Internet Draft INTERNET DRAFT Brian Haberman February 1999 Garry Kump (IBM) Hal Sandick (Nortel Networks) Protocol Independent Multicast Routing in the Internet Protocol Version 6 (IPv6) <draft-ietf-pim-ipv6-01.txt> 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 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 outlines recommendations in the use of Protocol Independent Multicast routing protocol to support Internet Protocol Version 6. It describes the changes needed in order to handle the differences between IPv6 and IPv4 and conform to the logic introduced by other routing protocols enabled for IPv6. Haberman, Kump, Sandick Expires August 1999 [Page i] Internet Draft PIM Multicast Routing for IPv6 February 1999 Contents 1. Definitions 1 2. Introduction 1 3. Definitions and Assumptions 1 4. Protocol Impact 1 4.1. Hello Message . . . . . . . . . . . . . . . . . . . . . . 1 4.2. Register Message . . . . . . . . . . . . . . . . . . . . 2 4.3. Register-Stop Message . . . . . . . . . . . . . . . . . . 2 4.4. Join/Prune, Graft, and Graft-Ack Messages . . . . . . . 2 4.5. Bootstrap Message . . . . . . . . . . . . . . . . . . . . 2 4.6. Assert Message . . . . . . . . . . . . . . . . . . . . . 3 4.7. Candidate-RP-Advertisement Message . . . . . . . . . . . 3 5. IPv6 Address Scoping 3 Haberman, Kump, Sandick Expires August 1999 [Page ii] Internet Draft PIM Multicast Routing for IPv6 February 1999 1. Definitions 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 [RFC 2119]. 2. Introduction This document describes a protocol for efficiently routing to multicast groups communicating with the Internet Protocol Version 6 (IPv6). This document will only describe recommendations for making PIM conform to practices implemented by other IPv6 routing protocols. The existing PIM drafts should be referenced for actual protocol operation. 3. Definitions and Assumptions - Link Local Address - A local-use, non-routable unicast IPv6 address [RFC 2373]. - All-PIM-Routers multicast address - A permanently assigned link-scoped IPv6 multicast address for the PIM protocol [RFC 2375]. It is assumed that a router running PIM for IPv6 will have a network unique, globally reachable IPv6 address that will be used for multiple hop messages. 4. Protocol Impact The following will outline suggested values for the PIM protocol messages in order to support IPv6. For most messages, the changes involve the addresses used in the IPv6 header. 4.1. Hello Message When sending a Hello Message, a PIM router must use a different set of IPv6 addresses in the IPv6 header. The IPv6 destination address must be the All-PIM-Routers multicast address. The IPv6 source address must be the IPv6 link local address of the interface on which this message is being forwarded. The link local address in the source address field will be used to determine neighbor adjacency Haberman, Kump, Sandick Expires August 1999 [Page 1] Internet Draft PIM Multicast Routing for IPv6 February 1999 and for Designated Router(DR) election. It should be noted, that the DR will identify itself using its globally reachable IPv6 address. 4.2. Register Message The Register Message is addressed to the globally reachable IPv6 address of the Rendezvous Point(RP). The source address of the message is the globally reachable IPv6 address of the DR. The DR sending the Register Message obtains the globally reachable IPv6 address of the RP from the local RP-set information. 4.3. Register-Stop Message The Register-Stop Message is addressed in the same manner as the Register Message. The RP addresses the message to the globally reachable IPv6 address of the DR. The source address is the globally reachable IPv6 address of the RP. The RP obtains the globally reachable IPv6 address of the DR from the source address field of the Register Message received from the DR. 4.4. Join/Prune, Graft, and Graft-Ack Messages In the transmission of a Join/Prune Message, a router sets the IPv6 destination address to the All-PIM-Routers multicast address. The IPv6 source address is set to the link local address of the interface on which the message is forwarded. The Upstream Neighbor Address field is set to the link local address of the next hop router, which is obtained from the RPF lookup. If a link local address cannot be obtained for the upstream neighbor, the Upstream Neighbor Address field is set to a known IPv6 address for that neighbor. 4.5. Bootstrap Message When sending a Bootstrap Message, a PIM router sets the IPv6 destination address to the All-PIM-Routers multicast address. The source address is the link local address of the interface on which the message is forwarded. The Bootstrap Router(BSR) Address is set to the globally reachable IPv6 address of the BSR. Haberman, Kump, Sandick Expires August 1999 [Page 2] Internet Draft PIM Multicast Routing for IPv6 February 1999 4.6. Assert Message The Assert Message has an IPv6 destination address of the All-PIM-Routers multicast address and an IPv6 source address of the link local address of the interface forwarding the message. The link local address in the IPv6 source field is used to resolve ties in the assert process. Downstream routers save the winning assert router's link local address to resolve any future RPF requirements. 4.7. Candidate-RP-Advertisement Message The Candidate-RP-Advertisement Message uses the globally reachable IPv6 address of the BSR as the IPv6 destination address. The source address is the globally reachable IPv6 address of the candidate RP. The RP Address field is set to the globally reachable IPv6 address of the candidate RP. Each candidate RP router creates this message and unicasts it to the BSR. 5. IPv6 Address Scoping With the introduction of scoped addresses in IPv6, new issues arise in the distribution of scoped routes and the forwarding of scoped packets. Currently, work in the area of scoping has been limited. An Internet draft does exist that outlines the changes needed to routing protocols in order to support the IPv6 scoped addresses [SCOPE]. The main outstanding problem, with regard to scoping, is the PIM-SM bootstrap mechanism. The bootstrap mechanism is a centralized function, e.g. there is one bootstrap server per PIM domain. If the PIM-SM domain is not a subset of the address domain then the bootstrap mechanism, in its current form, cannot support scoped RP addressses and scoped group addresses. The bootstrap server will have to assemble and distribute sets of RP-group mappings that were appropriate to the intersection of the source and group address scopes. Extending the bootstrap server to support this environment is a topic for further study. Therefore, initially we will only consider the case where the PIM-SM domain is a subset of the scope address domain. Haberman, Kump, Sandick Expires August 1999 [Page 3] Internet Draft PIM Multicast Routing for IPv6 February 1999 References [RFC 2119] S. Bradner, "Key words for use in RFCs to Indicate Requirement Levels", RFC 2119, BCP14, March 1997. [RFC 2373] R. Hinden and S. Deering, "IP Version 6 Addressing Architecture", RFC 2373, July 1998. [RFC 2375] R. Hinden and S. Deering, "IPv6 Multicast Address Assignments", RFC 2375, July 1998. [SCOPE] B. Haberman, "Routing of Site-Scoped Addresses in the Internet Protocol Version 6 (IPv6)", currently draft-haberman-ipv6-site-route-00.txt. Security Considerations This document does not introduce any protocol changes that require any additional security considerations above and beyond those described in the original protocol specification documents. Author's Address Brian Haberman Garry Kump IBM Corporation 800 Park Office Drive Research Triangle Park, NC 27709 USA +1-919-254-2673 haberman@raleigh.ibm.com +1-919-254-2395 kump@us.ibm.com Hal Sandick Nortel Networks, Inc. 1009 Slater Rd., Suite 220 Durham, NC 27703 USA +1-919-832-8848 hsandick@baynetworks.com Haberman, Kump, Sandick Expires August 1999 [Page 4] Internet Draft PIM Multicast Routing for IPv6 February 1999 Haberman, Kump, Sandick Expires August 1999 [Page 5]