From: djc@scimitar.unx.sas.com (David J. Cherveny)
Newsgroups: comp.dcom.servers
Subject: Re: Looking at Terminal Servers
Date: 17 Nov 92 05:19:43 GMT
Organization: SAS Institute Inc.

In article <1992Nov14.013422.13818@u.washington.edu> pollock@u.washington.edu writes:
>We're currently looking at terminal servers to purchase.  Since we will
>buy only one server at this time, a detailed evauluation with demos, etc.
>is difficult to justify, so I'm turning to the Net for assistance.
>
>We are looking for the following features:
>
>1.  16 lines, with limited modem support (DSR/DTR, RTS/CTS - enough to
>    properly handshake and disconnect on a Micom Data PBX.
>
>2.  Good TCP/IP support, including SLIP now and PPP in the future. LAT
>    support is desirable, but can be a future add-on (if it's an extra
>    cost item, we won't buy it now).
>
>3.  Preferably, stand-alone operation, not dependent upon a host for
>    more than initial software installation (flash eprom, ROMs, etc).
> ...
>
>Joe Pollock
>The Evergreen State College
>pollock@u.washington.edu
>
>

We've been using Xyplex 1600's with very good results.


1. Has 16 lines, supports DSR/DTR *AND* RTS/CTS simultaneously.  Great for
   high speed ( v.32bs etc ) modems, especially with SLIP.  We've connected
   one to our MICOM successfully.  A little trickey getting the MICOM
   and XYPLEX wired and configed properly though.

   I'm using same terminal server for dial in and dial out using same
   pool of modems.  For dial out need to use TELNET protocol, either
   vanilla TELNET or a recent version of C KERMIT that supports TELNET
   protocol.  Useful for file xfers from UNIX systems.

2. TCP/IP support pretty good.  SLIP impelmentation is good except doesn't
   support compressed slip ( cslip ) or PPP yet.  Soon.  LAT support
   included.  TN3270 supported too.

3. 1600 is stand alone, has 1Mb ROM or FLASH card removable from front.
   EZ to upgrade.  The card is about the size of a credit card but thicker.

Remote console port, accessable via TELNET, is handy for trouble shooting
and configuring.  MONITOR commands let you repeatedly show the status of
some system paramiter or port status... handy for watching modem control
signals turn on/off during connection.

Most problems I've had have been quickely fixed by XYPLEX with a "special"
OS version Fed Exed to me.  Just replace the ROM card and reboot.

For example, had problem when TELNETing to the XYPLEX to access modems.
TELNET sends a null after a carriage-return.  The XYPLEX option to filter
this didn't do quite do the right thing.  Had fixed version in about a week.

I've also had one to fail.  Port status lights flash a diagnostic pattern.
They replaced via Fed Ex next day air.

A new version of 1600 is in new 9000 series rack.  Has 20 ports and 68020
instead of 68000.  Serial port speeds up to 115200 vs 38400 for 1600.  This
won't really be a factor until next generation modems become available.

Only a few problems/dislikes:

	VMS style commands -
		Either you love 'em or hate 'em.  Command history and
		editing makes it tollerable, IMHO.  VMS style help system
		too.  Does have "UNIX" style aliases.

	No compressed slip or ppp support -
		Comming soon I hear.

	Date/time -
		No internal time of day clock in 1600.  Must down
		load initial date/time from a boot server or a KERBEROS
		server.  But since most 1600's are "stand alone" you don't
		normally use a boot host so date/time doesn't carry
		accros reboots.  Turns out I'm using KERBEROS anyway
		for username/password authentication so the time bug
		is moot for me.

	KERBEROS not for everyone -
		KERBEROS system is OK but overkill for just terminal server
		username/password authentication.  Note that the XYPLEX
		only uses KERBEROS to check if username/password is correct...
		the "ticket" gets tossed out... so not usefull in a real
		KERBEROS enviroment.

	Manual is big -
		Sometimes too complete.  Sys admin section good.  Decent
		examples and has sorted reference section with list of commands.

	No syslogd support -
		I'd like syslogd support for logging reboots, login fails,
		etc.

	Accounting info incomplete -
		Good enough but I'ld like more.  SLIP sessions don't get logged.



David Cherveny					djc@unx.sas.com
Systems Programmer, Networking			(919)677-8000x6689