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Unread 05-21-2009, 02:18 PM   #10
carlosalbffgomes
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Default Give it a try

Oi André

As far as RTP proxy is concern, the about 200 ms overhead introduced by using it doesn't deteriorate considerably the audio quality. I have already used both configurations with EU and US servers and it's almost unnoticeable. For example, the RTP delay introduced by some VSP (for example, BlasterPhone and VoipBuster) are bigger than what we are talking about. And, I must say from what I've tested so far, Vono wouldn't work with 'Audio Optimization Path' setted to 'yes' (when I tried it and someone called me from Brazil, I loosed the audio about 10 minutes after the call initialization) and maybe 'Sym NAT' may work in your case. Understanding the SIP dialogues that take place in call's initialization, it may make all the difference because it means that, if you have 'Sym NAT' set to 'no', the SIP registration and the station answering the call wouldn't be on the same IP address. That is sufficient, some times, to make trouble with some routers through which the connection would pass through. So, at least to check if that works for you, I would give it a try.
Also I would like to use 'Optimization Audio Path' to 'yes', at least for some calls destinations. But this configuration was the best balanced I could get between reliability and call quality. There's no such thing as free lunch, so you must balance between variables to get the most you can.
Another option is to use another free service: mysipswitch (at My SIP Switch Use multiple VoIP providers with one SIP phone). This service only deals with SIP traffic, is free and works with Vono (I've already tried it). But it has no automatic backup as Voxalot have through SRV DNS.
Regards,
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