Q: Voice mail: the first 5 to 10 seconds got cut off

[3397premier]

We have users reported about their voice mail got cut off the first 5 to 10 seconds when they tried to listen to the voice mail. The phone we have is Polycom IP450 with firmware 3.3.1. Any one has this problem before? We have 3CX regular support, but all they can tell us is "Create a ticket" and never respond back . I am really appreciate your help, thanks

 

[leejor]

Perhaps you can clarify a bit..

Are the first few seconds perhaps not being recorded? Is this just on the first recording, or every recording, when there is more than one to listen to? Does it happen again if you repeat the message? What about using a different type of set to playback (3CX softphone?). Is this on every message, all users, or just occasionally? Any pattern, same caller, same incoming trunk group, etc.?

Has this been happening since 3CX was installed or did it begin recently?

 

[3397premier]

To answer your question, it happens every day on multiple messages. It seems to be with more of specific users, but we have roughly 150 of them and some may not be reporting the problem. We installed the phone system about two weeks ago and have had issues since then. We are fine with all other calls, just issues with voicemail. If we listen to it again its still cut out in the same spot. We haven't test with a softphone yet. We have around 105 SIP trunk, how do we check a particular one? We are still noobs to this phone system. If someone has multiple messages it can happen on all of them or just a few. It seems very random. We had like 3 people tell us about it and then today we heard from two others, so really not sure if specific to users. Let me know if you have further questions.

Thank you,

 

[3397premier]

We just found out all voice mail problem from the government's incoming all, still we are trying to figure out the solution. If any of you have the same problem, please share your knowledge, thanks.

 

[leejor]

Make use of Wireshark, perhaps during a slow period, and see if there are any SIP messages (one way or the other) being sent at the time the audio "begins". If there is, it may be a clue as to what is happening.

 

[3397premier]

Make use of Wireshark, perhaps during a slow period, and see if there are any SIP messages (one way or the other) being sent at the time the audio "begins". If there is, it may be a clue as to what is happening.

Thanks for your quick reply Leejor, ususally when I run wireshark with filter below:

Capture packet in pcap-ng format
Buffer size : 10 MB (default 1MB)
Capture filter: port 5060
Use multi files, split each file in 1 MB
Capture for 1 days

For this voice mail problem, should I run without those filter to let it capture all the information or I can use those filter, thanks for your help. We only have voice mail cut off the first 10 second only from SSA department, and they have different numbers from different location.

 

[leejor]

I'm really not sure. You are best (if you can) to do this during off-hours so you don't have to wade through a lot of other call traffic. You are looking for any messaging sent (either way) that coincides with the start of the voice being recorded. So..from when the call first rings in to where they hang up would obviously, cover it.

Compare that capture to one from a number that has no audio cut-off. Is there a SIP "event" that points to why there is a delay?

 

[3397premier]

We did a PCAP on the call where the voicemail is cutoff for the first few seconds. We are finding that the audio is completely missing. We ran the PCAP on our network NIC. If it is missing there, does that mean it has to do with our ISP or SIP provider?

We setup another 3CX server on a Win 7 64bit machine, connected directly to the modem bypassing the firewall and switches. Still had the same issue. We tried a Polycom 450 with two different firmware versions and a Polycom 650 and softphone with same result.

 

[leejor]

Did you discover any SIP message (answer message?), sent to the far end,just before the audio begins, that might be "enabling" it?

Since the problem seems to be with callers from one particular PBX (unless you have discovered other callers experiencing the same problem), it seem would seem that the issue is something to do with their board.

 

[3397premier]

Sorry to ask probably a stupid question, but what do you mean by sent to the far end? I am not sure what type of phone system they use, but do you think it has something to do with their phone system and how it delivers the audio?

We found on the PCAP it shows -

Out of Seq: 2(0.1%) Wrong Timestamp: 2(0.1%)

All other voicemails we have looked at show -

Out of Seq: 0(0.0%) Wrong Timestamp: 0(0.0%)

Not sure what all that means and if that is telling us what may be wrong. Please let me know what you think.

Thanks for the help.

 

[leejor]

Sorry to ask probably a stupid question, but what do you mean by sent to the far end? I am not sure what type of phone system they use, but do you think it has something to do with their phone system and how it delivers the audio?

My thought is that if it is a VoIP PBX, and the connection between your PBX and theirs passes over only VoIP providers, there is a possibility, that, at some point, just before their audio begins, there is a SIP message, sent to them. If their trunking is strictly analogue or an ISDN PRI, then an answer message (supervision) should be the only thing they would receive after your end did in fact answer, which should be as soon be earlier in the time line of the call, not a few seconds into the recording of the voicemail.

I don't know why this would be happening, it shouldn't, but It just sounds like there is some sort of "trigger" that informs their particular PBX that is is now that time to complete the voice path. It may just be a timeout delay, of some sort because their PBX had not yet received something that it should have, by that point. I wonder if any other people that they are calling are having the same issue?

It does not make any sense as to why this is happening with just one set of callers (one PBX), and I'm sort of grasping at straws. About the only thing you can do from your end is to see if it is something that is being sent just before audio begins. If you don't find anything, then you may have to accept that it is a problem at their end, and live with it.

 

[microage]

We're experiencing this as well from a select group of customers. Did you ever find a solution for this?

 

[Allen_Miller]

Reading through this I was hoping there was a solution posted. I have a client that has similar - voicemails from one company are missing the first few seconds of audio.

Allen