SUMMARY: cisco 2511 terminal server on Sun

From: Deborah Crocker <>
Date: Tue Mar 19 2002 - 14:46:55 EST
Here is the summary of responses. Individual responses are at the end.

Many are using the Cisco 2511 terminal server. It does not buffer the
clients on a per port basis. So, for instance, if you have a machine
crash and you want to see the POST output after the fact, you can't. It
would be lost. The only way to save output is to be on that port with
a telnet session running its own scroll-back buffer.

It also does send a break signal (stop-a) when power-cycled. This
can be gotten around, however. Sol 8 (and 7 and 2.6 suitably patched)
have another option for the "KEYBOARD_ABORT" setting. By uncommenting
"KEYBOARD_ABORT=alternate" in /etc/default/kbd, then typing "kbd -i"
to read in the new setting, the Stop-A sequence on the SERIAL port is
changed. The altername stop sequence is described in the man page for
"zs" (on a Sol 8 system - I don't think the patches update the man
page on 7 or 2.6). It is "carriage return, tilde, control-B".

So, I am prepared to go with these 2511's that we have and will not
explicitly budget in funds. Note that there is an earlier summary
regarding terminal servers that support SSH (see Tuesday, March 12,
2002 - SUMMARY: SSH for Terminal Servers).  The 2511 won't support SSH,
however, I plan on have a private VLAN for these so that is not an issue
(although, see the response by Kevin Graham below...)

Thanks for all help

D. Crocker
Univ. of Alabama

----------- Original question ------------------
We're going to have some Cisco 2511 terminal servers come
available. They've been running our dial-up service but that is being
replaced. My question is: Are these terminal servers acceptable as
terminal-concentrators on sun boxes? [in other words: Is there any problem
with these sending 'break' signals? Do they have any output buffering
so we can review past output in case of errors during the boot sequence?]
Can't find this info on the cisco site. We're also asking Cisco but
I'd like to hear from people who might be using these.

----------- Individual summaries ---------------
I'm using one.  The telnet session that I use has buffering, so I don't
have to rely on Cisco's (which isn't there).  It doesn't automatically
send the break signal to my servers, but I can do so through the telnet
Chad Rytting
We use cisco 2509/2511 as terminal servers with sun HW and they works just fine.
The one thing we did do was to change the stop-a key sequence on the servers
because, sometimes, if some inadvertently (sic?) powered off the terminal
server, it would take the box to the ok prompt.  We found the problem with
zyplex terminal servers as well, so this was not a problem unique to cisco.
Bob Fulwiler
> with these sending 'break' signals? Do they have any output buffering

	Yes the break issue does exist on those boxes.
	You'd better to replace the standard break sequence with ~^b (see
/etc/default/keyboard for details).

> so we can review past output in case of errors during the boot sequence?]

	The answer is No.
Yura Pismerov
I am not sure about the output buffering, however I had one of my cisco's
power off and they did send a break, hence taking down everything connected
to it.  Hard lesson to learn.  However, there are ways to turn on alternate
break sequence to get around that problem.  Mine is working great.  I
actually have 4 of them
Ryan McEwan
They work great, I've had several dozen in production for almost 2 years
without any problems. Definately the best console servers I've run across.
One nice side part too is Sun used the same serial-over-RJ45 pinout as
Cisco -- likewise, you can use the Cisco 'rolled' (green, blue, black flat
console cables) to connect them, w/o any additional connectors.

If you have them loaded w/ memory and flash, see if one of your networking
guys can chase down a crypto image for them, and you can even have ssh
support. Direct ssh to each line probably won't ever be an option though,
as this requires 12.2, and there's no chance of squeezing a 12.2 crypto
image onto a 2500....
Kevin Graham
Hey, I have one myself - it does ok as a terminal server, but
yes, on a powercycle of the 2511 it will send out break to
anything attached to it. You can turn this off on Sun boxes

solaris 8: Edit /etc/default/kbd - change KEYBOARD_ABORT to
alternate. Run 'kbd -a alternate' to make changes for the
current session.
solaris 7: Requires patch 107589-02 or higher - then do solaris
8 instructions
solaris 2.6: Requires patch 105924-10 or higher - then do
solaris 8 instructions.

This way, you can still send a break to the box if necessary,
but the default break that the 2511 might generate will be

Enterprise class Sun boxes, just change the key to the 'lock'
position to ignore breaks.

As for output buffering, I'm not sure what you mean. You can
view the complete boot history of the 2511, and have it log
to a remote server for most anything. If you mean buffering of
the clients that are connected, AFAIK it does not do that. You
can simply change your syslog on those hosts to record all kern.debug
messages to a log file, and that should pick up the boot process.
Matthew Hall
sunmanagers mailing list
Received on Tue Mar 19 13:47:19 2002

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