PDN-GW – Packet Data Network Gateway
Like the SGW, the Packet Data Network Gateway (PDN GW) is the termination point of the packet data interface towards the Packet Data Network(s). The PDN GW provides connectivity to the UE to external packet data networks by being the point of exit and entry of traffic for the UE.Please note that A UE may have simultaneous connectivity with more than one PDN GW for accessing multiple PDNs.
In LTE, data plane traffic is carried over virtual connections called service data flows (SDFs)
As an anchor point for sessions towards the external Packet Data Networks, the PDN GW supports:
• Policy enforcement features (applies operator-defined rules for resource allocation and usage)
• Packet filtering (for example, deep packet inspection for application type detection)
• Charging support (for example, per-URL charging)
• Another key role of the PDN GW is to act as the anchor for mobility between 3GPP and non-3GPP technologies such as WiMAX and 3GPP2 (CDMA 1X and EvDO