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diff --git a/doc/rfc/rfc8690.txt b/doc/rfc/rfc8690.txt new file mode 100644 index 0000000..8fc7524 --- /dev/null +++ b/doc/rfc/rfc8690.txt @@ -0,0 +1,288 @@ + + + + +Internet Engineering Task Force (IETF) N. Nainar +Request for Comments: 8690 C. Pignataro +Updates: 8287 Cisco Systems, Inc. +Category: Standards Track F. Iqbal +ISSN: 2070-1721 Individual + A. Vainshtein + ECI Telecom + December 2019 + + + Clarification of Segment ID Sub-TLV Length for RFC 8287 + +Abstract + + RFC 8287 defines the extensions to perform LSP Ping and Traceroute + for Segment Routing IGP-Prefix and IGP-Adjacency Segment Identifiers + (SIDs) with the MPLS data plane. RFC 8287 proposes three Target + Forwarding Equivalence Class (FEC) Stack sub-TLVs. While RFC 8287 + defines the format and procedure to handle those sub-TLVs, it does + not sufficiently clarify how the length of the Segment ID sub-TLVs + should be computed to be included in the Length field of the sub- + TLVs. This ambiguity has resulted in interoperability issues. + + This document updates RFC 8287 by clarifying the length of each of + the Segment ID sub-TLVs defined in RFC 8287. + +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/rfc8690. + +Copyright Notice + + Copyright (c) 2019 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 Simplified BSD License text as described in Section 4.e of + the Trust Legal Provisions and are provided without warranty as + described in the Simplified BSD License. + +Table of Contents + + 1. Introduction + 2. Terminology + 3. Requirements Notation + 4. Length Field Clarification for Segment ID Sub-TLVs + 4.1. IPv4 IGP-Prefix Segment ID Sub-TLV + 4.2. IPv6 IGP-Prefix Segment ID Sub-TLV + 4.3. IGP-Adjacency Segment ID Sub-TLV + 5. IANA Considerations + 6. Security Considerations + 7. Normative References + Acknowledgements + Contributors + Authors' Addresses + +1. Introduction + + [RFC8287] defines the extensions to MPLS LSP Ping and Traceroute for + Segment Routing IGP-Prefix and IGP-Adjacency Segment Identifiers + (SIDs) with the MPLS data plane. [RFC8287] proposes three Target FEC + Stack sub-TLVs. While RFC 8287 defines the format and procedure to + handle those sub-TLVs, it does not sufficiently clarify how the + length of the Segment ID sub-TLVs should be computed to be included + in the Length field of the sub-TLVs, which may result in + interoperability issues. + + This document updates [RFC8287] by clarifying the length of each + Segment ID sub-TLVs defined in [RFC8287]. + +2. Terminology + + This document uses the terminology defined in [RFC8402], [RFC8029], + and [RFC8287]; readers are expected to be familiar with the terms as + used in those documents. + +3. Requirements Notation + + 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. + +4. Length Field Clarification for Segment ID Sub-TLVs + + Section 5 of [RFC8287] defines three different Segment ID sub-TLVs + that can be included in the Target FEC Stack TLV defined in + [RFC8029]. The length of each sub-TLV MUST be calculated as defined + in this section. + + The TLV representations defined in Sections 5.1, 5.2, and 5.3 of + [RFC8287] are updated to clarify the length calculations, as shown in + Sections 4.1, 4.2, and 4.3, respectively. The updated TLV + representations contain explicitly defined lengths. + +4.1. IPv4 IGP-Prefix Segment ID Sub-TLV + + The sub-TLV length for the IPv4 IGP-Prefix Segment ID MUST be set to + 8, as shown in the TLV format below: + + 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 = 34 (IPv4 IGP-Prefix SID)| Length = 8 | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | IPv4 prefix | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + |Prefix Length | Protocol | Reserved | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + +4.2. IPv6 IGP-Prefix Segment ID Sub-TLV + + The sub-TLV length for the IPv6 IGP-Prefix Segment ID MUST be set to + 20, as shown in the TLV format below: + + 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 = 35 (IPv6 IGP-Prefix SID)| Length = 20 | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | | + | | + | IPv6 Prefix | + | | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + |Prefix Length | Protocol | Reserved | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + +4.3. IGP-Adjacency Segment ID Sub-TLV + + The sub-TLV length for the IGP-Adjacency Segment ID varies depending + on the Adjacency Type and Protocol. In any of the allowed + combinations of Adjacency Type and Protocol, the sub-TLV length MUST + be calculated by including 2 octets of the Reserved field. Table 1 + lists the length for different combinations of Adj. Type and + Protocol. + + +----------+-------------------------------------+ + | Protocol | Length for Adj. Type | + | +----------+------+------+------------+ + | | Parallel | IPv4 | IPv6 | Unnumbered | + +==========+==========+======+======+============+ + | OSPF | 20 | 20 | 44 | 20 | + +----------+----------+------+------+------------+ + | ISIS | 24 | 24 | 48 | 24 | + +----------+----------+------+------+------------+ + | Any | 20 | 20 | 44 | 20 | + +----------+----------+------+------+------------+ + + Table 1: IGP-Adjacency SID Length Computation + + For example, when the Adj. Type is set to Parallel Adjacency and the + Protocol is set to 0, the sub-TLV will be as below: + + 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 = 36 (IGP-Adjacency SID) | Length = 20 | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Adj. Type = 1 | Protocol = 0 | Reserved | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Local Interface ID (4 octets) | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Remote Interface ID (4 octets) | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Advertising Node Identifier (4 octets) | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Receiving Node Identifier (4 octets) | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + +5. IANA Considerations + + IANA has listed this document as an additional reference for the + following entries in the "Sub-TLVs for TLV Types 1, 16, and 21" + registry: + + +----------+----------------------------+---------------------+ + | Sub-Type | Sub-TLV Name | Reference | + +==========+============================+=====================+ + | 34 | IPv4 IGP-Prefix Segment ID | Section 5.1 of | + | | | [RFC8287]; RFC 8690 | + +----------+----------------------------+---------------------+ + | 35 | IPv6 IGP-Prefix Segment ID | Section 5.2 of | + | | | [RFC8287]; RFC 8690 | + +----------+----------------------------+---------------------+ + | 36 | IGP-Adjacency Segment ID | Section 5.3 of | + | | | [RFC8287]; RFC 8690 | + +----------+----------------------------+---------------------+ + + Table 2: Sub-TLVs for TLV Types 1, 16, and 21 (Updated Entries) + +6. Security Considerations + + This document updates [RFC8287] and does not introduce any additional + security considerations. + +7. 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>. + + [RFC8029] Kompella, K., Swallow, G., Pignataro, C., Ed., Kumar, N., + Aldrin, S., and M. Chen, "Detecting Multiprotocol Label + Switched (MPLS) Data-Plane Failures", RFC 8029, + DOI 10.17487/RFC8029, March 2017, + <https://www.rfc-editor.org/info/rfc8029>. + + [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>. + + [RFC8287] Kumar, N., Ed., Pignataro, C., Ed., Swallow, G., Akiya, + N., Kini, S., and M. Chen, "Label Switched Path (LSP) + Ping/Traceroute for Segment Routing (SR) IGP-Prefix and + IGP-Adjacency Segment Identifiers (SIDs) with MPLS Data + Planes", RFC 8287, DOI 10.17487/RFC8287, December 2017, + <https://www.rfc-editor.org/info/rfc8287>. + + [RFC8402] Filsfils, C., Ed., Previdi, S., Ed., Ginsberg, L., + Decraene, B., Litkowski, S., and R. Shakir, "Segment + Routing Architecture", RFC 8402, DOI 10.17487/RFC8402, + July 2018, <https://www.rfc-editor.org/info/rfc8402>. + +Acknowledgements + + The authors would like to thank Michael Gorokhovsky and Manohar + Doppalapudi for investigating the interoperability issue during + European Advanced Network Test Center (EANTC) testing. + +Contributors + + The following individual contributed to this document: Zafar Ali, + Cisco Systems, Inc. + +Authors' Addresses + + Nagendra Kumar Nainar + Cisco Systems, Inc. + 7200-12 Kit Creek Road + Research Triangle Park, NC 27709 + United States of America + + Email: naikumar@cisco.com + + + Carlos Pignataro + Cisco Systems, Inc. + 7200-11 Kit Creek Road + Research Triangle Park, NC 27709 + United States of America + + Email: cpignata@cisco.com + + + Faisal Iqbal + Individual + Canada + + Email: faisal.ietf@gmail.com + + + Alexander Vainshtein + ECI Telecom + Israel + + Email: vainshtein.alex@gmail.com |