SGW-U
Serving Gateway User plane function

The SGW-U is the user data plane ingress and egress point of the E-UTRAN side of the EPC when control and user plane separation is in place. As such, when the subscriber moves around the E-UTRAN, their point of attachment to the EPC remains fixed at the SGW-U (unless the network decides that a SGW-U relocation is required). A single subscriber may be supported by multiple SGW-U if connectivity to multiple PDNs are in place. Additional responsibilities include lawful interception of subscriber traffic, inter-operator accounting, as well as downlink data buffering whilst the subscriber is paged.