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Checking references for intended status: Proposed Standard ---------------------------------------------------------------------------- (See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) No issues found here. Summary: 0 errors (**), 0 flaws (~~), 1 warning (==), 1 comment (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Network Work group N. Nainar 3 Internet-Draft C. Pignataro 4 Updates: 8287 (if approved) Cisco Systems, Inc. 5 Intended status: Standards Track F. Iqbal 6 Expires: February 9, 2020 Individual 7 A. Vainshtein 8 ECI Telecom 9 August 8, 2019 11 RFC8287 Sub-TLV Length Clarification 12 draft-ietf-mpls-rfc8287-len-clarification-04 14 Abstract 16 RFC8287 defines the extensions to MPLS LSP Ping and Traceroute for 17 Segment Routing IGP-Prefix and IGP-Adjacency Segment Identifier 18 (SIDs) with an MPLS data plane. RFC8287 proposes 3 Target FEC Stack 19 Sub-TLVs. While the standard defines the format and procedure to 20 handle those Sub-TLVs, it does not sufficiently clarify how the 21 length of the Segment ID Sub-TLVs should be computed to include in 22 the Length field of the Sub-TLVs which may result in interoperability 23 issues. 25 This document updates RFC8287 by clarifying the length of each 26 Segment ID Sub-TLVs defined in RFC8287. 28 Status of This Memo 30 This Internet-Draft is submitted in full conformance with the 31 provisions of BCP 78 and BCP 79. 33 Internet-Drafts are working documents of the Internet Engineering 34 Task Force (IETF). Note that other groups may also distribute 35 working documents as Internet-Drafts. The list of current Internet- 36 Drafts is at https://datatracker.ietf.org/drafts/current/. 38 Internet-Drafts are draft documents valid for a maximum of six months 39 and may be updated, replaced, or obsoleted by other documents at any 40 time. It is inappropriate to use Internet-Drafts as reference 41 material or to cite them other than as "work in progress." 43 This Internet-Draft will expire on February 9, 2020. 45 Copyright Notice 47 Copyright (c) 2019 IETF Trust and the persons identified as the 48 document authors. All rights reserved. 50 This document is subject to BCP 78 and the IETF Trust's Legal 51 Provisions Relating to IETF Documents 52 (https://trustee.ietf.org/license-info) in effect on the date of 53 publication of this document. Please review these documents 54 carefully, as they describe your rights and restrictions with respect 55 to this document. Code Components extracted from this document must 56 include Simplified BSD License text as described in Section 4.e of 57 the Trust Legal Provisions and are provided without warranty as 58 described in the Simplified BSD License. 60 Table of Contents 62 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 63 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 64 3. Requirements notation . . . . . . . . . . . . . . . . . . . . 3 65 4. Length field clarification for Segment ID Sub-TLVs . . . . . 3 66 4.1. IPv4 IGP-Prefix Segment ID Sub-TLV . . . . . . . . . . . 3 67 4.2. IPv6 IGP-Prefix Segment ID Sub-TLV . . . . . . . . . . . 3 68 4.3. IGP-Adjacency Segment ID Sub-TLV . . . . . . . . . . . . 4 69 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5 70 6. Security Considerations . . . . . . . . . . . . . . . . . . . 5 71 7. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 5 72 8. Acknowledgement . . . . . . . . . . . . . . . . . . . . . . . 5 73 9. Normative References . . . . . . . . . . . . . . . . . . . . 5 74 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 6 76 1. Introduction 78 [RFC8287] defines the extensions to MPLS LSP Ping and Traceroute for 79 Segment Routing IGP-Prefix and IGP-Adjacency Segment Identifier 80 (SIDs) with an MPLS data plane. [RFC8287] proposes 3 Target FEC 81 Stack Sub-TLVs. While the standard defines the format and procedure 82 to handle those Sub-TLVs, it does not sufficiently clarify how the 83 length of the Segment ID Sub-TLVs should be computed to include in 84 the Length field of the Sub-TLVs which may result in interoperability 85 issues. 87 This document updates [RFC8287] by clarifying the length of each 88 Segment ID Sub-TLVs defined in [RFC8287]. 90 2. Terminology 92 This document uses the terminologies defined in [RFC8402], [RFC8029], 93 [RFC8287] and so the readers are expected to be familiar with the 94 same. 96 3. Requirements notation 98 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 99 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and 100 "OPTIONAL" in this document are to be interpreted as described in BCP 101 14 [RFC2119] [RFC8174] when, and only when, they appear in all 102 capitals, as shown here. 104 4. Length field clarification for Segment ID Sub-TLVs 106 Section 5 of [RFC8287] defines 3 different Segment ID Sub-TLVs that 107 will be included in Target FEC Stack TLV defined in [RFC8029]. The 108 length of each Sub-TLVs MUST be calculated as defined in this 109 section. 111 The TLVs representation defined in section 5.1, 5.2 and 5.3 of 112 [RFC8287] are updated to clarify the length calculation as shown in 113 section 4.1, 4.2 and 4.3 respectively. The updated TLV 114 representation contain explicitly defined length. 116 4.1. IPv4 IGP-Prefix Segment ID Sub-TLV 118 The Sub-TLV length for IPv4 IGP-Prefix Segment ID MUST be set to 8 as 119 shown in the below TLV format: 121 0 1 2 3 122 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 1 123 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 124 |Type = 34 (IPv4 IGP-Prefix SID)| Length = 8 | 125 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 126 | IPv4 prefix | 127 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 128 |Prefix Length | Protocol | Reserved | 129 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 131 4.2. IPv6 IGP-Prefix Segment ID Sub-TLV 133 The Sub-TLV length for IPv6 IGP-Prefix Segment ID MUST be set to 20 134 as shown in the below TLV format: 136 0 1 2 3 137 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 1 138 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 139 |Type = 35 (IPv6 IGP-Prefix SID)| Length = 20 | 140 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 141 | | 142 | | 143 | IPv6 Prefix | 144 | | 145 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 146 |Prefix Length | Protocol | Reserved | 147 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 149 4.3. IGP-Adjacency Segment ID Sub-TLV 151 The Sub-TLV length for IGP-Adjacency Segment ID varies depending on 152 the Adjacency Type and Protocol. In any of the allowed combination 153 of Adjacency Type and Protocol, the sub-TLV length MUST be calculated 154 by including 2 octets of Reserved field. Table 1 below list the 155 length for different combinations of Adj.Type and Protocol. 157 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 158 | Protocol | Length for Adj.Type | 159 + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 160 | | Parallel | IPv4 | IPv6 | Unnumbered| 161 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 162 | OSPF | 20 | 20 | 44 | 20 | 163 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 164 | ISIS | 24 | 24 | 48 | 24 | 165 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 166 | Any | 20 | 20 | 44 | 20 | 167 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 168 Table 1. IGP-Adjacency SID Length Comparison 170 For example, when the Adj. Type is set to Parallel Adjacency and the 171 Protocol is set to 0, the Sub-TLV will be as below: 173 0 1 2 3 174 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 1 175 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 176 |Type = 36 (IGP-Adjacency SID) | Length = 20 | 177 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 178 | Adj. Type = 1 | Protocol = 0 | Reserved | 179 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 180 | Local Interface ID (4 octets) | 181 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 182 | Remote Interface ID (4 octets) | 183 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 184 | Advertising Node Identifier (4 octets) | 185 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 186 | Receiving Node Identifier (4 octets) | 187 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 189 5. IANA Considerations 191 This document does not introduce any IANA consideration. 193 6. Security Considerations 195 This document updates [RFC8287] and does not introduce any additional 196 security considerations. 198 7. Contributors 200 The below individuals contributed to this document: 202 Zafar Ali, Cisco Systems, Inc. 204 8. Acknowledgement 206 The authors would like to thank Michael Gorokhovsky and Manohar 207 Doppalapudi for investigating the interop issue during EANTC test. 209 9. Normative References 211 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 212 Requirement Levels", BCP 14, RFC 2119, 213 DOI 10.17487/RFC2119, March 1997, 214 . 216 [RFC8029] Kompella, K., Swallow, G., Pignataro, C., Ed., Kumar, N., 217 Aldrin, S., and M. Chen, "Detecting Multiprotocol Label 218 Switched (MPLS) Data-Plane Failures", RFC 8029, 219 DOI 10.17487/RFC8029, March 2017, 220 . 222 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 223 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 224 May 2017, . 226 [RFC8287] Kumar, N., Ed., Pignataro, C., Ed., Swallow, G., Akiya, 227 N., Kini, S., and M. Chen, "Label Switched Path (LSP) 228 Ping/Traceroute for Segment Routing (SR) IGP-Prefix and 229 IGP-Adjacency Segment Identifiers (SIDs) with MPLS Data 230 Planes", RFC 8287, DOI 10.17487/RFC8287, December 2017, 231 . 233 [RFC8402] Filsfils, C., Ed., Previdi, S., Ed., Ginsberg, L., 234 Decraene, B., Litkowski, S., and R. Shakir, "Segment 235 Routing Architecture", RFC 8402, DOI 10.17487/RFC8402, 236 July 2018, . 238 Authors' Addresses 240 Nagendra Kumar Nainar 241 Cisco Systems, Inc. 242 7200-12 Kit Creek Road 243 Research Triangle Park, NC 27709 244 US 246 Email: naikumar@cisco.com 248 Carlos Pignataro 249 Cisco Systems, Inc. 250 7200-11 Kit Creek Road 251 Research Triangle Park, NC 27709 252 US 254 Email: cpignata@cisco.com 256 Faisal Iqbal 257 Individual 258 Canada 260 Email: faisal.iqbal@msn.com 262 Alexander Vainshtein 263 ECI Telecom 264 Israel 266 Email: vainshtein.alex@gmail.com