Path: utzoo!utgpu!water!watmath!clyde!att!chinet!les
From: les@chinet.UUCP (Leslie Mikesell)
Newsgroups: comp.dcom.modems
Subject: Re: TrailBlazer and UUCP
Message-ID: <6469@chinet.UUCP>
Date: 2 Sep 88 14:30:32 GMT
References: <467@njsmu.UUCP> <6453@chinet.UUCP> <4560@umix.cc.umich.edu>
Reply-To: les@chinet.UUCP (Leslie Mikesell)
Organization: Chinet - Public Access Unix
Lines: 33

In article <4560@umix.cc.umich.edu> honey@citi.umich.edu (Peter Honeyman) writes:
 [kermit <-> uucp]

>i echo les' question -- why would anyone bother? -- but not his other
>sentiments.

OK, I'm open to suggestions.  What is the best way to do file transfers over
a satellite link?  I will be working with a ku band system using a double
hop (small dish <-> large hub <-> small dish) which will make at least a
2 second delay plus any internal packet contention. Physically, the connection
looks like an X.25 pad. Preliminary tests showed throughput using 'g' protocol
over a 2400 baud connection to be about the same as a 300 baud direct line.
I will also be talking to non-unix machines over the same connections, some
tty-like, some with an alternate protocol (probably kermit, using long packets
and/or sliding windows depending on the remote).

An alternative to 'g' protocol would help, but that would still have a
large overhead on the upper level transactions when the files are small.
Since mail files tend to be small and also generate an additional X file,
perhaps they should be bundled together up to a certain size before
transmission. 

Also keep in mind that I do not have uucp source so any changes will have to
be a replacement for uucico rather than a modification. None of the remote
sites are currently running SysVr3 which rules out the (perhaps best)
solution of writing a STREAMS driver for the link and using 'e' protocol.
I believe that I can compile code for all of the unix machines involved
at present, but that may not always be true.  These last difficulties are
the reason I suggested that people are buying the 'g' spoofing trailblazers
for unix machines rather than switching to a protocol that doesn't require
any help.

Les Mikesell