required." OBJECT pwLocalIfString MIN-ACCESS read-only DESCRIPTION "Write access is not required." OBJECT pwLocalCapabAdvert MIN-ACCESS read-only DESCRIPTION "Write access is not required." OBJECT pwFragmentCfgSize MIN-ACCESS read-only DESCRIPTION "Write access is not required." OBJECT pwFcsRetentionCfg MIN-ACCESS read-only DESCRIPTION "Write access is not required." OBJECT pwOutboundLabel MIN-ACCESS read-only DESCRIPTION "Write access is not required." OBJECT pwInboundLabel MIN-ACCESS read-only DESCRIPTION "Write access is not required." OBJECT pwName MIN-ACCESS read-only DESCRIPTION "Write access is not required." OBJECT pwDescr MIN-ACCESS read-only DESCRIPTION "Write access is not required." OBJECT pwAdminStatus SYNTAX INTEGER { up(1), down(2) } MIN-ACCESS read-only DESCRIPTION "Write access is not required. The support of value testing(3) is not required." OBJECT pwOperStatus SYNTAX INTEGER { up(1), down(2), notPresent(5), lowerLayerDown(6) } Nadeau & Zelig Standards Track [Page 55] RFC 5601 PW MIB July 2009 DESCRIPTION "The support of the values testing(3) and dormant(4) is not required." OBJECT pwRowStatus SYNTAX RowStatus { active(1) } MIN-ACCESS read-only DESCRIPTION "Write access is not required." OBJECT pwStorageType MIN-ACCESS read-only DESCRIPTION "Write access is not required." OBJECT pwOamEnable MIN-ACCESS read-only DESCRIPTION "Write access is not required." OBJECT pwGenAGIType MIN-ACCESS read-only DESCRIPTION "Write access is not required." OBJECT pwGenLocalAIIType MIN-ACCESS read-only DESCRIPTION "Write access is not required." OBJECT pwGenRemoteAIIType MIN-ACCESS read-only DESCRIPTION "Write access is not required." OBJECT pwUpDownNotifEnable MIN-ACCESS read-only DESCRIPTION "Write access is not required." OBJECT pwDeletedNotifEnable MIN-ACCESS read-only DESCRIPTION "Write access is not required." OBJECT pwNotifRate MIN-ACCESS read-only DESCRIPTION "Write access is not required." ::= { pwCompliances 2 } -- Units of conformance. pwBasicGroup OBJECT-GROUP OBJECTS { pwType, pwOwner, Nadeau & Zelig Standards Track [Page 56] RFC 5601 PW MIB July 2009 pwPsnType, pwIfIndex, pwCwPreference, pwLocalIfMtu, pwOutboundLabel, pwInboundLabel, pwName, pwDescr, pwCreateTime, pwUpTime, pwLastChange, pwAdminStatus, pwOperStatus, pwLocalStatus, pwRowStatus, pwStorageType, pwOamEnable } STATUS current DESCRIPTION "Collection of objects that are required in all implementations that support the PW MIB module." ::= { pwGroups 1 } pwPwIdGroup OBJECT-GROUP OBJECTS { pwID } STATUS current DESCRIPTION "Collection of objects required for PW ID configuration and signaling." ::= { pwGroups 2 } pwGeneralizedFecGroup OBJECT-GROUP OBJECTS { pwGroupAttachmentID, pwLocalAttachmentID, pwRemoteAttachmentID, pwGenAGIType, pwGenLocalAIIType, pwGenRemoteAIIType } STATUS current DESCRIPTION "Collection of objects required for generalized FEC Nadeau & Zelig Standards Track [Page 57] RFC 5601 PW MIB July 2009 configuration and signaling." ::= { pwGroups 3 } pwFcsGroup OBJECT-GROUP OBJECTS { pwFcsRetentionCfg, pwFcsRetentionStatus } STATUS current DESCRIPTION "Collection of objects required for FCS retention configuration and signaling." ::= { pwGroups 4 } pwFragGroup OBJECT-GROUP OBJECTS { pwFragmentCfgSize, pwRmtFragCapability } STATUS current DESCRIPTION "Collection of objects required for fragmentation configuration and signaling." ::= { pwGroups 5 } pwPwStatusGroup OBJECT-GROUP OBJECTS { pwRemoteCapabilities, pwRemoteStatusCapable, pwRemoteStatus } STATUS current DESCRIPTION "Collection of objects required for PW status configuration and signaling." ::= { pwGroups 6 } pwGetNextGroup OBJECT-GROUP OBJECTS { pwIndexNext } STATUS current DESCRIPTION "Collection of objects for getting the next available Nadeau & Zelig Standards Track [Page 58] RFC 5601 PW MIB July 2009 index." ::= { pwGroups 7 } pwPriorityGroup OBJECT-GROUP OBJECTS { pwSetUpPriority, pwHoldingPriority } STATUS current DESCRIPTION "Collection of objects for controlling the PW setup and holding priority." ::= { pwGroups 8 } pwAttachmentGroup OBJECT-GROUP OBJECTS { pwAttachedPwIndex } STATUS current DESCRIPTION "Collection of objects for PW configuration as ifIndex." ::= { pwGroups 9 } pwPerformanceGeneralGroup OBJECT-GROUP OBJECTS { pwPerfTotalErrorPackets } STATUS current DESCRIPTION "Collection of general objects needed for managing the total running performance parameters." ::= { pwGroups 10 } pwPeformance1DayIntervalGroup OBJECT-GROUP OBJECTS { pwPerf1DayIntervalValidData, pwPerf1DayIntervalTimeElapsed, pwPerf1DayIntervalInHCPackets, pwPerf1DayIntervalInHCBytes, pwPerf1DayIntervalOutHCPackets, pwPerf1DayIntervalOutHCBytes } STATUS current DESCRIPTION "Collection of objects needed for a PW running 1-day Nadeau & Zelig Standards Track [Page 59] RFC 5601 PW MIB July 2009 interval performance collection." ::= { pwGroups 11 } pwPerformanceIntervalGeneralGroup OBJECT-GROUP OBJECTS { pwTimeElapsed, pwValidIntervals, pwPerfIntervalValidData, pwPerfIntervalTimeElapsed } STATUS current DESCRIPTION "Collection of general objects needed for managing the interval performance parameters." ::= { pwGroups 12 } pwPeformanceIntervalGroup OBJECT-GROUP OBJECTS { pwPerfCurrentInPackets, pwPerfCurrentInBytes, pwPerfCurrentOutPackets, pwPerfCurrentOutBytes, pwPerfIntervalInPackets, pwPerfIntervalInBytes, pwPerfIntervalOutPackets, pwPerfIntervalOutBytes } STATUS current DESCRIPTION "Collection of 32-bit objects needed for PW performance collection in 15-minute intervals." ::= { pwGroups 13 } pwHCPeformanceIntervalGroup OBJECT-GROUP OBJECTS { pwPerfCurrentInHCPackets, pwPerfCurrentInHCBytes, pwPerfCurrentOutHCPackets, pwPerfCurrentOutHCBytes, pwPerfIntervalInHCPackets, pwPerfIntervalInHCBytes, pwPerfIntervalOutHCPackets, pwPerfIntervalOutHCBytes } Nadeau & Zelig Standards Track [Page 60] RFC 5601 PW MIB July 2009 STATUS current DESCRIPTION "Collection of HC objects needed for PW performance collection in 15-minute intervals." ::= { pwGroups 14 } pwMappingTablesGroup OBJECT-GROUP OBJECTS { pwIndexMappingPwIndex, pwPeerMappingPwIndex, pwGenFecIndexMappingPwIndex } STATUS current DESCRIPTION "Collection of objects contained in the reverse mapping tables." ::= { pwGroups 15 } pwNotificationControlGroup OBJECT-GROUP OBJECTS { pwUpDownNotifEnable, pwDeletedNotifEnable, pwNotifRate } STATUS current DESCRIPTION "Collection of objects for controlling the PW notifications." ::= { pwGroups 16 } pwNotificationGroup NOTIFICATION-GROUP NOTIFICATIONS { pwUp, pwDown, pwDeleted } STATUS current DESCRIPTION "Collection of PW notifications objects." ::= { pwGroups 17 } pwSignalingGroup OBJECT-GROUP OBJECTS { pwPeerAddrType, pwPeerAddr, Nadeau & Zelig Standards Track [Page 61] RFC 5601 PW MIB July 2009 pwLocalGroupID, pwLocalIfString, pwLocalCapabAdvert, pwRemoteGroupID, pwCwStatus, pwRemoteIfMtu, pwRemoteIfString } STATUS current DESCRIPTION "Collection of objects for use in implementations that support the PW signaling." ::= { pwGroups 18 } END 13. Security Considerations It is clear that this MIB module is potentially useful for monitoring PW-capable PEs. This MIB module can also be used for configuration of certain objects, and anything that can be configured can be incorrectly configured, with potentially disastrous results. There are a number of management objects defined in this MIB module with a MAX-ACCESS clause of read-write and/or read-create. Such objects may be considered sensitive or vulnerable in some network environments. The support for SET operations in a non-secure environment without proper protection can have a negative effect on network operations. These are the tables and objects and their sensitivity/vulnerability: o the pwTable contains objects to configure PW parameters on a Provider Edge (PE) device. Unauthorized access to objects in this table could result in disruption of traffic on the network. The objects pwUpDownNotifEnable and pwNotifRate control the reports from the network element to the EMS. Unauthorized access to these objects could result in disruption of configuration and status change reporting, resulting mis-view of the network conditions. The use of stronger mechanisms such as SNMPv3 security should be considered where possible. Specifically, SNMPv3 VACM and USM MUST be used with any v3 agent that implements this MIB module. Administrators should consider whether read access to these objects should be allowed, since read access may be undesirable under certain circumstances. Nadeau & Zelig Standards Track [Page 62] RFC 5601 PW MIB July 2009 Some of the readable objects in this MIB module (i.e., objects with a MAX-ACCESS other than not-accessible) may be considered sensitive or vulnerable in some network environments. It is thus important to control even GET and/or NOTIFY access to these objects and possibly to even encrypt the values of these objects when sending them over the network via SNMP. These are the tables and objects and their sensitivity/vulnerability: o the pwTable, pwPerfCurrentTable, pwPerfIntervalTable, pwPerf1DayIntervalTable, pwIndexMappingTable, pwPeerMappingTable, and pwGenFecIndexMappingTable collectively show the pseudowire connectivity topology and its performance characteristics. If an administrator does not want to reveal this information, then these tables should be considered sensitive/vulnerable. SNMP versions prior to SNMPv3 did not include adequate security. Even if the network itself is secure (for example by using IPsec), even then, there is no control as to who on the secure network is allowed to access and GET/SET (read/change/create/delete) the objects in this MIB module. It is RECOMMENDED that implementers consider the security features as provided by the SNMPv3 framework (see [RFC3410], section 8), including full support for the SNMPv3 cryptographic mechanisms (for authentication and privacy). Further, deployment of SNMP versions prior to SNMPv3 is NOT RECOMMENDED. Instead, it is RECOMMENDED to deploy SNMPv3 and to enable cryptographic security. It is then a customer/operator responsibility to ensure that the SNMP entity giving access to an instance of this MIB module is properly configured to give access to the objects only to those principals (users) that have legitimate rights to indeed GET or SET (change/create/delete) them. 14. IANA Considerations 14.1. ifType for PW IANA has assigned a value (246) for PW in the IANAifType-MIB called ifPwType. 14.2. PW MIB Modules OBJECT IDENTIFIER Values A PW may appear as ifIndex in the ifTable, and therefore the pwStdMIB OBJECT IDENTIFIER has been assigned under the 'transmission' subtree, as the common practice in assigning OBJECT IDENTIFIERs for MIB modules representing entities in the ifTable. Nadeau & Zelig Standards Track [Page 63] RFC 5601 PW MIB July 2009 All other MIB modules related to PW management SHOULD be assigned under the 'mib-2' subtree; individual requests will appear in the MIB module memo's IANA Considerations section. 14.3. IANA Considerations for PW-STD-MIB The MIB module in this document uses the following IANA-assigned OBJECT IDENTIFIER values recorded in the SMI Numbers registry: Descriptor OBJECT IDENTIFIER value ---------- ----------------------- pwStdMIB { transmission 246 } 14.4. IANA Considerations for IANA-PWE3-MIB The MIB module in this document uses the following IANA-assigned OBJECT IDENTIFIER values recorded in the SMI Numbers registry: Descriptor OBJECT IDENTIFIER value ---------- ----------------------- ianaPwe3MIB { mib-2 174 } 15. Acknowledgments We thank Orly Nicklass for her dedicated review and significant edit in various sections of the document, and Kiran Koushik for his contribution. The individuals listed below contributed significantly to this document: Dave Danenberg - Litchfield Communications Sharon Mantin - Corrigent Systems 16. References 16.1. Normative References [BCP14] Bradner, S., "Key words for use in RFCs to Indicate requirement Levels", BCP 14, RFC 2119, March 1997. [RFC2578] McCloghrie, K., Ed., Perkins, D., Ed., and J. Schoenwaelder, Ed., "Structure of Management Information Version 2 (SMIv2)", STD 58, RFC 2578, April 1999. Nadeau & Zelig Standards Track [Page 64] RFC 5601 PW MIB July 2009 [RFC2579] McCloghrie, K., Ed., Perkins, D., Ed., and J. Schoenwaelder, Ed., "Textual Conventions for SMIv2", STD 58, RFC 2579, April 1999. [RFC2580] McCloghrie, K., Perkins, D., and J. Schoenwaelder, "Conformance Statements for SMIv2", STD 58, RFC 2580, April 1999. [RFC2863] McCloghrie, K. and F. Kastenholz, "The Interfaces Group MIB", RFC 2863, June 2000. [RFC3411] Harrington, D., Presuhn, R., and B. Wijnen, "An Architecture for Describing Simple Network Management Protocol (SNMP) Management Frameworks", STD 62, RFC 3411, December 2002. [RFC3413] Levi, D., Meyer, P., and B. Stewart, "Simple Network Management Protocol (SNMP) Applications", STD 62, RFC 3413, December 2002. [RFC3593] Tesink, K., Ed., "Textual Conventions for MIB Modules Using Performance History Based on 15 Minute Intervals", RFC 3593, September 2003. [RFC3705] Ray, B. and R. Abbi, "High Capacity Textual Conventions for MIB Modules Using Performance History Based on 15 Minute Intervals", RFC 3705, February 2004. [RFC3931] Lau, J., Townsley, M., and I. Goyret, "Layer Two Tunneling Protocol - Version 3 (L2TPv3)", RFC 3931, March 2005. [RFC4001] Daniele, M., Haberman, B., Routhier, S., and J. Schoenwaelder, "Textual Conventions for Internet Network Addresses", RFC 4001, February 2005. [RFC4446] Martini, L., "IANA Allocations for Pseudowire Edge to Edge Emulation (PWE3)", BCP 116, RFC 4446, April 2006. [RFC4447] Martini, L., Rosen, E., El-Aawar, N., Smith, T., and G. Heron, "Pseudowire Setup and Maintenance Using the Label Distribution Protocol (LDP)", RFC 4447, April 2006. [RFC4623] Malis, A. and M. Townsley, "Pseudowire Emulation Edge-to- Edge (PWE3) Fragmentation and Reassembly", RFC 4623, August 2006. Nadeau & Zelig Standards Track [Page 65] RFC 5601 PW MIB July 2009 [RFC4720] Malis, A., Allan, D., and N. Del Regno, "Pseudowire Emulation Edge-to-Edge (PWE3) Frame Check Sequence Retention", RFC 4720, November 2006. [RFC4863] Martini, L. and G. Swallow, "Wildcard Pseudowire Type", RFC 4863, May 2007. [RFC5542] Nadeau, T., Ed., Zelig, D., Ed., and O. Nicklass, Ed., "Definitions of Textual Conventions for Pseudowires (PW) Management", RFC 5542, May 2009. 16.2. Informative References [CEPMIB] Zelig, D., Ed., Cohen, R., Ed., and T. Nadeau, Ed., "SONET/SDH Circuit Emulation Service Over Packet (CEP) Management Information Base (MIB) Using SMIv2", Work in Progress, January 2008. [RFC3410] Case, J., Mundy, R., Partain, D., and B. Stewart, "Introduction and Applicability Statements for Internet- Standard Management Framework", RFC 3410, December 2002. [RFC3916] Xiao, X., Ed., McPherson, D., Ed., and P. Pate, Ed., "Requirements for Pseudo-Wire Emulation Edge-to-Edge (PWE3)", RFC 3916, September 2004. [RFC3985] Bryant, S. and P. Pate, "Pseudo Wire Emulation Edge-to- Edge (PWE3) Architecture", RFC 3985, March 2005. [RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an IANA Considerations Section in RFCs", BCP 26, RFC 5226, May 2008. [RFC5602] Zelig, D., Ed., and T. Nadeau, Ed., "Pseudowire (PW) over MPLS PSN Management Information Base (MIB)", RFC 5602, July 2009. Nadeau & Zelig Standards Track [Page 66] RFC 5601 PW MIB July 2009 Authors' Addresses Thomas D. Nadeau (editor) BT BT Centre 81 Newgate Street London EC1A 7AJ United Kingdom EMail: tom.nadeau@bt.com David Zelig (editor) Oversi Networks 1 Rishon Letzion St. Petah Tikva Israel Phone: +972 77 3337 750 EMail: davidz@oversi.com Nadeau & Zelig Standards Track [Page 67]