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VOIP service drops out when support answers -solved

Posted: Mon Dec 01, 2014 7:28 pm
by ocular
Have Exetel ADSL2 and exetel voip, gigaset hardware, If I phone support 0280301002 and take part in the que with the music in the background and you are number x waiting to speak to representative....... and then when I get to number 1 and support answers the audio drops out and I am not sure if exetel can hear me or not. Presumably not as I have asked for a return call on my mobile and nothing happens. Have tried 1300 788 141 and 0280301000 with the same problem.
Dont have issues when call other numbers via voip

I have tried this about six times in the last 6 months and have never been able to hold a conversation via voip with a exetel representative. I can wait in the que with background music for 15 minutes and then the call drops when support answers.

Can anyone else hold a conversation with exetel via their voip service?

Re: VOIP service drops out when support answers

Posted: Tue Dec 02, 2014 12:43 am
by Sumudu D
Hi ocular,
ocular wrote:Have Exetel ADSL2 and exetel voip, gigaset hardware, If I phone support 0280301002 and take part in the que with the music in the background and you are number x waiting to speak to representative....... and then when I get to number 1 and support answers the audio drops out and I am not sure if exetel can hear me or not. Presumably not as I have asked for a return call on my mobile and nothing happens. Have tried 1300 788 141 and 0280301000 with the same problem.
Dont have issues when call other numbers via voip

I have tried this about six times in the last 6 months and have never been able to hold a conversation via voip with a exetel representative. I can wait in the que with background music for 15 minutes and then the call drops when support answers.

Can anyone else hold a conversation with exetel via their voip service?
We can see number of VoIP services that you have with exetel. Would you provide us the number that you have the problem with or you may raise this issue directly to us via residentialsupport@exetel.com.au from your nominated email address on the record quoting this forum link on the body of the email.

Cheers.. :)

Re: VOIP service drops out when support answers

Posted: Tue Dec 02, 2014 8:45 pm
by ocular
OK voip number on the exetel adsl service via the gigset C470IP ends in 5554. This is the system I have used in the past over the last 6 months and the audio drops out as the que gets to exetel support. Have just tried ringing support on my android softphone (acrobits) via Telstra 3G (speedtest ping 25ms D/L 4.5Mbps U/L 0.7 Mbps - better than my ADSL(optus wholesale)) at peak times) via another exetel voip number ending in 4834. After 5 minutes on hold got to at least position 1 then call continued without audio. Tried immediately again and on que for 17.5 minutes and then got to position 2 and audio dropped but connection was still active on software. Again I don't have any particular problem with this android softphone setup with other numbers when I have a good internet connection.

Are there any exetel customers out there who can hold a conversation with exetel voip to exetel support? I just need some faith to continue wasting a lot of time trying to find out at what level this problem is. Could it be part of the que system as it clicks over from a digital recording to live interaction?

Re: VOIP service drops out when support answers

Posted: Tue Dec 02, 2014 10:24 pm
by Dazzled
I have done so, through an ATA, though not recently.

Re: VOIP service drops out when support answers

Posted: Tue Dec 02, 2014 11:16 pm
by ShaminG
ocular wrote:OK voip number on the exetel adsl service via the gigset C470IP ends in 5554. This is the system I have used in the past over the last 6 months and the audio drops out as the que gets to exetel support. Have just tried ringing support on my android softphone (acrobits) via Telstra 3G (speedtest ping 25ms D/L 4.5Mbps U/L 0.7 Mbps - better than my ADSL(optus wholesale)) at peak times) via another exetel voip number ending in 4834. After 5 minutes on hold got to at least position 1 then call continued without audio. Tried immediately again and on que for 17.5 minutes and then got to position 2 and audio dropped but connection was still active on software. Again I don't have any particular problem with this android softphone setup with other numbers when I have a good internet connection.

Are there any exetel customers out there who can hold a conversation with exetel voip to exetel support? I just need some faith to continue wasting a lot of time trying to find out at what level this problem is. Could it be part of the que system as it clicks over from a digital recording to live interaction?
I tested the both numbers for any calls over to support queue and can't see any records since 19th November. Could you please post the number you dialed and the approximate time stamps so I can investigate this further with our VoIP team.

Edit : Don't worry about the time stamps, we will investigate the server logs via the VoIP numbers :)

Re: VOIP service drops out when support answers

Posted: Wed Dec 03, 2014 12:07 pm
by lodperera
Hi Ocular,

We receive the "contact header" as your private IP, although it should mention your public IP. Therefore the ACK packet we send you once you get connected to an agent gets lost as it is going to the private IP.

You should change the configuration of your device external IP to reflect your public IP to fix this issue. Contact manufacturer for further assistance.

Image

Regards
LOD

Re: VOIP service drops out when support answers

Posted: Wed Dec 03, 2014 11:58 pm
by ocular
Thanks for that,essentially a one way audio problem, presumably exetel could here me. why does the problem only exist when connected to exetel support when the tech comes on. The audio from the que system is obviously coming back but it all falls over when the tech comes on. I thought that Voip servers handled this problem by ignoring the IP address of the sip message and instead used the public IP of the incoming packet header.

The C470IP documentation says I can force the external IP to show in the sip message by using a stun server. Does exetel have a stun server they can recommend that I use?

Also could you check the logs for the 4834 voip number to 0280301000
12 dec 6.56pm Brisbane time for 5mins
12 dec 7.02pm for 19 mins and check if the same problem exists.

Will then see if I can adjust acrobits softphone ( was tested over 3G) on smartphone
Little strange that problem only seems to occur when I phone exetel to exetel.
Will also try fiddling with sip alg on router

Re: VOIP service drops out when support answers

Posted: Thu Dec 04, 2014 11:50 am
by ocular
PM sent with logfile from acrobits softphone from call to exetel support via Telstra 3G of call that drops out after tech answers, using voip number 4834 ( same behaviour as when i use the gigaset C470IP setup)


Tried third setup with another exetel voip number 1398 on grandstream ATA to exetel support number and all works fine, able to talk to support staff.

When used the softphone acrobits on smartphone via 3G voip 4834 to call exetel number on grandstream ata (ie exetel to exetel) there is no audio problems (unlike when call exetel support number). So there does seem to be a component of this problem that is specific to the exetel support number.

Re: VOIP service drops out when support answers

Posted: Thu Dec 04, 2014 4:22 pm
by lodperera
Hi Ocular,

Exetel support number ends up in Exetel office PBX, When an agent answers the call an ACK packet is sent to your contact header. In this case it is a private IP. This is why the call drops off as your device never receives it.

As per your PM it seems that the acrobits softphone sends us the same private IP in the contact header making the call drop off.

Regards
LOD

Re: VOIP service drops out when support answers

Posted: Thu Dec 04, 2014 5:31 pm
by ocular
Thanks for explaining that, how come this is only a problem when I phone exetel support and is not an issue when I phone pstn, mobile or other exetel voip numbers via acrobits softphone via exetel sip server?

Re: VOIP service drops out when support answers

Posted: Fri Dec 05, 2014 10:30 am
by lodperera
This is due to the VoIP architecture of Exetel and NAT handling methods used.

When you make a call to support your audio stream is kept alive and there is a call routing update when an agent answers. Our SIP server send the second ACK packet to your contact header as Exetel use the contact header to update an ongoing conversation as part of the NAT handling method.

Which is why Exetel requires the public address in the contact header to reflect the standard practice.

Re: VOIP service drops out when support answers

Posted: Sat Dec 06, 2014 12:23 am
by ocular
Which is why Exetel requires the public address in the contact header to reflect the standard practice.
Only seems to obey standard practice requiring public IP address when call 0280301000, I have several voip numbers and I can call between them without having to resort to the changes below

This is what I had to do to fix the audio drop out

5554 turned on sip alg on tplink td-w8960n, had previously turned this off to allow dialing between different C470IP base stations. Had to change outbound proxy from always to auto and then could use direct internal ip dialing between base stations.

4834 acrobits softphone on android using Telstra 3G network, contacted acrobits support and they directed me to
Link http://www.acrobits.cz/hesk/knowledgebase.php?article=4

Enabled Stun Server (stun.acrobits.cz) and changed Global IP from internal to external and now works when ring 0280301000. if the 3G provider has symmetrical nat then stun servers don't work. Acrobits has a great syslog in software for debugging.

Now can phone pstn , mobile , exetel voip and 0280301000 without problems from gigaset C470IP thru exetel adsl and also using acrobits softphone via android thru Telstra 3g network with exetel voip.

Re: VOIP service drops out when support answers

Posted: Sat Dec 06, 2014 9:39 am
by Dazzled
Thanks for posting the solution.