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RE: perle jetstream settings

Harris, David \(SBS US\) david.k.harris@siemens.com
Fri, 11 Aug 2006 20:09:46 -0700 (PDT)

  I've played with the Rack+ units, and not the JetStream...

  If you have bursty traffic, it sounds like it's the JetStream, based
on what you have said. (You indicated that the Rack+ doesn't exhibit the
symptom when connected to the same serial ports, if I understand you
correctly.) Here's a few things to think about and try;

  You may find a serial setting, but it may also be that the CPU of the
JetStream can't keep up with the high rates during prolonged bursts.
Another option is that the serial rate may be too slow, and the CPU is
time-slicing to check all of the other ports before getting back to the
next batch from the busy port(s).

  You could try to increase the serial port speed on the JetStream and
the serial console you conenct to, and see if the JetStream can keep up.
(Do you have cabling to support hardware flow control? In the cable and
the adapters? Are the serial ports on both devices set to use the flow
control? If not, a higher speed may incur some data loss, because you
may overfill the UART buffers with the higher data rate.)

  If the higher data rate works, it may indicate that the JetStream has
an issue polling the various ports. This could point to an issue
handling the interrupts from the UARTs, or servicing a busy network
interface. (Are you attaching the JetStream to a switch port, or a busy


-----Original Message-----
From: users-bounces@conserver.com [mailto:users-bounces@conserver.com]
On Behalf Of Marion Hakanson
Sent: Friday, August 11, 2006 2:31 PM
To: users@conserver.com
Subject: perle jetstream settings


I'm a long-time conserver user, and a long-time terminal-server user,
but this is the first time I've used conserver with a terminal-server.
We're setting conserver up to connect to a Perle JetStream 8548 in
reverse-telnet mode.  Our console master host platform is Solaris-10 on
both Sun Blade 150 and also Solaris-10_x86 on a P4 PC.

One thing I've noticed is that reverse telnet connections seem to have
very bursty output on this unit.  Instead of a steady stream of
characters that a direct (hardwired) serial connection gives, you get a
batch of characters (maybe 4-5 lines of text) in a quick burst, pause,
then another batch, etc.  This happens when using both conserver and
plain old telnet to connect to a port, so it's nothing wrong with
conserver itself.

As I said, I've used terminal servers for years, but this is my first
experience with the JetStream product.  We also have an old IOLAN+ Rack
unit, and the IOLAN+ does not exhibit this bursty output behavior, even
when given the same serial-line output from identical hardware.  The
Perle seems to behave the same when the port is in "reverse raw" mode
and conserver is set with the "protocol raw" option to match.

We're running ports at 9600bps almost without exception, and no serial
flow control is in effect at this time.  Network gear is all switched
10/100, operating at 100Mbps (except for the IOLAN+).  I'm wondering if
folks have guidance as to settings that one can tune on either the
JetStream or on the Solaris side to give smoother serial output with
this arrangement.

Thanks and regards,


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