[Bugs] Wrong Interface Type in PFCP Session Establishment Request for IP Based PDU Session

[bertuola]

Describe the bug

The Source Interface Type used in PFCP Session Establishment Request should be Core for IP based PDU Session; instead, the value is SGi-LAN/N6-LAN, referring to a Ethernet based PDU Session (3GPP 29.244, 8.2.2-1).

Also the 3GPP Interface Type IE is missing (3GPP 29.244, 8.2.118).

To Reproduce

Steps to reproduce the behavior:

1. Run a TestRegistration scenario and check the wireshark trace.

Expected behavior

Here how the PFCP Establishment Request should look like:

PFCP_Establishment_Request_Reference.txt

Screenshots

Environment (please complete the following information):

• free5GC Version: 3.4.1
• OS: Ubuntu 20.04.6
• Kernel version: 5.4.0-174-generic

Trace File

Configuration File

PCAP File

TestRegistration.zip

[ming-hsien]

Hello, Tks for you for your questions.
May I ask if you can provide the version of 3GPP 29.244 for reference?

[bertuola]

The Interface Value has been defined since beginning, while Interface Type is defined starting from v15.6.0 released on 2019-06-13.

[ianchen0119]

Hi @bertuola

Refer to 5.4.8 Traffic Steering in 3GPP TS 29.244

The CP function shall control the processing of the traffic received from the (S)Gi-LAN or N6-LAN in the UP function
as specified in the rest of this specification for traffic received from any other interface, but with PDR(s) including a
PDI with the Source Interface indicating "SGi-LAN/N6-LAN". The UP function shall distinguish packets coming from
(S)Gi-LAN/N6-LAN based on local configuration.

I think our current implementation is correct.
As for the interface CORE, it be used to indicate the data from the anchor UPF (You will see in the dl pdr, applied to I-UPF, in ULCL deployment).

Also the 3GPP Interface Type IE is missing (3GPP 29.244, 8.2.118).

Refer to Table 7.5.2.2-2: PDI IE within PFCP Session Establishment Request, described in TS 29.244
The Source Interface Type IE is optional.
Is this IE should be set in your use case?
If yes, please let us know.

Thank you.

[bertuola]

Hi.

I agree Interface Type IE is optional; regarding the Source Interface Type, I don't.

There are different PDU Session Types that can be established in 5GC: IP Based (Source Interface Type=Core), or Ethernet Based (Source Interface Type=SGi-LAN/N6-LAN), or Unstructured.

To confirm it, here the same request made by LoadCore/Ixia simulator:

[ianchen0119]

Hi @bertuola

I think you were right.
we will fix this issue, thanks for your information.