Cisco IE-3400 Lagging cli output, Intermittent SSH & snmpwalk

[bong31]

Hi guys,

We have above device with version 17.12.3 that has delay in showing the output of cli command and intermittent when trying to ssh to and from and also intermittent when snmpwalk from remote remote server. Typing cli any commands speed is normal but the output of the cli is lagging for few seconds. Also, tried ssh and snmpwalk but intermittent(sometimes can and sometimes can't) within few minute interval. Dataplane traffic is normal. Routing is normal. Case is already opened to cisco and on-going investigation. I would like to understand what may have caused this issue and what is the possible solution. I appreciate if anyone can share who encountered this issue before and/or  can shed light on this. 

[Flavio Miranda]

@bong31 

 Did you check CPU?  It can be easilly CPU and or memory spikes.

[bong31]

Thanks Flavio for the response. No abnormalities observed though in cpu and memory when tac checked. We even compared to other working switches in production and no difference. From logs, same no clue also.

[Flavio Miranda]

Another possibility is spanning-tree, If you have It running

[bong31]

Yes, stp is running. Did checked the switch configuration related to stp seems no anomaly. Compared the stp status on other working switch no difference also. What puzzles me is that why it affects only management plane.

[Elliot Dierksen]

Is there anything along the path the could be causing fragmentation of large TCP packets? I have seen CLI sessions freeze when it generated packets from large amounts of output if there was a link along the way that didn't supported the MSS that the CLI session negotiated.

[Georg Pauwen]

Hello,

what is the uptime of the IE-3400 ? I know this sounds very basic, but did you reboot the device ?

[bong31]

Update: We have rebooted but doesn't resolve the issue. After troubleshooting with TAC, he deduced the issue with the routing coz when we try to shut one of the uplink and bring up again try on the other uplink the ssh and snmpwalk is responding normally. Later we found out the 2x distribution downlinks SVI ip addresses going to the switch are swapped. After the corrective configuration of IPs on 2x distribution links the issue disappear.