network goes down every 20 mins

[stavros0]

Hi,
Every 20 minutes my network crashes. then after 5 minutes of down time it rectifies itself and everything is fine for another 20 minutes. there are two cisco 7200 and two 3500's on the network.

Is it possible that im being attacked (DDOS attack)causing the buffer to fill up with junk and after 20 mins overflows and causes the routers to reboot?

Is this a Cisco problem?
Has Anyone ever experienced this before?

Help please as its been going on for 2 days now and our Cisco experts are stumped!

S

 

[CPaul123]

Did you check your routing tables? It maybe a routing loop.

 

[scraig84]

Can you define "crashes"? That's awfully ambiguous. 20 minutes is the default MAC table timeout for most switches - so possibly you are having an issue there?

Anyway, to be able to troubleshoot something like this there would need to be a lot more info provided as to the design of the network and the exact nature of the problem.