PDU session establishment in 5G
In Chapter 2, we discussed a Protocol Data Unit (PDU) session, wherein we learned that a PDU provides end-to-end connectivity to user equipment (UE) to avail of data services. A PDU session can be imagined to be a pipe that is associated with every UE and is identified by a PDU session ID; this pipe is used for the user data to flow between the 5G packet core to the UE. The PDU session ID is generated by the UE. Figure 7.1 shows a PDU session along with various Quality of Service (QoS) flows associated with it:
Figure 7.1 – PDU session in 5G
The establishment of a PDU session involves the UE along with a number of network functions. These network functions exchange messages with each other, and when all these message transactions are successful, a PDU session is finally established.
Figure 7.2 describes the procedure through which this end-to-end connectivity is established. It can be noticed here that the participating...
