srsRAN gNB with srsUE tun interface is not created

[gustavobsch]

Issue Description

[Describe the issue in detail] I'm following the recently created 'srsRAN gNB with srsUE' user guide and when I run srsue it can register with the open5gs network fine, it gets a valid IP from the DN assigned the problem is the tun_srsue interface is not created

Setup Details

[Specify details of the test setup. This would help us reproduce the problem reliably] srsRan 23.3 using the gnb.yml and ue.conf config from the referenced guide

Expected Behavior

[What you expect to happen] The tun_srsue should get created in order for IP traffic flow to/from the simulated UE

Actual Behaviour

[What happens instead e.g. error message] The tun_srsue is not created, I run 'ip link' and it doesn't show. I can't ping either

Steps to reproduce the problem

[Tell us how to reproduce this issue e.g. RF setup, application config files] Compile srsran_4G and srsran with zmq support Use the config files provided and then run it with

$ sudo ip netns add ue1
$ sudo ./srsue ue.conf
Built in Release mode using commit 921f17484 on branch master.

Opening 1 channels in RF device=zmq with args=tx_port=tcp://*:2001,rx_port=tcp://gnb-zmq:2000,base_srate=11.52e6
Supported RF device list: UHD bladeRF zmq file
CHx base_srate=11.52e6
Current sample rate is 1.92 MHz with a base rate of 11.52 MHz (x6 decimation)
CH0 rx_port=tcp://gnb-zmq:2000
CH0 tx_port=tcp://*:2001
Current sample rate is 11.52 MHz with a base rate of 11.52 MHz (x1 decimation)
Current sample rate is 11.52 MHz with a base rate of 11.52 MHz (x1 decimation)
Waiting PHY to initialize ... done!
Attaching UE...
Random Access Transmission: prach_occasion=0, preamble_index=0, ra-rnti=0x39, tti=174
Random Access Complete.     c-rnti=0x4601, ta=0
RRC Connected
PDU Session Establishment successful. IP: 172.16.10.14
RRC NR reconfiguration successful.

Additional Information

[Any additional information, configuration or data that might be necessary to reproduce the issue]

I'm running both gnb and srsue on Kubernetes. The pods have elevated privileges and tun interface can get created manually as I show below. I also tested the UERANSIM software UE and the tun interface gets properly created so I don't think kubernetes is the cause but it might be related.

$ sudo ip tuntap add mode tun dev tun0
$ ip link show dev tun0
4: tun0: <POINTOPOINT,MULTICAST,NOARP> mtu 1500 qdisc noop state DOWN mode DEFAULT group default qlen 500
    link/none 

[emunicio]

I may be experiencing the same issue. However, while I see tun_srsue interface created with ip netns exec ue1 ip addr , the UE can't ping nor the GW neither its own IP.

[herlesupreeth]

@gustavobsch As @emunicio mentioned, the tun interface gets created in the namespace you create (i.e. ue1). So in order to see the tun interface you need to execute ip netns exec ue1 ip addr

@emunicio Have you tried pinging as follows?

ip netns exec ping <IP_ADDRESS>

[emunicio]

Yes, the problem was that the local IP of the conf file of the gnb was wrong ;-) I guess we can close this