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Vonage Ah ... you wish to enter the murky world of international call terminations do
Ah ... you wish to enter the murky world of international call terminations do you :twisted: ?
Vonage sends your outbound calls to typically a Global Crossing gateway located in the U.S. The location of the gateway varies (I can't figure out exactly why for the moment).
Now Global Crossing (GC) has your phone call on their network and Vonage is basically done with the call. International calls operate like a "spot market" with rates changing daily if not hourly. Based upon your call destination, GC selects the cheapest partner of the day and sends your call along the way. The call may or may not continue in an IP format at that stage.
GC does monitor it's partners for quality circuits (basically looking for calls of short duration which they equate to people hanging up due to poor quality). So why is an AT&T Int'l call better. Simple - because AT&T has a reputation to maintain AND more important does not want you calling to complain (as it cost a bunch of money for them to speak with you). Thus - AT&T closely monitors their termination partners and acts quickly to remove anyone who starts to cause trouble.
There are literally hundreds of termination companies in the world and managing these relationships is often complex and larger carriers have entire departments who do nothing more than work on these agreements. The objective being giving me the best service at the lowest price.
Now on to voice quality issues related to Voip
Many of posters have indicated they have just fine upload and download speeds as reported by a variety of speed testers. However, that's really not the problem.
The issue is two fold, latency and the CODEC.
As you speak the DSP takes your voice and chops it up into samples. Using the algo of the CODEC, the DSP (in your MOT or Cisco box) then basically does the equal to Winzip and encodes the voice sample and puts it into an IP packet. It then drops the IP packet over to the Ethernet Forwarding chip (also in your MOT/Cisco box).
The forwarder now try to send the upstream. Voip uses UDP meaning basically the forwarder dumps the voice packets into the Internet and simply hopes they reach the far end AND in the correct order
The FAR END (the gateway receiving the packets) knows that packets may actually be received out of order. Thus it has something called a 'jitter buffer'. Basically it introduce a slight delay in order to ensure it has all the packets. But what if a packet is delayed. As voice is 'real time' it can only wait so long thus after a pre-determined period of time, the FAR END has no choice but to un-ZIP the packets and turn it back into voice.
Missing packets mean missing voice samples and they result in the clipping, static or general poor voice quality you hear.
There are standards for CODEC development. But there is still an element of art in how a CODEC 'zips and 'unzips the packets. It's much improved from early Voip days but still could be improved further. As it's built into your box and the remote gateway, there is basically little you can do to improve. Time will help.
Read The Full Thread: Vonage Sound Quality
• I have now been using Vonage for 4 months now - but I have never achieved satisfactory
• Vonage terminates both international and national long distance in the same
• Thanks for the prompt and excellent response, ckoehncke.
I also have a regular
• And I forgot to ask. If the CODEC in Cisco and Motorola boxes is crap, what do you
• I think maybe 150 up is a bit low. If you use the max setting for bandwidth it uses
• My OptimumOnline connection gives me more than 900kb/sec up, so I've never had
• Try the speed test and see what results you get:
https://secure.vonage.com/vonage-subscribe/subs
• Thanks again folks for your help. I ran the speedtest provided on the Vonage site,
• Like wine, critics all over the map on what CODEC sounds best. Vonage currently
ckoehncke posted "Ah ... you wish to enter the murky world of international call terminations do" on 03/06/2004 |
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