RANAP (Radio Access Network Application Part)

Also known as: Radio Access Network Application Part

RANAP is the 3GPP signalling protocol between the UTRAN RNC and the 3G core (MSC or SGSN) over the Iu interface (TS 25.413). It handles UE context, RAB assignment, paging, security mode control and relocation. RANAP is typically carried over SS7 SCCP/MTP or SIGTRAN M3UA, which makes 3G core interfaces reachable from SS7 attackers when Iu links are exposed.

Categories: Radio Access NetworkCore NetworkSignaling

RANAP in context

The radio access network is where mobile devices attach to the operator's infrastructure. Attacks in this layer include IMSI catching, rogue base stations and downgrade attacks; defenses rest on mutual authentication, integrity-protected signaling and Open RAN supply-chain hygiene.

The mobile core carries subscriber sessions, mobility and policy. In 4G it is the EPC (MME, HSS, S/PGW); in 5G it is the Service-Based Architecture with AMF, SMF, UPF, AUSF, UDM and the NRF.

To place RANAP in the wider telecom-security picture, review 5G SA, AMF, Base Station (BS), Capacity Planning, CAPEX and CSCF — each entry cross-references back to this page so you can walk the topic in either direction.

Related terms

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