HTTP/1.1 200 OK Date: Tue, 09 Apr 2002 00:14:25 GMT Server: Apache/1.3.20 (Unix) Last-Modified: Tue, 13 Apr 1999 21:59:47 GMT ETag: "2e6e07-23db-3713be53" Accept-Ranges: bytes Content-Length: 9179 Connection: close Content-Type: text/plain INTERNET DRAFT Brian Haberman April 1999 (IBM) Static Allocation of Multicast Addresses in the Internet Protocol Version 6 (IPv6) Status of This Memo This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC 2026. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet-Drafts. Internet-Drafts are draft documents valid for a maximum of six months, and may be updated, replaced, or obsoleted by other documents at any time. It is not appropriate to use Internet-Drafts as reference material, or to cite them other than as a ``working draft'' or ``work in progress.'' The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. Abstract This document defines a mechanism for statically allocating IPv6 multicast addresses by network prefixes. This approach will integrate seamlessly with the Multicast Address Dynamic Client Allocation Protocol (MADCAP). It will also remove the need to support the Multicast Address Set Claim (MASC) Protocol for IPv6. Haberman Expires October 1999 [Page i] Internet Draft Static Allocation of IPv6 Multicast Addresses April 1999 Contents 1. Keywords 1 2. Introduction 1 3. IPv6 Multicast Address Format 1 4. Static Allocation 1 4.1. Globally routable prefixes . . . . . . . . . . . . . . . 1 4.2. Site-local prefixes . . . . . . . . . . . . . . . . . . . 2 4.3. Link-local prefixes . . . . . . . . . . . . . . . . . . . 2 5. Security Considerations 2 6. References 3 7. Author's Address 3 8. Full Copyright Statement 3 Haberman Expires October 1999 [Page ii] Internet Draft Static Allocation of IPv6 Multicast Addresses April 1999 1. Keywords 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 RFC 2119 [RFC2119]. 2. Introduction One of the most common problems with IPv4 multicast is the limited size of the multicast address range. This limited range size has led to several mechanisms for allocating IPv4 multicast addresses. With the address architecture introduced for IPv6 [ADDARCH], the address range constraint does not hinder IPv6 multicast. Because of the increased address size, it is feasible to allocate multicast addresses statically in IPv6. This work describes the mechanism for the static allocation of IPv6 multicast addresses based on the IPv6 network prefix. It will work seamlessly with the MADCAP [MADCAP] protocol. Because this is a static allocation, it will eliminate the need for running the MASC protocol [MASC]. 3. IPv6 Multicast Address Format The IPv6 address architecture defines an IPv6 multicast address as follows : | 8 | 4 | 4 | 112 bits | +--------+----+----+---------------------------------------------+ |11111111|flgs|scop| group ID | +--------+----+----+---------------------------------------------+ The legal values for the flgs and scop field are defined in the IPv6 address architecture [ADDARCH]. 4. Static Allocation 4.1. Globally routable prefixes The mechanism for allocating IPv6 multicast addresses will be to imbed an IPv6 unciast network prefix in the multicast address starting at bit 16. The resulting multicast address will have the following format if Haberman Expires October 1999 [Page 1] Internet Draft Static Allocation of IPv6 Multicast Addresses April 1999 the network prefix was taken from an address format that must contain an EUI-64 based interface identifier (Section 2.4 of [ADDARCH]). | 8 | 4 | 4 | 64 bits | 48 bits | +--------+----+----+---------------------------------------------+ |11111111|flgs|scop| IPv6 unicast network prefix | group ID | +--------+----+----+---------------------------------------------+ This format will allow for 2^48 group IDs for each unique (scop, prefix) pair. 4.2. Site-local prefixes If a node attempting to obtain an IPv6 multicast address does not have a globally routable network prefix, it can use a site-local address prefix in the same manner. In this case, the multicast address format will be : | 8 | 4 | 4 | 10 bits |38 bits | 16 bits | 48 bits | +--------+----+----+---------------------------------------------+ |11111111|flgs|scop|1111111011 | 0 | subnet ID | group ID | +--------+----+----+---------------------------------------------+ With this format, the scop field of the address can be no greater than site-local (5), defined in Section 2.7 of [ADDARCH]. 4.3. Link-local prefixes If a node only has a link-local address, section 2.5.8 of [ADDARCH], it can only use a multicast address with a scop field no greater than link-local (2). For this case, the multicast address format is as follows : | 8 | 4 | 4 | 112 bits | +--------+----+----+---------------------------------------------+ |11111111|flgs|scop| group ID | +--------+----+----+---------------------------------------------+ 5. Security Considerations Haberman Expires October 1999 [Page 2] Internet Draft Static Allocation of IPv6 Multicast Addresses April 1999 6. References [RFC2119] S. Bradner, "Key words for use in RFCs to Indicate Requirement Levels", RFC 2119, BCP14, March 1997. [ADDARCH] R. Hinden and S. Deering, "IP Version 6 Addressing Architecture", RFC 2373, July 1998. [MADCAP] B. Patel, M. Shah, and S. Hanna, "Multicast Address Dynamic Client Allocation Protocol (MADCAP)", draft-ietf-malloc-madcap-04.txt, February 1999. [MASC] D. Estrin, R. Govindan, M. Handley, S. Kumar, P. Radoslavov, and D. Thaler, "The Multicast Address-Set Claim (MASC) Protocol", draft-ietf-malloc-masc-01.txt, August 1998. 7. Author's Address Brian Haberman IBM Corporation 800 Park Office Drive Research Triangle Park, NC 27709 USA +1-919-254-2673 haberman@raleigh.ibm.com 8. Full Copyright Statement Copyright (C) The Internet Society (1999). All Rights Reserved. This document and translations of it may be copied and furnished to others, and derivative works that comment on or otherwise explain it or assist in its implementation may be prepared, copied, published and distributed, in whole or in part, without restriction of any kind, provided that the above copyright notice and this paragraph are included on all such copies and derivative works. However, this document itself may not be modified in any way, such as by removing the copyright notice or references to the Internet Society or other Internet organizations, except as needed for the purpose of developing Internet standards in which case the procedures for copyrights defined in the Internet Standards process must Haberman Expires October 1999 [Page 3] Internet Draft Static Allocation of IPv6 Multicast Addresses April 1999 be followed, or as required to translate it into languages other than English. The limited permissions granted above are perpetual and will not be revoked by the Internet Society or its successors or assigns. This document and the information contained herein is provided on an "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Haberman Expires October 1999 [Page 4]