Switching between unicast and multicast bearer to receive MBMS services is known as service continuity. When UE detects it is moving out from the MBSFN Area coverage and no other MBSFN Area is available to get the same ongoing MBMS service, it sends indication to the GCS AS (content provider for broadcast and mulitcast services) . After receiving indication from UE, application server establishes a unicast bearer for an UE using the Rx interface with PCRF. Once the unicast bearer is established for UE, AS starts sending MBMS data through unicast bearer.
UE and AS (application server) exchange messages using the GC1 interface.
