SUMMARY: [asterisk-biz] Does VoIP Really Work for Serious Business?

[Herman Webley]

On Fri, 2006-03-10 at 08:30 -0500, Matthew Crocker wrote:
> On Mar 10, 2006, at 8:24 AM, Hugh L. Johnson wrote:
> 
> > It's all about latency.  The roundtrip ping times across my DSL  
> > circuit
> > (Verizon ATM cloud) to my ISP's router (One hop away) are approx 25ms.
> > My ISP has a PRI which I use for all incoming and local outgoing  
> > calls.
> > For these calls the quality is better than when I had an analog  
> > phone at
> > home.
> 
> No, it is all about jitter.  Latency is irrelevant unless it is above  
> 150-200ms.  Rapidly changing latency (aka Jitter) is what kills VoIP  
> quality because the echo cancelers  can't train up properly.

How does jitter hinder the echo canceler training?

As an aside more jitter means more jitter buffer to avoid voice drop
outs. Of course a jitter buffer introduces additional latency equal to
the buffer. And of course additional latency equals worse echo :)

Loads of fun this VoPI is ...

-Herman