We have a carrier that we receive calls from over SIP. They are getting the call from the PSTN and then sending to us as sip. We then get other calls to our FS via sip from other carriers that are also from the PSTN. We bridge these calls in FS. All connections to FS are sip. So. Party1--PSTN--Carrier1--FS--Carrier2--PSTN-party2 Problem is that Party2 hears echo of themselves. We chased it down and Carrier1 says it is because Party1's carrier is setting a bit in the ss7 connection that they are doing echo cancel (when in fact, they are not). So Carrier1 does not do any EC on the call before passing it to us. Is there any way that I could do the EC on this call in FS?
From what I have read on the list, it looks like the Zaptel Hardware or OSLEC type of EC would not work here since there is no zaptel/t1 connection involved with FS.
On Jul 30, 2009, at 8:27 AM, DA wrote:
We have a carrier that we receive calls from over SIP. They are getting the call from the PSTN and then sending to us as sip. We then get other calls to our FS via sip from other carriers that are also from the PSTN. We bridge these calls in FS. All connections to FS are sip. So.
Party1--PSTN--Carrier1--FS--Carrier2--PSTN-party2
Problem is that Party2 hears echo of themselves. We chased it down and Carrier1 says it is because Party1's carrier is setting a bit in the ss7 connection that they are doing echo cancel (when in fact, they are not). So Carrier1 does not do any EC on the call before passing it to us.
I would take it up with the carrier since that is the point where the echo is introduced.
Is there any way that I could do the EC on this call in FS?
Nope.
From what I have read on the list, it looks like the Zaptel Hardware or OSLEC type of EC would not work here since there is no zaptel/t1 connection involved with FS.
Only on TDM, You do not need EC on VOIP to VOIP calls.
We may have seen this also once before. But in this case, it is 'needed' (or would be helpful) because the telco is not doing the EC correctly. I can see how the originating telco should be the one to fix the problem. But it always seems that is easier said than done. Is there no way at all to cancel echo when FS is only in the voip media stream like this? -----Original Message----- From: freeswitch-users-bounces@lists.freeswitch.org [mailto:freeswitch-users-bounces@lists.freeswitch.org] On Behalf Of Brian West
From what I have read on the list, it looks like the Zaptel Hardware or OSLEC type of EC would not work here since there is no zaptel/t1 connection involved with FS.
Only on TDM, You do not need EC on VOIP to VOIP calls.
Its not technically feasible to do so its also resource intensive for something that you shouldn't have to be dealing with in the first place. Take a cluebat and beat your telco if they don't fix it. /b On Jul 30, 2009, at 9:26 AM, Frank @ Impact wrote:
We may have seen this also once before.
But in this case, it is 'needed' (or would be helpful) because the telco is not doing the EC correctly.
I can see how the originating telco should be the one to fix the problem. But it always seems that is easier said than done.
Is there no way at all to cancel echo when FS is only in the voip media stream like this?
While it might not be feasible it may be possible (and I don't see why not). There are many, many commercial devices that claim to do this. Then again there are just as many devices that claim to do everything and anything... I agree with Brian. It shouldn't be something you have to deal with. On Thu, Jul 30, 2009 at 10:31 AM, Brian West<brian@freeswitch.org> wrote:
Its not technically feasible to do so its also resource intensive for something that you shouldn't have to be dealing with in the first place. Take a cluebat and beat your telco if they don't fix it.
/b
-- Kristian Kielhofner http://www.astlinux.org http://blog.krisk.org http://www.star2star.com http://www.submityoursip.com http://www.voalte.com
Kristian Kielhofner wrote:
While it might not be feasible it may be possible (and I don't see why not).
There are many, many commercial devices that claim to do this. Then again there are just as many devices that claim to do everything and anything...
People tell me commercial offerings claim to do this, but nobody ever points me at an example. There are two key issues that stop EC over VoIP working. 1. There is no way you will ever get EC to work over a low bit rate codec. Even if you use nothing but G.711 on your local hop, you have no idea what transcoding may occur downstream. So, in the general case it won't work however you configure your setup. 2. EC is an adaptive process, requiring is a stable loop length. As soon as a jitter buffer somewhere makes an adjustment the EC's tunning will blow up. If you are lucky it might eventually retune, but in the meantime the pain in your ear could be quite severe. :-) Steve
participants (5)
-
Brian West
-
DA
-
Frank ＠ Impact
-
Kristian Kielhofner
-
Steve Underwood