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Miscellaneous warnings: ---------------------------------------------------------------------------- == The copyright year in the IETF Trust and authors Copyright Line does not match the current year -- The document date (October 30, 2016) is 2734 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) -- Obsolete informational reference (is this intentional?): RFC 4971 (Obsoleted by RFC 7981) -- Obsolete informational reference (is this intentional?): RFC 7752 (Obsoleted by RFC 9552) Summary: 1 error (**), 0 flaws (~~), 1 warning (==), 3 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Network Working Group Z. Li 3 Internet-Draft Sam aldrin 4 Intended status: Standards Track Huawei Technologies 5 Expires: May 3, 2017 J. Tantsura 6 G. Mirsky 7 Ericsson 8 S. Zhuang 9 Huawei Technologies 10 October 30, 2016 12 BGP Link-State Extensions for Seamless BFD 13 draft-li-idr-bgp-ls-sbfd-extensions-00 15 Abstract 17 [RFC7880] defines a simplified mechanism to use Bidirectional 18 Forwarding Detection (BFD) with large portions of negotiation aspects 19 eliminated, thus providing benefits such as quick provisioning as 20 well as improved control and flexibility to network nodes initiating 21 the path monitoring. The link-state routing protocols (IS-IS, OSPF 22 and OSPFv3) have been extended to advertise the Seamless BFD (S-BFD) 23 Discriminators. 25 This draft defines extensions to the BGP Link-state address-family to 26 carry the S-BFD Discriminators information via BGP. 28 Requirements Language 30 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 31 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 32 document are to be interpreted as described in RFC 2119 [RFC2119]. 34 Status of This Memo 36 This Internet-Draft is submitted in full conformance with the 37 provisions of BCP 78 and BCP 79. 39 Internet-Drafts are working documents of the Internet Engineering 40 Task Force (IETF). Note that other groups may also distribute 41 working documents as Internet-Drafts. The list of current Internet- 42 Drafts is at http://datatracker.ietf.org/drafts/current/. 44 Internet-Drafts are draft documents valid for a maximum of six months 45 and may be updated, replaced, or obsoleted by other documents at any 46 time. It is inappropriate to use Internet-Drafts as reference 47 material or to cite them other than as "work in progress." 48 This Internet-Draft will expire on May 3, 2017. 50 Copyright Notice 52 Copyright (c) 2016 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 [RFC7880] defines a simplified mechanism to use Bidirectional 83 Forwarding Detection (BFD)[RFC5880] with large portions of 84 negotiation aspects eliminated, thus providing benefits such as quick 85 provisioning as well as improved control and flexibility to network 86 nodes initiating the path monitoring. 88 [RFC7883] defines a mean of advertising one or more S-BFD 89 Discriminators using the IS-IS Router Capability TLV. [RFC7884] 90 defines a new OSPF Router Information (RI) TLV that allows OSPF 91 routers to flood the S-BFD discriminator values associated with a 92 target network identifier. This mechanism is applicable to both 93 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 [RFC7880]. 110 3. Problem and Requirement 112 Seamless MPLS [I-D.ietf-mpls-seamless-mpls] extends the core domain 113 and integrates aggregation and access domains into a single MPLS 114 domain. In a large network, the core and aggregation networks can be 115 organized as different autonomous systems. Although the core and 116 aggregation networks are segmented into different autonomous systems, 117 but an E2E LSP will be created using hierarchical-labeled BGP LSPs 118 based on iBGP-labeled unicast within each AS, and eBGP-labeled 119 unicast to extend the LSP across AS boundaries. Meanwhile, the 120 customer will see only two service-end points in the Seamless MPLS 121 network. In order to detect the possible failure quickly and protect 122 the network/trigger re-routing, BFD MAY be used for the Service Layer 123 (e.g. for MPLS VPNs, PW ) and the Transport Layer, so the need 124 arises that the BFD session has to span across AS domain. 126 The link-state routing protocols (IS-IS, OSPF and OSPFv3) have been 127 extended to advertise the S-BFD Discriminators. But flooding based 128 propagation of the S-BFD Discriminators using IGPs is limited by the 129 perimeter of the IGP domain. For advertising the S-BFD 130 Discriminators which span across IGP domains (e.g. multiple ASes), 131 the Border Gateway Protocol (BGP) is better suited as its propagation 132 perimeter is not limited like the IGPs. This draft defines 133 extensions requirement to the BGP Link-state address-family to carry 134 the S-BFD Discriminators information via BGP. 136 4. BGP-LS Extensions for S-BFD Discriminators Exchanging 138 The BGP-LS NLRI can be a node NLRI, a link NLRI or a prefix NLRI. 139 The corresponding BGP-LS attribute is a node attribute, a link 140 attribute or a prefix attribute. BGP-LS [RFC7752] defines the TLVs 141 that map link-state information to BGP-LS NLRI and BGP-LS attribute. 143 This document adds additional BGP- LS attribute TLVs to encode the 144 S-BFD Discriminators information. 146 [RFC7880] defines the following TLVs to encode the S-BFD 147 Discriminators information. 149 The ISIS Router CAPABILITY TLV as defined in [RFC4971] will be used 150 to advertise S-BFD discriminators. A new Sub-TLV is defined as 151 described below. S-BFD Discriminators Sub-TLV is formatted as 152 specified in [RFC5305]. 154 No. of octets 155 +-----------------------------+ 156 | Type (20) | 1 157 +-----------------------------+ 158 | Length (multiple of 4) | 1 159 +-----------------------------+ 160 | Discriminator Value(s) | 4/Discriminator 161 : : 162 +-----------------------------+ 163 Figure 1: S-BFD Discriminators Sub-TLV for ISIS 165 Inclusion of the S-BFD Discriminators sub-TLV in a Router Capability 166 TLV is optional. Multiple S-BFD Discriminators sub-TLVs MAY be 167 advertised by an IS. 169 [RFC7884] defines the following TLVs to encode the S-BFD 170 Discriminators information. The format of the S-BFD Discriminator 171 TLV is as follows: 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 | Length | 177 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 178 | Discriminator 1 | 179 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 180 | Discriminator 2 (Optional) | 181 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 182 | ... | 183 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 184 | Discriminator n (Optional) | 185 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 186 Figure 2: S-BFD Discriminators TLV for OSPF 188 Type - S-BFD Discriminator TLV Type (11) 189 Length - Total length of the discriminator (Value field) in octets, 190 not including the optional padding. The Length is a multiple of 4 191 octets, and consequently specifies how many Discriminators are 192 included in the TLV. 194 Value - S-BFD network target discriminator value or values. 196 Routers that do not recognize the S-BFD Discriminator TLV Type MUST 197 ignore the TLV. S-BFD discriminator is associated with the BFD 198 Target Identifier type, which allows de-multiplexing to a specific 199 task or service. 201 These TLVs are mapped to BGP-LS attribute TLVs in the following way. 202 The new information in the Link-State NLRIs and attributes is encoded 203 in Type/Length/Value triplets. 205 0 1 2 3 206 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 1 207 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 208 | Type | Length | 209 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 210 // Value (variable) // 211 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 212 Figure 3: BGP-LS TLV format 214 The 2 octet Type field values are defined in Table 1. The next 2 215 octet Length field encodes length of the rest of the TLV. The Value 216 portion of the TLV is variable and is equal to the corresponding 217 Value portion of the TLV defined in [RFC7883] and [RFC7884]. 219 The following 'Node Attribute' TLVs are defined: 221 +---------------+-------------------------+----------+--------------+ 222 | TLV Code | Description | Length | ISIS/OSPF | 223 | Point | | | TLV/Sub-TLV | 224 +---------------+-------------------------+----------+--------------+ 225 | TBD | S-BFD Discriminators | variable | TBD | 226 | ... | ... | ... | ... | 227 +---------------+-------------------------+----------+--------------+ 228 Table 1: Node Attribute TLVs 230 These TLVs can ONLY be added to the Node Attribute associated with 231 the Node NLRI that originates the corresponding S-BFD Discriminator 232 TLV. 234 5. Operations 236 Existing BGP and BGP-LS operational procedures apply. No new 237 operation procedures are defined in this document. 239 6. IANA Considerations 241 This document requests assigning code-points from the registry for 242 BGP-LS attribute TLVs based on table Table 1. 244 7. Security Considerations 246 Procedures and protocol extensions defined in this document do not 247 affect the BGP security model. See [RFC6952] for details. 249 8. Acknowledgements 251 The authors would like to thank Nan Wu for his contributions to this 252 work. 254 9. References 256 9.1. Normative References 258 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 259 Requirement Levels", BCP 14, RFC 2119, 260 DOI 10.17487/RFC2119, March 1997, 261 . 263 9.2. Informative References 265 [I-D.ietf-mpls-seamless-mpls] 266 Leymann, N., Decraene, B., Filsfils, C., Konstantynowicz, 267 M., and D. Steinberg, "Seamless MPLS Architecture", draft- 268 ietf-mpls-seamless-mpls-07 (work in progress), June 2014. 270 [RFC4971] Vasseur, JP., Ed., Shen, N., Ed., and R. Aggarwal, Ed., 271 "Intermediate System to Intermediate System (IS-IS) 272 Extensions for Advertising Router Information", RFC 4971, 273 DOI 10.17487/RFC4971, July 2007, 274 . 276 [RFC5305] Li, T. and H. Smit, "IS-IS Extensions for Traffic 277 Engineering", RFC 5305, DOI 10.17487/RFC5305, October 278 2008, . 280 [RFC5880] Katz, D. and D. Ward, "Bidirectional Forwarding Detection 281 (BFD)", RFC 5880, DOI 10.17487/RFC5880, June 2010, 282 . 284 [RFC6952] Jethanandani, M., Patel, K., and L. Zheng, "Analysis of 285 BGP, LDP, PCEP, and MSDP Issues According to the Keying 286 and Authentication for Routing Protocols (KARP) Design 287 Guide", RFC 6952, DOI 10.17487/RFC6952, May 2013, 288 . 290 [RFC7752] Gredler, H., Ed., Medved, J., Previdi, S., Farrel, A., and 291 S. Ray, "North-Bound Distribution of Link-State and 292 Traffic Engineering (TE) Information Using BGP", RFC 7752, 293 DOI 10.17487/RFC7752, March 2016, 294 . 296 [RFC7880] Pignataro, C., Ward, D., Akiya, N., Bhatia, M., and S. 297 Pallagatti, "Seamless Bidirectional Forwarding Detection 298 (S-BFD)", RFC 7880, DOI 10.17487/RFC7880, July 2016, 299 . 301 [RFC7883] Ginsberg, L., Akiya, N., and M. Chen, "Advertising 302 Seamless Bidirectional Forwarding Detection (S-BFD) 303 Discriminators in IS-IS", RFC 7883, DOI 10.17487/RFC7883, 304 July 2016, . 306 [RFC7884] Pignataro, C., Bhatia, M., Aldrin, S., and T. Ranganath, 307 "OSPF Extensions to Advertise Seamless Bidirectional 308 Forwarding Detection (S-BFD) Target Discriminators", 309 RFC 7884, DOI 10.17487/RFC7884, July 2016, 310 . 312 Authors' Addresses 314 Zhenbin Li 315 Huawei Technologies 316 Huawei Bld., No.156 Beiqing Rd. 317 Beijing 100095 318 China 320 Email: lizhenbin@huawei.com 321 Sam Aldrin 322 Huawei Technologies 323 2330 Central Expressway 324 Santa Clara CA 95051 326 Email: sam.aldrin@huawei.com 328 Jeff Tantsura 329 Ericsson 330 200 Holger Way 331 San Jose CA 95134 332 USA 334 Email: jeff.tantsura@ericsson.com 336 Greg Mirsky 337 Ericsson 338 300 Holger Way 339 San Jose CA 95134 340 USA 342 Email: gregory.mirsky@ericsson.com 344 Shunwan Zhuang 345 Huawei Technologies 346 Huawei Bld., No.156 Beiqing Rd. 347 Beijing 100095 348 China 350 Email: zhuangshunwan@huawei.com