Packet data network gateway

The PGW is the gateway which terminates the SGi interface towards PDN. If UE is accessing multiple PDNs, there may be more than one PGW for that UE, however a mix of S5/S8 connectivity and Gn/Gp connectivity is not supported for that UE simultaneously.

PGW is responsible to act as an "anchor" of mobility between 3GPP and non-3GPP technologies. PGW provides connectivity from the UE to external PDN by being the point of entry or exit of traffic for the UE. The PGW manages policy enforcement, packet filtration for users, charging support and LI.

Possible to use non-3GPP technologies are: WiMAX, CDMA 1X and EvDO.

                                                                               

PGW functions include:                                          

1.       Per-user based packet filtering (by e.g. deep packet inspection);

2.       Lawful Interception;

3.       UE IP address allocation;

4.       Transport level packet marking in the uplink and downlink, e.g. setting the DiffServ Code Point, based on the QCI of the associated EPS bearer;

5.       Accounting for inter-operator charging;