P-GW
Packet Data Network Gateway

The P-GW serves as an ingress and egress point to the EPC from a PDN (Packet Data Network) such as the Internet. When a subscriber establishes an EPS (Evolved Packet System) bearer to a given PDN, the P-GW serves as the point of attachment to that PDN for the life of the EPS bearer (regardless of any mobility procedures). Packet filtering is a key role of the P-GW in order to ensure that downlink data has the appropriate QoS applied. This is associated with PCC (Policy and Charging Control), with the P-GW typically housing PCEF (Policy and Charging Enforcement Function) capabilities.