UPF not forwarding packets received in GTP tunnel with UERANSIM

Q/A
4

Thanks a lot for your feedback @ksr!

Checking your indications and post contents, I still have a couple of questions:

  1. Reviewing the contents of GTP packets captured in free5gc VM’s ens20 interface (associated to UPF userplane), it seems that encapsulated ICMP packets have a correct checksum. Attached screenshoot over previous captures here, after activating wireshark IPv4 checksum validation - https://osqa-ask.wireshark.org/questions/36739/header-checksum-0xdfbb-validation-disabled/-

    checksum validation
    checksum validation1890×825 53.6 KB

  2. I’ve been also checking checksum offloading to ethernet card deactivation with ethtool command, but with no positive effect. Can you please confirm that it is required even with the evidences indicated above? If it is the case, what are the interfaces where it has to be configured? userplane interface in UERANSIM? UPF userplane interface in free5gc? free5gc interface with internet gateway?

Thanks a lot for your patience and support!

Regards,
José María