CURRENT_MEETING_REPORT_


Reported by Dino Farinacci/cisco Systems

MOSPF Minutes

The Multicast Extensions to OSPF Working Group met Thursday, August 1,
at the Atlanta IETF. The meeting Agenda was:


   o Introductions, roster, assign note taker.
   o Progress of draft.
   o Review of July draft.
   o Progress of implementation.
   o OSIfication of specification.
   o Multicast scoping.


Progress of Draft.

John Moy (author of spec), felt the specification was ready for protocol
review but not quite ready to implement from.  The following are missing
sections:


   o System requirements.  (i.e., manipulating multicast filters in
     media controllers).

   o Data structures.

   o Detailed description for forwarding multicast datagrams.

   o Detailed description for forwarding cache construction.

   o Additions to base OSPF specification.

      -  How to flood group-membership LSAs.
      -  Database Description process with new option bits.
      -  Generation of Summary LSAs.


Review of July Draft.

Changes from previous draft (distributed at St.  Louis IETF) included:


   o Added concept of a ``Inter-area multicast forwarder''.  The reason
     for this is that all ABRs do not need to forward multicast traffic.

   o Inter-AS multicast section is new.

   o Requirements on Inter-AS protocol are identified.  Must determine

                                   1





     if a multicast datagram came from outside of AS or from its own AS
     going outside.

   o Reverse costs will be used for inter-area and inter-AS
     multicasting.  John Moy described a scenario where problems will
     occur when reverse costs are used (in the case of the above bullet)
     in combination with forward costs used inside an area.  It was
     determined that the problem can be corrected if reverse costs are
     used everywhere.


Progress of Implementations.

Initially there will be two implementations from Proteon and public
domain source gated (Cornell).

Steve Deering, from Xerox, is working on modifications to the BSD Unix
kernel for forwarding multicast datagrams.  He briefly described the
data structure for the forwarding cache.  The key to access the cache is
based on the tuple (source network, destination group, TOS).

OSIfication of Specification.

Steve Deering presented IP multicasting to the ANSI X3S3.3 committee.
The group is interested to use this research for OSI multicasting but no
work has begun.

Multicast Scoping.


   o TTL is used in multicasting to limit scope.  The problem with TTL
     usage is that it does not take into account administrative
     boundaries.

   o Scope should be based on the group address.

   o It was noted that the first 256 assigned multicast addresses are
     meant for local wire only.

   o Scott Brim, from Cornell, has proposed to provide scoping in IGMP.

   o Scoping boundaries should have multiple levels.  For example,
     (Site, AS, Country, Continent).


Attendees

Jim Beers                beers@nr-tech.cit.cornell.edu
Scott Brim               swb@nr-tech.cit.cornell.edu
Chi Chu                  chi@sparta.com
Richard Colella          colella@osi3.ncsl.nist.gov
Steve Deering            deering@xerox.com
Dino Farinacci           dino@cisco.com

                                   2





Dennis Ferguson          dennis@canet.ca
Robert Griffioen         rgriff@bnr.ca
Jeffrey Honig            jch@nr-tech.cit.cornell.edu
Phani Jujjavarapu        phani@cisco.com
April Merrill            abmerri@tycho.ncsc.mil
Greg Minshall            minshall@wc.novell.com
John Moy                 jmoy@proteon.com
Karen O'Donoghue         kodonog@relay.nswc.navy.mil
Bob Stewart              rlstewart@eng.xyplex.com
David Waitzman           djw@bbn.com
Robert Woodburn          woody@cseic.saic.com
L. Michele Wright        uncng!michele@uunet.uu.net
Osmund de Souza          desouza@osdpc.ho.att.com



                                   3