[c-nsp] 2970 turns into a hub for a few moments

[Afsheen Bigdeli]

This will happen if the CAM table becomes full or exhausted - the switch 
won't learn any new MAC addresses (and broadcast / multicast / unknown 
unicast MAC addresses get flooded).

What does the memory and cpu utilization look like on the switch? Can 
you provide the IOS version and/or a sanitized config?

--afsheenb



Vincent De Keyzer wrote:
> Hello,
> 
>  
> 
> a few days ago, some people on the office network started to complain about
> application timeouts/cuts (a few times a day). Since different people were
> complaining about different applications, the network seemed the right place
> to look at.
> 
>  
> 
> We have placed several laptops in several points of the network, running a
> sensible application plus Ethereal. What we saw was very weird: from time to
> time (and it coincides with the applications timeouts), the switches starts
> forwarding to the laptop ports traffic that is neither broadcast, nor
> unicast for the laptops. Just like if the switch would become a hub from
> time to time. It lasts for "a few seconds" (we still need to narrow this
> down), then it starts behaving normally again. We believe that this produces
> some temporary congestion on the network, which causes the applications
> problems.
> 
>  
> 
> Does anyone have an idea on what could be causing this?
> 
>  
> 
> Vincent
> 
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