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slow response behavior


Customer having very big switched network.

Customer questioned me. Suddenly network became very slow, how will you identify the problem?




Re: slow response behavior

Hi SK,

Exactly same issue happened in Wipro Technologies Mumbai few years back when everything in network was slow and choked.

Its not easy to find out where exactly the problem is but what you can do is check the "sh logs" if you some some kind of spanning tree errors.

Also check spanning tree status with "sh spantree status" and see the status of last TCN. Do you see many TCN counters and if yes check the mac address from where last TCN is received and trace the switches.

Somehow I doubt there is some flapping going between the 2 switches which is resulting in aging out the mac entries in 15 sec and resulting in flooding in switches.

Also check the errors on uplink ports if any.



Re: slow response behavior

b4 knowing what exactly the problem is, can you tell me what type of switches are being used in the network, i mean the core switch, the distribution switch, access-layer switch, whether vlan is configured on the network? one of the possibility could be the broadcast , then looping then hubs might be used some where else, poor cabling etc.... since you say customer is having big switched network, i don't think so they would hav used hubs & poor cabling solutions, what i meant to say is, even that could also lead in to such situations, so ensure those things.

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