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I have a Catalyst 2900 that's sending out an STP packet about once ever 1-2 seconds. Is that excessive?

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2 Answers 2

up vote 4 down vote accepted

Is that excessive?

In short: No.

You can start getting worried once you start seeing ARP request frequencies three or four orders of magnitude more than that.

As an aside, your screenshot does not show ARP packets. It shows STP packets, which perform a completely different task.

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lol sorry, I meant to put STP. So it's not excessive to see STP packets once a second from a switch? –  blsub6 Oct 21 '10 at 20:48
    
Nope - the switch uses those for loop detection, so they're completely normal. –  EEAA Oct 21 '10 at 21:08
    
You should be happy that it checks this every second, it keeps your network safe from burning up. –  pauska Oct 21 '10 at 21:13
    
awesome, thanks for your answers everyone –  blsub6 Oct 21 '10 at 23:09
    
Would like to add that it is called the Spamming Tree Protocol for a reason :-) –  3molo Mar 31 '12 at 10:39

The default STP hello time for STP root bridge is normally 2 seconds, so this looks pretty normal to me. The hello time is the interval at which the root bridge sends an STP BPDU onto the network.

http://en.wikipedia.org/wiki/BPDU#Bridge_Protocol_Data_Units_.28BPDUs.29

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