https://app.kbone.net/vault/rfc/docid/4078
RFC3725: Best Current Practices for Third Party Call Control (3pcc) in the Session Initiation Protocol (SIP)
Network Working Group J. Rosenberg Request for Comments: 3725 dynamicsoft BCP: 85 J. Peterson Category: Best Current Practice Neustar ...
https://app.kbone.net/vault/rfc/docid/4509
RFC4117: Transcoding Services Invocation in the Session Initiation Protocol (SIP) Using Third Party Call Control (3pcc)
Network Working Group G. Camarillo Request for Comments: 4117 Ericsson Category: Informational E. Burger Brooktrout ...