Internet Info 1994 March/Internet Info CD-ROM (Walnut Creek) (March 1994).iso/inet/ietf/ospf/ospf-minutes-92jul.txt

Text File | 1993-02-17 | 8KB | 176 lines

Editor's Note:  Minutes received 7/31

CURRENT_MEETING_REPORT_


Reported by John Moy/Proteon

Minutes of the Open Shortest Path First IGP Working Group (OSPF)

The OSPF Working Group met at the July 1992 IETF in Boston.  The Minutes
from that meeting follow.

The meeting began with a review of the four documents that are currently
be considered for publication by the Working Group:


  1. The updated OSPF V2 specification.  This will supersede RFC 1247.
     Unfortunately, the document was not available prior to the meeting.
     (A limited number of paper copies of the updated specification were
     made available to implementors, and the specification was made
     available for anonymous ftp after the meeting.)  An excerpt from
     the document briefly detailing the changes was handed out, and the
     changes (all backward- compatible) were discussed.  It was also
     decided to make one additional change:  it will now be possible to
     specify a set of area address ranges that will not be advertised in
     summary-LSAs.  This will enable a network administrator to hide
     certain networks within their local areas.  This change has already
     been implemented by some vendors.
  2. The updated OSPF V2 MIB. This will supersede RFC1253.  Fred Baker
     outlined the proposed changes.  It was also decided to make
     additions for the multicast routing extensions and the new NSSA
     area option.  An addition to the Area Range Group was also made for
     the above ``hidden network'' feature.  An additional request for a
     network mask in the new external-LSA table entries was not acted
     upon.
  3. The OSPF Trap MIB. Rob Coltun led the discussion.  There was some
     question whether an additional error code should be added for
     receiving Illegal-LSAs.  It was decided that this would probably
     already show up as retransmissions by the faulty sender, and as
     such was unnecessary.  It was also decided to have the
     ospfLsdbApproachingOverflow trap occur at a configurable database
     size, instead of 90 percent of the maximum (as stated in the
     draft).
  4. The OSPF NSSA option.  Rob Coltun spent some time explaining how
     they work, spending time on the translation between type-7 and
     type-5 LSAs, and how you could distinguish a ``local'' type-7
     default from one that can be translated into a global type-5
     default.  No changes were made to this document.


Osmund deSouza presented a proposal for running OSPF over Frame relay.
There was general agreement on the problem:  Frame relay is in general
not full-mesh connected, and the network administrator sometimes wants
to assign different costs to different PVCs.  For these reasons, OSPF's

                                   1





non-broadcast model is not directly applicable.  There was also general
agreement on the solution:  instead of treating the connection to Frame
relay as a single OSPF interface, define an OSPF interface as some
collection of PVCs.  There was a long discussion of how to represent
this in terms of MIB II and the OSPF MIB. It was decided that Osmund et.
al., with the help of Fred Baker, would rewrite their present document
more along the lines of a usage document.  With this document in hand,
it would be hoped that equipment from different vendors would be able to
interoperate using OSPF over Frame relay.

John Moy presented an alternative model for running OSPF over Frame
relay, where there would be a single interface to the frame relay net
and a) neighbors would be discovered dynamically using Inverse ARP b)
OSPF Hellos would be used to build a spanning tree among Frame relay
connected routers, for purpose of update distribution (database
synchronization) c) by default, only these spanning tree links
(adjacencies) would be included in router-LSAs and d) to get better
routing across the Frame relay, more PVCs could be included in the
router-LSAs or (not as good) a variant of short-cut routing could be
used.  John's main reason for preferring this approach is that it didn't
need a human to configure it, and that it was optimal in terms of
routing traffic.  This proposal was not generally well received, being
characterized as either too complicated or too different than current
practice.  John said that he would write it up anyway if he had the
time.

John Moy presented a proposal for dealing with OSPF Database Overflow.
In this proposal, only the number of type-5 LSAs would be limited.  The
reasoning being that these constitute a majority of the database in
places like the NSF regionals.  A limit for the number of these LSAs
would be set identically in each of these routers, either via SNMP or
negotiated in a new LSA type or in OSPF Hellos.  Then, when the limit is
reached in a router it a) won't accept any more and b) will flush all
its self-originated type-5 LSAs, refusing to originate any more.  The
claim is that this logic produces an identical database in all routers,
with less than the configured maximum number of type 5 LSAs, no
continual retransmissions, and all internal routing intact.
Enhancements to this scheme could involve limiting other LSA types
(e.g., summaries), and to begin again to originate type-5 LSAs after a
random time lag to automatically deal with temporary overflow.

John said that a similar scheme has been used in Proteon routers for
several years.  The proposal was characterized by some Working Group
members as being like congestion control, and some desire for an
additional congestion-avoidance-like mechanism was expressed.  Some
people also requested a way to prioritize the order in which excess
advertisements are flushed (e.g., you might want to flush the default
routes last).  John promised to sort through the enhancements and
publish a coherent Internet Draft.

Rob Coltun ended the meeting with a quick discussion on how hierarchical
routing information might be injected into OSPF, in order to support any
of the schemes for IPV7.


                                   2





Attendees

J. Allard                [e-mail]
William Babson           [e-mail]
Dennis Baker             [e-mail]
Fred Baker               [e-mail]
John Ballard             [e-mail]
Ken Benstead             [e-mail]
Geetha Brown             [e-mail]
Steve Buchko             [e-mail]
Greg Celmainis           [e-mail]
Frank Chen               [e-mail]
Dean Cheng               [e-mail]
Robert Ching             natadm![e-mail]
Chris Chiotasso          [e-mail]
Henry Clark              [e-mail]
Rob Coltun               [e-mail]
Jim Comen                [e-mail]
Michael Davison          [e-mail]
Osmund de Souza          [e-mail]
Dino Farinacci           [e-mail]
AnneMarie Freitas        [e-mail]
Vince Fuller             [e-mail]
Kelly Furlong            [e-mail]
Der-Hwa Gan              [e-mail]
Ian Heavens              [e-mail]
Jeffrey Honig            [e-mail]
Steven Hubert            [e-mail]
Ronald Jacoby            [e-mail]
Dwight Jamieson          [e-mail]
Dan Jordt                [e-mail]
John Krawczyk            [e-mail]
Alan Kullberg            [e-mail]
Whay Lee                 [e-mail]
Anthony Lisotta          [e-mail]
Robin Littlefield        [e-mail]
John Moy                 [e-mail]
Erik Nordmark            [e-mail]
Benny Rodrig             [e-mail]
Manoel Rodrigues         [e-mail]
Henry Sanders            [e-mail]
Hellen Sears             [e-mail]
Martha Steenstrup        [e-mail]
Linda Tom                [e-mail]
Kannan Varadhan          [e-mail]
Scott Wasson             [e-mail]
Luanne Waul              [e-mail]
Honda Wu                 natadm![e-mail]



                                   3