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Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Networking Working Group Ran. Chen 3 Internet-Draft Shaofu. Peng 4 Intended status: Standards Track Jie. Han 5 Expires: March 1, 2019 ZTE Corporation 6 August 28, 2018 8 Anycast-SID FRR in SR 9 draft-chen-spring-anycast-sid-frr-00 11 Abstract 13 This document specifies the fast redundancy protection mechanism, 14 aimed at providing protection of the links and domain boundary nodes 15 for network that use segment routing. 17 Status of This Memo 19 This Internet-Draft is submitted in full conformance with the 20 provisions of BCP 78 and BCP 79. 22 Internet-Drafts are working documents of the Internet Engineering 23 Task Force (IETF). Note that other groups may also distribute 24 working documents as Internet-Drafts. The list of current Internet- 25 Drafts is at https://datatracker.ietf.org/drafts/current/. 27 Internet-Drafts are draft documents valid for a maximum of six months 28 and may be updated, replaced, or obsoleted by other documents at any 29 time. It is inappropriate to use Internet-Drafts as reference 30 material or to cite them other than as "work in progress." 32 This Internet-Draft will expire on March 1, 2019. 34 Copyright Notice 36 Copyright (c) 2018 IETF Trust and the persons identified as the 37 document authors. All rights reserved. 39 This document is subject to BCP 78 and the IETF Trust's Legal 40 Provisions Relating to IETF Documents 41 (https://trustee.ietf.org/license-info) in effect on the date of 42 publication of this document. Please review these documents 43 carefully, as they describe your rights and restrictions with respect 44 to this document. Code Components extracted from this document must 45 include Simplified BSD License text as described in Section 4.e of 46 the Trust Legal Provisions and are provided without warranty as 47 described in the Simplified BSD License. 49 Table of Contents 51 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 52 2. Conventions used in this document . . . . . . . . . . . . . . 2 53 3. Motivation . . . . . . . . . . . . . . . . . . . . . . . . . 2 54 4. Anycast-SID FRR Solution . . . . . . . . . . . . . . . . . . 2 55 4.1. Domain boundary nodes protection . . . . . . . . . . . . 2 56 4.2. Links and nodes protection in Inter-Area scenario . . . . 4 57 5. Security Considerations . . . . . . . . . . . . . . . . . . . 4 58 6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 4 59 7. Normative references . . . . . . . . . . . . . . . . . . . . 4 60 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 5 62 1. Introduction 64 This document extends the use of Anycast-SID FRR to provide links and 65 domain boundary nodes that use segment routing. 67 2. Conventions used in this document 69 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 70 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 71 document are to be interpreted as described in RFC2119. 73 3. Motivation 75 The procedures specified in this document, in combination with 76 [I-D.ietf-spring-segment-routing] provide the fast redundancy 77 protection. 79 The procedures specified in this document aims at providing 80 protection of the links and domain boundary nodes for network that 81 use segment routing 83 4. Anycast-SID FRR Solution 85 4.1. Domain boundary nodes protection 87 The solution consists of three parts. 89 o Configure the same anycast prefix and associated prefix-sid for 90 each domain boundary node that forms redundant protection, then 91 the anycast prefix and associated prefix-sid with Anycast-Group 92 flag should be advertised to the neighbor node. 94 o Create the anycast-group forwarding entry (i.e. FRR entry) after 95 the direct neighbor node of the domain boundary nodes receive the 96 prefix-sid with Anycast-Group flag advertisement. The anycast- 97 group forwarding entry includes the forwarding information which 98 points to each of the domain boundary node , then the forwarding 99 entry pointing to the main domain boundary (one of the direct 100 connected boundary nodes from the PLR) is set to the active state, 101 and others are set to the backup state. Only the direct neighbor 102 of the domain boundary nodes need to set up the anycast-group 103 forwarding entry. 105 o if the neighbor node detects the main domain boundary node 106 failure, the neighbor node immediately activates the backup entry. 107 Note that the backup entry contains the node-sid of the slave 108 boundary node, and the packet will be forwarded based on the node- 109 sid, not the anycast prefix-sid again. 111 +-----------------------+ +---------------+ +------------------+ 112 | SID:20 SID:30 | | | | SID:60 | 113 | A2-----A3------GW11------C1------GW21------A6 | 114 | / \ / | |\ / \ /| | \ | 115 | / \ / | | \ / \ / | | \ | 116 |SID:10/ \ / | | \ / \ / | | \ SID:80 | 117 | A1 / SID:100 / / SID:200 A8 | 118 | \ / \ | | / \ / \ | | / | 119 | \ / \ | | / \ / \ | | / | 120 | \ / \ | |/ \ / \| | / | 121 | A4-----A5------GW12------C2------GW22-------A7 | 122 | SID:40 SID:50 | | | | SID:70 | 123 +-----------------------+ +---------------+ +------------------+ 125 Figure 1 127 The figure above describes a network example with two groups of the 128 domain boundary nodes. The GW11 and GW12 are in the same anycast 129 group. They are all configured with the same anycast prefix and the 130 same prefix-sid 100, in addition, GW11 has node-sid 110 and GW12 has 131 node-sid 120. All these prefix-sid should be advertised to the 132 Neighbors(e.g, node A3 and A5), and the anycast-group forwarding 133 entry will be set up by the direct Neighbor node A3 and A5. For 134 example, the anycast-group forwarding entry created by A3 contains a 135 master item which points to anycast-sid 100 and a slave item which 136 points to node-sid 120. 138 When A3 detects GW11 failure, it immediately diverting traffic from 139 GW11 to A4 (e.g. the best next-hop to node-sid 120) according to the 140 anycast-group forwarding entry. 142 It is an implementation choice for data-plane whether the slave item 143 only points to node-sid 120 for cascade table lookup, or integrates 144 the forwarding information of node-sid 120 (such as a single next- 145 hop, a TI-LFA FRR index for cascade table lookup, or an ECMP index 146 for cascade table lookup). 148 Note that the anycast-group FRR described in this document could co- 149 exist with other FRR solutions, such as LFA/RLFA/TI-LFA. The 150 anycast-group FRR solution needn't complex alternate path 151 computation, it just reuses the forwarding information which points 152 to the slave boundary node. 154 4.2. Links and nodes protection in Inter-Area scenario 156 TBD. 158 5. Security Considerations 160 TBD. 162 6. Acknowledgements 164 TBD. 166 7. Normative references 168 [I-D.ietf-isis-segment-routing-extensions] 169 Previdi, S., Ginsberg, L., Filsfils, C., Bashandy, A., 170 Gredler, H., Litkowski, S., Decraene, B., and J. Tantsura, 171 "IS-IS Extensions for Segment Routing", draft-ietf-isis- 172 segment-routing-extensions-19 (work in progress), July 173 2018. 175 [I-D.ietf-ospf-ospfv3-segment-routing-extensions] 176 Psenak, P., Filsfils, C., Previdi, S., Gredler, H., 177 Shakir, R., Henderickx, W., and J. Tantsura, "OSPFv3 178 Extensions for Segment Routing", draft-ietf-ospf-ospfv3- 179 segment-routing-extensions-15 (work in progress), August 180 2018. 182 [I-D.ietf-ospf-segment-routing-extensions] 183 Psenak, P., Previdi, S., Filsfils, C., Gredler, H., 184 Shakir, R., Henderickx, W., and J. Tantsura, "OSPF 185 Extensions for Segment Routing", draft-ietf-ospf-segment- 186 routing-extensions-25 (work in progress), April 2018. 188 [I-D.ietf-spring-segment-routing] 189 Filsfils, C., Previdi, S., Ginsberg, L., Decraene, B., 190 Litkowski, S., and R. Shakir, "Segment Routing 191 Architecture", draft-ietf-spring-segment-routing-15 (work 192 in progress), January 2018. 194 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 195 Requirement Levels", BCP 14, RFC 2119, 196 DOI 10.17487/RFC2119, March 1997, 197 . 199 [RFC3031] Rosen, E., Viswanathan, A., and R. Callon, "Multiprotocol 200 Label Switching Architecture", RFC 3031, 201 DOI 10.17487/RFC3031, January 2001, 202 . 204 Authors' Addresses 206 Ran Chen 207 ZTE Corporation 208 No.50 Software Avenue,Yuhuatai District 209 Nanjing, Jiangsu Province 210012 210 China 212 Phone: +86 025 88014636 213 Email: chen.ran@zte.com.cn 215 Shaofu Peng 216 ZTE Corporation 217 No.68 Zijinghua Road,Yuhuatai District 218 Nanjing, Jiangsu Province 210012 219 China 221 Email: peng.shaofu@zte.com.cn 223 Jie Han 224 ZTE Corporation 225 No.68 Zijinghua Road,Yuhuatai District 226 Nanjing, Jiangsu Province 210012 227 China