CURRENT_MEETING_REPORT_ Reported by Tony Ballardie/UCL Minutes of the Inter-Domain Multicast Routing BOF (IDMR) The IDMR BOF session was held on Friday during the Columbus IETF meeting. The meeting was chaired by Tony Ballardie. The Minutes were taken by Benny Rodrig. The CBT Protocol was discussed for the duration of the session, in particular, the changes in the protocol since last November's IDMR BOF session. Multicast Scope Control One possible solution to multicast scope control was presented, based on having a separate group per level of scope required. This resulted in a considerable debate as to how multicast scoping should be defined and the requirements of users it should be able to satisfy. The solution presented was deemed unsuitable, and it was agreed to continue the the discussion on the idmr mailing list. The conclusion was that the Group should work towards a concise definition of multicast scope control. Part of the group initiation procedure includes the group initiator (host) updating DNS (via a system administrator) with the relevant group information. The concern was raised that the procedure is likely to be too slow. This part of group initiation may need to be revised to keep group join latency to a minimum. Multicast Data Packets There was a brief discussion on the issue of multicast data packets carrying the group-id as an IP option. The conclusion however, was that there was no more suitable alternative. When a parent/parent link fails, it was decided that both the flush-tree and re-join mechanisms should be implemented. Which of the two mechanisms eventually becomes redundant can only be decided after a period of performance testing. It was decided that non-primary cores should be less stringent in accepting join-requests. Also, an additional error detection mechanism is required by routers to distinguish on-tree packets arriving via a child as link-level unicast. The draft includes no mention of child-parent ``keepalives'' and no mention of a handshake protocol between a group initiator and potential cores for that group. The draft needs updating in these respects. The control packet format should contain a group-id TYPE as an additional protocol independence feature. Finally, Paul Francis gave a brief description of how CBT will run over 1 Pip. Attendees Anthony Ballardie A.Ballardie@cs.ucl.ac.uk Jim Beers Jim.Beers@cornell.edu Robert Braden braden@isi.edu Scott Brim Scott_Brim@cornell.edu David Carr Carr@acsu.buffalo.edu Stephen Casner casner@isi.edu Steve Deering deering@parc.xerox.com Steve DeJarnett steve@ibmpa.awdpa.ibm.com Ed Ellesson ellesson@vnet.ibm.com Chip Elliott celliot@bbn.com Dino Farinacci dino@cisco.com Paul Francis Francis@thumper.bellcore.com Chris Gunner gunner@dsmail.enet.dec.com Joel Halpern jmh@network.com Ken Hayward Ken.Hayward@bnr.ca Robert Hinden hinden@eng.sun.com Frank Hoffmann hoffmann@dhdibm1.bitnet Gerd Holzhauer holzhauer1@applelink.apple.com Tony Li tli@cisco.com Charles Lynn clynn@bbn.com Kent Malave kent@bach.austin.ibm.com Jun Matsukata jm@eng.isas.ac.jp David Meyer meyer@ns.uoregon.edu Gerry Meyer gerry@spider.co.uk Greg Minshall minshall@wc.novell.com Matthew Morrisey morrisey@wpsp01.hq.aflc.af.mil William Owens owens@acsu.buffalo.edu Laura Pate pate@gateway.mitre.org Geir Pedersen Geir.Pedersen@usit.uio.no Willi Porten porten@gmd.de Benny Rodrig 4373580@mcimail.com Sally Tarquinio sallyt@gateway.mitre.org Fumio Teraoka tera@csl.sony.co.jp Paul Traina pst@cisco.com 2