What is PDU session in 5G?

My friend: Hi Ibrahim, I have a question for you.

Me: Go ahead.

My friend: What is the meaning of PDU Session in 5G?

Me: In 5G, we use a “PDU Session” to provide end-to-end user plane connectivity between the UE and a specific Data Network (DN) through the User Plane Function (UPF). A PDU Session supports one or more QoS Flows. There is a one-to-one mapping between QoS Flow and QoS profile, i.e. all packets belonging to a specific QoS Flow have the
same “5G Quality of Service Identifier” (5Ql).

My friend: So, what about 4G, is it same concept?

Me: No, 4G uses an “EPS Bearer” to provide end-to-end user plane connectivity between the UE and an Access Point Name (APN) through the Packet Gateway (P-GW). There is a one-to-one mapping between EPS Bearer and QoS profile, i.e. all packets belonging to a specific EPS Bearer have the same “Quality of Service Class Identifier” (QCI). But, take care as PDU Sessions are applicable when using a 5G Core Network.

A Non-Standalone Base Station architecture connected to a 4G Core Network uses EPS Bearers.

My friend: Thanks a lot. Me: You are welcomed.

Source: Ibrahim Sayed

Linkedin Profile: https://www.linkedin.com/in/ibrahim-sayed-88a7747-5g/