Voice Call Continuity
Unlicensed Mobile Access
3rd Generation Partnership Project
Session Initiation Protocol
IP Multimedia Subsystem
Application Server
Interwarking Wireless LAN
Packet Data Gateway
Internet Key Exchange v2
Extensible Authentication Protocol method for UMTS Authentication and Key Agreement
IMS controlled Model
Original Domain Controlled Model
Visited Mobile Switching Center
GSM Service Control Function
SIP Back To Back User Agent
Real-time Transport Protocol
VCC Domain transfer Number
VCC Domain transfer URI
SIP Uniform Resource Identifier
High Speed Packet Access
Long Term Evolution
British Telecom
UMA Network Controller
Mobile Switching Center
Generic Access Network