If one DRB can have several QoS profiles, why are there so many DRBs between the UE and gNB?

Hello Experts.

If one DRB can have several QoS profiles, why are there so many DRBs between the UE and gNB?

It is for multiple users.

Can a single UE have multiple DRBs and multiple Qos in a single DRB?

One option would be to combine speech and data on a single DRB with distinct QoS, or we could add voice and data, each on their own Qos and separate DRBs.

Single UE and multiple DRBs, Single DRB multiple QoS is possible.

Is is for applicable to both NSA & SA?

SA only.

It requires SDAP layer support to map flows properly.

For SA we are able to work on multi PDN, but for NSA working with single PDN due to some eNB limitations, so asked you once.

Multiple PDN should be supported with SA or NSA.

My question here is what are the various advantages in each scenario?

DRB having multiple flows is valid when the radio interface treatment (priority, delay) are same for the different flows.

gNB can use same DRB and it is easier for the scheduler to assign resources.

Multiple DRBs are required when radio interface treatment will be different - example for a VoNR call - SIP and Voice flows cannot be mapped to same DRB.

Multiple DRBs between the UE and the gNB in a cellular network is to accommodate different types of traffic and services with varying requirements.

Also, each DRB is associated with specific QoS parameters, such as guaranteed bit rate, maximum bit rate, latency, and priority.

By having multiple DRBs, the network can efficiently manage and prioritize various types of traffic, such as voice, video, data, and control signals.

This segmentation helps ensure that different services receive the appropriate level of service and that the network can handle different traffic characteristics effectively.

Hope I was able to explain and if any corrections by the experts, will be much appreciated.


I think this is practical for LTE, for 5G QoS is not per DRB it’s per QoS flow and in one DRB we can have multiple QoS flows with different QoS.