Path: utzoo!attcan!uunet!husc6!bu-cs!kwe
From: kwe@bu-cs.BU.EDU (kwe@bu-it.bu.edu (Kent W. England))
Newsgroups: comp.dcom.lans
Subject: Re: Terminal servers over ethernet?
Summary: devices must support flow control
Message-ID: <23612@bu-cs.BU.EDU>
Date: 5 Jul 88 16:33:16 GMT
References: <320@ucrmath.UUCP>  <3960@saturn.ucsc.edu>  <9816@e.ms.uky.edu>
Reply-To: kwe@buit13.bu.edu (Kent England)
Followup-To: comp.dcom.lans
Organization: Boston Univ. Information Tech. Dept.
Lines: 27

In article <9816@e.ms.uky.edu> david@ms.uky.edu (David Herron E-Mail Hack) writes:
>Be that as it may.  Do any of these boxes sufficiently emulate
>being hardwired that one can believe that they're hardwired?
>

With one very important difference.  A truly hardwired device may be
able to operate without benefit of flow control of any kind.  A
networked terminal, in my experience, must always support flow
control, even at speeds as low as 1200 bps.  I have never been able to
make a device that did not support flow control operate over a
terminal server.  Contention and lost packets...

>I know that with a real hardwired terminal, that the 4.3bsd rlogin
>works well/fast enough that if "feels" like it's a hardwired terminal.
>So *I* am ready to believe that one of these boxes doing rlogin
>would "feel" right.  The problem is convincing the others around me.
>

I would be concerned on large model servers like the cisco.  What
happens if everybody is active at the same time?  Do all 96 terminals
operate at 9600 bps average throughput?

There is work on SLIP support on terminal servers, although BU isn't
running SLIP yet.  I wonder how many SLIP ports a typical terminal
server could support?  Is SLIP more compute intensive than telnet?

	Kent England, Boston University