INTERNET DRAFT Brian Haberman
Garry Kump
(IBM)
Hal Sandick
(Bay)
Augest 1998
Protocol Independent Multicast Routing
in the Internet Protocol Version 6 (IPv6)
<draft-ietf-pim-ipv6-00.txt>
Status of This Memo
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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.
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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 . . . . . . . . . . . . . . . . . . . . . 2
4.7. Candidate-RP-Advertisement Message . . . . . . . . . . . 3
5. IPv6 Address Scoping 3
6. Additional Areas of Work 3
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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 routable IPv6 address that will serve as the
router's Router-ID.
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
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neighbor adjacency and for DR election. It should be noted, that the
DR will identify itself using its Router-ID.
4.2. Register Message
The Register Message is addressed to the Router-ID of the RP. The
source address of the message is the Router-ID of the DR. The DR
sending the Register Message obtains the Router-ID 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 Router-ID of
the DR. The source address is the Router-ID of the RP. The RP obtains
the Router-ID 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.
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 BSR Address is set to the Router-ID of
the BSR.
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
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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 Router-ID of the BSR
as the IPv6 destination address. The source address is the Router-ID
of the candidate RP. The RP Address field is set to the Router-ID 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]. Currently, this work only addresses PIM running within a
single site or organization.
6. Additional Areas of Work
The main area of additional work is in the support of site- and
organization-scoped IPv6 multicast addresses. If a PIM domain is
to cross an IPv6 scope domain, then guidelines for supporting the
following will have to be developed :
- Scoped RP addresses
- Scoped DR addresses
- Scoped BSR addresses
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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 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
IBM Corporation
800 Park Office Drive
Research Triangle Park, NC 27709
USA
+1-919-254-2673
haberman@raleigh.ibm.com
Garry Kump
IBM Corporation
800 Park Office Drive
Research Triangle Park, NC 27709
USA
+1-919-254-2395
kump@us.ibm.com
Hal Sandick
Bay Networks, Inc.
1009 Slater Rd., Suite 220
Durham, NC 27703
USA
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+1-919-941-1739
hsandick@baynetworks.com
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