仕様書
- [1] RFC 6086 - Session Initiation Protocol (SIP) INFO Method and Package Framework ( 版) http://tools.ietf.org/html/rfc6086#section-4.2.2
- [2] RFC 6086 - Session Initiation Protocol (SIP) INFO Method and Package Framework ( 版) http://tools.ietf.org/html/rfc6086#section-4.3.1
- [3] RFC 6086 - Session Initiation Protocol (SIP) INFO Method and Package Framework ( 版) http://tools.ietf.org/html/rfc6086#section-11.5