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Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 BIER Z. Zhang 3 Internet-Draft ZTE Corporation 4 Intended status: Standards Track Z. Zhang 5 Expires: January 31, 2021 Juniper Networks 6 I. Wijnands 7 Cisco Systems 8 H. Bidgoli 9 Nokia 10 M. McBride 11 Futurewei 12 July 30, 2020 14 BIER in IPv6 (BIERin6) 15 draft-zhang-bier-bierin6-07 17 Abstract 19 BIER is a new architecture for the forwarding of multicast data 20 packets. This document defines native IPv6 encapsulation for BIER 21 hop-by-hop forwarding or BIERin6 for short. 23 Requirements Language 25 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 26 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 27 document are to be interpreted as described in RFC2119. 29 Status of This Memo 31 This Internet-Draft is submitted in full conformance with the 32 provisions of BCP 78 and BCP 79. 34 Internet-Drafts are working documents of the Internet Engineering 35 Task Force (IETF). Note that other groups may also distribute 36 working documents as Internet-Drafts. The list of current Internet- 37 Drafts is at https://datatracker.ietf.org/drafts/current/. 39 Internet-Drafts are draft documents valid for a maximum of six months 40 and may be updated, replaced, or obsoleted by other documents at any 41 time. It is inappropriate to use Internet-Drafts as reference 42 material or to cite them other than as "work in progress." 44 This Internet-Draft will expire on January 31, 2021. 46 Copyright Notice 48 Copyright (c) 2020 IETF Trust and the persons identified as the 49 document authors. All rights reserved. 51 This document is subject to BCP 78 and the IETF Trust's Legal 52 Provisions Relating to IETF Documents 53 (https://trustee.ietf.org/license-info) in effect on the date of 54 publication of this document. Please review these documents 55 carefully, as they describe your rights and restrictions with respect 56 to this document. Code Components extracted from this document must 57 include Simplified BSD License text as described in Section 4.e of 58 the Trust Legal Provisions and are provided without warranty as 59 described in the Simplified BSD License. 61 Table of Contents 63 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 64 2. IPv6 Header . . . . . . . . . . . . . . . . . . . . . . . . . 3 65 2.1. IPv6 Options Considerations . . . . . . . . . . . . . . . 4 66 3. BIER Header . . . . . . . . . . . . . . . . . . . . . . . . . 4 67 4. IPv6 Encapsulation Advertisement . . . . . . . . . . . . . . 4 68 4.1. Format . . . . . . . . . . . . . . . . . . . . . . . . . 5 69 4.2. Inter-area prefix redistribution . . . . . . . . . . . . 5 70 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5 71 6. Security Considerations . . . . . . . . . . . . . . . . . . . 5 72 7. Acknowledgement . . . . . . . . . . . . . . . . . . . . . . . 6 73 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 6 74 8.1. Normative References . . . . . . . . . . . . . . . . . . 6 75 8.2. Informative References . . . . . . . . . . . . . . . . . 6 76 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7 78 1. Introduction 80 BIER [RFC8279] is a new architecture for the forwarding of multicast 81 data packets. It provides optimal forwarding through a "multicast 82 domain" and it does not necessarily precondition construction of a 83 multicast distribution tree, nor does it require intermediate nodes 84 to maintain any per-flow state. 86 This document specifies non-MPLS BIER forwarding in an IPv6 [RFC8200] 87 environment, refferred to as BIERin6, using non-MPLS BIER 88 encapsulation specified in [RFC8296]. 90 MPLS BIER forwarding in IPv6 is outside the scope of this document. 92 This document uses terminology defined in [RFC8279] and [RFC8296]. 94 [RFC8296] defines the BIER encapsulation format in MPLS and non-MPLS 95 environment. In case of non-MPLS environment, a BIER packet is the 96 payload of an "outer" encapsulation, which has a "next header" 97 codepoint that is set to a value that means "non-MPLS BIER". 99 That can be used as is in a pure IPv6 non-mpls environment. Between 100 two directly connected BFRs, a BIER header could directly follow link 101 layer header, e.g., an Ethernet header (with the Ethertype set to 102 0xAB37). But if the downstream BFR can not support Ethernet 103 encapsulation, IPv6 encapsulation can be used. If a BFR needs to 104 tunnel BIER packets to another BFR, e.g. per [RFC8279] Section 6.9, 105 IPv6 encapsulation can be used, with the destination address being 106 the downstream BFR and the Next Header field set to a to-be-assigned 107 value for "non-MPLS BIER". 109 +---------------+------------------------ 110 | IPv6 header | BIER header + data 111 | | 112 | Next Header = | 113 | BIER | 114 +---------------+------------------------ 116 The IPv6 encapsulation could be used even between two directly 117 connected BFRs in the following two cases: 119 o An operator mandates all traffic to be carried in IPv6. 121 o A BFR does not have BIER support in its "fast forwarding path" and 122 relies on "slow/software forwarding path", e.g. in environments 123 like [RFC7368] where high throughput multicast forwarding 124 performance is not critical. 126 2. IPv6 Header 128 Whenever IPv6 encapsulation is used for BIER forwarding, The Next 129 Header field in the IPv6 Header (if there are no extension headers), 130 or the Next Header field in the last extension header is set to TBD, 131 indicating that the payload is a BIER packet. 133 If the neighbor is directly connected, The destination address in 134 IPv6 header SHOULD be the neighbor's link-local address on this 135 router's outgoing interface, the source destination address SHOULD be 136 this router's link-local address on the outgoing interface, and the 137 IPv6 TTL MUST be set to 1. Otherwise, the destination address SHOULD 138 be the BIER prefix of the BFR neighbor, the source address SHOULD be 139 this router's BIER prefix, and the TTL MUST be large enough to get 140 the packet to the BFR neighbor. 142 The "Flow label" field in the IPv6 packet SHOULD be copied from the 143 entropy field in the BIER encapsulation. 145 2.1. IPv6 Options Considerations 147 For directly connected BIER routers, IPv6 Hop-by-Hop or Destination 148 options are irrelevant and SHOULD NOT be inserted by BFIR on the 149 BIERin6 packet. In this case IPv6 header, Next Header field should 150 be set to TBD. Any IPv6 packet arriving on BFRs and BFERs, with 151 multiple extension header where the last extension header has a Next 152 Header field set to TBD, SHOULD be discard and the node should 153 transmit an ICMP Parameter Problem message to the source of the 154 packet (BFIR) with an ICMP code value of TBD10 ('invalid options for 155 BIERin6'). 157 This also indicates that for disjoint BIER routers using IPv6 158 encapsulation, there SHOULD NOT be any IPv6 Hop-by-Hop or Destination 159 options be present in a BIERin6 packet. In this case, if additional 160 traffic engineering is required, IPv6 tunneling (i.e. BIERin6 over 161 SRv6) can be implemented. 163 BIER has its own OAM function, so generally the IPv6 OAM function is 164 not needed. But if the network operator takes the IPv6 packet OAM 165 function into account, the IPv6 OAM function can be used also. 167 3. BIER Header 169 The BIER header MUST be encoded per Section 2.2 of [RFC8296]. 171 The BIFT-id is either encoded per 172 [I-D.ietf-bier-non-mpls-bift-encoding] or per advertised by BFRs, as 173 specificed in [I-D.ietf-bier-lsr-ethernet-extensions]. 175 4. IPv6 Encapsulation Advertisement 177 When IPv6 encapsulation is not required between directly connected 178 BFRs, no signaling in addition to that specified in 179 [I-D.ietf-bier-lsr-ethernet-extensions] is needed. 181 Otherwise, a node that requires IPv6 encapsualtion MUST advertise the 182 BIER IPv6 transportation sub-sub-sub-TLV/sub-sub-TLV according to 183 local configuration or policy in the BIER domain to request other 184 BFRs to always use IPv6 encapsulation. 186 In presence of multiple encapsulation possibilities hop-by-hop it is 187 a matter of local policy which encapsulation is imposed and the 188 receiving router MUST accept all encapsulations that it advertised. 190 4.1. Format 192 The BIER IPv6 transportation is a new sub-sub-TLV of BIER Ethernet 193 Encapsulation sub-TLV defined in OSPFv3, and a new sub-sub-sub-TLV of 194 BIER Ethernet Encapsulation sub-sub-TLV defined in ISIS, as per 195 [I-D.ietf-bier-lsr-ethernet-extensions]. 197 0 1 2 3 198 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 1 199 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 200 | Type | Length | 201 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 203 o Type: For OSPF, value TBD1 (prefer 1) is used to indicate it is 204 the IPv6 transportation sub-TLV. For ISIS, value TBD2 (prefer 1) 205 is used to indicate it is the IPv6 transportation sub-sub-TLV. 207 o Length: 0. 209 4.2. Inter-area prefix redistribution 211 When BFR-prefixes are advertised across IGP areas per 212 [I-D.ietf-bier-lsr-ethernet-extensions] or redistributed across 213 protocol boundaries per [I-D.zwzw-bier-prefix-redistribute], the BIER 214 IPv6 transportation sub-sub-TLV or sub-sub-sub-TLV MAY be re- 215 advertised/re-distributed as well. 217 5. IANA Considerations 219 IANA is requested to assign a new "BIER" type for "Next Header" in 220 the "Assigned Internet Protocol Numbers" registry. 222 IANA is requested to assign a new "BIERin6" type for "invalid 223 options" in the "ICMP code value" registry. 225 IANA is requested to assign a new "BIER IPv6 transportation Sub-sub- 226 TLV" type in the "OSPFv3 BIER Ethernet Encapsulation sub-TLV" 227 Registry. 229 IANA is requested to set up a new "BIER IPv6 transportation Sub-sub- 230 sub-TLV" type in the "IS-IS BIER Ethernet Encapsulation sub-sub-TLV" 231 Registry. 233 6. Security Considerations 235 General IPv6 and BIER security considerations apply. 237 7. Acknowledgement 239 The authors would like to thank Tony Przygienda, Nagendra Kumar, Gyan 240 Mishra for their review and valuable comments. 242 8. References 244 8.1. Normative References 246 [RFC8200] Deering, S. and R. Hinden, "Internet Protocol, Version 6 247 (IPv6) Specification", STD 86, RFC 8200, 248 DOI 10.17487/RFC8200, July 2017, 249 . 251 [RFC8279] Wijnands, IJ., Ed., Rosen, E., Ed., Dolganow, A., 252 Przygienda, T., and S. Aldrin, "Multicast Using Bit Index 253 Explicit Replication (BIER)", RFC 8279, 254 DOI 10.17487/RFC8279, November 2017, 255 . 257 [RFC8296] Wijnands, IJ., Ed., Rosen, E., Ed., Dolganow, A., 258 Tantsura, J., Aldrin, S., and I. Meilik, "Encapsulation 259 for Bit Index Explicit Replication (BIER) in MPLS and Non- 260 MPLS Networks", RFC 8296, DOI 10.17487/RFC8296, January 261 2018, . 263 [RFC8401] Ginsberg, L., Ed., Przygienda, T., Aldrin, S., and Z. 264 Zhang, "Bit Index Explicit Replication (BIER) Support via 265 IS-IS", RFC 8401, DOI 10.17487/RFC8401, June 2018, 266 . 268 8.2. Informative References 270 [I-D.ietf-bier-bar-ipa] 271 Zhang, Z., Przygienda, T., Dolganow, A., Bidgoli, H., 272 Wijnands, I., and A. Gulko, "BIER Underlay Path 273 Calculation Algorithm and Constraints", draft-ietf-bier- 274 bar-ipa-06 (work in progress), November 2019. 276 [I-D.ietf-bier-idr-extensions] 277 Xu, X., Chen, M., Patel, K., Wijnands, I., and T. 278 Przygienda, "BGP Extensions for BIER", draft-ietf-bier- 279 idr-extensions-07 (work in progress), September 2019. 281 [I-D.ietf-bier-lsr-ethernet-extensions] 282 Dhanaraj, S., Wijnands, I., Psenak, P., Zhang, Z., Yan, 283 G., and J. Xie, "LSR Extensions for BIER over Ethernet", 284 draft-ietf-bier-lsr-ethernet-extensions-01 (work in 285 progress), July 2019. 287 [I-D.ietf-bier-non-mpls-bift-encoding] 288 Wijnands, I., Xu, X., and H. Bidgoli, "An Optional 289 Encoding of the BIFT-id Field in the non-MPLS BIER 290 Encapsulation", draft-ietf-bier-non-mpls-bift-encoding-02 291 (work in progress), August 2019. 293 [I-D.ietf-bier-ospfv3-extensions] 294 Psenak, P., Nainar, N., and I. Wijnands, "OSPFv3 295 Extensions for BIER", draft-ietf-bier-ospfv3-extensions-02 296 (work in progress), May 2020. 298 [I-D.zhang-bier-babel-extensions] 299 Zhang, Z. and T. Przygienda, "BIER in BABEL", draft-zhang- 300 bier-babel-extensions-03 (work in progress), May 2020. 302 [I-D.zwzw-bier-prefix-redistribute] 303 Zhang, Z., Bo, W., Zhang, Z., Wijnands, I., and Y. Liu, 304 "BIER Prefix Redistribute", draft-zwzw-bier-prefix- 305 redistribute-07 (work in progress), July 2020. 307 [RFC7368] Chown, T., Ed., Arkko, J., Brandt, A., Troan, O., and J. 308 Weil, "IPv6 Home Networking Architecture Principles", 309 RFC 7368, DOI 10.17487/RFC7368, October 2014, 310 . 312 Authors' Addresses 314 Zheng(Sandy) Zhang 315 ZTE Corporation 317 EMail: zzhang_ietf@hotmail.com 319 Zhaohui Zhang 320 Juniper Networks 322 EMail: zzhang@juniper.net 323 IJsbrand Wijnands 324 Cisco Systems 326 EMail: ice@cisco.com 328 Hooman Bidgoli 329 Nokia 331 EMail: hooman.bidgoli@nokia.com 333 Mike McBride 334 Futurewei 336 EMail: mmcbride@futurewei.com