Internet-Draft BGP-LS Extensions for IS-IS FR July 2022
Head & Przygienda Expires 6 January 2023 [Page]
Inter-Domain Routing
Intended Status:
J. Head, Ed.
Juniper Networks
T. Przygienda
Juniper Networks

BGP-LS Extensions for IS-IS Flood Reflection


This document defines new BGP-LS (BGP Link-State) TLVs in order to carry IS-IS Flood Reflection information.

Status of This Memo

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This Internet-Draft will expire on 6 January 2023.

Table of Contents

1. Introduction

BGP Link-State RFC7752 [RFC7752] defines mechanisms to advertise information about the underlying IGP in BGP NLRI to an external entity (e.g. a controller). New BGP-LS TLVs are required in order to faciliate IS-IS Flood Reflection [IS-IS-FR] extensions.

1.1. Requirements Language

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119 [RFC2119].

2. BGP-LS Extensions for IS-IS Flood Reflection

Controllers may need to compute traffic engineered paths across Flood Reflection clusters. This requires that they be aware of Flood Reflection specific details, such as Cluster ID, C-bit (which indicates Flood Reflector or Flood Reflector Client), or any sub-TLVs.

This document defines the following BGP-LS TLV code point value in accordance with RFC7752 rules:

Table 1: BGP-LS Flood Reflection TLV Code Points
TLV Code Point Description IS-IS TLV
TBD1 Flood Reflection TLV TBD1 (161) [IS-IS-FR]

TLV formats are described in detail in subsequent subsections.

3. BGP-LS TLVs for IS-IS Flood Reflection

This TLV advertises Flood Reflection details. The semantics of any fields within the TLV/sub-TLVs is described in [IS-IS-FR].

 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            |
|                  Flood Reflection Cluster ID                  |
|                          Sub-TLVs ...                         |
Figure 1: Flood Reflection TLVs


4. IANA Considerations

This section requests the following (suggested) values from the "BGP-LS Node Descriptor, Link Descriptor, Prefix Descriptor, and Attribute TLVs" registry for the following TLVs:

4.1. Requested TLV Entries

Table 2: Requested TLV Entries
TLV Code Point Description IS-IS TLV/Sub-TLV Reference
TBD1 (161) IS-IS Flood Reflection 161 This document.

5. 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 BGP security issues. Security considerations for acquiring and distributing BGP-LS information are discussed in [RFC7752].

The TLVs introduced in this document are used to propagate IS-IS Flood Reflection TLVs defined in [IS-IS-FR]. These TLVs represent IS-IS Flood Reflection state and are therefore assumed to support any/all of the required security and authentication mechanisms as described in [IS-IS-FR] to prevent any security issues when propagating the TLVs into BGP-LS.

6. Acknowledgements

7. References

7.1. Normative References

Przygienda, T., Bowers, C., Lee, Y., Sharma, A., and R. White, "IS-IS Flood Reflection", , <>.
Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, , <>.
Rekhter, Y., Li, T., and S. Hares, "A Border Gateway Protocol 4 (BGP-4)", , <>.
Murphy, S., "BGP Security Vulnerabilities Analysis", , <>.
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", , <>.
Gredler, H., Medved, J., Previdi, S., Farrel, A., and S. Ray, "North-Bound Distribution of Link-State and Traffic Engineering (TE) Information Using BGP", , <>.
Cotton, M., Leiba, B., and T. Narten, "Guidelines for Writing an IANA Considerations Section in RFCs", , <>.

Authors' Addresses

Jordan Head (editor)
Juniper Networks
1137 Innovation Way
Sunnyvale, CA
United States of America
Tony Przygienda
Juniper Networks
1137 Innovation Way
Sunnyvale, CA
United States of America