23.1213GPPArchitectural requirements for Release 1999Release 1999TS
The signalling plane consists of protocols for control and support of the transmission plane functions. The following signalling planes are used in UMTS between UE and 3G-SGSN.
Figure 4.42: Protocol Architecture for radio interface layer 3 towards the PS service domain
UMTS PS service domain Mobility Management and Session Management (GMM/SM): This protocol supports mobility management functionality such as PS attach, PS detach, security, routing area update, location update, PDP context activation, and PDP context deactivation.