PDN session (Packet Data Network session) refers to the establishment of a data connection between a mobile device and a specific Packet Data Network.

PDN session is established when a mobile device, connects to the mobile network and requests access to a specific Packet Data Network.

This allows the mobile device to get an IP address, and to access various IP-based services that are available on the connected Packet Data Network.

The PDN session has at least one EPS bearer (the default EPS bearer), and it may have one or more additional EPS bearers (dedicated EPS bearers).