Peer-to-peer video sharing is a basic service on top of the IP Multimedia Subsystem (IMS).
It could work with a pure IETF Session Initiation Protocol (SIP) infrastructure and simple HTTP Digest authentication.
So the IMS adds up extra security and management features that are normally required by a mobile operator by default.
Because this service does not involve any application server, it is difficult to make a good business model for it.
Two major operators started commercial implementations: "Turbo Call" [1] from Telecom Italia Mobile (TIM) in Italy and Telecomunicações Móveis Nacionais, SA (TMN) in Portugal.