SIP/2.0 200 OK
Via: SIP/2.0/UDP nm;branch=foo;rport=26810;received=224.63.228.126
From: <sip:nm@nm>;tag=root
To: <sip:nm2@nm2>;tag=196846744
Call-ID: 50000
CSeq: 42 OPTIONS
Allow: INVITE, ACK, BYE, CANCEL, OPTIONS, MESSAGE, SUBSCRIBE, NOTIFY, INFO
Accept: application/sdp
User-Agent: IP Camera
Content-Length: 0