Re: Summary of responses so far and proposal moving forward[WasRe: [tcpm] Is this a problem?]

[Joe Touch <[e-mail]>]

Mark Allman wrote:
> [hat off]
> 
> I am not sure where in this thread to weigh in, so I am just replying to
> the last thing in my inbox.
> 
> I think a couple of things:
...
>   + I disagree with the reading of RFCs 793 & 1122 that a connection
>     that is doing zero window probing must remain up forever as long as
>     the probes are being ACKed.  I think in 'times of trouble' a TCP is
>     well within its rights to terminate a connection and I do not think
>     that should in any way be viewed as non-compliant.  TCP connections
>     are local resources and therefore should remain under local
>     control.  If something locally determines that resources are low and
>     connection should be terminated for whatever reason then I don't see
>     how that is any of anyone else's business.

The point of 1122 is that TCP isn't the one to decide this, AND that
connections with zero windows with ACKs aren't to be singled out.
Applications can kill connections, and certainly the OS can just shut
down. However, an OS that decides to kill connections because it runs
out of resources is noncompliant.

That OS is required to reserve per-connection resources when connections
are created. It can halt new connections.

It *CANNOT* kill existing connections to make up for poor resource
management and call itself compliant with the current language in 1122.

>     That doesn't mean I think the words in 1122 are wrong.  That means I
>     think that if folks would call a stack that has run out of memory
>     (or, hits some threshold, say) and therefore kills some connections
>     that are doing ZWP "non-conformant" then they are simply wrong and
>     applying too much protocol lawyering and too little common sense.

The lack of common sense came when the OS designer failed to allocate
sufficient per-connection resources. Throw your stones in their
direction, please.

Joe

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