asterisk users - Jan 2007 - mysterious SIP packets to Cogent

In my SOHO setting even when nobody is using the phone my firewall drops 
outgoing packets from the asterisk box to a Cogent server, din't find 
naything through Google about it:

(out: eth0 xxx.xxx.xxx.xxx.:2129 -> 66.250.40.33:24441 UDP len:193 ttl:64).

Anyone know what this traffic is supposed to be good for?

Greetings
--AvH