serving gateway (LTE) (SGW)

The Serving Gateway (SGW) is a network component of the Evolved Packet Core( EPC), i.e., the core structure of LTE networks. Together with the Packet Gateway( PGW) for the Public Data Network( PDN), it forms the SAE gateway of the SAE architecture, System Architecture Evolution (SAE). Both gateways, the SGW and the PGW are logically separate entities that are combined in the Evolved Packet Gateway( EPG).

As a network component, the Serving Gateway is a router that routes data packets between two networks to the end user. It is connected to the Evolved Node B( eNB), which is functionally a radio base station, and the Evolved Packet Data Gateway (ePGW), from where the data is forwarded to the exchanges, PDN Gateway (PGW) or the Internet. The PDN Gateway provides the connection to 2nd and 3rd generation mobile networks( 2G and 3G).

Architecture of the Evolved Packet Core (EPC)

The Policy and Charging Enforcement Function( PCEF) is implemented in the serving gateway and controls the gating and quality of service( QoS) of individual IP flows in favor of the Policy and Charging Rules Function( PCRF).