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Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 BIER WG Z. Zhang 3 Internet-Draft ZTE Corporation 4 Intended status: Standards Track A. Przygienda 5 Expires: May 6, 2020 Juniper Networks 6 November 3, 2019 8 BIER in BABEL 9 draft-zhang-bier-babel-extensions-02 11 Abstract 13 BIER introduces a novel multicast architecture. It does not require 14 a signaling protocol to explicitly build multicast distribution 15 trees, nor does it require intermediate nodes to maintain any per- 16 flow state. 18 Babel defines a distance-vector routing protocol that operates in a 19 robust and efficient fashion both in wired as well as in wireless 20 mesh networks. This document defines a way to carry necessary BIER 21 signaling information in Babel. 23 Status of This Memo 25 This Internet-Draft is submitted in full conformance with the 26 provisions of BCP 78 and BCP 79. 28 Internet-Drafts are working documents of the Internet Engineering 29 Task Force (IETF). Note that other groups may also distribute 30 working documents as Internet-Drafts. The list of current Internet- 31 Drafts is at https://datatracker.ietf.org/drafts/current/. 33 Internet-Drafts are draft documents valid for a maximum of six months 34 and may be updated, replaced, or obsoleted by other documents at any 35 time. It is inappropriate to use Internet-Drafts as reference 36 material or to cite them other than as "work in progress." 38 This Internet-Draft will expire on May 6, 2020. 40 Copyright Notice 42 Copyright (c) 2019 IETF Trust and the persons identified as the 43 document authors. All rights reserved. 45 This document is subject to BCP 78 and the IETF Trust's Legal 46 Provisions Relating to IETF Documents 47 (https://trustee.ietf.org/license-info) in effect on the date of 48 publication of this document. Please review these documents 49 carefully, as they describe your rights and restrictions with respect 50 to this document. Code Components extracted from this document must 51 include Simplified BSD License text as described in Section 4.e of 52 the Trust Legal Provisions and are provided without warranty as 53 described in the Simplified BSD License. 55 Table of Contents 57 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 58 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 2 59 3. Advertisement of BIER information . . . . . . . . . . . . . . 2 60 3.1. BIER BFR-prefix and BIER sub-TLV . . . . . . . . . . . . 3 61 3.1.1. BIER sub-TLV . . . . . . . . . . . . . . . . . . . . 3 62 3.2. BIER MPLS Encapsulation sub-sub-TLV . . . . . . . . . . . 4 63 4. Tree types and tunneling . . . . . . . . . . . . . . . . . . 4 64 5. Security Considerations . . . . . . . . . . . . . . . . . . . 5 65 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5 66 7. Normative References . . . . . . . . . . . . . . . . . . . . 5 67 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 6 69 1. Introduction 71 [RFC8279] introduces a novel multicast architecture. It does not 72 require a signaling protocol to explicitly build multicast 73 distribution trees, nor does it require intermediate nodes to 74 maintain any per-flow state. All procedures necessary to support 75 BIER are abbreviated by the "BIER architecture" moniker in this 76 document. 78 [I-D.ietf-babel-rfc6126bis] define a distance-vector routing protocol 79 under the name of "Babel". Babel operates in a robust and efficient 80 fashion both in ordinary wired as well as in wireless mesh networks. 82 2. Terminology 84 The terminology of this documents follows [RFC8279], [RFC6126], 85 [RFC7557] and [I-D.ietf-babel-rfc6126bis]. 87 3. Advertisement of BIER information 89 In case a router is configured with BIER information, and Babel is 90 the routing protocol used, such a router MAY use Babel protocol to 91 announce the BIER information using the BIER sub-TLV specified below. 93 3.1. BIER BFR-prefix and BIER sub-TLV 95 BFR-prefix and according information is carried in a Babel Update TLV 96 per [I-D.ietf-babel-rfc6126bis]. A new sub-TLV is defined to convey 97 further BIER information such as BFR-id, sub-domain-id and BSL. Two 98 sub-sub-TLVs are carried as payload of BIER sub-TLV. 100 The mandatory bit of BIER sub-TLV should be set to 0. If a router 101 cannot recognize a sub-TLV, the router MUST ignore this unknown sub- 102 TLV. 104 3.1.1. BIER sub-TLV 106 The BIER sub-TLV format aligns exactly with the definition and 107 restrictions in [RFC8401] and [RFC8444]. It is a sub-TLV of Babel 108 update TLV. The prefix MUST NOT be summarized and the according sub- 109 TLV MUST be treated as optional and transitive. 111 0 1 2 3 112 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 1 113 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 114 | Type | Length | 115 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 116 | BAR | IPA | subdomain-id | 117 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 118 | BFR-id | 119 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 120 | sub-sub-TLVs (variable) | 121 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 122 Figure 1: BIER sub-TLV 124 o Type: as indicated in IANA section. 126 o Length: 1 octet. Include the length of BIER sub-TLV and potential 127 length of the sub-sub-TLVs. 129 o BAR: BIER Algorithm. Specifies a BIER-specific algorithm used to 130 calculate underlay paths to reach BFERs. Values are allocated 131 from the "BIER Algorithms" registry. 1 octet. 133 o IPA: IGP Algorithm. Specifies an IGP Algorithm to either modify, 134 enhance, or replace the calculation of underlay paths to reach 135 BFERs as defined by the BAR value. Values are from the IGP 136 Algorithm registry. 1 octet. 138 o subdomain-id: Unique value identifying the BIER sub-domain. 1 139 octet. 141 o BFR-id: A 2 octet field encoding the BFR-id, as documented in 142 [RFC8279]. If no BFR-id has been assigned this field is set to 143 the invalid BFR-id. 145 3.2. BIER MPLS Encapsulation sub-sub-TLV 147 The BIER MPLS Encapsulation sub-sub-TLV can be carried by BIER sub- 148 TLV. The format and restrictions are aligned with [RFC8401] and 149 [RFC8444]. This sub-sub-TLV carries the information for the BIER 150 MPLS encapsulation including the label range for a specific BSL for a 151 certain pair. 153 0 1 2 3 154 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 1 155 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 156 | Type | Length | 157 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 158 | Max SI |BS Len | Label | 159 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 160 Figure 2: MPLS Encapsulation sub-sub-TLV 162 o Type: value of 1 indicating MPLS encapsulation. 164 o Length: 1 octet 166 o Max SI: Maximum Set Identifier (Section 1 of [RFC8279]) used in 167 the encapsulation for this BIER subdomain for this BitString 168 length, 1 octet. Each SI maps to a single label in the label 169 range. The first label is for SI=0, the second label is for SI=1, 170 etc. If the label associated with the Maximum Set Identifier 171 exceeds the 20-bit range, the sub-sub-TLV MUST be ignored. 173 o Local BitString Length (BS Len): Encoded BitString length as per 174 [RFC8296]. 4 bits. 176 o Label: First label, 20 bits. The labels are as defined in 177 [RFC8296]. 179 4. Tree types and tunneling 181 Since Babel is performing a diffusion computation, support for 182 different tree types is not as natural as with link-state protocols. 183 Hence this specification is assuming that normal Babel reachability 184 computation is performed without further modifications. 186 BIER architecture does not rely on all routers in a domain performing 187 BFR procedures. How to support tunnels that will allow to tunnel 188 BIER across such routers in Babel is for further study. 190 5. Security Considerations 192 TBD 194 6. IANA Considerations 196 A new type of Babel update sub-TLV needs to be defined for BIER 197 information advertisement. 199 7. Normative References 201 [I-D.ietf-babel-rfc6126bis] 202 Chroboczek, J. and D. Schinazi, "The Babel Routing 203 Protocol", draft-ietf-babel-rfc6126bis-15 (work in 204 progress), October 2019. 206 [RFC6126] Chroboczek, J., "The Babel Routing Protocol", RFC 6126, 207 DOI 10.17487/RFC6126, April 2011, 208 . 210 [RFC7557] Chroboczek, J., "Extension Mechanism for the Babel Routing 211 Protocol", RFC 7557, DOI 10.17487/RFC7557, May 2015, 212 . 214 [RFC8279] Wijnands, IJ., Ed., Rosen, E., Ed., Dolganow, A., 215 Przygienda, T., and S. Aldrin, "Multicast Using Bit Index 216 Explicit Replication (BIER)", RFC 8279, 217 DOI 10.17487/RFC8279, November 2017, 218 . 220 [RFC8296] Wijnands, IJ., Ed., Rosen, E., Ed., Dolganow, A., 221 Tantsura, J., Aldrin, S., and I. Meilik, "Encapsulation 222 for Bit Index Explicit Replication (BIER) in MPLS and Non- 223 MPLS Networks", RFC 8296, DOI 10.17487/RFC8296, January 224 2018, . 226 [RFC8401] Ginsberg, L., Ed., Przygienda, T., Aldrin, S., and Z. 227 Zhang, "Bit Index Explicit Replication (BIER) Support via 228 IS-IS", RFC 8401, DOI 10.17487/RFC8401, June 2018, 229 . 231 [RFC8444] Psenak, P., Ed., Kumar, N., Wijnands, IJ., Dolganow, A., 232 Przygienda, T., Zhang, J., and S. Aldrin, "OSPFv2 233 Extensions for Bit Index Explicit Replication (BIER)", 234 RFC 8444, DOI 10.17487/RFC8444, November 2018, 235 . 237 Authors' Addresses 239 Zheng(Sandy) Zhang 240 ZTE Corporation 241 No. 50 Software Ave, Yuhuatai Distinct 242 Nanjing 243 China 245 Email: zhang.zheng@zte.com.cn 247 Tony Przygienda 248 Juniper Networks 250 Email: prz@juniper.net