Problems with Windows Session Border Controller / 3CX Tunnel

[FredyWenger]

Hi
I just have installed two SBC's on two Windows 2016 servers (one is the default, the second is the "emergency", for the case, that the first server should be down).
After the setup, the SBC's were working principally, but had errors in the error log:

Example:
RR | 20181011-174327.392 | 3CXTunnel | TUNL | 6248 | Bridge.cpp:712 | Has no registered RTP session for local destination 172.16.1.5:64101

I then have searched the internet for the error and found various already closed ("not open for comments") 3cx threads, e.g.:
https://www.3cx.com/community/threads/3cx-sbc-errors-has-no-registered-rtp-session.46284/
https://www.3cx.com/community/threads/3cx-tunnel-session-border-controller.49855/
https://www.3cx.com/community/threads/sbc-error-log-and-dropped-calls.53229/

Therefore, I (had to) create this new thread…
I followed the hints in the threads and first set "SecurityMode=1" to 0.
The errors were still produced…
Then, I have changed the setting of TunnelAddr= and PbxSipIP= from the url (FQDN) to the IP and the errors were gone…
Notes:
- the url can be resolved, if I do a ping on the servers
- by setup of the SBC, the url has to be entered (IP is not accepted as input - has to be changed in the
config-file after the setup)

So I post this thread, to signal (to 3cx), that the problem still seems to be there actual, to help other users and to ask 3cx for details to the error-log entry.

Questions to 3cx:
What exactly (technical) happens, if the error "Has no registered RTP session for local destination" is written in the error log...?

• As I wrote, the SBC works principally also with the errors… I have read in some postings, that this could cause "jitters" during calls and a (voice) delay of a few seconds by start of a call.

What can cause the problem...?

• As I wrote, the url can be resolved, if I ping the url on the machines (so it should not be a base DNS problem) and the error messages goes away, as soon as the url's are changed to the IP (whereby the setup don't accept the IP and they have to be changed later in the config file).

Can you bring some light in the dark, please...? ​

Thanks

 

[cobaltit]

I don't generally go looking for ghosts as I have enough work to do already. I can say that we use a SBC in the office with FQDN and have no issues. I'll go check the logs to see if the 'errors' are there but I wouldn't worry about it unless you have an actual issue.

 

[cobaltit]

Ok so I checked our SBC here and I have logging turned off. I just set it to 'ERR' so we'll see what shows up. I have the following settings:

TunnelAddr is set to my 3CX FQDN
PbxSipIP is set to the public IP of 3CX (Cloud-based)
SecurityMode = 1

 

[cobaltit]

Wait I just re-read your post and you had PbxSipIP set to the FQDN? It should be set to the IP of the interface. It clearly says that in the notes in the config file as well as the guides for both Windows and Linux installs.