Components and Interfaces

Logical Components of SSG EPDG

EPDG Core — the main component responsible for coordinating modules and managing tunneling parameters, ensuring QoS;

Authorization Module (AM, Authorization Management) — manages authorization interfaces, with flexible scenario settings for integration with the operator's IS. Responsible for interaction with the operator's AAA server if available or can completely replace it for internal and external services;

Tunnel Management Module (TMM, Tunneling Management) — manages the binding of IPSec and GTP tunnels. Responsible for interaction with the operator's PGW, with flexible configuration scenarios for working with different interfaces.

In the SSG EPDG, a single fast-epdg process is responsible for the operation and interaction of all logical components.

Supported Interfaces

Input
SWa (SWm)	For external systems, such as TWAG. Applied in AAA-proxy case
SWu	From UE
S6b	From operator's PGW, for organizing flow from PGW to HSS on incoming call
Output
SWx	To HSS
SWm	To AAA
S2b	To PGW for signaling traffic
S5/S8	To PGW for signaling traffic (when S2b is unavailable)
S2a	To PGW in TWAN mode