Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!ucbvax!unisoft!cander
From: cander@unisoft.UUCP (Charles Anderson)
Newsgroups: comp.dcom.modems
Subject: Re: Are Trailblazers good for SLIP 9600 Baud? What then?
Message-ID: <2109@unisoft.UUCP>
Date: 3 Jul 89 17:23:44 GMT
References: <219@csis.oz>
Lines: 27

From article <219@csis.oz>, by scott@csis.oz (Scott Milton):
> 
> Do Trailblazers work well with SLIP?
> What modems should I use for 9600 Baud SLIP?
> 
> I have been told that because TCP sends acknowledgments for every packet,
> that Trailblazers don't work well, as they are designed for large traffic
> flows in a single direction for longer periods. With SLIP they spend alot of
> the time working out that they have to change direction. There is presumably
> also some overhead in doing error correction, which should be handled by the
> TCP layer?

I recently set up SLIP on Apollos (a non-trivial task) using
Trailblazers running at 9600 baud.  I found that SLIP between two
serial ports without modems ran at roughly 75% of the maximum
throughput (9600 baud) and that with the TB's in the loop performance
was roughly 50% of 9600 baud, not too bad of a performance hit.  The
test I performed was a simple rcp from one node to an other.  If I were
running rcp's in both directions, the throughput might have been less.
Also it should be noted that intereactive performance (using rlogin)
over the SLIP line with TB's was real dismal.  To say it was "bursty",
would be putting it kindly.

-- 

Charles.
{sun, amdahl, ucbvax, pyramid, uunet}!unisoft!cander