Support for non-default QoS flows

[fxie00]

I want to explore 5G QoS flows with UERANSIM. I use UERANSIM (v3.2.6) for UE and gNB (VM A) and open5gs (v2.6.1) for core (VM B). I configure 2 QoS flows, one default (non-GBR) with QFI 9 for IP traffic and the other with QFI 3 for UDP traffic, via open5gs WebUI for the UE. The DNN is a VM (VM C) connected to the core (VM B).

From VM C, I generated two flows, ping (IP traffic) and iperf (UDP traffic), with destination being the UE (VM A). I expect that open5gs would mark the ping packets with QFI 9 and the UDP packets with QFI 3. However, I observed that both ping and iperf packets carry the default QFI 9.

From some previous discussion, I learnt that:

1. open5gs supports non-default 5G QoS flows for CP;
2. UERANSIM may not support 5G QoS flows.

I want to figure out why both IP and UDP traffic are placed in the default QoS flow. My questions are:

1. Is it true that UERANSIM does not support non-default 5G QoS flows?
2. If UE/gNB does not support non-default 5G QoS flows but core does, will core (UPF) place all traffic into the default 5G QoS flow?
3. Are there any workarounds for using UERANSIM for non-default 5G QoS flows?

Any help would be highly appreciated.

Feng