> Subject: Re: sup difficulties... 
> Date: Fri, 02 Feb 1996 17:02:55 -0500
> From: "Perry E. Metzger" <perry@piermont.com>
> 
> Peter Seebach writes:
> > Is there a good way to make sup more robust over slow or lossy networks?
> > There's an overloaded router between be and sup.netbsd.org which drops
> > packets...  About one in 8, I'd guess.
> 
> The right thing is for us to implement the TCP Selective Ack options;
> normally this wouldn't be easy to deploy but since we control the
> operating systems...
> 
> TCP selective ack dramatically reduces lossage and performance hits on
> lossy nets.

Actually, selective acks only really help when there's a lot of data
in the pipe at one time.

As best I can tell from observing its behavior, the `sup' protocol is
not a streaming protocol.. when sup's actually updating/fetching the
files, it winds up degenerating into a request/response for each file
being frobbed.  Given that most of the source files are small, this
turns into a lock-step ping-pong pretty quickly, and selective acks
won't help in that case..

						- Bill