Path: utzoo!utgpu!water!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!bloom-beacon!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?
Message-ID: <23731@bu-cs.BU.EDU>
Date: 8 Jul 88 17:20:08 GMT
References: <320@ucrmath.UUCP>   <9877@g.ms.uky.edu>
Reply-To: kwe@buit13.bu.edu (Kent England)
Followup-To: comp.dcom.lans
Organization: Boston Univ. Information Tech. Dept.
Lines: 34

>[I started to write out some problems we've had here related to UB
> NIU-180's we've got and have tried to use in a number of ways.  But
> it started to get rather long ... if someone is interested in seeing
> a horror story I can post it.]
>-- 
><---- David Herron -- The E-Mail guy

	I don't want to jump in the middle of a flame, but I can say
that my original comments about needing serial port flow control at
slow baud rates on networked terminal servers was based, like Dave
Herron's, on U-B NIU-180s running XNS over broadband.

	I had a consistent problem dropping characters on terminal to
modem connections over the U-B NIU "dataswitch" (ie through a pair of
terminal servers) when the devices did not have flow control enabled.
I had no problems when flow control was enabled, but I always lost
characters when there was no flow control.  I do not have enough
experience with Annexen or cisco's or even U-B Access/One to know if
better hardware and software eliminate this problem, but I think they
would only improve the situation, not eliminate lost characters.

	If you care to comment on why you think that flow control
should be required or not be required on serial ports running through
terminal server pairs or serial ports connected to telnet servers,
please go ahead.

	In my opinion, there is always the risk of temporary network
errors or buffer overflow that requires flow control capability on the
serial devices to avoid loss of characters (assuming no error recovery
protocol in the attached devices and error recovery in the terminal
servers).  I think this applies at all baud rates, even as low as
1200.

	Kent England, Boston U