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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 A. Przygienda 5 Expires: July 11, 2020 Juniper Networks, Inc. 6 I. Wijnands 7 Cisco Systems 8 H. Bidgoli 9 Nokia 10 M. McBride 11 Futurewei 12 January 8, 2020 14 BIER in IPv6 (BIERin6) 15 draft-zhang-bier-bierin6-04 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 July 11, 2020. 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 . . . . . . . . . . . . . . . 3 66 3. BIER Header . . . . . . . . . . . . . . . . . . . . . . . . . 4 67 4. IPv6 Encapsulation Advertisement . . . . . . . . . . . . . . 4 68 4.1. Format . . . . . . . . . . . . . . . . . . . . . . . . . 4 69 4.2. Inter-area prefix redistribution . . . . . . . . . . . . 5 70 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5 71 6. Security Considerations . . . . . . . . . . . . . . . . . . . 5 72 7. Acknowledgement . . . . . . . . . . . . . . . . . . . . . . . 5 73 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 5 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 protocol" 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). If a BFR needs to tunnel BIER packets to another BFR, e.g. 103 per [RFC8279] Section 6.9, IPv6 encapsulation can be used, with the 104 destination address being the downstream BFR and the Next Header 105 field set to a to-be-assigned value for "non-MPLS BIER". 107 The IPv6 encapsulation could be used even between two directly 108 connected BFRs in the following two cases: 110 o An operator mandates all traffic to be carried in IPv6. 112 o A BFR does not have BIER support in its "fast forwarding path" and 113 relies on "slow/software forwarding path", e.g. in environments 114 like [RFC7368] where high throughput multicast forwarding 115 performance is not critical. 117 2. IPv6 Header 119 Whenever IPv6 encapsulation is used for BIER forwarding, The Next 120 Header field in the IPv6 Header (if there are no extension headers), 121 or the Next Header field in the last extension header is set to TBD, 122 indicating that the payload is a BIER packet. 124 If the neighbor is directly connected, The destination address in 125 IPv6 header SHOULD be the neighbor's link-local address on this 126 router's outgoing interface, the source destination address SHOULD be 127 this router's link-local address on the outgoing interface, and the 128 IPv6 TTL MUST be set to 1. Otherwise, the destination address SHOULD 129 be the BIER prefix of the BFR neighbor, the source address SHOULD be 130 this router's BIER prefix, and the TTL MUST be large enough to get 131 the packet to the BFR neighbor. 133 The Flow-ID in the IPv6 packet SHOULD be copied from the entropy 134 field in the BIER encapsulation. 136 2.1. IPv6 Options Considerations 138 RFC 8200 section 4, defines the IPv6 extension headers. Currently 139 there are two defined extension headers, Hop-by-Hop and Destination 140 options header, which can carry a variable number of options. These 141 extension headers are inserted by the source node. 143 For directly connected BIER routers, IPv6 Hop-by-Hop or Destination 144 options are irrelevant and SHOULD NOT be inserted by BFIR on the 145 BIERin6 packet. In this case IPv6 header, Next Header field should 146 be set to TBD. Any IPv6 packet arriving on BFRs and BFERs, with 147 multiple extension header where the last extension header has a Next 148 Header field set to TBD, SHOULD be discard and the node should 149 transmit an ICMP Parameter Problem message to the source of the 150 packet (BFIR) with an ICMP code value of TBD10 ('invalid options for 151 BIERin6'). 153 This also indicates that for disjoint BIER routers using IPv6 154 encapsulation, there SHOULD NOT be any IPv6 Hop-by-Hop or Destination 155 options be present in a BIERin6 packet. In this case, if additional 156 traffic engineering is required, IPv6 tunneling (i.e. BIERin6 over 157 SRv6) can be implemented. 159 3. BIER Header 161 The BIER header MUST be encoded per Section 2.2 of [RFC8296]. 163 The BIFT-id is either encoded per 164 [I-D.ietf-bier-non-mpls-bift-encoding] or per advertised by BFRs, as 165 specificed in [I-D.dhanaraj-bier-lsr-ethernet-extensions]. 167 4. IPv6 Encapsulation Advertisement 169 When IPv6 encapsulation is not required between directly connected 170 BFRs, no signaling in addition to that specified in 171 [I-D.dhanaraj-bier-lsr-ethernet-extensions] is needed. 173 Otherwise, a node that requires IPv6 encapsualtion MUST advertise the 174 BIER IPv6 transportation sub-TLV/sub-sub-TLV according to local 175 configuration or policy in the BIER domain to request other BFRs to 176 always use IPv6 encapsulation. 178 In presence of multiple encapsulation possibilities hop-by-hop it is 179 a matter of local policy which encapsulation is imposed and the 180 receiving router MUST accept all encapsulations that it advertised. 182 4.1. Format 184 The BIER IPv6 transportation is a new sub-TLV of BIER defined in OSPF 185 [RFC8444], and a new sub-sub-TLV of BIER Info sub-TLV defined in ISIS 186 [RFC8401]. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 194 o Type: For OSPF, value TBD1 (prefer 12) is used to indicate it is 195 the IPv6 transportation sub-TLV. For ISIS, value TBD2 (prefer 3) 196 is used to indicate it is the IPv6 transportation sub-sub-TLV. 198 o Length: 0. 200 4.2. Inter-area prefix redistribution 202 When BFR-prefixes are advertised across IGP areas per 203 [I-D.dhanaraj-bier-lsr-ethernet-extensions] or redistributed across 204 protocol boundaries per [I-D.zwzw-bier-prefix-redistribute], the BIER 205 IPv6 transportation sub-TLV or sub-sub-TLV MAY be re-advertised/re- 206 distributed as well. 208 5. IANA Considerations 210 IANA is requested to assign a new "BIER" type for "Next Header" in 211 the "Assigned Internet Protocol Numbers" registry. 213 IANA is requested to assign a new "BIERin6" type for "invalid 214 options" in the "ICMP code value" registry. 216 IANA is requested to assign a new "BIER IPv6 transportation Sub-TLV" 217 type in the "OSPFv2 Extended Prefix TLV Sub-TLVs" Registry. 219 IANA is requested to set up a new "BIER IPv6 transportation Sub-sub- 220 TLV" type in the "IS-IS BIER Info sub-TLV" Registry. 222 6. Security Considerations 224 General IPv6 and BIER security considerations apply. 226 7. Acknowledgement 228 The authors would like to thank Jeffrey Zhang for his review and 229 valuable contributions. 231 8. References 232 8.1. Normative References 234 [RFC8200] Deering, S. and R. Hinden, "Internet Protocol, Version 6 235 (IPv6) Specification", STD 86, RFC 8200, 236 DOI 10.17487/RFC8200, July 2017, 237 . 239 [RFC8279] Wijnands, IJ., Ed., Rosen, E., Ed., Dolganow, A., 240 Przygienda, T., and S. Aldrin, "Multicast Using Bit Index 241 Explicit Replication (BIER)", RFC 8279, 242 DOI 10.17487/RFC8279, November 2017, 243 . 245 [RFC8296] Wijnands, IJ., Ed., Rosen, E., Ed., Dolganow, A., 246 Tantsura, J., Aldrin, S., and I. Meilik, "Encapsulation 247 for Bit Index Explicit Replication (BIER) in MPLS and Non- 248 MPLS Networks", RFC 8296, DOI 10.17487/RFC8296, January 249 2018, . 251 [RFC8401] Ginsberg, L., Ed., Przygienda, T., Aldrin, S., and Z. 252 Zhang, "Bit Index Explicit Replication (BIER) Support via 253 IS-IS", RFC 8401, DOI 10.17487/RFC8401, June 2018, 254 . 256 [RFC8444] Psenak, P., Ed., Kumar, N., Wijnands, IJ., Dolganow, A., 257 Przygienda, T., Zhang, J., and S. Aldrin, "OSPFv2 258 Extensions for Bit Index Explicit Replication (BIER)", 259 RFC 8444, DOI 10.17487/RFC8444, November 2018, 260 . 262 8.2. Informative References 264 [I-D.dhanaraj-bier-lsr-ethernet-extensions] 265 Dhanaraj, S., Wijnands, I., Psenak, P., Zhang, Z., Yan, 266 G., and J. Xie, "LSR Extensions for BIER over Ethernet", 267 draft-dhanaraj-bier-lsr-ethernet-extensions-00 (work in 268 progress), January 2019. 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-non-mpls-bift-encoding] 282 Wijnands, I., Xu, X., and H. Bidgoli, "An Optional 283 Encoding of the BIFT-id Field in the non-MPLS BIER 284 Encapsulation", draft-ietf-bier-non-mpls-bift-encoding-02 285 (work in progress), August 2019. 287 [I-D.zhang-bier-babel-extensions] 288 Zhang, Z. and T. Przygienda, "BIER in BABEL", draft-zhang- 289 bier-babel-extensions-02 (work in progress), November 290 2019. 292 [I-D.zwzw-bier-prefix-redistribute] 293 Zhang, Z., Bo, W., Zhang, Z., and I. Wijnands, "BIER 294 Prefix Redistribute", draft-zwzw-bier-prefix- 295 redistribute-03 (work in progress), September 2019. 297 [RFC7368] Chown, T., Ed., Arkko, J., Brandt, A., Troan, O., and J. 298 Weil, "IPv6 Home Networking Architecture Principles", 299 RFC 7368, DOI 10.17487/RFC7368, October 2014, 300 . 302 Authors' Addresses 304 Zheng(Sandy) Zhang 305 ZTE Corporation 307 EMail: zzhang_ietf@hotmail.com 309 Tony Przygienda 310 Juniper Networks, Inc. 312 EMail: prz@juniper.net 314 IJsbrand Wijnands 315 Cisco Systems 317 EMail: ice@cisco.com 319 Hooman Bidgoli 320 Nokia 322 EMail: hooman.bidgoli@nokia.com 323 Mike McBride 324 Futurewei 326 EMail: mmcbride@futurewei.com