Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!mailrus!ukma!david
From: david@ms.uky.edu (David Herron -- One of the vertebrae)
Newsgroups: comp.dcom.modems
Subject: Re: Microcom QX/V.32c evaluation
Message-ID: <12332@s.ms.uky.edu>
Date: 3 Aug 89 00:16:35 GMT
References: <361@larouch.UUCP>
Reply-To: david@ms.uky.edu (David Herron -- One of the vertebrae)
Organization: U of Kentucky, Mathematical Sciences
Lines: 71

In article <361@larouch.UUCP> jparnas@larouch.UUCP (Jacob Parnas) writes:
>During normal tip session, I got over 3300 cps effective throughput 
>catting a 115000 byte /etc/hosts file.  Interactive response was fantastic.
>There were delays on character echos.  Simply amazing throughput.

That's the kind of experience I'd expect for a V.32 modem -- and about
what we were getting in the terminal room at Usenix.  That is, what we
*would* be getting if all our sessions were to local hosts.  My login
sessions ran reasonably well -- well enough that I was reading news
from there.  Others who were less fortunately connected than I were
experiencing long delays, especiallly the chap from Scotland.

The terminal room was run off a T2500 ... I don't know what baud rate
and/or compression was used.

>SLIP response was fairly good as well.  I'm runing generic 4.3 BSD SLIP.
>Cating /etc/hosts over slip went at about 2600-2700 cps.  ftp of /etc/hosts
>went at about 2.2 kilobytes/second.  Binary files seemed to ftp at between
>1.2 and 1.5 kilobytes/second.

For reference:

I've been doing some experimentation recentlly with the SLIP driver that
comes with Ultrix.  Between a Vs2000 and a uVaxII over a 9600 baud straight
serial wire:

	terminal sessions were bursty.  Individual bursts were at the
	right speed, but there were pauses.

	an xterm run over that link was even burstier

	ftp of a largish file (140K /etc/termcap) went at 8kbits/sec
	or about 90% of line speed.  This was over a *quiet* line

	copying largish files into an NFS mounted file system failed
	strangely, but I was using the same packet-size parameters
	as we use over ETHER.  Probably I was simply overrunning some
	buffering somewhere.

	ping time is 200 ms.

You're getting 22,000 bits per sec on a 38,400 line or about 66% of line speed.

Yes I know that things don't work as efficiently at higher baud rates.
Rather, that it's nowhere near a simple comparison ...


Over another link ... this one is again at 9600 baud.  But it has two
terminal networks in between the two machines.  One is a state-wide
AT&T ISN network that we call KECNET, the other part is a connection 
through the campus-wide Ung. Bass broadband network & terminal servers.
We lose hardware flow control because the ISN net doesn't do it.  One
end is the same uVaxII and the other end is an 11/750 in Louisville.

	Terminal sessions are burstier

	haven't tried xterm

	ftp of largish files gets ~3.5 k bits per sec -- <50% line utilization

	haven't tried NFS

	for some reason this link has routed traffic going over it and
	the other doesn't.  This link also has the MTU set down to 256 bytes.

	ping time is 500 ms.
-- 
<- David Herron; an MMDF guy                              <david@ms.uky.edu>
<- ska: David le casse\*'      {rutgers,uunet}!ukma!david, david@UKMA.BITNET
<- "Amiga software is as good and as bad as PC software.  The difference is 
<-  that AmigaDOS waves bye-bye before it dies, while the PC just freezes."