Feature Description

AMF supports interworking procedures to work with EPS. The procedures use the GTP-C based N26 interface between AMF and MME. Interworking procedures with N26 provides IP address continuity on inter-system mobility to UEs that support 5GC NAS and EPS NAS and operate in single registration mode. Interworking procedures using the N26 interface enables the exchange of MM and SM states between the source and target network.

To support N26 interface, AMF needs to support UDP proxy and GTPC Endpoint.

  • UDP Proxy: Single instance of UDP proxy running on the system. UPD proxy receives/sends the UDP packets to/from GTPC Endpoint.

  • GTPC Endpoint: The GTPC Endpoint (GTPC EP) POD handles the GTPC messages between AMF and MME. In order to enable interworking between EPC and the NG core, N26 interface is used as an inter-CN interface between the MME and 5GS AMF.