Disclosed is a method and system for performing a Serving Radio Network Subsystem ("SRNS") Relocation for a given User Equipment ("UE") in a Universal Mobile Telecommunications System ("UMTS") network between a UMTS radio network and a UMTS core network, in which the UMTS radio network and the UMTS core network are logically separated, the method comprising: sending a Relocation Required message from the serving Radio Network Controller ("RNC") to the core network; and sending a Relocation Request message from the core network to the Target RNC.