RANAP
Radio Access Network Application Part

RANAP operates over the Iu-PS interface and provides two main functions; the support of AS (Access Stratum) signalling between the RNC and the SGSN and the encapsulation of NAS (Non Access Stratum) signalling passing between the mobile and the core network. With respect to AS signalling, RANAP supports procedures such as RAB (Radio Access Bearer) assignment and management, relocation, location reporting, paging and security management. RANAP uses the services of SCCP which in turn resides on either IP or ATM (Asynchronous Transfer Mode).