Network Working Group
Request for Comments: 38
Stephen M. Wolfe
20 March 1970

Comments on Network Protocol

from NWG/RFC #36

The proposed protocol does not allow for the possible multiplexing of connections over links.

Generally, this presents no problem, but it might cause loading restrictions in the future. Two cases where routing multiple connections over the same link are apparent:

         a) Where a user has several high speed connections, such as
            between processes that transmit files over the network.
            Assigning these connections to the same link limits the
            percentage of network resources that may be used by that
            user. This becomes particularly important when several
            store-and-forward IMP's are used by the network to effect
            the communication.
         b) When two hosts each have their own independent network and
            desire to allow access to the other hosts's network over
            the ARPA net, a shortage of links may develop. Again, the
            assignment of several connections to the same link could
            help solve the problem.

The following changes in the protocol would make possible the future use of multiplexed links. It is not necessary to add the multiplexing, itself, to the protocol at this time.

         a) The END and RDY must specify relevant sockets in addition to
            the link number. Only the local socket name need be
         b) Problems arise with the RSM and SPD commands. Should they
            refer to an entire link, or just to a given connection?
            Since there is a proposal to modify the RFNM to accommodate
            these commands, it might be better to add another set of
            commands to block and unblock a connection, but I am not
            convinced that that is the best solution.
         c) The destintation socket must be added to the header of each
            message on the data link. Presumably this would consist of
            32 bits immediately after the header and before the marking.

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