The MME uses the SBc interface, between the MME and the Cell Broadcast Center (CBC), for warning message delivery and control functions.
The MME provides support for Commercial Mobile Alert System (CMAS) — SBc interface and underlying protocols. Warning Messages can be received from a CBC over the SBc-AP interface and relayed to all relevant eNodeBs over the S1-AP interface.
The CMAS functionality is enabled in the networks to provide warning notifications to subscribers.
From release 18.4 onwards, a valid license key is required to enable the SBc interface. Contact your Cisco account representative for information on how to obtain a license.