idnits 2.17.1 draft-tantsura-bgp-ls-segment-routing-msd-00.txt: Checking boilerplate required by RFC 5378 and the IETF Trust (see https://trustee.ietf.org/license-info): ---------------------------------------------------------------------------- No issues found here. Checking nits according to https://www.ietf.org/id-info/1id-guidelines.txt: ---------------------------------------------------------------------------- No issues found here. Checking nits according to https://www.ietf.org/id-info/checklist : ---------------------------------------------------------------------------- No issues found here. Miscellaneous warnings: ---------------------------------------------------------------------------- == The copyright year in the IETF Trust and authors Copyright Line does not match the current year == The document doesn't use any RFC 2119 keywords, yet seems to have RFC 2119 boilerplate text. -- The document date (July 6, 2015) is 3207 days in the past. Is this intentional? Checking references for intended status: Proposed Standard ---------------------------------------------------------------------------- (See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) == Unused Reference: 'I-D.ietf-spring-segment-routing-mpls' is defined on line 174, but no explicit reference was found in the text == Unused Reference: 'I-D.ietf-isis-segment-routing-extensions' is defined on line 186, but no explicit reference was found in the text == Unused Reference: 'I-D.ietf-ospf-segment-routing-extensions' is defined on line 192, but no explicit reference was found in the text == Outdated reference: A later version (-13) exists of draft-ietf-idr-ls-distribution-11 == Outdated reference: A later version (-16) exists of draft-ietf-pce-segment-routing-05 == Outdated reference: A later version (-22) exists of draft-ietf-spring-segment-routing-mpls-01 == Outdated reference: A later version (-25) exists of draft-ietf-isis-segment-routing-extensions-05 == Outdated reference: A later version (-27) exists of draft-ietf-ospf-segment-routing-extensions-05 Summary: 0 errors (**), 0 flaws (~~), 10 warnings (==), 1 comment (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 IDR Working Group J. Tantsura 3 Internet-Draft G. Mirsky 4 Intended status: Standards Track Ericsson 5 Expires: January 7, 2016 July 6, 2015 7 Signaling Maximum SID Depth using Border Gateway Protocol Link-State 8 draft-tantsura-bgp-ls-segment-routing-msd-00 10 Abstract 12 This document discusses use of BGP-LS to expose node and/or link on a 13 node MSD "Maximum SID Depth" to a centralized controller (PCE/SDN). 15 Status of This Memo 17 This Internet-Draft is submitted in full conformance with the 18 provisions of BCP 78 and BCP 79. 20 Internet-Drafts are working documents of the Internet Engineering 21 Task Force (IETF). Note that other groups may also distribute 22 working documents as Internet-Drafts. The list of current Internet- 23 Drafts is at http://datatracker.ietf.org/drafts/current/. 25 Internet-Drafts are draft documents valid for a maximum of six months 26 and may be updated, replaced, or obsoleted by other documents at any 27 time. It is inappropriate to use Internet-Drafts as reference 28 material or to cite them other than as "work in progress." 30 This Internet-Draft will expire on January 7, 2016. 32 Copyright Notice 34 Copyright (c) 2015 IETF Trust and the persons identified as the 35 document authors. All rights reserved. 37 This document is subject to BCP 78 and the IETF Trust's Legal 38 Provisions Relating to IETF Documents 39 (http://trustee.ietf.org/license-info) in effect on the date of 40 publication of this document. Please review these documents 41 carefully, as they describe your rights and restrictions with respect 42 to this document. Code Components extracted from this document must 43 include Simplified BSD License text as described in Section 4.e of 44 the Trust Legal Provisions and are provided without warranty as 45 described in the Simplified BSD License. 47 Table of Contents 49 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 50 1.1. Conventions used in this document . . . . . . . . . . . . 2 51 1.1.1. Terminology . . . . . . . . . . . . . . . . . . . . . 2 52 1.1.2. Requirements Language . . . . . . . . . . . . . . . . 3 53 2. Problem Statement . . . . . . . . . . . . . . . . . . . . . . 3 54 3. MSD supported by a node . . . . . . . . . . . . . . . . . . . 3 55 4. MSD supported on a link . . . . . . . . . . . . . . . . . . . 3 56 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4 57 6. Security Considerations . . . . . . . . . . . . . . . . . . . 4 58 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 4 59 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 4 60 8.1. Normative References . . . . . . . . . . . . . . . . . . 4 61 8.2. Informative References . . . . . . . . . . . . . . . . . 5 62 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 5 64 1. Introduction 66 When Segment Routing tunnels are computed by a centralized 67 controller, it is crucial that the controller knows MSD "Maximum SID 68 Depth" of the node or link SR tunnel exits over, so it doesn't 69 download a path with SID (label stack) of depth more than the node or 70 link configured is capable of imposing.This document describes how to 71 use BGP-LS to expose the MSD of the node or link configured to a 72 centralized controller. 74 1.1. Conventions used in this document 76 1.1.1. Terminology 78 BGP-LS: Distribution of Link-State and TE Information using Border 79 Gateway Protocol 81 MSD: Maximum SID Depth 83 PCC: Path Computation Client 85 PCE: Path Computation Element 87 PCEP: Path Computation Element Protocol 89 SID: Segment Identifier 91 SR: Segment routing 93 1.1.2. Requirements Language 95 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 96 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and 97 "OPTIONAL" in this document are to be interpreted as described in 98 [RFC2119]. 100 2. Problem Statement 102 In existing technology only PCEP has extension to signal the MSD (SR 103 PCE Capability TLV/ METRIC Object as defined in 104 [I-D.ietf-pce-segment-routing],If PCEP is not supported by the node 105 (head-end of the SR tunnel) controller has no way to learn the MSD of 106 the node/link configured. 108 3. MSD supported by a node 110 Node MSD is a number in the range of 0-254. 0 represents lack of 111 ability to push MSD of any depth, any other value represents that of 112 the node. 114 Node MSD is encoded in the Opaque Node Attribute TLV, as defined in 115 [I-D.ietf-idr-ls-distribution] 117 0 1 2 3 118 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 1 119 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 120 | Type | Length | 121 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 122 // Opaque node attributes (variable) // 123 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 125 Figure 1: Opaque Node attribute format 127 4. MSD supported on a link 129 Link MSD is a number in the range of 0-254.The value of 0 represents 130 lack of ability to push MSD of any depth, any other value represents 131 that of the link. 133 Link MSD is encoded in the Opaque Link Attribute TLV, as defined in 134 [I-D.ietf-idr-ls-distribution] 135 0 1 2 3 136 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 1 137 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 138 | Type | Length | 139 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 140 // Opaque link attributes (variable) // 141 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 143 Figure 2: Opaque link attribute format 145 5. IANA Considerations 147 TBA 149 6. Security Considerations 151 This document does not introduce security issues beyond those 152 discussed in [I-D.ietf-idr-ls-distribution] 154 7. Acknowledgements 156 We like to thank Nikos Triantafillis for the valuable comments. 158 8. References 160 8.1. Normative References 162 [I-D.ietf-idr-ls-distribution] 163 Gredler, H., Medved, J., Previdi, S., Farrel, A., and S. 164 Ray, "North-Bound Distribution of Link-State and TE 165 Information using BGP", draft-ietf-idr-ls-distribution-11 166 (work in progress), June 2015. 168 [I-D.ietf-pce-segment-routing] 169 Sivabalan, S., Medved, J., Filsfils, C., Crabbe, E., 170 Lopez, V., Tantsura, J., Henderickx, W., and J. Hardwick, 171 "PCEP Extensions for Segment Routing", draft-ietf-pce- 172 segment-routing-05 (work in progress), May 2015. 174 [I-D.ietf-spring-segment-routing-mpls] 175 Filsfils, C., Previdi, S., Bashandy, A., Decraene, B., 176 Litkowski, S., Horneffer, M., Shakir, R., Tantsura, J., 177 and E. Crabbe, "Segment Routing with MPLS data plane", 178 draft-ietf-spring-segment-routing-mpls-01 (work in 179 progress), May 2015. 181 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 182 Requirement Levels", BCP 14, RFC 2119, March 1997. 184 8.2. Informative References 186 [I-D.ietf-isis-segment-routing-extensions] 187 Previdi, S., Filsfils, C., Bashandy, A., Gredler, H., 188 Litkowski, S., Decraene, B., and J. Tantsura, "IS-IS 189 Extensions for Segment Routing", draft-ietf-isis-segment- 190 routing-extensions-05 (work in progress), June 2015. 192 [I-D.ietf-ospf-segment-routing-extensions] 193 Psenak, P., Previdi, S., Filsfils, C., Gredler, H., 194 Shakir, R., Henderickx, W., and J. Tantsura, "OSPF 195 Extensions for Segment Routing", draft-ietf-ospf-segment- 196 routing-extensions-05 (work in progress), June 2015. 198 Authors' Addresses 200 Jeff Tantsura 201 Ericsson 203 Email: jeff.tantsura@ericsson.com 205 Greg Mirsky 206 Ericsson 208 Email: gregory.mirsky@ericsson.com