network down

[Manish Manwal]

hi all

our full network down for few second in every two or three days.

is it our core switch problem or anythings else, please give me some solution for that or suggestion to check, exactly what happening.

[Leo Laohoo]

How many minutes is this outage?

Are there any appliances crashing or rebooting during this time?

[Manish Manwal]

for few second. maximum 3 sec

[Leo Laohoo]

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@Manish Manwal wrote:
for few second. maximum 3 sec

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How were you able to determine that there was a 3 second outage for several days?

[Manish Manwal]

no

[Manish Manwal]

I SAY MAX 3 SEC.
SOMETIME IT MAY BE 1 or may be ms.

[Fotiosmark]

1st, how big is the network? Do you have a diagram?

Show spanning tree commands would be usefull.

It sounds like a spanning tree issue.

Give a Diagram 1st.

[Manish Manwal]

find the attachment, except that there is more then 500 switches more , some of them is manageable or some of them unmanageable   

[Fotiosmark]

You should start by checking the Logs on the Core switches, maybe there is a link flapping and a spanning tree Recalc occurs.

Then check the Spanning tree also. See which STP is using, if all switches are using the same STP such as PVST or MST, see which one is the Root, blocked ports etc.

Try to cross reference the ports on spanning tree the the CDP neighbors.

Hope that helps.