Optimize Audio Path not fully working with Betamax (webcalldirect)
 

Hi All,

I have been making calls from my Sipura SPA-841 using webcalldirect as my VSP in my Voxalot account. I followed the instructions HowTo: 6 Steps To Optimize Your Audio with the hope to reduce latency, except that I did not do step 4, codecs.

I am in the USA, as are most of my call destinations. As one might expect, latency has been a bit of an issue for me because the webcalldirect servers are in Europe. In an attempt to solve the latency issue I hooked up Ethereal (packet sniffer) and made a test call to a USA number. The call connected using the G711u codec in both directions and RTP packets (audio path) were being sent to and received from one IP address, 64.34.173.199 (premium.voxalot.com).

After about 6.5 seconds the audio was renegotiated, or partly renegotiated. Only the packets outbound from my VoIP phone were sent directly to 194.120.0.189 (a webcalldirect server in The Netherlands). The inbound audio was still coming to me from 64.34.173.199 (premium.voxalot.com). The result was kind of a 3 legged conversation loop which still had enough latency to make for somewhat difficult conversation.

OK, so now that you know the story, is there any way I can get the calls to fully renegotiate so that audio packets will come to me directly from webcalldirect and not via Voxalot?