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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 (April 25, 2017) is 2530 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 Huawei 4 Intended status: Standards Track Sam aldrin 5 Expires: October 27, 2017 Google, Inc 6 J. Tantsura 7 Individual 8 G. Mirsky 9 ZTE Corp. 10 S. Zhuang 11 Huawei 12 April 25, 2017 14 BGP Link-State Extensions for Seamless BFD 15 draft-li-idr-bgp-ls-sbfd-extensions-01 17 Abstract 19 [RFC7880] defines a simplified mechanism to use Bidirectional 20 Forwarding Detection (BFD) with large portions of negotiation aspects 21 eliminated, thus providing benefits such as quick provisioning as 22 well as improved control and flexibility to network nodes initiating 23 the path monitoring. The link-state routing protocols (IS-IS, OSPF 24 and OSPFv3) have been extended to advertise the Seamless BFD (S-BFD) 25 Discriminators. 27 This draft defines extensions to the BGP Link-state address-family to 28 carry the S-BFD Discriminators information via BGP. 30 Requirements Language 32 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 33 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 34 document are to be interpreted as described in RFC 2119 [RFC2119]. 36 Status of This Memo 38 This Internet-Draft is submitted in full conformance with the 39 provisions of BCP 78 and BCP 79. 41 Internet-Drafts are working documents of the Internet Engineering 42 Task Force (IETF). Note that other groups may also distribute 43 working documents as Internet-Drafts. The list of current Internet- 44 Drafts is at http://datatracker.ietf.org/drafts/current/. 46 Internet-Drafts are draft documents valid for a maximum of six months 47 and may be updated, replaced, or obsoleted by other documents at any 48 time. It is inappropriate to use Internet-Drafts as reference 49 material or to cite them other than as "work in progress." 51 This Internet-Draft will expire on October 27, 2017. 53 Copyright Notice 55 Copyright (c) 2017 IETF Trust and the persons identified as the 56 document authors. All rights reserved. 58 This document is subject to BCP 78 and the IETF Trust's Legal 59 Provisions Relating to IETF Documents 60 (http://trustee.ietf.org/license-info) in effect on the date of 61 publication of this document. Please review these documents 62 carefully, as they describe your rights and restrictions with respect 63 to this document. Code Components extracted from this document must 64 include Simplified BSD License text as described in Section 4.e of 65 the Trust Legal Provisions and are provided without warranty as 66 described in the Simplified BSD License. 68 Table of Contents 70 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 71 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 72 3. Problem and Requirement . . . . . . . . . . . . . . . . . . . 3 73 4. BGP-LS Extensions for S-BFD Discriminators Exchanging . . . . 4 74 5. Operations . . . . . . . . . . . . . . . . . . . . . . . . . 6 75 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6 76 7. Security Considerations . . . . . . . . . . . . . . . . . . . 6 77 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 6 78 9. References . . . . . . . . . . . . . . . . . . . . . . . . . 6 79 9.1. Normative References . . . . . . . . . . . . . . . . . . 6 80 9.2. Informative References . . . . . . . . . . . . . . . . . 7 81 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8 83 1. Introduction 85 [RFC7880] defines a simplified mechanism to use Bidirectional 86 Forwarding Detection (BFD)[RFC5880] with large portions of 87 negotiation aspects eliminated, thus providing benefits such as quick 88 provisioning as well as improved control and flexibility to network 89 nodes initiating the path monitoring. 91 [RFC7883] defines a mean of advertising one or more S-BFD 92 Discriminators using the IS-IS Router Capability TLV. [RFC7884] 93 defines a new OSPF Router Information (RI) TLV that allows OSPF 94 routers to flood the S-BFD discriminator values associated with a 95 target network identifier. This mechanism is applicable to both 96 OSPFv2 and OSPFv3. 98 The link-state routing protocols (IS-IS, OSPF and OSPFv3) have been 99 extended to advertise the S-BFD Discriminators. But flooding based 100 propagation of the S-BFD Discriminators using IGPs is limited by the 101 perimeter of the IGP domain. For advertising the S-BFD 102 Discriminators which span across IGP domains (e.g. multiple ASes), 103 the Border Gateway Protocol (BGP) is better suited as its propagation 104 perimeter is not limited like the IGPs. 106 This draft defines extensions to the BGP Link-state address-family to 107 carry the S-BFD Discriminators information via BGP. 109 2. Terminology 111 This memo makes use of the terms defined in [RFC7880]. 113 3. Problem and Requirement 115 Seamless MPLS [I-D.ietf-mpls-seamless-mpls] extends the core domain 116 and integrates aggregation and access domains into a single MPLS 117 domain. In a large network, the core and aggregation networks can be 118 organized as different autonomous systems. Although the core and 119 aggregation networks are segmented into different autonomous systems, 120 but an E2E LSP will be created using hierarchical-labeled BGP LSPs 121 based on iBGP-labeled unicast within each AS, and eBGP-labeled 122 unicast to extend the LSP across AS boundaries. Meanwhile, the 123 customer will see only two service-end points in the Seamless MPLS 124 network. In order to detect the possible failure quickly and protect 125 the network/trigger re-routing, BFD MAY be used for the Service Layer 126 (e.g. for MPLS VPNs, PW ) and the Transport Layer, so the need 127 arises that the BFD session has to span across AS domain. 129 The link-state routing protocols (IS-IS, OSPF and OSPFv3) have been 130 extended to advertise the S-BFD Discriminators. But flooding based 131 propagation of the S-BFD Discriminators using IGPs is limited by the 132 perimeter of the IGP domain. For advertising the S-BFD 133 Discriminators which span across IGP domains (e.g. multiple ASes), 134 the Border Gateway Protocol (BGP) is better suited as its propagation 135 perimeter is not limited like the IGPs. This draft defines 136 extensions requirement to the BGP Link-state address-family to carry 137 the S-BFD Discriminators information via BGP. 139 4. BGP-LS Extensions for S-BFD Discriminators Exchanging 141 The BGP-LS NLRI can be a node NLRI, a link NLRI or a prefix NLRI. 142 The corresponding BGP-LS attribute is a node attribute, a link 143 attribute or a prefix attribute. BGP-LS [RFC7752] defines the TLVs 144 that map link-state information to BGP-LS NLRI and BGP-LS attribute. 145 This document adds additional BGP- LS attribute TLVs to encode the 146 S-BFD Discriminators information. 148 [RFC7880] defines the following TLVs to encode the S-BFD 149 Discriminators information. 151 The ISIS Router CAPABILITY TLV as defined in [RFC4971] will be used 152 to advertise S-BFD discriminators. A new Sub-TLV is defined as 153 described below. S-BFD Discriminators Sub-TLV is formatted as 154 specified in [RFC5305]. 156 No. of octets 157 +-----------------------------+ 158 | Type (20) | 1 159 +-----------------------------+ 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 [RFC7884] defines the following TLVs to encode the S-BFD 172 Discriminators information. The format of the S-BFD Discriminator 173 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 (11) 192 Length - Total length of the discriminator (Value field) in octets, 193 not including the optional padding. The Length is a multiple of 4 194 octets, and consequently specifies how many Discriminators are 195 included in the TLV. 197 Value - S-BFD network target discriminator value or values. 199 Routers that do not recognize the S-BFD Discriminator TLV Type MUST 200 ignore the TLV. S-BFD discriminator is associated with the BFD 201 Target Identifier type, which allows de-multiplexing to a specific 202 task or service. 204 These TLVs are mapped to BGP-LS attribute TLVs in the following way. 205 The new information in the Link-State NLRIs and attributes is encoded 206 in Type/Length/Value triplets. 208 0 1 2 3 209 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 1 210 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 211 | Type | Length | 212 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 213 // Value (variable) // 214 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 215 Figure 3: BGP-LS TLV format 217 The 2 octet Type field values are defined in Table 1. The next 2 218 octet Length field encodes length of the rest of the TLV. The Value 219 portion of the TLV is variable and is equal to the corresponding 220 Value portion of the TLV defined in [RFC7883] and [RFC7884]. 222 The following 'Node Attribute' TLVs are defined: 224 +---------------+-------------------------+----------+--------------+ 225 | TLV Code | Description | Length | ISIS/OSPF | 226 | Point | | | TLV/Sub-TLV | 227 +---------------+-------------------------+----------+--------------+ 228 | TBD | S-BFD Discriminators | variable | TBD | 229 | ... | ... | ... | ... | 230 +---------------+-------------------------+----------+--------------+ 231 Table 1: Node Attribute TLVs 233 These TLVs can ONLY be added to the Node Attribute associated with 234 the Node NLRI that originates the corresponding S-BFD Discriminator 235 TLV. 237 5. Operations 239 Existing BGP and BGP-LS operational procedures apply. No new 240 operation procedures are defined in this document. 242 6. IANA Considerations 244 This document requests assigning code-points from the registry for 245 BGP-LS attribute TLVs based on table Table 1. 247 7. Security Considerations 249 Procedures and protocol extensions defined in this document do not 250 affect the BGP security model. See [RFC6952] for details. 252 8. Acknowledgements 254 The authors would like to thank Nan Wu for his contributions to this 255 work. 257 9. References 259 9.1. Normative References 261 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 262 Requirement Levels", BCP 14, RFC 2119, 263 DOI 10.17487/RFC2119, March 1997, 264 . 266 9.2. Informative References 268 [I-D.ietf-mpls-seamless-mpls] 269 Leymann, N., Decraene, B., Filsfils, C., Konstantynowicz, 270 M., and D. Steinberg, "Seamless MPLS Architecture", draft- 271 ietf-mpls-seamless-mpls-07 (work in progress), June 2014. 273 [RFC4971] Vasseur, JP., Ed., Shen, N., Ed., and R. Aggarwal, Ed., 274 "Intermediate System to Intermediate System (IS-IS) 275 Extensions for Advertising Router Information", RFC 4971, 276 DOI 10.17487/RFC4971, July 2007, 277 . 279 [RFC5305] Li, T. and H. Smit, "IS-IS Extensions for Traffic 280 Engineering", RFC 5305, DOI 10.17487/RFC5305, October 281 2008, . 283 [RFC5880] Katz, D. and D. Ward, "Bidirectional Forwarding Detection 284 (BFD)", RFC 5880, DOI 10.17487/RFC5880, June 2010, 285 . 287 [RFC6952] Jethanandani, M., Patel, K., and L. Zheng, "Analysis of 288 BGP, LDP, PCEP, and MSDP Issues According to the Keying 289 and Authentication for Routing Protocols (KARP) Design 290 Guide", RFC 6952, DOI 10.17487/RFC6952, May 2013, 291 . 293 [RFC7752] Gredler, H., Ed., Medved, J., Previdi, S., Farrel, A., and 294 S. Ray, "North-Bound Distribution of Link-State and 295 Traffic Engineering (TE) Information Using BGP", RFC 7752, 296 DOI 10.17487/RFC7752, March 2016, 297 . 299 [RFC7880] Pignataro, C., Ward, D., Akiya, N., Bhatia, M., and S. 300 Pallagatti, "Seamless Bidirectional Forwarding Detection 301 (S-BFD)", RFC 7880, DOI 10.17487/RFC7880, July 2016, 302 . 304 [RFC7883] Ginsberg, L., Akiya, N., and M. Chen, "Advertising 305 Seamless Bidirectional Forwarding Detection (S-BFD) 306 Discriminators in IS-IS", RFC 7883, DOI 10.17487/RFC7883, 307 July 2016, . 309 [RFC7884] Pignataro, C., Bhatia, M., Aldrin, S., and T. Ranganath, 310 "OSPF Extensions to Advertise Seamless Bidirectional 311 Forwarding Detection (S-BFD) Target Discriminators", 312 RFC 7884, DOI 10.17487/RFC7884, July 2016, 313 . 315 Authors' Addresses 317 Zhenbin Li 318 Huawei 319 Huawei Bld., No.156 Beiqing Rd. 320 Beijing 100095 321 China 323 Email: lizhenbin@huawei.com 325 Sam Aldrin 326 Google, Inc 328 Email: aldrin.ietf@gmail.com 330 Jeff Tantsura 331 Individual 333 Email: jefftant.ietf@gmail.com 335 Greg Mirsky 336 ZTE Corp. 338 Email: gregimirsky@gmail.com 340 Shunwan Zhuang 341 Huawei 342 Huawei Bld., No.156 Beiqing Rd. 343 Beijing 100095 344 China 346 Email: zhuangshunwan@huawei.com