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Is this intentional? 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: 'RFC8279' is defined on line 186, but no explicit reference was found in the text -- Duplicate reference: RFC2119, mentioned in 'RFC8174', was also mentioned in 'RFC2119'. Summary: 0 errors (**), 0 flaws (~~), 3 warnings (==), 2 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Network Working Group H. Bidgoli, Ed. 3 Internet-Draft Nokia 4 Intended status: Standards Track S. Venaas 5 Expires: 28 April 2022 Cisco System, Inc. 6 M. Mishra 7 Cisco System 8 Z. Zhang 9 Juniper Networks 10 M. McBride 11 Futurewei Technologies Inc. 12 25 October 2021 14 PIM Light 15 draft-hb-pim-light-00 17 Abstract 19 This document specifies a new Protocol Independent Multicast 20 interface which does not need PIM Hello to accept PIM Join/Prunes or 21 PIM Asserts. 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 28 April 2022. 40 Copyright Notice 42 Copyright (c) 2021 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 (https://trustee.ietf.org/ 47 license-info) in effect on the date of publication of this document. 48 Please review these documents carefully, as they describe your rights 49 and restrictions with respect to this document. Code Components 50 extracted from this document must include Simplified BSD License text 51 as described in Section 4.e of the Trust Legal Provisions and are 52 provided without warranty as described in the Simplified BSD License. 54 Table of Contents 56 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 57 2. Conventions used in this document . . . . . . . . . . . . . . 2 58 2.1. Definitions . . . . . . . . . . . . . . . . . . . . . . . 2 59 3. PIM Light Interface . . . . . . . . . . . . . . . . . . . . . 3 60 3.1. PLI Configuration . . . . . . . . . . . . . . . . . . . . 4 61 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4 62 5. Security Considerations . . . . . . . . . . . . . . . . . . . 4 63 6. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 4 64 7. References . . . . . . . . . . . . . . . . . . . . . . . . . 4 65 7.1. Normative References . . . . . . . . . . . . . . . . . . 4 66 7.2. Informative References . . . . . . . . . . . . . . . . . 5 67 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 5 69 1. Introduction 71 It might be desirable to create a PIM interface between routers where 72 only PIM Join/Prunes and Asserts packets are triggered over it 73 without having a full PIM neighbor discovery. As an example, this 74 type of PIM interface can be useful in some scenarios where the 75 multicast state needs to be signaled over a network or medium which 76 is not capable of creating full PIM neighborship between its Peer 77 Routers. These type of PIM interfaces are called PIM Light 78 Interfaces (PLI). 80 2. Conventions used in this document 82 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 83 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and 84 "OPTIONAL" in this document are to be interpreted as described in BCP 85 14 [RFC2119] [RFC8174] when, and only when, they appear in all 86 capitals, as shown here. 88 2.1. Definitions 90 This draft uses definitions used in [RFC7761] 92 3. PIM Light Interface 94 RFC [RFC7761] section 4.3.1 describes the PIM nighbor discovery via 95 Hello messages. It also describes that PIM Join/Prune or Assert 96 messages are not accepted from a router unless a Hello message has 97 been heard from that router. 99 In some scenarios it is desired to build a multicast state between 100 two directly attach or remote routers without establishing a PIM 101 neighborship. There could be many reasons for this desired, but one 102 example is the desired to signal multicast states upstream between 103 two PIM Domains via a network or medium that is not optimized for PIM 104 Neighbor establishment. A BIER network is an example of this, where 105 the BIER network is connecting two PIM domains as per 106 [draft-hfa-bier-pim-signaling] and the multicast states from the 107 hosts to the source are signaled via two edge PIM networks through 108 the BIER domain. 110 A PIM Light Interface (PLI) does accept Join/Prune and Assert 111 messages from a unknown PIM router, without receiving a PIM Hello 112 message form other routers. Lack of Hello Messages on a PLI means 113 there is no mechanism to learn about the neighboring PIM routers on 114 each interface and there is no DR Priority options communicated 115 between Routers either. As such the router doesn't create any 116 General-Purpose state for neighboring PIM routers and it accepts and 117 installs each Join message from upstream routers in its multicast 118 routing table. 120 Because of this a PLI needs to be created in very especial cases and 121 the application that is using these PLIs should ensure there is no 122 multicast duplication of packets. As an example, multiple upstream 123 routers sending the same multicast stream to a single downstream 124 router. 126 As an example, in a BIER domain which is connecting 2 PIM networks. 127 A PLI can be established between two edge BIER routers and only 128 multicast states communicated via PIM Join/prunes over the BIER 129 domain. In this case to ensure there is no multicast stream 130 duplication the PIM routers attached on each side of the BIER domain 131 might want to establish PIM Adjacency via [RFC7761] to ensure DR 132 selection on the edge of the BIER router and PLI is used in core of 133 the BIER Domain. 135 3.1. PLI Configuration 137 Since a PLI doesn't support PIM Hello Messages to discover other PIM 138 routers, for security reasons, there needs to be a mechanism to 139 enable PLI on an interface or the router. This can be achieved via 140 different methods and is implementation specific. As an example: 142 * For Point to Point interface PLI can be enabled on an interface 143 that is accepting the PIM Join/Prune or Assert messages only. 145 * A PLI can also be configured on a logical interface or a tunnel 146 interface, like a MPLS tunnel or a GRE tunnel to accept PIM Join/ 147 Prune or Assert messages. 149 * In some cases it is not possible to configure a PLI between two 150 routers, as an example in a BIER network where multicast states 151 are communicated via PIM Join/Prunes. As per 152 [draft-hfa-bier-pim-signaling] there can be multiple BIER Edge 153 routers that can signal their desire for a multicast state. In 154 these scenarios the router needs to be configured to support PLI 155 and only accept PIM Join/Prune or Assert messages based on this 156 global configuration 158 4. IANA Considerations 160 IANA is requested to assign a value (TBD) to the BIER Information 161 Vector PIM Join Attribute from the PIM Join Attribute Types registry. 163 5. Security Considerations 165 6. Acknowledgments 167 7. References 169 7.1. Normative References 171 [draft-hfa-bier-pim-signaling] 172 "H.Bidgoli, F.XU, J. Kotalwar, I. Wijnands, M.Mishra, Z. 173 Zhang, "PIM Signaling Through BIER Core"", July 2021. 175 [RFC2119] "S. Brandner, "Key words for use in RFCs to Indicate 176 Requirement Levels"", March 1997. 178 [RFC7761] "B.Fenner, M.Handley, H. Holbrook, I. Kouvelas, R. Parekh, 179 Z.Zhang "PIM Sparse Mode"", March 2016. 181 [RFC8174] "B. Leiba, "ambiguity of Uppercase vs Lowercase in RFC 182 2119 Key Words"", May 2017. 184 7.2. Informative References 186 [RFC8279] "Wijnands, IJ., Rosen, E., Dolganow, A., Przygienda, T. 187 and S. Aldrin, "Multicast using Bit Index Explicit 188 Replication"", October 2016. 190 Authors' Addresses 192 Hooman Bidgoli (editor) 193 Nokia 194 Ottawa 195 Canada 197 Email: hooman.bidgoli@nokia.com 199 Stig 200 Cisco System, Inc. 201 San Jose, 202 United States of America 204 Email: stig@cisco.com 206 Mankamana Mishra 207 Cisco System 208 Milpitas, 209 United States of America 211 Email: mankamis@cisco.com 213 Zhaohui Zhang 214 Juniper Networks 215 Boston, 216 United States of America 218 Email: zzhang@juniper.com 220 Mike 221 Futurewei Technologies Inc. 222 Santa Clara, 223 United States of America 224 Email: michael.mcbride@futurewei.com