ken@gvax.UUCP (07/09/87)
Now that the battle of the ISO and TCP (or was it OSI and Internet?) people seems to have died down, let me pose a question on a different issue: I feel that we lack adequate protocol support for multicasting at the transport level -- the protocol layer closest to the hardware. Dave Cheriton has proposed that VTMP be widely adopted to address this need. The general point is that to make the most effective use of the hardware multicast features we are seeing, one needs a software protocol that is based on a multicast abstraction. My question is this: What other transport requirements do people have that are inadequately addressed by the current generation of transport protocols? I think of transport protocols as including things like UDP XNS, TCP, X.25, etc. (all you OSI buffs: I am sure I got the layer definition wrong, but no need to correct me; we both know what I mean). What sort of transport mechanisms or features would be needed to redress the requirement you face? I am more interested by the problem of software abstractions than of ``speed:'' we all want speed, the problem is that you throw a lot of bandwidth away if the message transport doesn't understand enough about your class of applications. For example, what realtime problems do people face? Do a lot of people need reliable datagrams? What sorts of situations have had people really cussing at TCP and the other ``standards''?
joseph@solaris.UUCP (Joseph Bannister) (07/31/87)
In addition to Cheriton's research, I would point out the work being performed by ISO in the area of "Multi-peer Protocols". The work is being performed out of TC97/SC21/WG1, I believe. I presume that all of this effort will culminate in a second addendum to the Basic Reference Model for OSI (ISO 7498) defining the architectural framework for mulit-peer data communication services. This means that the Basic Reference Model for OSI will now cover three modes of operation: connection-oriented, connectionless, and multi-peer. My understanding is that the work is very high level, emphasizing generic principles of multi-peer interaction. It will probably be some time before specific multi-peer services and protocols are defined. Interested parties should probably contact the ANSI X3T5.1 committee for more information or documents related to multi-peer operation.