A Method for Generating Link-Scoped IPv6 Multicast Addresses
RFC 4489
Document | Type |
RFC - Proposed Standard
(April 2006; No errata)
Updates RFC 3306
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Authors | Myung-Ki Shin , Hyoung-Jun Kim , Park Jung-Soo | ||
Last updated | 2015-10-14 | ||
Stream | IETF | ||
Formats | plain text html pdf htmlized bibtex | ||
Stream | WG state | (None) | |
Document shepherd | No shepherd assigned | ||
IESG | IESG state | RFC 4489 (Proposed Standard) | |
Action Holders |
(None)
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Consensus Boilerplate | Unknown | ||
Telechat date | |||
Responsible AD | Margaret Cullen | ||
Send notices to | (None) |
Network Working Group J-S. Park Request for Comments: 4489 M-K. Shin Updates: 3306 H-J. Kim Category: Standards Track ETRI April 2006 A Method for Generating Link-Scoped IPv6 Multicast Addresses Status of This Memo This document specifies an Internet standards track protocol for the Internet community, and requests discussion and suggestions for improvements. Please refer to the current edition of the "Internet Official Protocol Standards" (STD 1) for the standardization state and status of this protocol. Distribution of this memo is unlimited. Copyright Notice Copyright (C) The Internet Society (2006). Abstract This document specifies an extension to the multicast addressing architecture of the IPv6 protocol. The extension allows the use of Interface Identifiers (IIDs) to allocate multicast addresses. When a link-local unicast address is configured at each interface of a node, an IID is uniquely determined. After that, each node can generate its unique multicast addresses automatically without conflicts. The alternative method for creating link-local multicast addresses proposed in this document is better than known methods like unicast- prefix-based IPv6 multicast addresses. This memo updates RFC 3306. Table of Contents: 1. Introduction ....................................................2 2. Applicability ...................................................2 3. Link-Scoped Multicast Address Format ............................3 4. Example .........................................................3 5. Consideration of Lifetime .......................................4 6. Security Considerations .........................................4 7. Acknowledgements ................................................4 8. References ......................................................5 Park, et al. Standards Track [Page 1] RFC 4489 Link-Scoped IPv6 Multicast April 2006 1. Introduction This document defines an extension to the multicast portion of the IPv6 addressing architecture [RFC4291]. The current architecture does not contain any built-in support for dynamic address allocation. The extension allows for use of IIDs to allocate multicast addresses. When a link-local unicast address is configured at each interface of a node, an IID is uniquely determined. After that, each node can generate its unique multicast addresses automatically without conflicts. That is, these addresses could safely be configured at any time after Duplicate Address Detection (DAD) has completed. This method for the link-local scope is preferred over unicast- prefix-based IPv6 multicast addresses [RFC3306], since by delegating multicast addresses using the IID, each node can generate its multicast addresses automatically without allocation servers. This method works better than the unicast-prefix-based method with applications in serverless environments such as ad-hoc and network mobility. This document restricts the usage of defined fields such as the scop, plen, and network prefix fields of [RFC3306]. Therefore, this document specifies encoded information for link-local scope in multicast addresses. The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [RFC2119]. 2. Applicability The allocation technique in this document is designed to be used in any environment in which link-local scope IPv6 multicast addresses are assigned or selected. This method goes especially well with nodes supplying multicast services in a zeroconf/serverless environment. For example, multicast addresses less than or equal to link-local scope are themselves generated by nodes supplying multicast services without conflicts. Also, hosts that are supplied multicast services from multicast servers then make multicast addresses of multicast servers using ND (address resolution) and well-known group IDs [RFC2461]. Consequently, this technique MUST only be used for link scoped multicast addresses. If you want to use multicast addresses greater than link-local scope, you need to use other methods as described in [RFC3306]. Park, et al. Standards Track [Page 2] RFC 4489 Link-Scoped IPv6 Multicast April 2006 3. Link-Scoped Multicast Address Format This document specifies a new format that incorporates IID in the link-local scope multicast addresses. Figure 1 illustrates the new format for link-scoped multicastShow full document text