home *** CD-ROM | disk | FTP | other *** search
-
-
- CURRENT_MEETING_REPORT_
-
-
- Reported by Claudio Topolcic/ BBN
-
- The CO-IP Working Group met at the May 1-4 IETF Meeting at
- Carnegie-Mellon University. During the Tuesday sessions we tried to
- pick up where we had left off in Florida State. We heard updates on
- DARTNet and the TWBNet. Tony Mazraani gave a progress report on the
- COIP kernel and a presentation on Washington University's work on
- Resource Management in Broadcast Lans. Work toward defining experiments
- for the DARTNet was hindered since not all the key people were present.
- We spent the balance of the sessions discussing the current draft of the
- ST-2 protocol specification.
-
- Charlie Lynn had previously edited and distributed the current draft of
- the ST-2 protocol specification. He had also written up a number of
- issues that needed more thinking. The group discussed these issues and
- a few others that came up during the meetings.
-
- A number of editorial comments to the draft were discussed. These
- included some minor restructuring to minimize repetition and increase
- clarity. More forward and backward pointers were suggested, as well as
- more examples. Numerous editing changes were suggested.
-
- We discussed the relation between ST and IP. We decided to allow two
- forms of the ST header. The short form is as had previously been
- specified. A long form is structured like an IP header so that it can
- be processed by IP-only agents, and takes the place of the concept of IP
- encapsulation. The long form may also be used when IP security is
- required or to reduce either deliberate or accidental denial of service
- problems.
-
- The issue of use of multicast lead to a lot of discussion. Ideally, we
- would like to be able for an ST agent to request that the local network
- dynamically create a multicast group for use by a stream, as its use
- could reduce the network bandwidth required to support the stream.
- Unfortunately, there does not seem to be much support for dynamic
- management of multicast addresses (how does a ``user'' dynamically
- request a multicast address at a given protocol layer, what agent(s) on
- a network robustly assign multicast addresses, how are the assigned
- addresses mapped into addresses for use above the network layer, e.g.,
- IP multicast addresses, how are the assigned addresses reliably
- released/garbage collected, etc.).
-
- It was felt that trying to create such a service was a challenging
- problem tangential to the work of the Working Group and should be
- delegated to some other group. The result was to either to use
- replication instead of multicast, or to use static multicast groups.
- The problem with the former is wasted bandwidth, that with the latter is
- scaling -- what were formerly seperable problems (solvable by each
- stream independantly) now become problems which must be solved in common
- by all streams on a network. HID negotiation is one example.
-
- 1
-
-
-
-
-
-
- We discussed mechanisms by which changes could be made to established
- streams. For example, it may be desirable to allow a request to change
- a stream's bandwidth to allow a range of possible bandwidths. Also,
- when a new target is added to a stream, it would be desirable to
- decrease the stream's bandwidth, if that is allowed by the stream, if
- the new target can only be added with that decreased bandwidth. These
- features causes some difficulties in coordinating the changes among the
- ST agents, as well as the applications, while maintaining the
- uninterrupted flow of data packets.
-
- Other specific issues discussed included the following:
-
-
- 1. A Target cannot be an IP multicast group.
- 2. The ACCEPT message should be delayed until the HID negotiation has
- been completed.
- 3. We are not addressing the issues of spoofing (beyond the security
- features to be provided for IP by SDNS), intentional denial of
- service, or unintentional denial of service resulting from broken
- routes.
- 4. The structure of the ``Group of Streams'' specification.
- 5. Whether source routes would be strict, loose, strict in ST and
- loose in IP, or something else. This issue was not resolved.
-
-
- ATTENDEES
-
- Fred Bohle fab@saturn.acc.com
- Terry Braun tob@kinetics.com
- Stephen Casner casner@isi.edu
- Danny Cohen cohen@isi.edu
- Richard Fox sytek!rfox@sun.com
- Jonathan Goldick goldick@b.psc.edv
- Jack Hahn hahn@umd5.umd.edu
- Charles Lynn clynn@bbn.com
- Tony Mazraani tonym@flora.wustl.edu
- Zaw-Sing Su zsu@sri.com
- Ian Thomas ian@chipcom.com
- Claudio Topolcic topolcic@bbn.com
- Dave Wood wood@gateway.mitre.org
-
-
-
- 2
-