OPTIONS sip:user@example.com SIP/2.0
To: sip:user@example.com
From: <sip:caller@example.com>;tag=323
Max-Forwards: 70
Call-ID:  transports.kijh4akdnaqjkwendsasfdj
Accept: application/sdp
CSeq: 60 OPTIONS
Via: SIP/2.0/UDP t1.example.com;branch=z9hG4bKkdjuw
Via: SIP/2.0/SCTP t2.example.com;branch=z9hG4bKklasjdhf
Via: SIP/2.0/TLS t3.example.com;branch=z9hG4bK2980unddj
Via: SIP/2.0/UNKNOWN t4.example.com;branch=z9hG4bKasd0f3en
Via: SIP/2.0/TCP t5.example.com;branch=z9hG4bK0a9idfnee
l: 0
