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Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Network Working Group S. Zhuang 3 Internet-Draft Z. Li 4 Intended status: Standards Track Sam aldrin 5 Expires: June 28, 2016 Huawei Technologies 6 J. Tantsura 7 G. Mirsky 8 Ericsson 9 December 26, 2015 11 BGP Link-State Extensions for Seamless BFD 12 draft-zhuang-idr-bgp-ls-sbfd-extensions-01 14 Abstract 16 [I-D.ietf-bfd-seamless-base] defines a simplified mechanism to use 17 Bidirectional Forwarding Detection (BFD) with large portions of 18 negotiation aspects eliminated, thus providing benefits such as quick 19 provisioning as well as improved control and flexibility to network 20 nodes initiating the path monitoring. The link-state routing 21 protocols (IS-IS, OSPF and OSPFv3) have been extended to advertise 22 the Seamless BFD (S-BFD) Discriminators. 24 This draft defines extensions to the BGP Link-state address-family to 25 carry the S-BFD Discriminators information via BGP. 27 Requirements Language 29 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 30 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 31 document are to be interpreted as described in RFC 2119 [RFC2119]. 33 Status of This Memo 35 This Internet-Draft is submitted in full conformance with the 36 provisions of BCP 78 and BCP 79. 38 Internet-Drafts are working documents of the Internet Engineering 39 Task Force (IETF). Note that other groups may also distribute 40 working documents as Internet-Drafts. The list of current Internet- 41 Drafts is at http://datatracker.ietf.org/drafts/current/. 43 Internet-Drafts are draft documents valid for a maximum of six months 44 and may be updated, replaced, or obsoleted by other documents at any 45 time. It is inappropriate to use Internet-Drafts as reference 46 material or to cite them other than as "work in progress." 48 This Internet-Draft will expire on June 28, 2016. 50 Copyright Notice 52 Copyright (c) 2015 IETF Trust and the persons identified as the 53 document authors. All rights reserved. 55 This document is subject to BCP 78 and the IETF Trust's Legal 56 Provisions Relating to IETF Documents 57 (http://trustee.ietf.org/license-info) in effect on the date of 58 publication of this document. Please review these documents 59 carefully, as they describe your rights and restrictions with respect 60 to this document. Code Components extracted from this document must 61 include Simplified BSD License text as described in Section 4.e of 62 the Trust Legal Provisions and are provided without warranty as 63 described in the Simplified BSD License. 65 Table of Contents 67 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 68 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 69 3. Problem and Requirement . . . . . . . . . . . . . . . . . . . 3 70 4. BGP-LS Extensions for S-BFD Discriminators Exchanging . . . . 3 71 5. Operations . . . . . . . . . . . . . . . . . . . . . . . . . 6 72 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6 73 7. Security Considerations . . . . . . . . . . . . . . . . . . . 6 74 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 6 75 9. References . . . . . . . . . . . . . . . . . . . . . . . . . 6 76 9.1. Normative References . . . . . . . . . . . . . . . . . . 6 77 9.2. Informative References . . . . . . . . . . . . . . . . . 6 78 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7 80 1. Introduction 82 [I-D.ietf-bfd-seamless-base] defines a simplified mechanism to use 83 Bidirectional Forwarding Detection (BFD)[RFC5880] with large portions 84 of negotiation aspects eliminated, thus providing benefits such as 85 quick provisioning as well as improved control and flexibility to 86 network nodes initiating the path monitoring. 88 [I-D.ietf-isis-sbfd-discriminator] defines a mean of advertising one 89 or more S-BFD Discriminators using the IS-IS Router Capability TLV. 90 [I-D.ietf-ospf-sbfd-discriminator] defines a new OSPF Router 91 Information (RI) TLV that allows OSPF routers to flood the S-BFD 92 discriminator values associated with a target network identifier. 93 This mechanism is applicable to both OSPFv2 and OSPFv3. 95 The link-state routing protocols (IS-IS, OSPF and OSPFv3) have been 96 extended to advertise the S-BFD Discriminators. But flooding based 97 propagation of the S-BFD Discriminators using IGPs is limited by the 98 perimeter of the IGP domain. For advertising the S-BFD 99 Discriminators which span across IGP domains (e.g. multiple ASes), 100 the Border Gateway Protocol (BGP) is better suited as its propagation 101 perimeter is not limited like the IGPs. 103 This draft defines extensions to the BGP Link-state address-family to 104 carry the S-BFD Discriminators information via BGP. 106 2. Terminology 108 This memo makes use of the terms defined in 109 [I-D.ietf-bfd-seamless-base]. 111 3. Problem and Requirement 113 Seamless MPLS [I-D.ietf-mpls-seamless-mpls] extends the core domain 114 and integrates aggregation and access domains into a single MPLS 115 domain. In a large network, the core and aggregation networks can be 116 organized as different autonomous systems. Although the core and 117 aggregation networks are segmented into different autonomous systems, 118 but an E2E LSP will be created using hierarchical-labeled BGP LSPs 119 based on iBGP-labeled unicast within each AS, and eBGP-labeled 120 unicast to extend the LSP across AS boundaries. Meanwhile, the 121 customer will see only two service-end points in the Seamless MPLS 122 network. In order to detect the possible failure quickly and protect 123 the network/trigger re-routing, BFD MAY be used for the Service Layer 124 (e.g. for MPLS VPNs, PW ) and the Transport Layer, so the need 125 arises that the BFD session has to span across AS domain. 127 The link-state routing protocols (IS-IS, OSPF and OSPFv3) have been 128 extended to advertise the S-BFD Discriminators. But flooding based 129 propagation of the S-BFD Discriminators using IGPs is limited by the 130 perimeter of the IGP domain. For advertising the S-BFD 131 Discriminators which span across IGP domains (e.g. multiple ASes), 132 the Border Gateway Protocol (BGP) is better suited as its propagation 133 perimeter is not limited like the IGPs. This draft defines 134 extensions requirement to the BGP Link-state address-family to carry 135 the S-BFD Discriminators information via BGP. 137 4. BGP-LS Extensions for S-BFD Discriminators Exchanging 139 The BGP-LS NLRI can be a node NLRI, a link NLRI or a prefix NLRI. 140 The corresponding BGP-LS attribute is a node attribute, a link 141 attribute or a prefix attribute. BGP-LS 142 [I-D.ietf-idr-ls-distribution] defines the TLVs that map link-state 143 information to BGP-LS NLRI and BGP-LS attribute. This document adds 144 additional BGP- LS attribute TLVs to encode the S-BFD Discriminators 145 information. 147 [I-D.ietf-isis-sbfd-discriminator] defines the following TLVs to 148 encode the S-BFD Discriminators information. 150 The ISIS Router CAPABILITY TLV as defined in [RFC4971] will be used 151 to advertise S-BFD discriminators. A new Sub-TLV is defined as 152 described below. S-BFD Discriminators Sub-TLV is formatted as 153 specified in [RFC5305]. 155 No. of octets 156 +-----------------------------+ 157 | Type (to be assigned by | 1 158 | IANA - suggested value 20) | 159 +-----------------------------+ 160 | Length (multiple of 4) | 1 161 +-----------------------------+ 162 | Discriminator Value(s) | 4/Discriminator 163 : : 164 +-----------------------------+ 165 Figure 1: S-BFD Discriminators Sub-TLV for ISIS 167 Inclusion of the S-BFD Discriminators sub-TLV in a Router Capability 168 TLV is optional. Multiple S-BFD Discriminators sub-TLVs MAY be 169 advertised by an IS. 171 [I-D.ietf-ospf-sbfd-discriminator] defines the following TLVs to 172 encode the S-BFD Discriminators information. The format of the S-BFD 173 Discriminator TLV is as follows: 175 0 1 2 3 176 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 1 177 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 178 | Type | Length | 179 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 180 | Discriminator 1 | 181 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 182 | Discriminator 2 (Optional) | 183 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 184 | ... | 185 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 186 | Discriminator n (Optional) | 187 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 188 Figure 2: S-BFD Discriminators TLV for OSPF 190 Type - S-BFD Discriminator TLV Type 191 Length - Total length of the discriminator (Value field) in octets, 192 not including the optional padding. The Length is a multiple of 4 193 octets, and consequently specifies how many Discriminators are 194 included in the TLV. 196 Value - S-BFD network target discriminator value or values. 198 Routers that do not recognize the S-BFD Discriminator TLV Type MUST 199 ignore the TLV. S-BFD discriminator is associated with the BFD 200 Target Identifier type, which allows de-multiplexing to a specific 201 task or service. 203 These TLVs are mapped to BGP-LS attribute TLVs in the following way. 204 The new information in the Link-State NLRIs and attributes is encoded 205 in Type/Length/Value triplets. 207 0 1 2 3 208 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 1 209 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 210 | Type | Length | 211 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 212 // Value (variable) // 213 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 214 Figure 3: BGP-LS TLV format 216 The 2 octet Type field values are defined in Table 1. The next 2 217 octet Length field encodes length of the rest of the TLV. The Value 218 portion of the TLV is variable and is equal to the corresponding 219 Value portion of the TLV defined in 220 [I-D.ietf-isis-sbfd-discriminator] and 221 [I-D.ietf-ospf-sbfd-discriminator]. 223 The following 'Node Attribute' TLVs are defined: 225 +---------------+-------------------------+----------+--------------+ 226 | TLV Code | Description | Length | ISIS/OSPF | 227 | Point | | | TLV/Sub-TLV | 228 +---------------+-------------------------+----------+--------------+ 229 | TBD | S-BFD Discriminators | variable | TBD | 230 | ... | ... | ... | ... | 231 +---------------+-------------------------+----------+--------------+ 232 Table 1: Node Attribute TLVs 234 These TLVs can ONLY be added to the Node Attribute associated with 235 the Node NLRI that originates the corresponding S-BFD Discriminator 236 TLV. 238 5. Operations 240 Existing BGP and BGP-LS operational procedures apply. No new 241 operation procedures are defined in this document. 243 6. IANA Considerations 245 This document requests assigning code-points from the registry for 246 BGP-LS attribute TLVs based on table Table 1. 248 7. Security Considerations 250 Procedures and protocol extensions defined in this document do not 251 affect the BGP security model. See [RFC6952] for details. 253 8. Acknowledgements 255 The authors would like to thank Nan Wu for his contributions to this 256 work. 258 9. References 260 9.1. Normative References 262 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 263 Requirement Levels", BCP 14, RFC 2119, 264 DOI 10.17487/RFC2119, March 1997, 265 . 267 9.2. Informative References 269 [I-D.ietf-bfd-seamless-base] 270 Akiya, N., Pignataro, C., Ward, D., Bhatia, M., and J. 271 Networks, "Seamless Bidirectional Forwarding Detection 272 (S-BFD)", draft-ietf-bfd-seamless-base-05 (work in 273 progress), June 2015. 275 [I-D.ietf-idr-ls-distribution] 276 Gredler, H., Medved, J., Previdi, S., Farrel, A., and S. 277 Ray, "North-Bound Distribution of Link-State and TE 278 Information using BGP", draft-ietf-idr-ls-distribution-13 279 (work in progress), October 2015. 281 [I-D.ietf-isis-sbfd-discriminator] 282 Ginsberg, L., Akiya, N., and M. Chen, "Advertising S-BFD 283 Discriminators in IS-IS", draft-ietf-isis-sbfd- 284 discriminator-02 (work in progress), March 2015. 286 [I-D.ietf-mpls-seamless-mpls] 287 Leymann, N., Decraene, B., Filsfils, C., Konstantynowicz, 288 M., and D. Steinberg, "Seamless MPLS Architecture", draft- 289 ietf-mpls-seamless-mpls-07 (work in progress), June 2014. 291 [I-D.ietf-ospf-sbfd-discriminator] 292 Bhatia, M., Pignataro, C., Aldrin, S., and T. Ranganath, 293 "OSPF extensions to advertise S-BFD Target Discriminator", 294 draft-ietf-ospf-sbfd-discriminator-02 (work in progress), 295 September 2015. 297 [RFC4971] Vasseur, JP., Ed., Shen, N., Ed., and R. Aggarwal, Ed., 298 "Intermediate System to Intermediate System (IS-IS) 299 Extensions for Advertising Router Information", RFC 4971, 300 DOI 10.17487/RFC4971, July 2007, 301 . 303 [RFC5305] Li, T. and H. Smit, "IS-IS Extensions for Traffic 304 Engineering", RFC 5305, DOI 10.17487/RFC5305, October 305 2008, . 307 [RFC5880] Katz, D. and D. Ward, "Bidirectional Forwarding Detection 308 (BFD)", RFC 5880, DOI 10.17487/RFC5880, June 2010, 309 . 311 [RFC6952] Jethanandani, M., Patel, K., and L. Zheng, "Analysis of 312 BGP, LDP, PCEP, and MSDP Issues According to the Keying 313 and Authentication for Routing Protocols (KARP) Design 314 Guide", RFC 6952, DOI 10.17487/RFC6952, May 2013, 315 . 317 Authors' Addresses 319 Shunwan Zhuang 320 Huawei Technologies 321 Huawei Bld., No.156 Beiqing Rd. 322 Beijing 100095 323 China 325 Email: zhuangshunwan@huawei.com 326 Zhenbin Li 327 Huawei Technologies 328 Huawei Bld., No.156 Beiqing Rd. 329 Beijing 100095 330 China 332 Email: lizhenbin@huawei.com 334 Sam Aldrin 335 Huawei Technologies 336 2330 Central Expressway 337 Santa Clara CA 95051 339 Email: sam.aldrin@huawei.com 341 Jeff Tantsura 342 Ericsson 343 200 Holger Way 344 San Jose CA 95134 345 USA 347 Email: jeff.tantsura@ericsson.com 349 Greg Mirsky 350 Ericsson 351 300 Holger Way 352 San Jose CA 95134 353 USA 355 Email: gregory.mirsky@ericsson.com