Intermittent one-way audio.

[eihli]

What would cause occasional one-way audio? The problem is happening at a remote office. We have the IP/ports mapped directly to the phone (rather than using the proxy manager)

We will go a week or so where everything works fine, then one day about half of the calls will have one-way audio. The caller can hear us but we can't hear the caller.

FWIW, our connection is 1.5 down and .5 up DSL and we are far from their office so we have a lot of connection problems. But connection issues would just cause static/latency, right?

 

[davidbenwell]

This could be a bandwidth issue.

Example, of this would be Site A and Site B

Site A has 4Mb up and down

Site B as 8Mb down and 256k Up

not having enough upstream bandwidth would mean that Site A would not be able to hear you or at least not clearly.

there is a number of reasons why you would get 1 way audio, but without further informaton and investigation its hard.

What you are best doing, at a period where you get 1 way audio, is to test both connections to ensure they are both working 100% (no packet loss, low jitter etc)

 

[eihli]

I have tested the speeds while this is happening and both sites are getting what they usually do and there is no abnormal packet loss.

The firewall checker passed with no errors or warnings.

One bit of information that may help is that they are recording all calls. If I play back a recording that experienced one-way audio, I hear audio from both people. So the audio is reaching the PBX and is being recorded.

 

[davidbenwell]

can you confrim the make, model of the phones that you are using which have the problem?

and did you set theses up manually or via 3CX?

 

[eihli]

I set them up manually using this: http://www.3cx.com/blog/voip-howto/remote-extensions/

They are Linksys SPA942.

And here is an interesting update:

Today at lunch I set the phone up to use the proxy tunnel. I tested it and it worked. It worked for about 4 hours and then they had the one-way audio problem again.

So, here is a brief re-cap:

* Intermittent one-way audio for external extensions. Things will work fine for a few hours, then several calls will have one-way audio. The caller can hear the office, but the office can't hear the caller.
* Happens on multiple phones (both SPA 942).
* Happens both using the 3CX Tunnel and using static port forwarding.
* The PBX records audio both ways, even when the external extension can't hear the caller.

 

[eihli]

Just bumping this to the top in case anyone has any ideas.

The problem is still happening a couple of times each day.

 

[SY]

* Happens both using the 3CX Tunnel and using static port forwarding.
* The PBX records audio both ways, even when the external extension can't hear the caller.

It means that UDP streams from PBX dont not reach remote office.
What kind of IP address is assigned to remote office? Is it static or dynamic?

Thanks

 

[eihli]

Static.

 

[macgyverated]

Hello all,

I was wondering if anyone knew if the original poster ever solved his issue, because I am now experiencing the same thing.

I have 3cx v9 sp5 on a W7 64 bit box with high end hardware. It is connected to a T1 that is dedicated to the PBX. I have had roughly 20 extensions running well within our main office (where the 3CX PBX is located) for about a year and a half, all extensions using SPA509g phones. Recently, we opened a branch office about 4 miles away. It has a CBeyond T1 for voice and data. There are 5 PCs and Phones there.

The PCs work fine in terms of internet and network communication. The SPA509g phones (with the latest firmware and using the proxy tunnel) will connect and register with the 3CX box at our main office just fine. However, about every other call has one way audio, usually the remote office can hear the caller, but the caller cannot hear the remote office. Sometimes all calls over a 10 minute period will be fine, and then the one-way audio starts up again.

A couple noteworthy points:

1) If a call is answered and the calling party cannot hear our employee, if the employee puts the call on hold (not park or shared park) for just a second and then takes it off of hold, two way audio is restored.
2) The remote office had voice/internet services already established by the previous tenant through CBeyond. I have had CBeyond place a forward from the number that rang in to the building for the old tenant, to a DID that I already have set up at our main office. 3CX is instructed to take any calls coming in to that DID and ring them through to the 5 phones at the remote office.
3) I have "PBX Delivers audio" checked for the remote extensions.
4) I have tried port forwarding the proxy tunnel port in the router to the PC running the tunnel. No change in behavior.
5) Both alone and in combination with the above, I have set ports forwards to each phone's IP in the router on e a one-to-one basis. The phones all have static IPs, and I have a different SIP port set for each one (5060-5064). I have also tried forwarding these ports to the PC running the tunnel.
6) Turning STUN on while using the tunnel results in no audio at all.
7) I have had Symmetric RTP set to yes and no. Doesn't seem to make a difference.

I have cleared out the phones multiple times and used auto and manual provisioning based on instructions on the 3CX site. I am at my wits end. I'm wondering if a full upgrade top V10 SP5 might help solve my issues.

Any and all help would be greatly appreciated.

This shouldn't be this hard. The tunnel was devised to greatly simplify setup of remote extensions, and the instructions are relatively simple and straight forward. I have only deviated form the intsructions when the phones didn't work properly. Also, there is a lot of conflicting information as to whether STUN should be used in conjunction with the tunnel.

 

[cfive]

It may not be the same issue - but with v10 (any SP) i had intermittent 1-way audio issues using the tunnel and sip proxy manager. The issue may have existed before v10, I don't know. But via wireshark capture the issue was confirmed with the help of 3cx support.

You might contact 3cx support to see if a patched tunnel.exe and sip proxy manager may make a difference.

Also, are you port forwarding the tunnel port both UDP and TCP? Depending on the router involved, some will allow both TCP and UDP in one port forward, others it must be done seperately. With fortigate for example, you must first combine the seperate UDP 5090 and TCP 5090 into one set, and then forward that set. It seems to me that the 3cx instructions aren't clear on this, and I recall that both UDP and TCP are required.