11-27-2009 01:06 PM - edited 03-06-2019 08:45 AM
Hi All!
I started experiencing a weird problem with one of my 3750s today. It seems that connectivity to the managment IP has become sporadic...
I can ping it and get maybe 2-3 responses, then a couple minutes of no responses. However, the switch is still passing traffic normally, users connected to it are not experiencing any symptoms.
Switch is running IOS 12.2(44)SE2 and is connected via 802.1q trunk to 2801 with only 2 VLANs. There's really not a lot of traffic going through this switch. I can't connect to the switch from the directly connected router or elsewhere on my network.
I sat with my finger on the "Get Tree" button in my SNMP MIB Browser, to try gathering some data when it became available to begin narrowing down where the issue could be. Here's what I've found / checked so far:
I'm not able to reboot the device at the moment, I hope to do that this weekend, but I was curious if anyone has seen anything similar and had a fix other than rebooting. I'm not even sure if rebooting will help. Its odd that I can't manage the switch, but it is still passing voice and data traffic like it was yesterday. Thanks
Solved! Go to Solution.
11-27-2009 04:56 PM
We saw something kind of similar in a 6 switch stack . But our problem appeared to be the stackmaster had a slow memory leak and occassionally we would not be able to manage the stack for awhile then it would come back . Switch and port utilizations once we got in were low across all 6 switches . I'm speculating in our case because this box is used as a jump box into the rest of the net and maybe it was not releasing memory resources once we got out . We were also getting low free memory warnings from a snmp monitoring tool. We reloaded the entire 6 switch stack and so far we have not seen a reoccurence, think we are at 12.2.35SE something .
11-27-2009 01:55 PM
Can you post the config of your router and the switch? It sounds like the switch's default-gateway could be incorrect.
11-27-2009 04:55 PM
Everything you described sounds like a control plane issue, which is usually caused by high CPU or congestion.
1) manually look at the CPU usage and history on the box
2) do a 'show interface | i drops|line' and look for any output drops on uplinks
3) follow the high cpu troubleshooting guide for 3750 to gather some commands off the console if you plan to open a TAC case, so they have some something to go on.
4) really would need to examine a 'show tech' to figure this out and wouldn't hurt to do a SPAN session of the CPU.
All this stuff is in the high CPU guide for 3750s:
http://www.cisco.com/en/US/products/hw/switches/ps5023/products_tech_note09186a00807213f5.shtml
HTH,
Elly
11-27-2009 04:56 PM
We saw something kind of similar in a 6 switch stack . But our problem appeared to be the stackmaster had a slow memory leak and occassionally we would not be able to manage the stack for awhile then it would come back . Switch and port utilizations once we got in were low across all 6 switches . I'm speculating in our case because this box is used as a jump box into the rest of the net and maybe it was not releasing memory resources once we got out . We were also getting low free memory warnings from a snmp monitoring tool. We reloaded the entire 6 switch stack and so far we have not seen a reoccurence, think we are at 12.2.35SE something .
12-01-2009 08:32 AM
Thanks all. A reboot fixed it.
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