SGW is shown in diagram below. Some of the key roles of SGW are listed below:- (1). SGW is responsible for handovers with neighboring eNodeB’s. (2). Data transfer in terms of all packets across user plane. (3). Mobility interface (or anchors) to other 3GPP systems (2G and 3G) etc.
Serving (S) System Architecture Evolution Gateway (GW)- SGW
SGW also monitors and maintains context information related to the UE during idle state and generates paging requests when data for the UE arrives from the network (on Downlink).