UE(s) (User Equipment(s)) use the Fifth Generation System (5GS) to get data connectivity between applications on the UE and Data Networks (DNs) such as the ‘Internet’ or private corporate networks. Almost all applications running on the UE including voice require such data connectivity.
This chapter defines the data connectivity provided by the 5GS (Protocol Data Unit [PDU] Sessions, PDU Session continuity modes, traffic offloading, etc.). It then describes the 5GS Quality of Service (QoS) framework (QoS Flows, parameters of 5GS QoS, Reflective QoS, etc.). Finally, it gives an overview of session management including an overview on how applications can influence traffic routing and on policy control for PDU Sessions.
6.2 Basic Principles of PDU Sessions
6.2.1 What is a PDU Session?
The ‘PDU Session’ is the (new) abstraction for 5G user plane services like the concept of a Packet Data Network (PDN) connection in 4G Evolved Packet Core (EPC). A PDU Session provides connectivity between applications on a UE and a DN such as the ‘Internet’ or private corporate networks. A DN is identified by a Data Network Name (DNN) which is the equivalent of an Access Point Name (APN) in 4G EPC.
A PDU Session is associated with a single DNN and with a single slice (S‐NSSAI).
PDU Sessions can provide different ...