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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 Zheng. Zhang 4 Intended status: Standards Track ZTE Corporation 5 Expires: January 31, 2018 Vengada. Govindan 6 IJsbrand. Wijnands 7 Cisco 8 July 30, 2017 10 BGP Link-State extensions for BIER 11 draft-ietf-bier-bgp-ls-bier-ext-01 13 Abstract 15 Bit Index Explicit Replication (BIER) is an architecture that 16 provides optimal multicast forwarding through a "BIER domain" without 17 requiring intermediate routers to maintain any multicast related per- 18 flow state. BIER also does not require any explicit tree-building 19 protocol for its operation. A multicast data packet enters a BIER 20 domain at a "Bit-Forwarding Ingress Router" (BFIR), and leaves the 21 BIER domain at one or more "Bit-Forwarding Egress Routers" (BFERs). 22 The BFIR router adds a BIER header to the packet. The BIER header 23 contains a bitstring in which each bit represents exactly one BFER to 24 forward the packet to. The set of BFERs to which the multicast 25 packet needs to be forwarded is expressed by setting the bits that 26 correspond to those routers in the BIER header. 28 This document specifies extensions to the BGP Link-state address- 29 family in order to advertising BIER information. 31 Status of This Memo 33 This Internet-Draft is submitted in full conformance with the 34 provisions of BCP 78 and BCP 79. 36 Internet-Drafts are working documents of the Internet Engineering 37 Task Force (IETF). Note that other groups may also distribute 38 working documents as Internet-Drafts. The list of current Internet- 39 Drafts is at http://datatracker.ietf.org/drafts/current/. 41 Internet-Drafts are draft documents valid for a maximum of six months 42 and may be updated, replaced, or obsoleted by other documents at any 43 time. It is inappropriate to use Internet-Drafts as reference 44 material or to cite them other than as "work in progress." 46 This Internet-Draft will expire on January 31, 2018. 48 Copyright Notice 50 Copyright (c) 2017 IETF Trust and the persons identified as the 51 document authors. All rights reserved. 53 This document is subject to BCP 78 and the IETF Trust's Legal 54 Provisions Relating to IETF Documents 55 (http://trustee.ietf.org/license-info) in effect on the date of 56 publication of this document. Please review these documents 57 carefully, as they describe your rights and restrictions with respect 58 to this document. Code Components extracted from this document must 59 include Simplified BSD License text as described in Section 4.e of 60 the Trust Legal Provisions and are provided without warranty as 61 described in the Simplified BSD License. 63 Table of Contents 65 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 66 2. Conventions used in this document . . . . . . . . . . . . . . 3 67 3. BGP-LS Extensions for BIER . . . . . . . . . . . . . . . . . 3 68 3.1. The BIER TLV . . . . . . . . . . . . . . . . . . . . . . 3 69 3.1.1. The BIER MPLS Encapsulation Sub-TLV . . . . . . . . . 4 70 3.2. The BIER-TE TLV . . . . . . . . . . . . . . . . . . . . . 5 71 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5 72 5. Security Considerations . . . . . . . . . . . . . . . . . . . 6 73 6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 6 74 7. Normative references . . . . . . . . . . . . . . . . . . . . 6 75 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7 77 1. Introduction 79 Bit Index Explicit Replication (BIER) is an architecture that 80 provides optimal multicast forwarding through a "BIER domain" without 81 requiring intermediate routers to maintain any multicast related per- 82 flow state. BIER also does not require any explicit tree-building 83 protocol for its operation. A multicast data packet enters a BIER 84 domain at a "Bit-Forwarding Ingress Router" (BFIR), and leaves the 85 BIER domain at one or more "Bit-Forwarding Egress Routers" (BFERs). 86 The BFIR router adds a BIER header to the packet. The BIER header 87 contains a bitstring in which each bit represents exactly one BFER to 88 forward the packet to. The set of BFERs to which the multicast 89 packet needs to be forwarded is expressed by setting the bits that 90 correspond to those routers in the BIER header. 92 This document specifies extensions to the BGP Link-state address- 93 family in order to advertising BIER-specific. An external component 94 (e.g., a controller) then can collect BIER information in the 95 "northbound" direction within the BIER domain. 97 2. Conventions used in this document 99 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 100 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 101 document are to be interpreted as described in RFC2119. 103 3. BGP-LS Extensions for BIER 105 Each BFR MUST be assigned a "BFR-Prefix". A BFR's BFR-Prefix MUST be 106 an IP address (either IPv4 or IPv6) of the BFR, and MUST be unique 107 and routable within the BIER domain as described in section 2 of 108 [I-D.ietf-bier-architecture], and then external component (e.g., a 109 controller) need to collect BIER information of BIER routers are 110 associated with the BFR-Prefix in the "northbound" direction within 111 the BIER domain. 113 Given that the BIER information is associated with the prefix, the 114 BGP-LS Prefix Attribute TLV [I-D.ietf-idr-ls-distribution] can be 115 used to carry the BIER information. A new Prefix Attribute TLV and 116 Sub-TLV are defined for the encoding of BIER information. 118 3.1. The BIER TLV 120 A new Prefix Attribute TLV (defined in [I-D.ietf-idr-ls-distribution] 121 is defined for distributing BIER information. The new TLV is called 122 the BIER TLV. The BIER TLVs may appear multiple times. 124 The following BIER TLV is defined: 126 0 1 2 3 127 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 1 128 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 129 | Type | Length | 130 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 131 | reserved | subdomain-id | MT-ID | BSL | 132 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 133 | BFR-id | reserved | 134 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 135 | Sub-TLVs (variable) | 136 +- -+ 137 | | 139 Figure 1 141 Type:as indicated in IANA Considerations section. 143 Length: 2 octet. 145 Reserved: MUST be 0 on transmission, ignored on reception. May be 146 used in future versions. 148 Subdomain-id: Unique value identifying the BIER sub-domain, 1 octet. 150 MT-ID: Multi-Topology ID that identifies the topology that is 151 associated with the BIER sub-domain.1 octet. 153 BitString Length (BS Len): A 1 octet field encoding the supported 154 BitString length associated with this BFR-prefix.This field are 155 specified in section 3 of [I-D.ietf-bier-mpls-encapsulation].Given 156 that the bier router can support BSL values set, this field encoding 157 the BSL values set that BIER routers supported. 159 BFR-id: A 2 octet field encoding the BFR-id, as documented in 160 [I-D.ietf-bier-architecture]. If the BFR-id is zero, it means, the 161 advertising router is not advertising any BIER-id.In some 162 environment, BFR-id can be configured by NMS, The BFR-id should be 163 sent to a controller. 165 If multiple BIER Sub-TLVs are present, all having the same BS Length 166 and Subdomain-id values, first one MUST be used and subsequent ones 167 MUST be ignored. 169 3.1.1. The BIER MPLS Encapsulation Sub-TLV 171 The BIER MPLS Encapsulation Sub-TLV is a sub-TLV of the BIER TLV. 172 BIER MPLS Encapsulation Sub-TLV is used in order to advertise MPLS 173 specific information used for BIER. It MUST appear multiple times in 174 the BIER TLV as described in [I-D.ietf-bier-ospf-bier-extensions] 176 The following the BIER MPLS Encapsulation Sub-TLV is defined: 178 0 1 2 3 179 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 1 180 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 181 | Type | Length | 182 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 183 |Lbl Range Size | Label Range Base | 184 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 185 | BS Length | Reserved | 186 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 188 Figure 2 190 Type: as indicated in IANA Considerations section. 192 Length: 2 octet. 194 Label Range Size: A 1 octet field encoding the label range size of 195 the label range. It MUST be greater than 0, otherwise the TLV MUST 196 be ignored. 198 Label Range Base: A 3 octet field, where the 20 rightmost bits 199 represent the first label in the label range. 201 BS Length: Bitstring length for the label range that this router is 202 advertising per [I-D.ietf-bier-mpls-encapsulation]. 1 octet.The 203 values allowed in this field are specified in section 3 of 204 [I-D.ietf-bier-mpls-encapsulation]. 206 The "label range" is the set of labels beginning with the label range 207 base and ending with (label range base)+(label range size)-1. A 208 unique label range is allocated for each BitStream length and Sub- 209 domain-ID. These label is used for BIER forwarding as described in 210 [I-D.ietf-bier-architecture] and 211 [I-D.ietf-bier-mpls-encapsulation].Label ranges within the sub-TLV 212 MUST NOT overlap, otherwise the whole sub-TLV MUST be disregarded 214 BS length in multiple BIER MPLS Encapsulation Sub-TLV inside the same 215 BIER Sub-TLV MUST NOT repeat, otherwise only the first BIER MPLS 216 Encapsulation Sub-TLV with such BS length MUST be used and any 217 subsequent BIER MPLS Encapsulation Sub-TLVs with the same BS length 218 MUST be ignored. 220 3.2. The BIER-TE TLV 222 This TLV is used to collect BIER-TE information in the "northbound" 223 direction within the BIER-TE domain. 225 The section will be added in next version. 227 4. IANA Considerations 229 This document requests assigning code-points from the registry for 230 the new Prefix Attribute TLV and Sub-TLV. 232 +-------------------+---------------+-----------------+ 233 | TLV Code Point | Description | Value defined | 234 +-------------------+---------------+-----------------+ 235 | 1158( recommend ) | BIER | this document | 236 +-------------------+---------------+-----------------+ 238 Table 1: The new Prefix Attribute TLV 240 +-----------------+-------------------------------+-----------------+ 241 | Sub-TLV | Description | Value | 242 | Code Point | | | 243 +-----------------+-------------------------------+-----------------+ 244 | 1 ( recommend) | BIER MPLS Encapsulation | this document | 245 +------------+-------------------------------+----------------------+ 247 Table 2: The new Prefix Attribute Sub-TLV 249 5. Security Considerations 251 Procedures and protocol extensions defined in this document do not 252 affect the BGP security model. See [RFC6952] for details. 254 6. Acknowledgements 256 We would like to thank Peter Psenak (Cisco) for his comments and 257 support of this work. 259 7. Normative references 261 [I-D.ietf-bier-architecture] 262 Wijnands, I., Rosen, E., Dolganow, A., Przygienda, T., and 263 S. Aldrin, "Multicast using Bit Index Explicit 264 Replication", draft-ietf-bier-architecture-07 (work in 265 progress), June 2017. 267 [I-D.ietf-bier-isis-extensions] 268 Ginsberg, L., Przygienda, T., Aldrin, S., and Z. Zhang, 269 "BIER support via ISIS", draft-ietf-bier-isis- 270 extensions-04 (work in progress), March 2017. 272 [I-D.ietf-bier-mpls-encapsulation] 273 Wijnands, I., Rosen, E., Dolganow, A., Tantsura, J., 274 Aldrin, S., and I. Meilik, "Encapsulation for Bit Index 275 Explicit Replication in MPLS and non-MPLS Networks", 276 draft-ietf-bier-mpls-encapsulation-07 (work in progress), 277 June 2017. 279 [I-D.ietf-bier-ospf-bier-extensions] 280 Psenak, P., Kumar, N., Wijnands, I., Dolganow, A., 281 Przygienda, T., Zhang, Z., and S. Aldrin, "OSPF Extensions 282 for BIER", draft-ietf-bier-ospf-bier-extensions-07 (work 283 in progress), July 2017. 285 [I-D.ietf-idr-ls-distribution] 286 Gredler, H., Medved, J., Previdi, S., Farrel, A., and S. 287 Ray, "North-Bound Distribution of Link-State and TE 288 Information using BGP", draft-ietf-idr-ls-distribution-13 289 (work in progress), October 2015. 291 [RFC3630] Katz, D., Kompella, K., and D. Yeung, "Traffic Engineering 292 (TE) Extensions to OSPF Version 2", RFC 3630, 293 DOI 10.17487/RFC3630, September 2003, 294 . 296 [RFC6952] Jethanandani, M., Patel, K., and L. Zheng, "Analysis of 297 BGP, LDP, PCEP, and MSDP Issues According to the Keying 298 and Authentication for Routing Protocols (KARP) Design 299 Guide", RFC 6952, DOI 10.17487/RFC6952, May 2013, 300 . 302 Authors' Addresses 304 Ran Chen 305 ZTE Corporation 306 No.50 Software Avenue,Yuhuatai District 307 Nanjing, Jiangsu Province 210012 308 China 310 Phone: +86 025 88014636 311 Email: chen.ran@zte.com.cn 312 Zheng Zhang 313 ZTE Corporation 314 No.50 Software Avenue,Yuhuatai District 315 Nanjing, Jiangsu Province 210012 316 China 318 Email: zhang.zheng@zte.com.cn 320 Vengada Prasad Govindan 321 Cisco 323 Email: venggovi@cisco.com 325 IJsbrand Wijnands 326 Cisco 327 De Kleetlaan 6a 328 Diegem 1831 329 Belgium 331 Email: ice@cisco.com