Salut, CANCEL le voila:

-- SIP/802-0000002a is ringing
-- SIP/803-0000002b is ringing
-- SIP/804-0000002c is ringing
trixbox1*CLI>
<--- SIP read from UDP://178.32.41.64:5060 --->
CANCEL sip:xxn°voipnetxx@192.168.0.240 SIP/2.0
Via: SIP/2.0/UDP 178.32.41.64;branch=z9hG4bKce12.7a5f2dd6.0
From: "32xxmonn°telxx" <sip:0xxmonn°telxx@91.121.184.84>;tag=as15b6672 c
Call-ID: 5d84d0b822608e77602de16317b046fa@91.121.184.84:506 0
To: <sip:xxn°voipnetxx@178.32.41.64:5060>
CSeq: 102 CANCEL
Max-Forwards: 70
User-Agent: Enswitch SIP proxy
Content-Length: 0

La ligne qui nous intéresse c'est:

<--- SIP read from UDP://178.32.41.64:5060 --->
Donc c'est tou fournisseur qui met fin à la communication. (Enswitch SIP proxy)