Path: utzoo!news-server.csri.toronto.edu!rutgers!uwm.edu!rpi!usc!wuarchive!uunet!tiamat!jim
From: jim@tiamat.fsc.com ( IT Manager)
Newsgroups: comp.sys.hp
Subject: Re: Performance of LAN server vs. mux's?
Message-ID: <805@tiamat.fsc.com>
Date: 7 Mar 91 16:58:30 GMT
References: <29280002@teecs.UUCP>
Organization: Ahlstrom Filtration - Chattanooga,TN
Lines: 51

In article <29280002@teecs.UUCP>, belkin@teecs.UUCP (Hershel Belkin) writes:
> I have two questions, both concerning the use of a TCP/IP terminal
> server and a LAN card as a means of attaching terminals to a 9000/800-series
> machine (825 or 835):
> 
> 1. I am unclear whether or not the Arpa/Berkeley Services software is
>    required for this purpose.  The LAN will not be used for any other
>    purpose at this time.  Is the software that comes with the LAN (36967A)
>    sufficient for simple terminal connections?  (The server I plan to

The ARPA/Berkeley services will be needed.  Most terminal servers use
either Telnet or Rlogin to make the connection to the host.  Without the
ARPA/Berkelly services you won't have the necessary daemons to answer
the incoming requests on the telnet and rlogin TCP/IP ports.

>    use is a VISTA -- HP's is simply too costly!)

Amen, to that.  We decided to use Annex II servers from Xylogics, which
were still a little expensive, but have been great performers.  Also,
Xylogics distributes the boot/management software as source, so you can
use any machine with a socket library available to compile and run the
supplied software (we use HP-UX, Xenix, and SCO Unix).

> 2. Can someone give me some idea of how this configuration compares to
>    normal HP MUX (6-port) connections, in terms of performance?  The
>    situation calls for about 30 new terminals (and we have room for
>    5 new MUX cards, but that would exhaust our slots).  Is the TCP/IP
>    overhead significant in terms of CPU cycles?  I/O bandwidth?

Performance seems to be very good here, but our network load is very
low since the terminal servers are the primary traffic generators.  Things
might be very different if we had lots of workstations running X or NFS.

>    I prefer this solution since it is cheaper, and allows for further
>    expansion of ports, and also leaves us with some empty slots for
>    HP-IB cards, etc...  but will I pay a performance price?

I don't think so.  We went the TS route for exactly the reason you stated.
Plus, you can locate the TS's closer to the connected devices, so that
RS-232 cable lengths are shortened (we put our TS's out in the wiring
closets, and ran the Ethernet to them).

Currently, most of our users access the computer via a terminal server,
and since the terminal server supports port rates of 38400 baud, they're
probably seeing better performance than the users connected to mux ports
running at 19200.

--jim
------------- 
James B. O'Connor			jim@tiamat.fsc.com
Ahlstrom Filtration, Inc.		615/821-4022 x. 651