Re: legality of interleaving untagged message segments

Jeff Dwork said:
> A receiver capable of tracking out-of-order messages is more complex
> than one which requres in-order submission.  Support of out-of-order
> message submission must be negotiated prior to stream initialization.
>
> A possible implementation: The receiver declares the maximum number of
> simultaneous messages it will accept, possible values being an integer
> greater than 0 or the special value "NO_LIMIT" (perhaps represented as
> 0).
>
> A value of "1" means that all segments of message N must be submitted
> before any segments of message N+1.  A value of "NO_LIMIT" means that
> the receiver will accept any number of out-of-order messages up to the
> size of the RQ/S_RQ.
>
> Jeff
>


The potential optimizations to an "in-order receiver" are real, but they
definitely would not justify more session parameters negotiated on the wire.

What is proposed is far simpler, that untagged messages behave as though
their segments are submitted to the LLP atomically. For example, SCTP
has such a restriction on SCTP layer segmentation of user messages.
From the RDMAP layer this is entirely transparent. It is only an issue
to the implementation of the DDP layer.