RFC 8571
BGP - Link State (BGP-LS) Advertisement of IGP Traffic Engineering Performance Metric Extensions
Pages: 10
Proposed Standard
Proposed Standard
Internet Engineering Task Force (IETF) L. Ginsberg, Ed. Request for Comments: 8571 Cisco Systems, Inc. Category: Standards Track S. Previdi ISSN: 2070-1721 Q. Wu Huawei J. Tantsura Apstra, Inc. C. Filsfils Cisco Systems, Inc. March 2019 BGP - Link State (BGP-LS) Advertisement of IGP Traffic Engineering Performance Metric ExtensionsAbstract
This document defines new BGP - Link State (BGP-LS) TLVs in order to carry the IGP Traffic Engineering Metric Extensions defined in the IS-IS and OSPF protocols. Status of This Memo This is an Internet Standards Track document. 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). Further information on Internet Standards is available in 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/rfc8571.
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1. Introduction ....................................................2 2. Link Attribute TLVs for TE Metric Extensions ....................3 2.1. Unidirectional Link Delay TLV ..............................3 2.2. Min/Max Unidirectional Link Delay TLV ......................4 2.3. Unidirectional Delay Variation TLV .........................4 2.4. Unidirectional Link Loss TLV ...............................5 2.5. Unidirectional Residual Bandwidth TLV ......................5 2.6. Unidirectional Available Bandwidth TLV .....................6 2.7. Unidirectional Utilized Bandwidth TLV ......................6 2.8. Mappings to IGP Source Sub-TLVs ............................7 3. Security Considerations .........................................7 4. IANA Considerations .............................................8 5. References ......................................................8 5.1. Normative References .......................................8 5.2. Informative References .....................................9 Acknowledgements ...................................................9 Contributors .......................................................9 Authors' Addresses ................................................101. Introduction
BGP - Link State (BGP-LS) [RFC7752] defines Network Layer Reachability Information (NLRI) and attributes in order to carry link-state information. New BGP-LS Link Attribute TLVs are required in order to carry the Traffic Engineering Metric Extensions defined in [RFC8570] and [RFC7471].
2. Link Attribute TLVs for TE Metric Extensions
The following new Link Attribute TLVs are defined: TLV Code Point Value -------------------------------------------------------- 1114 Unidirectional Link Delay 1115 Min/Max Unidirectional Link Delay 1116 Unidirectional Delay Variation 1117 Unidirectional Link Loss 1118 Unidirectional Residual Bandwidth 1119 Unidirectional Available Bandwidth 1120 Unidirectional Utilized Bandwidth TLV formats are described in detail in the following subsections. TLV formats follow the rules defined in [RFC7752].2.1. Unidirectional Link Delay TLV
This TLV advertises the average link delay between two directly connected IGP link-state neighbors. The semantics and values of the fields in the TLV are described in [RFC8570] and [RFC7471]. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |A| RESERVED | Delay | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 1 where: Type: 1114 Length: 4
2.2. Min/Max Unidirectional Link Delay TLV
This TLV advertises the minimum and maximum delay values between two directly connected IGP link-state neighbors. The semantics and values of the fields in the TLV are described in [RFC8570] and [RFC7471]. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |A| RESERVED | Min Delay | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | RESERVED | Max Delay | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 2 where: Type: 1115 Length: 82.3. Unidirectional Delay Variation TLV
This TLV advertises the average link delay variation between two directly connected IGP link-state neighbors. The semantics and values of the fields in the TLV are described in [RFC8570] and [RFC7471]. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | RESERVED | Delay Variation | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 3 where: Type: 1116 Length: 4
2.4. Unidirectional Link Loss TLV
This TLV advertises the loss (as a packet percentage) between two directly connected IGP link-state neighbors. The semantics and values of the fields in the TLV are described in [RFC8570] and [RFC7471]. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |A| RESERVED | Link Loss | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 4 where: Type: 1117 Length: 42.5. Unidirectional Residual Bandwidth TLV
This TLV advertises the residual bandwidth between two directly connected IGP link-state neighbors. The semantics and values of the fields in the TLV are described in [RFC8570] and [RFC7471]. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Residual Bandwidth | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 5 where: Type: 1118 Length: 4
2.6. Unidirectional Available Bandwidth TLV
This TLV advertises the available bandwidth between two directly connected IGP link-state neighbors. The semantics and values of the fields in the TLV are described in [RFC8570] and [RFC7471]. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Available Bandwidth | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 6 where: Type: 1119 Length: 42.7. Unidirectional Utilized Bandwidth TLV
This TLV advertises the bandwidth utilization between two directly connected IGP link-state neighbors. The semantics and values of the fields in the TLV are described in [RFC8570] and [RFC7471]. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Utilized Bandwidth | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 7 where: Type: 1120 Length: 4
2.8. Mappings to IGP Source Sub-TLVs
This section documents the mappings between the Link Attribute TLVs defined in this document and the corresponding advertisements sourced by the IGPs. For OSPFv2 and OSPFv3, the advertisements are defined in [RFC7471]. For IS-IS, the advertisements are defined in [RFC8570]. +---------------------------------------+----------+----------------+ | Attribute Name | IS-IS | OSPFv2/OSPFv3 | | | Sub-TLV | Sub-TLV | +---------------------------------------+----------+----------------+ | Unidirectional Link Delay | 33 | 27 | +---------------------------------------+----------+----------------+ | Min/Max Unidirectional Link Delay | 34 | 28 | +---------------------------------------+----------+----------------+ | Unidirectional Delay Variation | 35 | 29 | +---------------------------------------+----------+----------------+ | Unidirectional Link Loss | 36 | 30 | +---------------------------------------+----------+----------------+ | Unidirectional Residual Bandwidth | 37 | 31 | +---------------------------------------+----------+----------------+ | Unidirectional Available Bandwidth | 38 | 32 | +---------------------------------------+----------+----------------+ | Unidirectional Utilized Bandwidth | 39 | 33 | +---------------------------------------+----------+----------------+ Figure 83. Security Considerations
Procedures and protocol extensions defined in this document do not affect the BGP security model. See the "Security Considerations" section of [RFC4271] for a discussion of BGP security. Also, refer to [RFC4272] and [RFC6952] for analyses of security issues for BGP. Security considerations for acquiring and distributing BGP-LS information are discussed in [RFC7752]. The TLVs introduced in this document are used to propagate the Traffic Engineering Metric Extensions defined in [RFC8570] and [RFC7471]. These TLVs represent the state and resource availability of the IGP link. It is assumed that the IGP instances originating these TLVs will support all the required security and authentication mechanisms (as described in [RFC8570] and [RFC7471]) in order to prevent any security issues when propagating the TLVs into BGP-LS.
The advertisement of the link attribute information defined in this document presents no additional risk beyond that associated with the existing link attribute information already supported in [RFC7752].4. IANA Considerations
IANA has made assignments in the "BGP-LS Node Descriptor, Link Descriptor, Prefix Descriptor, and Attribute TLVs" registry for the new Link Attribute TLVs as listed below: TLV Code Point Description -------------------------------------------------------- 1114 Unidirectional Link Delay 1115 Min/Max Unidirectional Link Delay 1116 Unidirectional Delay Variation 1117 Unidirectional Link Loss 1118 Unidirectional Residual Bandwidth 1119 Unidirectional Available Bandwidth 1120 Unidirectional Utilized Bandwidth5. References
5.1. Normative References
[RFC7471] Giacalone, S., Ward, D., Drake, J., Atlas, A., and S. Previdi, "OSPF Traffic Engineering (TE) Metric Extensions", RFC 7471, DOI 10.17487/RFC7471, March 2015, <https://www.rfc-editor.org/info/rfc7471>. [RFC7752] Gredler, H., Ed., Medved, J., Previdi, S., Farrel, A., and S. Ray, "North-Bound Distribution of Link-State and Traffic Engineering (TE) Information Using BGP", RFC 7752, DOI 10.17487/RFC7752, March 2016, <https://www.rfc-editor.org/info/rfc7752>. [RFC8570] Ginsberg, L., Ed., Previdi, S., Ed., Giacalone, S., Ward, D., Drake, J., and Q. Wu, "IS-IS Traffic Engineering (TE) Metric Extensions", RFC 8570, DOI 10.17487/RFC8570, March 2019, <https://www.rfc-editor.org/info/rfc8570>.
5.2. Informative References
[RFC4271] Rekhter, Y., Ed., Li, T., Ed., and S. Hares, Ed., "A Border Gateway Protocol 4 (BGP-4)", RFC 4271, DOI 10.17487/RFC4271, January 2006, <https://www.rfc-editor.org/info/rfc4271>. [RFC4272] Murphy, S., "BGP Security Vulnerabilities Analysis", RFC 4272, DOI 10.17487/RFC4272, January 2006, <https://www.rfc-editor.org/info/rfc4272>. [RFC6952] Jethanandani, M., Patel, K., and L. Zheng, "Analysis of BGP, LDP, PCEP, and MSDP Issues According to the Keying and Authentication for Routing Protocols (KARP) Design Guide", RFC 6952, DOI 10.17487/RFC6952, May 2013, <https://www.rfc-editor.org/info/rfc6952>.Acknowledgements
The authors wish to acknowledge comments from Ketan Talaulikar.Contributors
The following people have contributed substantially to this document and should be considered coauthors: Saikat Ray Individual Email: raysaikat@gmail.com Hannes Gredler RtBrick Inc. Email: hannes@rtbrick.com
Authors' Addresses
Les Ginsberg (editor) Cisco Systems, Inc. United States of America Email: ginsberg@cisco.com Stefano Previdi Huawei Italy Email: stefano@previdi.net Qin Wu Huawei 101 Software Avenue, Yuhua District Nanjing, Jiangsu 210012 China Email: bill.wu@huawei.com Jeff Tantsura Apstra, Inc. United States of America Email: jefftant.ietf@gmail.com Clarence Filsfils Cisco Systems, Inc. Brussels Belgium Email: cfilsfil@cisco.com