SGW stands for "Serving Gateway". It is a key component of the Evolved Packet Core (EPC) architecture in 4G LTE networks.

It serves as the anchor point for user plane data packets, it routes and forwards user data between the eNodeB (Evolved Node B), and the Packet Data Network Gateway (PGW).

Also it coordinates with the Mobility Management Entity (MME), to handle handovers between different eNodeBs, ensuring seamless connectivity for the UE.

In addition, it ensures the appropriate QoS treatment for user data flows, based on the subscriber's service requirements.

The SGW interacts with other key network elements, such as the MME, PGW, in order to perform its functions.