3500XL switches poor communications forwarding large packets.

[stevek1]

We have 3524s and 3548s extensively deployed as our office LAN switches and have found them to be quite reliable. However we have noticed as the bulk of this kit becomes older, we are having problems with several 3524s which seem to have issues forwarding packets. A specific test to illustrate the fault is carried out by sending large ping packets to a connected device from a telnet session to the switch. Heavy packet loss is experienced. This translates to the LAN being out of action as users may take 30 minutes just to logon to the domain. It is possibly a hardware transmission fault as we have noted CRC errors being recorded by some of the connected devices.

Has anyone seen similar symptoms with these switches? Is it a known problem?

Cheers, SteveK.

[cjacinto]

You could check it against the field notice on:

http://www.cisco.com/warp/customer/770/fn26174.shtml

[michael.griffiths]

1. Check the field notice specified earlier. Especially if the PCs have 10/100/1000 cards. We had much the same problem with ours and ended up replacing 100+ 3524s.

2. If your units are not covered by the field notice, make sure that you do not have a duplex mismatch. You would probably see quite a few late collisions if that is the problem.

3. One other suggestion: We have a few locations with older wire (Cat 3), and it will behave exactly how you suggest until we drop the connection to 10 meg.

[cmpiontek]

Steve,

Did you resolve this? I am having similar issues with my network, but I have 2950s and they are not listed in the bulletin. I was wondering if you found your problem.

Thanks, Cyndi

[stevek1]

No, not yet Cyndi.

The Field Notice details CRC errors as a symptom whereas we don't necessarily see that. This is why I thought it may be a transmission problem. When the switch is returned to us, it either doesn't show the same symptoms or it doesn't boot at all. In the case that it doesn't boot, there are random port LEDs lit and no console output.

Steve.

[michael.griffiths]

Steve,

We did not see CRC errors on our switches either, but they were covered by the field notice. Another telltale sign is that your switches don't boot. A ton of ours in that serial range did the same thing. Cisco told me that some of the capacitors had just burst, and you could physically see the damage inside the switch.

Again, if the switches fall in the serial range of the field notice, don't waste any time with them. Return them and the problem will be gone.

[glen.grant]

2950's are pretty new and i wouldn't think you should be seeing the bug issue on those switches .

[stevek1]

Thanks for your input guys and Cyndi,

From now on we are sending them back as covered by the field notice as you mentioned. We have had another 2 failures since I started this thread.

All the best,

Steve.