Moreover, the eNodeBs are also connected by means of the S1 interface to the EPC, more specifically to the MME by means of the S1-MME and to the S-GW by means of the S1-U.
The S1 interface supports a many-to-many relation between MMEs/S-GWs and eNodeBs.
The P-GW is interconnected with external networks using the SGi interface.