Thus spake "Jere Retzer" <retzerj@ohsu.edu>
Stephen Sprunk wrote:
Any point in the US is within 25ms RTT (or less) of a major exchange; eliminating this 25ms of latency will have no effect on VoIP unless you're already near the 250ms RTT limit for other reasons.<<<
Can you please upgrade to a MUA with standard quoting semantics?
25 MS is assuming that the only delay is due to the speed of light.
No. I'm asserting that every populated area in the U.S. is within 25ms ping time of a major exchange, absent congested pipes.
Add equipment, especially routers or other gear that requires manipulating packets and the delays add up quickly.
If your router(s), switch(es), or firewall(s) need more than 1ms to forward a packet, it's time to select a new vendor. It's 20 hops between my home and work box, including 2900mi of fiber, a couple firewalls, and a DSL link -- and that's only 80-90ms. We clearly don't need an exchange for every 100km2 to get acceptable RTT. What we need are uncongested pipes.
I once read that the most people wil tolerate on a regular basis is around 150-180 ms. I think that is much too high for regular use
ITU G.113 says users won't even notice the latency until it his 250ms. Do you have scientific studies that show 150-180ms is problematic? I'm sure the ITU (and a few hundred telcos) will be interested. Business experience shows users will tolerate over 1000ms latency if there's an economic incentive. There are many companies doing voice-over-internet that operate networks this way, and they're making a lot of money doing it. S