(?)
e.g.: for IMS: P-CSCF, S-CSCF, I-CSCF, MGW, HSS, PDF, AS
(?)
e.g.: VoIP, Streaming, Conferencing, Call, Internet, Messaging, E-Mail, Presence, QoS
(?)
e.g.: 3GPP TS 29.228, 3GPP TS 29.328, 3GPP TS 24.228, 3GPP TS 24.109, RFC 3588, RFC 3261, RFC 3310, etc.
(?)
Status, contracts, decision making process, reporting, etc.