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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 268, but no explicit reference was found in the text == Unused Reference: 'RFC8296' is defined on line 296, 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 (~~), 3 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: April 11, 2019 Vengada. Govindan 6 IJsbrand. Wijnands 7 Cisco 8 October 8, 2018 10 BGP Link-State extensions for BIER 11 draft-ietf-bier-bgp-ls-bier-ext-04 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 April 11, 2019. 48 Copyright Notice 50 Copyright (c) 2018 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 3.3. 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 [RFC8279], and then external component (e.g., a controller) need to 109 collect BIER information of BIER routers are associated with the BFR- 110 Prefix in the "northbound" direction within the BIER domain. 112 Given that the BIER information is associated with the prefix, the 113 BGP-LS Prefix Attribute TLV [RFC7752] can be used to carry the BIER 114 information. A new Prefix Attribute TLV and Sub-TLV are defined for 115 the encoding of BIER information. 117 3.1. The BIER TLV 119 A new Prefix Attribute TLV (defined in [RFC7752] is defined for 120 distributing BIER information. The new TLV is called the BIER TLV. 121 The BIER TLVs may appear multiple times. 123 The following BIER TLV is defined: 125 0 1 2 3 126 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 1 127 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 128 | Type | Length | 129 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 130 | BAR | IPA | subdomain-id | MT-ID | 131 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 132 | BFR-id | BS Length | Reserved | 133 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 134 | Sub-TLVs (variable) | 135 +- -+ 136 | | 138 Figure 1 140 Type:as indicated in IANA Considerations section. 142 Length: 2 octet. 144 Reserved: MUST be 0 on transmission, ignored on reception. May be 145 used in future versions. 147 BAR: A 1 octet field encoding the BIER Algorithm, used to calculate 148 underlay paths to reach BFERs. Values are allocated from the "BIER 149 Algorithms" registry which is defined in [RFC8401]. 151 IPA: A 1 octet field encoding the IGP Algorithm, used to either 152 modify,enhance, or replace the calculation of underlay paths to reach 153 BFERs as defined by the BAR value. Values are from the IGP Algorithm 154 registry. 156 Subdomain-id: Unique value identifying the BIER sub-domain, 1 octet. 158 MT-ID: Multi-Topology ID that identifies the topology that is 159 associated with the BIER sub-domain.1 octet. 161 BFR-id: A 2 octet field encoding the BFR-id, as documented in 162 [RFC8279]. If the BFR-id is zero, it means, the advertising router 163 is not advertising any BIER-id.In some environment, BFR-id can be 164 configured by NMS, The BFR-id should be sent to a controller. 166 BS Length: A 1 octet field encoding the Bitstring length as per 167 [[RFC8296]] 169 If the MT-ID value is outside of the values specified in [RFC4915], 170 the BIER Sub-TLV MUST be ignored. 172 3.2. The BIER MPLS Encapsulation Sub-TLV 174 The BIER MPLS Encapsulation Sub-TLV is a sub-TLV of the BIER TLV. 175 BIER MPLS Encapsulation Sub-TLV is used in order to advertise MPLS 176 specific information used for BIER. It MUST appear multiple times in 177 the BIER TLV as described in [I-D.ietf-bier-ospf-bier-extensions] 179 In some environment, each router allocates its labels, and advertises 180 it to the controller.That solution is simpler as the controller does 181 not need to deal with label allocation. If the controller has to 182 deal with Label allocation , there needs to be a (global) range 183 carved out such there are no conflicts. We can avoid all that by 184 having the router allocate the BIER Label range and advertise it to 185 the controller. 187 The following the BIER MPLS Encapsulation Sub-TLV is defined: 189 0 1 2 3 190 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 1 191 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 192 | Type | Length | 193 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 194 | Max SI | Label | 195 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 196 | BS Length | Reserved | 197 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 199 Figure 2 201 Type: as indicated in IANA Considerations section. 203 Length: 2 octet. 205 Max SI: A 1 octet field encoding the maximum Set Identifier(as 206 defined in [[RFC8279]]), used in the encapsulation for this BIER 207 subdomain for this BitString length. 209 Label: A 3 octet field, where the 20 rightmost bits represent the 210 first label in the label range. 212 BS Length: A 1 octet field encoding the Bitstring length as per 213 [[RFC8296]] 215 BS length in multiple BIER MPLS Encapsulation Sub-TLV inside the same 216 BIER Sub-TLV MUST NOT repeat, otherwise only the first BIER MPLS 217 Encapsulation Sub-TLV with such BS length MUST be used and any 218 subsequent BIER MPLS Encapsulation Sub-TLVs with the same BS length 219 MUST be ignored. 221 3.3. The BIER-TE TLV 223 This TLV is used to collect BIER-TE information in the "northbound" 224 direction within the BIER-TE domain. 226 The section will be added in next version. 228 4. IANA Considerations 230 This document requests assigning code-points from the registry for 231 the new Prefix Attribute TLV and Sub-TLV. 233 +-------------------+---------------+-----------------+ 234 | TLV Code Point | Description | Value defined | 235 +-------------------+---------------+-----------------+ 236 | 1158( recommend ) | BIER | this document | 237 +-------------------+---------------+-----------------+ 239 Table 1: The new Prefix Attribute TLV 241 +-----------------+-------------------------------+-----------------+ 242 | Sub-TLV | Description | Value | 243 | Code Point | | | 244 +-----------------+-------------------------------+-----------------+ 245 | 1 ( recommend) | BIER MPLS Encapsulation | this document | 246 +------------+-------------------------------+----------------------+ 248 Table 2: The new Prefix Attribute Sub-TLV 250 5. Security Considerations 252 Procedures and protocol extensions defined in this document do not 253 affect the BGP security model. See [RFC6952] for details. 255 6. Acknowledgements 257 We would like to thank Peter Psenak (Cisco) for his comments and 258 support of this work. 260 7. Normative references 262 [I-D.ietf-bier-ospf-bier-extensions] 263 Psenak, P., Kumar, N., Wijnands, I., Dolganow, A., 264 Przygienda, T., Zhang, Z., and S. Aldrin, "OSPFv2 265 Extensions for BIER", draft-ietf-bier-ospf-bier- 266 extensions-18 (work in progress), June 2018. 268 [RFC3630] Katz, D., Kompella, K., and D. Yeung, "Traffic Engineering 269 (TE) Extensions to OSPF Version 2", RFC 3630, 270 DOI 10.17487/RFC3630, September 2003, 271 . 273 [RFC4915] Psenak, P., Mirtorabi, S., Roy, A., Nguyen, L., and P. 274 Pillay-Esnault, "Multi-Topology (MT) Routing in OSPF", 275 RFC 4915, DOI 10.17487/RFC4915, June 2007, 276 . 278 [RFC6952] Jethanandani, M., Patel, K., and L. Zheng, "Analysis of 279 BGP, LDP, PCEP, and MSDP Issues According to the Keying 280 and Authentication for Routing Protocols (KARP) Design 281 Guide", RFC 6952, DOI 10.17487/RFC6952, May 2013, 282 . 284 [RFC7752] Gredler, H., Ed., Medved, J., Previdi, S., Farrel, A., and 285 S. Ray, "North-Bound Distribution of Link-State and 286 Traffic Engineering (TE) Information Using BGP", RFC 7752, 287 DOI 10.17487/RFC7752, March 2016, 288 . 290 [RFC8279] Wijnands, IJ., Ed., Rosen, E., Ed., Dolganow, A., 291 Przygienda, T., and S. Aldrin, "Multicast Using Bit Index 292 Explicit Replication (BIER)", RFC 8279, 293 DOI 10.17487/RFC8279, November 2017, 294 . 296 [RFC8296] Wijnands, IJ., Ed., Rosen, E., Ed., Dolganow, A., 297 Tantsura, J., Aldrin, S., and I. Meilik, "Encapsulation 298 for Bit Index Explicit Replication (BIER) in MPLS and Non- 299 MPLS Networks", RFC 8296, DOI 10.17487/RFC8296, January 300 2018, . 302 [RFC8401] Ginsberg, L., Ed., Przygienda, T., Aldrin, S., and Z. 303 Zhang, "Bit Index Explicit Replication (BIER) Support via 304 IS-IS", RFC 8401, DOI 10.17487/RFC8401, June 2018, 305 . 307 Authors' Addresses 309 Ran Chen 310 ZTE Corporation 311 No.50 Software Avenue,Yuhuatai District 312 Nanjing, Jiangsu Province 210012 313 China 315 Phone: +86 025 88014636 316 Email: chen.ran@zte.com.cn 318 Zheng Zhang 319 ZTE Corporation 320 No.50 Software Avenue,Yuhuatai District 321 Nanjing, Jiangsu Province 210012 322 China 324 Email: zhang.zheng@zte.com.cn 325 Vengada Prasad Govindan 326 Cisco 328 Email: venggovi@cisco.com 330 IJsbrand Wijnands 331 Cisco 332 De Kleetlaan 6a 333 Diegem 1831 334 Belgium 336 Email: ice@cisco.com