How it Works

This section describes how this feature works.

A subscriber session is idle when data traffic activity is not steered towards it as it is inactive for a stipulated time.

The session manager on the user plane tracks the state of the call line. Sessions for which the session manager does not record the call line data traffic are determined as idle. Using the idle session timeout configuration, you can set the time interval for which the session can remain idle before it times out. The idle timeout configuration is set when the session is established. The SGW-U sends the timeout configuration to the user plane in the Sx Session Establishment Request. In case of multi-PDN calls, the calls directed towards a stale session are cleared after the inactivity report is generated for all PDNs.

Every second, the SGW-U monitors the data traffic activity to determine the session's idleness status. On identifying a stale session, the user plane updates the User Plane Inactivity Report in the Sx Session Usage Report and sends it to cnSGW-C to convey that the session is idle. Further, the cnSGW-C initiates a session deletion request towards its peers.

Based on the network environment, configure the idle timeout configuration in seconds. The accepted range of the timeout value is 1–4294967295 seconds. The timeout configuration is applicable at the SGW-U service profile level enabling the idle timeout handling for the set of subscribers handled by the SGW-U service.