RE: Switch on Network and Looped to Itself Crashes Client Access

Not necessarily. You connection was fine but you probably did not get
any traffic to the iSeries do to your switch being overloaded with the
looped traffic. Nice thing about switches, they do not send unnecessary
traffic down all ports.

Chris Bipes
Director of Information Services
CrossCheck, Inc.

-----Original Message-----
From: midrange-l-bounces@xxxxxxxxxxxx
[mailto:midrange-l-bounces@xxxxxxxxxxxx] On Behalf Of Burns, Bryan
Sent: Thursday, December 06, 2007 1:05 PM
To: MIDRANGE-L@xxxxxxxxxxxx
Subject: Switch on Network and Looped to Itself Crashes Client Access

Monday at 4:15 p.m. users lost their "client access" sessions and could
not re-establish connectivity. PC's couldn't ping the iSeries. Twinax
connectivity was fine. I was able to get into the HMC from home and got
a terminal session and surprisingly, there were no outstanding QSYSOPR
messages. Our VP was able to telnet from our second partition into the
one where client access was not working. IBM support said it was a
network problem. Problem was limited to Client Access only. Our Novell
file network was fine along with the VPN I used to connect to the HMC
from home.

At 11 p.m., we finally solved this problem when we removed a 2 foot
patch cable that was looped from port 1 to port 2 on the same $25 Cisco
OfficeConnect Switch on the production floor. This switch connects a
printer and a thin client to an HP ProCurve switch which connects to the
CISCO switch that our iSeries interface connects to. A production
worker was having trouble with the printer and tried to "help" by
plugging the loose end of a patch cable into the switch.

Our network people think the iSeries just couldn't keep up with the
traffic and that is why we couldn't use Client Access. But wouldn't
there be some type of message indicating a threshold, or something of
that nature, has been reached on the iSeries interface?