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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 167, 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: 16 May 2022 Cisco System, Inc. 6 M. Mishra 7 Cisco System 8 Z. Zhang 9 Juniper Networks 10 M. McBride 11 Futurewei Technologies Inc. 12 12 November 2021 14 PIM Light 15 draft-hb-pim-light-01 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 16 May 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 . . . . . . . . . . . . . . . . . 4 67 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 4 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 or has no need for creating full PIM neighborship 77 between its Peer Routers. These type of PIM interfaces are called 78 PIM Light 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 neighbor 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 or more PIM Domains via a network or medium that is not optimized 104 for or does not require PIM Neighbor establishment. An example is a 105 BIER network connecting multiple PIM domains and PIM Join/prune 106 messages are tunneled via bier as per 107 [draft-ietf-bier-pim-signaling]. 109 A PIM Light Interface (PLI) does accept Join/Prune and Assert 110 messages from a unknown PIM router, without receiving a PIM Hello 111 message form the router. Lack of Hello Messages on a PLI means there 112 is no mechanism to learn about the neighboring PIM routers on each 113 interface and there is no DR Priority options communicated between 114 Routers either. As such the router doesn't create any General- 115 Purpose state for neighboring PIM routers and it accepts and installs 116 each Join message from upstream routers in its multicast routing 117 table. 119 Because of this a PLI needs to be created in very especial cases and 120 the application that is using these PLIs should ensure there is no 121 multicast duplication of packets. As an example, multiple upstream 122 routers sending the same multicast stream to a single downstream 123 router. 125 As an example, in a BIER domain which is connecting 2 PIM networks. 126 A PLI can be used to connect edge BIER routers and only multicast 127 states communicated via PIM Join/prunes over the BIER domain. In 128 this case to ensure there is no multicast stream duplication the PIM 129 routers attached on each side of the BIER domain might want to 130 establish PIM Adjacency via [RFC7761] to ensure DR selection on the 131 edge of the BIER router while PLI is used in core of the BIER Domain. 133 3.1. PLI Configuration 135 Since a PLI doesn't require PIM Hello Messages and PIM neighbor 136 adjacency is not checked for join/prune/assert messages, there needs 137 to be a mechanism to enable PLI on interfaces for security purpose, 138 while on some other interfaces this may be enabled automatically. An 139 example of the latter is the logical interface for a BIER sub-domain 140 [draft-ietf-bier-pim-signaling]. 142 4. IANA Considerations 144 5. Security Considerations 146 6. Acknowledgments 148 7. References 150 7.1. Normative References 152 [draft-ietf-bier-pim-signaling] 153 "H.Bidgoli, F.XU, J. Kotalwar, I. Wijnands, M.Mishra, Z. 154 Zhang, "PIM Signaling Through BIER Core"", July 2021. 156 [RFC2119] "S. Brandner, "Key words for use in RFCs to Indicate 157 Requirement Levels"", March 1997. 159 [RFC7761] "B.Fenner, M.Handley, H. Holbrook, I. Kouvelas, R. Parekh, 160 Z.Zhang "PIM Sparse Mode"", March 2016. 162 [RFC8174] "B. Leiba, "ambiguity of Uppercase vs Lowercase in RFC 163 2119 Key Words"", May 2017. 165 7.2. Informative References 167 [RFC8279] "Wijnands, IJ., Rosen, E., Dolganow, A., Przygienda, T. 168 and S. Aldrin, "Multicast using Bit Index Explicit 169 Replication"", October 2016. 171 Authors' Addresses 173 Hooman Bidgoli (editor) 174 Nokia 175 Ottawa 176 Canada 177 Email: hooman.bidgoli@nokia.com 179 Stig 180 Cisco System, Inc. 181 San Jose, 182 United States of America 184 Email: stig@cisco.com 186 Mankamana Mishra 187 Cisco System 188 Milpitas, 189 United States of America 191 Email: mankamis@cisco.com 193 Zhaohui Zhang 194 Juniper Networks 195 Boston, 196 United States of America 198 Email: zzhang@juniper.com 200 Mike 201 Futurewei Technologies Inc. 202 Santa Clara, 203 United States of America 205 Email: michael.mcbride@futurewei.com