Can two or more SGW be connected with each other in LTE-EPC

Question

Is it possible to establish link between 2 or more Serving Gate Way (S-GW) directly in LTE system? --OR-- SGWs are connected through Packet Data network gate ways (PDN-GW)

Answer 1

There is no interface between SGWs. All the signalling within the LTE network is controlled by MME. During the attach procedure, SGW and PGW selection is done by MME. As part UE mobility, in some scenarios SGW gets changed for an UE and this time again MME takes decision to select appropriate SGW. In case of SGW relocation, MME initiates handover signalling towards the selected SGW. Old SGW and the new SGW does not talk to each other directly.