No Audio Between Remote Extensions

[joebocop]

Hi again everyone,

We are running 3CX PhoneSystem 12.5. Repeated runs of the "firewall checker" have revealed that all ports are forwarded "properly", according to the PBX. Presence is functioning on remote extension using 3CXPhone.

Remote extensions, including desk phones located in remote offices, as well as iOS 3CXPhone and Android 3CXPhone clients are able to:

• - place calls out over PSTN and VoIP trunks, including to remote extension destinations
  - receive calls placed into the PBX from PSTN and VoIP trunks, including to remote extension destinations
  - place calls to non-remote extensions
  - receive calls from non-remote extensions

They are not able to:

• - place calls directly amongst themselves by dialing only the extension

The behaviour I see is that the call is placed, and connects without any problem, but there is no audio in either direction. What next steps should I be taking to troubleshoot this problem?

Thanks again for the expertise.

 

[jasit]

two things to check,

1) check if your router has SIP ALG installed and disable it.
2) The other thing to try is having your PBX control Audio for extensions at the remote site.

 

[jasit]

two things to check,

1) check if your router has SIP ALG installed and disable it.
2) The other thing to try is having your PBX control Audio for extensions at the remote site.

 

[leejor]

You may wish to consider using the 3CX SBC. One way audio issues seem to be quite common when a number of remote extensions are run behind the same router with no SBC used. It can also depend on your router.

In the mean time (as suggested) try checking the option in 3CX (per extension), PBX delivers audio.

 

[joebocop]

HI, and thanks for the help!

SIP ALG is disabled on the main office firewall (PFSense), as well as the remote office firewall (Juniper SRX210).

I will try the "PBX delivers audio" option for two extensions. Does this also affect audio being sent/received from that extension's desk phone? What is mean't by the info text "Improved compatibility but reduces performance" associated with "PBX delivers audio"?

Thanks again.

 

[leejor]

the PBX delivers audio option is usually used to fix problems such as yours. Ideally audio packets would low direct from one set to another as this puts less load on the 3Cx server not to mention using bandwidth, a particular issue with remote extensions as every call will now go to and from the PBX. So, a solution, but not the best, in all cases.

If you cannot find another solution to the one way audio issue, you might want to seriously consider the Raspberry Pi SBC as cost is minimal.

http://www.3cx.com/blog/docs/3cx-session-border-controller/

 

[joebocop]

Thanks again leejor, you are always an enormous help on this forum.

My conundrum is that the SBC isn't useful for "mobile" devices, such as those connecting over 3G/LTE. If I had an office location with a bunch of "remote extensions", I would definitely go the RPi route, but my real issue here is that two iPad users, each with an LTE connection, are not able to call one another using their 3CXPhone iOS applications. Rather, they are ABLE to call one another, but there is no sound.

Interesting, today I was able to get a fully functional call placed between an Android 3CXPhone client connected over LTE in another town (on a different cell network), to an iOS 3CXPhone client connected over 3G in our main town location. Wondering if the problem lies in calls placed over the same carrier network. Ugh.

I also tried the "tunnel" but was only able to get one-way audio, and then DTM didn't work when hitting IVRs over the PSTN gateway.

Lots of moving parts here. I haven't tried "PBX Delivers Audio" yet, but I will. Thank you for explaining the implications, as I really had no clue what the performance hit implied.

 

[leejor]

Sorry, I was under impression, that in your case, the majority of users having this issue were located behind a single (remote) router.

I did encounter a one way audio problem with an IPhone user just the other day, and at this point I'm not sure that it was resolved as they were headed out of town. When the 3CX phone first started they said that saw something flash on the screen about the App wanting to use the mic, but they weren't sure what they selected. I was wondering if the problem had anything to do with that as I'm not an iPhone user myself. They could hear audio but it was as if the mic was muted.

 

[JoelBlaha]

Quick thanks for the PBX Delivers Audio idea. Had an office using session border control and things like provisioning and presence worked, but got no audio either way. Checked the PBX Delivers Audio box and everything was straightened out.

 

[YiannisH_3CX]

Hello there,
Pbx delivers audio is required for remote extensions using STUN and are behind the same router/public IP in order to communicate with each other. You can find more details regarding this is in our academy.
http://www.3cx.com/3cxacademy/videos/intermediate/configuring-remote-extensions/

 

[[email protected]]

I have pbx delivers audio on all my extensions, sbc ones, local to the pbx ones and remote stun ones.

Is there a disadvantage to pbx delivers audio? 45 extensions in all 30 local, 14 sbc , 1 remote stun.

 

[YiannisH_3CX]

Pbx delivers audio stresses the PBX machine and increases the minimum hardware requirements depending on how many extensions and simultaneous calls you have. If your machine can take the extra stress then no issue.

 

[leejor]

It also increases data usage as all call audio must pass through the PBX, and not set to set, at the remote location. This might be a major concern depending on your network capacity and current traffic.

 

[[email protected]]

I will start new thread on this, as I have more questions.