The MME provides support for Closed Subscriber Groups (CSG). This enables the MME to provide access control and mobility management for subscribers who are permitted to access one or more CSG cells of the PLMN as a member of the CSG for a Home eNodeB (HeNB).
A CSG ID is a unique identifier within the scope of the PLMN which identifies a Closed Subscriber Group in the PLMN associated with a CSG cell or group of CSG cells.
The MME performs access control for CSG a UE will not be permitted to access the network through a CSG cell unless either the UE's subscription data includes the same CSG ID as the CSG cell, or if the CSG cell is operating in hybrid mode. The MME also optionally reports the UE's CSG information to the S-GW/P-GW, based on the MME's CLI mme-service configuration. The S-GW/P-GW, in turn, informs the MME when it should report user CSG information.