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Checking references for intended status: Proposed Standard ---------------------------------------------------------------------------- (See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) == Unused Reference: 'RFC3630' is defined on line 254, but no explicit reference was found in the text ** Downref: Normative reference to an Informational RFC: RFC 6952 ** Obsolete normative reference: RFC 7752 (Obsoleted by RFC 9552) Summary: 2 errors (**), 0 flaws (~~), 2 warnings (==), 1 comment (--). 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: November 11, 2019 Vengada. Govindan 6 IJsbrand. Wijnands 7 Cisco 8 MAY 10, 2019 10 BGP Link-State extensions for BIER 11 draft-ietf-bier-bgp-ls-bier-ext-05 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 https://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 November 11, 2019. 48 Copyright Notice 50 Copyright (c) 2019 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 (https://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 3.2. The BIER MPLS Encapsulation Sub-TLV . . . . . . . . . . . 4 70 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5 71 5. Security Considerations . . . . . . . . . . . . . . . . . . . 6 72 6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 6 73 7. Normative references . . . . . . . . . . . . . . . . . . . . 6 74 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7 76 1. Introduction 78 Bit Index Explicit Replication (BIER) is an architecture that 79 provides optimal multicast forwarding through a "BIER domain" without 80 requiring intermediate routers to maintain any multicast related per- 81 flow state. BIER also does not require any explicit tree-building 82 protocol for its operation. A multicast data packet enters a BIER 83 domain at a "Bit-Forwarding Ingress Router" (BFIR), and leaves the 84 BIER domain at one or more "Bit-Forwarding Egress Routers" (BFERs). 85 The BFIR router adds a BIER header to the packet. The BIER header 86 contains a bitstring in which each bit represents exactly one BFER to 87 forward the packet to. The set of BFERs to which the multicast 88 packet needs to be forwarded is expressed by setting the bits that 89 correspond to those routers in the BIER header. 91 This document specifies extensions to the BGP Link-state address- 92 family in order to advertising BIER-specific. An external component 93 (e.g., a controller) then can collect BIER information in the 94 "northbound" direction within the BIER domain. 96 2. Conventions used in this document 98 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 99 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 100 document are to be interpreted as described in RFC2119. 102 3. BGP-LS Extensions for BIER 104 Each BFR MUST be assigned a "BFR-Prefix". A BFR's BFR-Prefix MUST be 105 an IP address (either IPv4 or IPv6) of the BFR, and MUST be unique 106 and routable within the BIER domain as described in section 2 of 107 [RFC8279], and then external component (e.g., a controller) need to 108 collect BIER information of BIER routers are associated with the BFR- 109 Prefix in the "northbound" direction within the BIER domain. 111 Given that the BIER information is associated with the prefix, the 112 BGP-LS Prefix Attribute TLV [RFC7752] can be used to carry the BIER 113 information. A new Prefix Attribute TLV and Sub-TLV are defined for 114 the encoding of BIER information. 116 3.1. The BIER TLV 118 A new Prefix Attribute TLV (defined in [RFC7752] is defined for 119 distributing BIER information. The new TLV is called the BIER TLV. 120 The BIER TLVs may appear multiple times. 122 The following BIER TLV is defined: 124 0 1 2 3 125 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 1 126 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 127 | Type | Length | 128 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 129 | BAR | IPA | subdomain-id | MT-ID | 130 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 131 | BFR-id | BS Length | Reserved | 132 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 133 | Sub-TLVs (variable) | 134 +- -+ 135 | | 137 Figure 1 139 Type:as indicated in IANA Considerations section. 141 Length: 2 octet. 143 Reserved: MUST be 0 on transmission, ignored on reception. May be 144 used in future versions. 146 BAR: A 1 octet field encoding the BIER Algorithm, used to calculate 147 underlay paths to reach BFERs. Values are allocated from the "BIER 148 Algorithms" registry which is defined in [RFC8401]. 150 IPA: A 1 octet field encoding the IGP Algorithm, used to either 151 modify,enhance, or replace the calculation of underlay paths to reach 152 BFERs as defined by the BAR value. Values are from the IGP Algorithm 153 registry. 155 Subdomain-id: Unique value identifying the BIER sub-domain, 1 octet. 157 MT-ID: Multi-Topology ID that identifies the topology that is 158 associated with the BIER sub-domain.1 octet. 160 BFR-id: A 2 octet field encoding the BFR-id, as documented in 161 [RFC8279]. If the BFR-id is zero, it means, the advertising router 162 is not advertising any BIER-id.In some environment, BFR-id can be 163 configured by NMS, The BFR-id should be sent to a controller. 165 BS Length: A 1 octet field encoding the Bitstring length as per 166 [RFC8296]. 168 If the MT-ID value is outside of the values specified in [RFC4915], 169 the BIER Sub-TLV MUST be ignored. 171 3.2. The BIER MPLS Encapsulation Sub-TLV 173 The BIER MPLS Encapsulation Sub-TLV is a sub-TLV of the BIER TLV. 174 BIER MPLS Encapsulation Sub-TLV is used in order to advertise MPLS 175 specific information used for BIER. It MUST appear multiple times in 176 the BIER TLV as described in [RFC8444] 178 In some environment, each router allocates its labels, and advertises 179 it to the controller.That solution is simpler as the controller does 180 not need to deal with label allocation. If the controller has to 181 deal with Label allocation , there needs to be a (global) range 182 carved out such there are no conflicts. We can avoid all that by 183 having the router allocate the BIER Label range and advertise it to 184 the controller. 186 The following the BIER MPLS Encapsulation Sub-TLV is defined: 188 0 1 2 3 189 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 1 190 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 191 | Type | Length | 192 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 193 | Max SI | Label | 194 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 195 | BS Length | Reserved | 196 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 198 Figure 2 200 Type: as indicated in IANA Considerations section. 202 Length: 2 octet. 204 Max SI: A 1 octet field encoding the maximum Set Identifier(as 205 defined in [RFC8279]), used in the encapsulation for this BIER 206 subdomain for this BitString length. 208 Label: A 3 octet field, where the 20 rightmost bits represent the 209 first label in the label range. 211 BS Length: A 1 octet field encoding the Bitstring length as per 212 [RFC8296] 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 4. IANA Considerations 222 This document requests assigning code-points from the registry for 223 the new Prefix Attribute TLV and Sub-TLV. 225 +-------------------+---------------+-----------------+ 226 | TLV Code Point | Description | Value defined | 227 +-------------------+---------------+-----------------+ 228 | 1174( recommend ) | BIER | this document | 229 +-------------------+---------------+-----------------+ 231 Table 1: The new Prefix Attribute TLV 233 +-----------------+-------------------------------+-----------------+ 234 | Sub-TLV | Description | Value | 235 | Code Point | | | 236 +-----------------+-------------------------------+-----------------+ 237 | 1 ( recommend) | BIER MPLS Encapsulation | this document | 238 +------------+-------------------------------+----------------------+ 240 Table 2: The new Prefix Attribute Sub-TLV 242 5. Security Considerations 244 Procedures and protocol extensions defined in this document do not 245 affect the BGP security model. See [RFC6952] for details. 247 6. Acknowledgements 249 We would like to thank Peter Psenak (Cisco) for his comments and 250 support of this work. 252 7. Normative references 254 [RFC3630] Katz, D., Kompella, K., and D. Yeung, "Traffic Engineering 255 (TE) Extensions to OSPF Version 2", RFC 3630, 256 DOI 10.17487/RFC3630, September 2003, 257 . 259 [RFC4915] Psenak, P., Mirtorabi, S., Roy, A., Nguyen, L., and P. 260 Pillay-Esnault, "Multi-Topology (MT) Routing in OSPF", 261 RFC 4915, DOI 10.17487/RFC4915, June 2007, 262 . 264 [RFC6952] Jethanandani, M., Patel, K., and L. Zheng, "Analysis of 265 BGP, LDP, PCEP, and MSDP Issues According to the Keying 266 and Authentication for Routing Protocols (KARP) Design 267 Guide", RFC 6952, DOI 10.17487/RFC6952, May 2013, 268 . 270 [RFC7752] Gredler, H., Ed., Medved, J., Previdi, S., Farrel, A., and 271 S. Ray, "North-Bound Distribution of Link-State and 272 Traffic Engineering (TE) Information Using BGP", RFC 7752, 273 DOI 10.17487/RFC7752, March 2016, 274 . 276 [RFC8279] Wijnands, IJ., Ed., Rosen, E., Ed., Dolganow, A., 277 Przygienda, T., and S. Aldrin, "Multicast Using Bit Index 278 Explicit Replication (BIER)", RFC 8279, 279 DOI 10.17487/RFC8279, November 2017, 280 . 282 [RFC8296] Wijnands, IJ., Ed., Rosen, E., Ed., Dolganow, A., 283 Tantsura, J., Aldrin, S., and I. Meilik, "Encapsulation 284 for Bit Index Explicit Replication (BIER) in MPLS and Non- 285 MPLS Networks", RFC 8296, DOI 10.17487/RFC8296, January 286 2018, . 288 [RFC8401] Ginsberg, L., Ed., Przygienda, T., Aldrin, S., and Z. 289 Zhang, "Bit Index Explicit Replication (BIER) Support via 290 IS-IS", RFC 8401, DOI 10.17487/RFC8401, June 2018, 291 . 293 [RFC8444] Psenak, P., Ed., Kumar, N., Wijnands, IJ., Dolganow, A., 294 Przygienda, T., Zhang, J., and S. Aldrin, "OSPFv2 295 Extensions for Bit Index Explicit Replication (BIER)", 296 RFC 8444, DOI 10.17487/RFC8444, November 2018, 297 . 299 Authors' Addresses 301 Ran Chen 302 ZTE Corporation 303 No.50 Software Avenue,Yuhuatai District 304 Nanjing, Jiangsu Province 210012 305 China 307 Phone: +86 025 88014636 308 Email: chen.ran@zte.com.cn 310 Zheng Zhang 311 ZTE Corporation 312 No.50 Software Avenue,Yuhuatai District 313 Nanjing, Jiangsu Province 210012 314 China 316 Email: zhang.zheng@zte.com.cn 318 Vengada Prasad Govindan 319 Cisco 321 Email: venggovi@cisco.com 322 IJsbrand Wijnands 323 Cisco 324 De Kleetlaan 6a 325 Diegem 1831 326 Belgium 328 Email: ice@cisco.com