The Timer-based GBR Bearer Deactivation, a proprietary feature of StarOS, allows MME to retain dedicated bearers of a User Equipment (UE) when eNodeB sends a S1-AP Context Release to enable the UE to resume a VoLTE call on receiving a new Service Request or RCC Connection. For example, if a subscriber is out of coverage for a short period of time during a VoLTE call, the GBR bearer would be retained and the session is not lost.
MME provides a configurable timer for which the GBR bearers are preserved when a UE Context Release Request message with "Radio Connection With UE Lost" cause code is received from the eNodeB. MME preserves the GBR bearers for the configured time.
A valid license key is required to enable this feature. Contact your Cisco Account or Support representative for information on how to obtain a license. This license was not enforced in earlier releases.