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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 24, 2017 Vengada. Govindan 6 IJsbrand. Wijnands 7 Cisco 8 July 23, 2016 10 BGP Link-State extensions for BIER 11 draft-chenvgovindan-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 24, 2017. 48 Copyright Notice 50 Copyright (c) 2016 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 | | 134 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 135 | Sub-TLVs (variable) | 136 +- -+ 137 | | 139 Figure 1 141 Type: TBD. 143 Length: 2 octet. 145 Subdomain-id: Unique value identifying the BIER sub-domain, 1 octet. 147 MT-ID: Multi-Topology ID that identifies the topology that is 148 associated with the BIER sub-domain.1 octet. 150 BitString Length (BS Len): A 1 octet field encoding the supported 151 BitString length associated with this BFR-prefix.This field are 152 specified in section 3 of [I-D.ietf-bier-architecture].Given that the 153 bier router can support BSL values set, this field encoding the BSL 154 values set that BIER routers supported. 156 BFR-id: A 2 octet field encoding the BFR-id, as documented in 157 [I-D.ietf-bier-architecture]. If the BFR-id is zero, it means, the 158 advertising router is not advertising any BIER-id. 160 If multiple BIER Sub-TLVs are present, all having the same BS Length 161 and Subdomain-id values, first one MUST be used and subsequent ones 162 MUST be ignored. 164 3.1.1. The BIER MPLS Encapsulation Sub-TLV 166 The BIER MPLS Encapsulation Sub-TLV is a sub-TLV of the BIER TLV. 167 BIER MPLS Encapsulation Sub-TLV is used in order to advertise MPLS 168 specific information used for BIER. It MUST appear multiple times in 169 the BIER TLV as described in [I-D.ietf-bier-ospf-bier-extensions] 171 The following the BIER MPLS Encapsulation Sub-TLV is defined: 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 |Lbl Range Size | Label Range Base | 179 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 180 | BS Length | Reserved | 181 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 183 Figure 2 185 Type: TBD. 187 Length: 2 octet. 189 Label Range Size: A 1 octet field encoding the label range size of 190 the label range. It MUST be greater than 0, otherwise the TLV MUST 191 be ignored. 193 Label Range Base: A 3 octet field, where the 20 rightmost bits 194 represent the first label in the label range. 196 BS Length: Bitstring length for the label range that this router is 197 advertising per [I-D.ietf-bier-mpls-encapsulation]. 1 octet.The 198 values allowed in this field are specified in section 3 of 199 [I-D.ietf-bier-mpls-encapsulation]. 201 The "label range" is the set of labels beginning with the label range 202 base and ending with (label range base)+(label range size)-1. A 203 unique label range is allocated for each BitStream length and Sub- 204 domain-ID. These label is used for BIER forwarding as described in 205 [I-D.ietf-bier-architecture] and 206 [I-D.ietf-bier-mpls-encapsulation].Label ranges within the sub-TLV 207 MUST NOT overlap, otherwise the whole sub-TLV MUST be disregarded 209 BS length in multiple BIER MPLS Encapsulation Sub-TLV inside the same 210 BIER Sub-TLV MUST NOT repeat, otherwise only the first BIER MPLS 211 Encapsulation Sub-TLV with such BS length MUST be used and any 212 subsequent BIER MPLS Encapsulation Sub-TLVs with the same BS length 213 MUST be ignored. 215 3.2. The BIER-TE TLV 217 This TLV is used to collect BIER-TE information in the "northbound" 218 direction within the BIER-TE domain. 220 The section will be added in next version. 222 4. IANA Considerations 224 This document requests assigning code-points from the registry for 225 the new Prefix Attribute TLV and Sub-TLV. 227 +-------------------+---------------+-----------------+ 228 | TLV Code Point | Description | Value defined | 229 +-------------------+---------------+-----------------+ 230 | 1158( recommend ) | BIER | this document | 231 +-------------------+---------------+-----------------+ 233 Table 1: The new Prefix Attribute TLV 235 +-----------------+-------------------------------+-----------------+ 236 | Sub-TLV | Description | Value | 237 | Code Point | | | 238 +-----------------+-------------------------------+-----------------+ 239 | 1 ( recommend) | BIER MPLS Encapsulation | this document | 240 +------------+-------------------------------+----------------------+ 242 Table 2: The new Prefix Attribute Sub-TLV 244 5. Security Considerations 246 Procedures and protocol extensions defined in this document do not 247 affect the BGP security model. See [RFC6952] for details. 249 6. Acknowledgements 251 We would like to thank Peter Psenak (Cisco) for his comments and 252 support of this work. 254 7. Normative references 256 [I-D.ietf-bier-architecture] 257 Wijnands, I., Rosen, E., Dolganow, A., Przygienda, T., and 258 S. Aldrin, "Multicast using Bit Index Explicit 259 Replication", draft-ietf-bier-architecture-04 (work in 260 progress), July 2016. 262 [I-D.ietf-bier-isis-extensions] 263 Ginsberg, L., Przygienda, T., Aldrin, S., and Z. Zhang, 264 "BIER support via ISIS", draft-ietf-bier-isis- 265 extensions-02 (work in progress), March 2016. 267 [I-D.ietf-bier-mpls-encapsulation] 268 Wijnands, I., Rosen, E., Dolganow, A., Tantsura, J., 269 Aldrin, S., and I. Meilik, "Encapsulation for Bit Index 270 Explicit Replication in MPLS Networks", draft-ietf-bier- 271 mpls-encapsulation-05 (work in progress), July 2016. 273 [I-D.ietf-bier-ospf-bier-extensions] 274 Psenak, P., Kumar, N., Wijnands, I., Dolganow, A., 275 Przygienda, T., Zhang, Z., and S. Aldrin, "OSPF Extensions 276 for BIER", draft-ietf-bier-ospf-bier-extensions-02 (work 277 in progress), March 2016. 279 [I-D.ietf-idr-ls-distribution] 280 Gredler, H., Medved, J., Previdi, S., Farrel, A., and S. 281 Ray, "North-Bound Distribution of Link-State and TE 282 Information using BGP", draft-ietf-idr-ls-distribution-13 283 (work in progress), October 2015. 285 [RFC3630] Katz, D., Kompella, K., and D. Yeung, "Traffic Engineering 286 (TE) Extensions to OSPF Version 2", RFC 3630, 287 DOI 10.17487/RFC3630, September 2003, 288 . 290 [RFC6952] Jethanandani, M., Patel, K., and L. Zheng, "Analysis of 291 BGP, LDP, PCEP, and MSDP Issues According to the Keying 292 and Authentication for Routing Protocols (KARP) Design 293 Guide", RFC 6952, DOI 10.17487/RFC6952, May 2013, 294 . 296 Authors' Addresses 298 Ran Chen 299 ZTE Corporation 300 No.50 Software Avenue,Yuhuatai District 301 Nanjing, Jiangsu Province 210012 302 China 304 Phone: +86 025 88014636 305 Email: chen.ran@zte.com.cn 307 Zheng Zhang 308 ZTE Corporation 309 No.50 Software Avenue,Yuhuatai District 310 Nanjing, Jiangsu Province 210012 311 China 313 Email: zhang.zheng@zte.com.cn 315 Vengada Prasad Govindan 316 Cisco 318 Email: venggovi@cisco.com 319 IJsbrand Wijnands 320 Cisco 321 De Kleetlaan 6a 322 Diegem 1831 323 Belgium 325 Email: ice@cisco.com