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Does a Cisco IP Phone use STP?

I just plugged in a 7940 into my C3750 with BPDU guard enabled and it err-disabled the port as it saw a BPDU sent from the phone? A shut/no shut fixed the problem but it has happened more than once.

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Cisco Employee

Re: Does a Cisco IP Phone use STP?

No. A phone by itself does not generate BPDUs but will forward them. Check out my reply to your other post today.

http://forums.cisco.com/eforum/servlet/NetProf?page=netprof&forum=Network%20Infrastructure&topic=LAN%2C%20Switching%20and%20Routing&CommCmd=MB%3Fcmd%3Dpass_through%26location%3Doutline%40%5E1%40%40.1dda506b/0#selected_message

One other possibility is the phone was bad and looping back whatever packets it received from the switch including BPDUs causing this problem.

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