rfc2976
[p.~44]{Pand9506:Emerging}
rfc2205
rfc1889
rfc2326
rfc2974
rfc1321
[p.~154]{Stev94:TCP1}
rfc1191
Scho9608:Multicast
rfc2368
rfc1890
rfc2426
rfc2849
rfc2076
draft-ietf-sip-call-flows
rfc3015
rfc2732