Section: 20.2A MBMS heartbeat
Content: The MBMS heartbeat procedure enables the BM-SC and MBMS GW to detect an SGmb path failure or the restart of the peer MBMS node, as specified in 3GPP TS 23.007[ Restoration procedures ]  [104]. The use of this procedure shall be negotiated between the BM-SC and MBMS GW upon contacting the peer node for the first time. NOTE: The MBMS Heartbeat procedure however applies per (BM-SC, MBMS GW) pair, i.e. not per MBMS session. When this procedure is applied, the BM-SC and MBMS GW shall detect an SGmb path failure or the restart of the peer MBMS node as specified in clause 29 of 3GPP TS 23.007[ Restoration procedures ]  [104]. The BM-SC and MBMS GW shall maintain a local restart counter which shall be incremented monotonically whenever the MBMS node restarts with loss of previous states. The MBMS heartbeat message shall include the Restart Counter AVP set to the local restart counter of the sending node. The Restart-Counter AVP may also be included in any other SGmb messages e.g. if contacting the peer node for the first time or if the local restart counter has been incremented.