[asterisk-users] Global VoIP Calls?

[Gordon Henderson]

On Sat, 23 Aug 2008, Gavin Henry wrote:

> Dear All,
>
> What setup would you recommend for making VoIP calls whilst bringing
> latency down between offices at:
>
> * Edinburgh
> * Kuala Lumpur
> * Singapore
> * Tokyo
> * Seoul
> * Beijing
> * San Francisco
>
> Some of the Asia offices are > 300ms some > 200ms.
>
> Any advice greatly apreciated.

Probably not the right answer, but ... Find a local ITSP in each country 
and place all your outgoing calls via them and let them deal with it via 
the PSTN.

Mayby not in the true spirit of VoIP, and not free either, but if it works 
and you get some good rates, then it might well be worth it.

Or provide both solutions - let the offices call each other via VoIP, but 
if too laggy, fall-back to VoIP -> PSTN... (-> VoIP)

You'll be at the mercy of your local Internet providers and usually, 
there's not a lot you can do to influence traffic routing - other than 
pick another ISP - maybe you can find out which ISPs use cable/fibre and 
which use satellite connections and favour the wired ones...

But if you want to keep it VoIP, then what I'd do is get access to a PC in 
each location and start running traceroutes (use 'mtr' if you can) and 
work out the best paths - you might find that there are better ways then 
simply providing 6 IAX trunks at each location - eg. you might find it 
better to route calls from SF to Seoul via the Tokyo office (ie. use 
canreinvite=no to force the data path if using SIP or notransfer=yes in 
IAX with appropriate dial-rules) if SF to Tokyo to Seoul goes via cable, 
but SF to Seoul goes via satellite...

So logon to those 7 asterisk boxes and run 6 mtr's from each to each other 
site - leave them going for an hour, then analyse the results. (Good 
luck!)

However, you'll still be at the mercy of the ISPs who might change their 
routing on a day to day basis, depending on what their influences are...

But at the end of the day ye canny change the laws o' physics!

Gordon
(Scottish, so fully licensed to utter that phrase ;-)