VOLTE, INVITE create 408 Request Timeout

[JulienSrcdImta]

Hi @herlesupreeth,

I have failed voice calls on my platform:
"4G Volte deployement with B210:
docker compose -f 4g-volte-deploy.yaml up
docker compose -f srsenb.yaml up -d && docker container attach srsenb"

Sometimes calls work without problems but often I have PCSCF sending "408 Request Timeout".
I understand (but I am not sure) that the SCSCF is forwarding the INVITE from the caller to the callee through the PCSCF.
I don't know what's happen in PCSF but it's like he cannot join the callee.
I made ping from inside the PCSF container on the callee ip address and it works.

In the log below there is 7 calls ok but the last one fails (INVITE in message 33315 and Timeout in 33453)

with_2_iode_7_calls_succeeds_last_one_rejected.pcap.zip

When this problem occurs, i cannot call anymore and I must disconnect/reconnect both phones with airplane mode.

Any idea of what happens ?

Thanks,
Julien

[herlesupreeth]

Interesting, are you sure you are using the latest commits in this repo?

Looks like P-CSCF is unable to forward the INVITE to the UE and get stuck. Seems to be a bug in kamailio.

When this problem occurs, i cannot call anymore and I must disconnect/reconnect both phones with airplane mode.

This is because when the call failed over IMS, UE attempts call over circuit switched network (which is not there). This also fails and then UE gets released from the network

[herlesupreeth]

Can you please send me the p-cscf logs with DEBUG enabled when the above call fails occurs?

[JulienSrcdImta]

No, I am pointing on:
commit b538301 (HEAD -> master, origin/master, origin/HEAD)
Author: herlesupreeth herlesupreeth@gmail.com
Date: Mon Feb 26 12:06:28 2024 +0100

More parameter section of open5gs config under global section

I will be out of the lab for one week, but when I'll be back, I'll update and send you the PCSCF log.

Thanks for your support and explanations.

[JulienSrcdImta]

Hi @herlesupreeth,

I updated the repo to the last commit but I have the same error.

I took the pcscf log but I am not sure about how to enable DEBUG level.
In kamailio_pcscf.cfg I commented line 38 and 39 to let only the debug=4 and log_stderror=yes :

#!ifdef WITH_DEBUG
debug=4
log_stderror=yes
#!else
#debug=2
#log_stderror=no
#!endif

Then I took the log with:
docker logs -f pcscf &> /tmp/with_asus_op8_call_rejected_2_pcsf_log_debug.txt

If it is not the good way please tell me how to do it.

with_asus_op8_call_rejected_2_pcsf_log_debug.txt
with_asus_op8_call_rejected_2.pcap.zip

[herlesupreeth]

@JulienSrcdImta sorry for the late response. In your latest pcap you attached I see all calls successfully completing and I dont see any issue. Did you face any issue?

[herlesupreeth]

Nevermind, I found the packet number where the issue. Will let you know if I find any issue. I found one unrelated bug will fix that too.

[herlesupreeth]

Here is how to enable logs in debug.

Change the following in pcscf.cfg

##!define WITH_DEBUB

to

#!define WITH_DEBUG

[JulienSrcdImta]

Thank you.
Yes I face an issue after several call success.
The first "strange" sip packet in the log is number 21846.

Otherwise I am surprised with your comment to activate debug in pcscf.
the sharp symbol "#" seems to be used for comments.
So I see no difference between:
##!define WITH_DEBUB
and
#!define WITH_DEBUG