topic Re: Connections dropping in Operating System - HP-UX

Connections dropping

Dawn Countryman_1 — Thu, 07 Jun 2001 15:46:38 GMT

We are running MQSERIES and seeing channel drops on a connection across our wan. IBM says it's a network issue, the Network folks say is a server issue. I new to HP-UX need help.

I'm attaching output from lanadmin and netstat -s and my kernel configuration. My nddconf file has no parameters set, so I'm taking the defaults. I'm seeing drops on my netstat command but am not sure it's due to contraints on my end or the remote server end.
Any help would be greatly appreciated!!

Re: Connections dropping

Dawn Countryman_1 — Thu, 07 Jun 2001 15:52:13 GMT

Here's the attachment.

Re: Connections dropping

Brian Hackley — Mon, 11 Jun 2001 18:41:27 GMT

Hello Dawn,
I don't have an answer for you, but do have a suggestion to consider:
These kinds of problems ususally require a sniffer trace to be run at each end of the connection to determine what is being dropped or reset on the connection. You could try using host-based tools e.g. nettl / tcpdump but you'll save a lot of work using the analysis and debug features you'd find in a sniffer.
Good luck,
-> Brian Hackley

Re: Connections dropping

Dawn Countryman_1 — Tue, 19 Jun 2001 18:59:25 GMT

Thanks, I had already sent a trace to HP with no luck. No more MQ channel drops, networking replaced the switch! Thanks anyway.

Re: Connections dropping

Craig Gilmore — Tue, 19 Jun 2001 19:24:18 GMT

Dawn,

From looking at the netstat listing, there are not alot of connections being dropped after they have been established. What I do see is that there are alot of retransmit timeouts. This would definately indicate a problem with some piece of equipment on the network. Now, tracing it down to the specific piece of equipment is where the WORK begins. You would need to start breaking your network into smaller and smaller sections and see if the retransmissions increase or go away. This is the part where the sniffer trace or a nettl trace might help. You can create an artificial load on the network to stress test it with the netperf package. You can read more about netperf at www.netperf.org.

The easy way to deal with the problem is to just replace equipment, chances are good that if the switch replacement corrects the problem then there was a switch problem.