Counter check procedure used by eNodeB to verify the current uplink and downlink count for a bearer.
The purpose of using this procedure is "check whether an intruder has inserted the packet or not.
In this procedure, eNodeB sends "Counter Check" message for a set of DRBs to an UE.
In turn, UE sends "Counter check response" to eNodeB. Based of the response eNodeB may take some action like re-activation of AS security or release of a particular bearer or even release of ue connection itself.