2.5.9 Protocol Independent Multicast (pim)

NOTE: This charter is a snapshot of the 45th IETF Meeting in Oslo, Norway. It may now be out-of-date. Last Modified: 06-Jul-99


T. Pusateri <pusateri@juniper.net>
L. Wei <lwei@cisco.com>

Routing Area Director(s):

David Oran <oran@cisco.com>
Rob Coltun <rcoltun@siara.com>

Routing Area Advisor:

Rob Coltun <rcoltun@siara.com>

Mailing Lists:

General Discussion:pim@catarina.usc.edu
To Subscribe: pim-request@catarina.usc.edu
Archive: http://www.juniper.net/~pusateri/pim.html

Description of Working Group:

The Protocol Independent Multicast (PIM) Working Group is chartered to standardize and promote the Protocol Independent Multicast Version 2 (PIMv2), Sparse Mode and Dense Mode, as a scalable, efficient and robust multicast routing protocol, capable of supporting thousands of groups, different types of multicast applications, and all major underlying layer-2 subnetwork technologies. The working group will decide if there is a need for any follow on work or version 3 of the protocol.

This working group will act as a consultant to any PIM-over-Foo proposals, including but not limited to PIM-over-ATM, using PIM for multiprotocol label switching, and PIM-over-UDLR links.


1) PIM-SM v2 specification (standards track)

This document is a specification for Sparse Mode Protocol Independent Multicast.

2) PIM-DM v2 speficication (standards track)

This document is a specification for Dense Mode Protocol Independent Multicast.

3) PIM MIB (standards track)

This document contains the MIB definitions for PIMv2.

Goals and Milestones:

Aug 98


Hold the first Working Group meeting and discuss the charter and the state of progress on the chartered items.

Aug 98


Update the PIM-DM version 2 Internet-draft. Go to WG last call. Submision to IESG for considerations as proposed standard.

Aug 98


Resubmit the latest PIM-SM version 2 specification to IESG for consideration as a proposed standard RFC

Dec 98


Submit Internet-Draft describing use of IP security with PIM.

Dec 98


Submit updated PIM-SM and PIM-DM internet-drafts, clarifying any inconsistencies or ambiguities in the previous drafts.

Apr 99


Submit PIM-SM version 2 and PIM-DM version 2 specifications to IESG for consideration as Draft Standards.

Apr 99


Submit PIM-SM and PIM-DM Applicability Statements

Apr 99


Submit PIMv2 MIB to IESG for consideration as proposed standard.

Nov 99


Submit PIMv2 MIB to IESG for consideration as draft standard.


No Request For Comments

Current Meeting Report

PIM Working Group

Draft Minutes from July 13, 1999, Oslo, Norway
Feel free to send corrections to pim@catarina.usc.edu.
Reported by: Tom Pusateri <pusateri@juniper.net>

Spec status
Liming Wei said that a new version of the sparse mode spec will be submitted as soon as some diagrams have been redrawn. This version will include the Hello priority option and will also include the new Generation ID option.

The PIM authentication draft has not changed and has been through working group last call. It is ready to be submitted to the IESG as soon as the sparse mode spec is ready.

The dense mode draft was also updated recently based on comments from Bill Fenner.

[Were any other changes required before doing a working group last call on the dense mode document? If so, please send concerns to the list as soon as possible.]

The PIM MIB work was originally being done in the IDMR working group. Dave Thaler is making some minor modifications based on feedback from the IESG. This is supposed to be completed by August 31st.

Bidirectional Tree PIM
Deborah Estrin gave the working group an update on Bidirectional Tree PIM. The draft is available from ftp://ftpeng.cisco.com/dino/draft-farinacci-bidir-pim-01.txt. There was some concern over the use of an IP option in the forwarding path. A proposal to allow an alternative mechanism to the IP option at the expense of (S,G) state between the source and the RP will be written up and reviewed.

Deborah also presented an approach to using extended addresses with bidirectional PIM. A concern over the requirement of an IP option to carry the extended address was raised.

[Note: This work is not in the charter. I think it is a valuable addition to the Protocol and support updating the charter to include it. Please send feedback to the mailing list if you have objections to the charter being updated to include this.]

Other Extensions
State refresh for PIM dense mode was presented by Isidor Kouvelas. This attempts to reduce the periodic flooding and re-pruning of data in a dense mode domain. This draft introduces a trade-off of increasing the complexity of the protocol in exchange for reducing the unnecessary flooding of data.

[Note: This work is not in the charter. A discussion on whether or not this item should be included in the charter should be carried out on the mailing list.]

Simple Key Management for PIM was discussed by Thomas Hardjono. This was presented as a way to do automatic key distribution for PIM authentication as posed in the PIM authentication draft by Liming Wei. There were some concern raised over the fact that the existing key was used to distribute the new key since the existing key may be compromised.

[Note: This work is not in the charter. A discussion on whether or not this item should be included in the charter should be carried out on the mailing list.]


Bidirectional PIM with Extended Addresses (work/design in progress)
Extending PIM to Support Bi-Directional Shared Trees: overview and status
A QoS-Aware Routing Framework for PIM-SM Based IP-Multicast
PIM DM State-Refresh Developments
Simple Key Management for PIM Authentication Keys