Internet Engineering Task Force Sean Olson Internet draft Adam Roach Gonzalo Camarillo Ericsson December 2001 Expires May 2002 Support for IPv6 in SDP Status of this Memo This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC2026. 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 inappropriate to use Internet- Drafts as reference material or to cite them other than as "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 describes the use of IPv6 addresses [1] in conjunction with the Session Description Protocol (SDP) [2]. Specifically, this document clarifies existing text in SDP with regards to the syntax of IPv6 addresses. 1. Introduction SDP is intended for describing multimedia sessions for the purposes of session announcement, session invitation, and other forms of multimedia session initiation. It is a text format description that provides many details of a multimedia session including: the originator of the session, a URL related to the session, the connection address for the session media(s), and optional attributes for the session media(s). Each of these pieces of information may involve one or more IPv6 addresses. The ABNF for IP addresses in SDP currently leaves the syntax for IPv6 addresses undefined. This Internet-Draft attempts to complete the ABNF to include IPv6 addresses. Accordingly, the address type "IP6" indicating an IPv6 address, should be allowed in the connection field, "c=", of the SDP. The ABNF already reflects this, though the "Connection Data" text under section 6 of RFC2328 currently only defines the "IP4" address type. Olson, et. al. [Page 1] 2. Terminology 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. 3. Syntax RFC2373 [1] gives an ABNF for the text representation of IPv6 addresses in Appendix B. RFC2732 [3] covers the text representation of IPv6 addresses when used within a URL. Using the ABNF described in these documents, the following updated ABNF for SDP is proposed. uri = ; defined in RFC1630 and RFC2732 multicast-address = IP4-multicast | IP6-multicast IP4-multicast = m1 3*( "." decimal-uchar ) "/" ttl [ "/" integer ] ; IPv4 multicast addresses may be in the range ; 224.0.0.0 to 239.255.255.255 m1 = ("22" ("4"|"5"|"6"|"7"|"8"|"9")) | ("23" DIGIT )) IP6-multicast = hexpart [ ":" IP4-multicast ] "/" ttl [ "/" integer ] ; IPv6 address starting with FF00 addr = FQDN | unicast-address FQDN = 4*(alpha-numeric|"-"|".") ; fully qualified domain name as specified in ; RFC1035 unicast-address = IP4-address | IP6-address IP4-address = b1 "." decimal-uchar "." decimal-uchar "." b4 | "0.0.0.0" b1 = decimal-uchar ; less than "224"; not "0" or "127" b4 = decimal-uchar ; not "0" IP6-address = *( HEXDIGIT | "." | ":" ) ; As defined in the IPv6 addressing architecture Olson, et. al. [Page 2] 4. Additional IPv6 Issues in SDP 4.1 IPv6 Addresses with Embedded IPv4 Addresses RFC2373 defines two ways in which an IPv4 address may be encoded in an IPv6 address. In both forms, the lower 32 bits of the IPv6 address contain the IPv4 address. The first form is an "IPv4 compatible IPv6 address" and it has the format: | 80 bits | 16 | 32 bits | +--------------------------------------+--------------------------+ |0000..............................0000|0000| IPv4 address | +--------------------------------------+----+---------------------+ The second form of address is used to represent the addresses of IPv4-only nodes (those that *do not* support IPv6) as IPv6 addresses. This type of address is termed an "IPv4-mapped IPv6 address" and has the format: | 80 bits | 16 | 32 bits | +--------------------------------------+--------------------------+ |0000..............................0000|FFFF| IPv4 address | +--------------------------------------+----+---------------------+ The difference in format is significant and MAY be treated differently in SDP implementations. 5. Example SDP description with IPv6 addresses The following is an example SDP description using the above ABNF for IPv6 addresses. In particular, the origin, URI, and connection fields contain IPv6 addresses. The URI contains an IPv4 compatible IPv6 address. v=0 o=nasa1 971731711378798081 0 IN IP6 2201:056D::112E:144A:1E24 s=(Almost) live video feed from Mars-II sattelite u=http://[::FFFF:10.2.12.126]/marsII p=+1 713 555 1234 c=IN IP6 FF00:03AD::7F2E:172A:1E24 t=3338481189 3370017201 m=audio 6000 RTP/AVP 2 a=rtpmap:2 G726-32/8000 m=video 6024 RTP/AVP 107 a=rtpmap:107 H263-1998/90000 6. Backward compatibility An implementation that does not understand or wish to accept the IPv6 extensions to the SDP grammar MUST reject the SDP. 7. IANA Considerations This document updates the definition of the IP6 addrtype parameter found in RFC2327. 8. Security Considerations No additional considerations above what is stated in section 7 of RFC2327. Olson, et. al. [Page 3] 9. References [1] R. Hinden and S. Deering, "IP Version 6 Addressing Architecture", RFC2373, IETF. [2] M. Handley and V. Jacobson, "Session Description Protocol", RFC2327, IETF. [3] R. Hinden, et. al., "Format for Literal IPv6 Addresses in URL's", RFC2732, IETF. [4] D. Crocker and P. Overell, "Augmented BNF for Syntax Specifications: ABNF", RFC2234, IETF. [5] S. Bradner, "Key words for use in RFCs to Indicate Requirement Levels", RFC2119, IETF. 10. Author's Addresses Sean Olson Richardson, Texas USA Email: seancolson AT yahoo.com Gonzalo Camarillo Ericsson Advanced Signalling Research Lab. FIN-02420 Jorvas Finland Phone: +358 9 299 3371 Fax: +358 9 299 3118 Email: Gonzalo.Camarillo@ericsson.com Adam Roach Ericsson Richardson, Texas USA Phone: +1 972 583 7594 Fax: +1 972 669 0154 Email: Adam.Roach@ericsson.com Olson, et. al. [Page 4]