eMBMS is introduced in LTE network to support multi-casting and broad-casting services through eNodeB's. There are various components need to implement to provide MBMS services. One MBMS service can cover multiple MBSFN areas. All the cells belong to same MBSFN area are timely synchronized. I mean to say, all the cells of same MBSFN area broadcast same data at the same time. Since all the cells broadcast same data at the same time, UE receives better quality signal.
Following are the entities need to be present to support MBMS in lte network.
1. BMSC (have SG-mb and SGi-mb)
2. MBMS-GW (M1 interface, Sm interface, SG-mb and SGi-mb)
3. MME (Sm and M3 interface)
4. MCE (M3 and M2 interfaces)
5. eNodeB (M1 and M2 interfaces)
MCE, MBMS-GW and BM-SC server are fully dedicated for MBMS services.
MME and eNodeB should have support of Sm interface and M2 interface respectively.