Ping does not come back to UE

Q/A
#1

Hi all,

I have installed free5gc on a kubernetes cluster and everything is ok. Now, to test it, I have installed UERANSIM in the same cluster and I have only one failure. The UE raises the tunnel and, with the network configuration in the UPF correctly, it can ping through that interface. The problem is that the ping is not redirected to the UE, it stays in the UPF. What could be the problem? I am running out of ideas.

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Error at SMF:

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Thanks in advance

#2

Hi @avrodriguez,

Could you please check the following things?

  1. The version of gtp5g should be “1.0.3a” (modinfo gtp5g, and make sure the right version loaded by dmesg linux utility)

  2. Make sure the uplink and downlink flow rules in upf by
    sudo echo #gtpiface #id > /proc/gtp5g/pdr
    sudo cat /proc/gtp5g/pdr
    sudo echo #gtpiface #id > /proc/gtp5g/far
    sudo cat /proc/gtp5g/far
    sudo echo #gtpiface #id > /proc/gtp5g/qer
    sudo cat /proc/gtp5g/qer

  3. Compare the result of step2 with wireshark trace of upfgtp and N3 interface

#3

Hi @muthuramanecs03g,

I have tried below command but it says “operation not permitted” (as root user in container).
echo “gtpinterface_name” > /proc/gtp5g/pdr

I think we will need to run the UPF container in privileged mode. Could you please check if above comand is correct. Not sure what is #id .

The services UE,RAN ,upf,amf , natapp are running inside containers in microk8s cluster.
gtp5g version is 1.0.3b

Two issues we are seeing:-

  1. ping -I eth1 “upf_ip_eth1” is working as UPF is sending icmp echo replies to UE ( as seen in ngrep capture) but in UE we cannot see packets receiving.
  2. “ping -I eth1 google.com” is working but in upf , no packet captured.

-Thank you.

Flow rules and IP filtering
#4

@deconixmj,

The right command could be
sudo echo “gtpinterface_name PDRID” > /proc/gtp5g/pdr

#5