Once a month, a few days after microsoft puts out their patches (and 
then puts out the fix for their patches). 

VOIP phones have regular mac filters. 

Jamey Heary wrote:

>HI,
>  I would like to hear from those of you that are using the certified 
>device timer what your time interval is set to and why.  I'd especially 
>like to get information from those of you that are using OOB CCA in an IP 
>Telephony environment where the linkdown trap doesn't fire.  Any 
>explanations or experiences you have had tweaking this timer would be much 
>appreciated.
>
>thank you,
>Jamey
>  
>