Latency is most often a function of available bandwidth.
In a wide open pipe, the latency is a function of serialization (converting data into bits) and processing to put it "on the wire," then distance ... with TCP-type connections showing more latency (because transmissions must be acknowledged (ACK'd)) than UDP-type connections.
Congestion causes the data to be buffered beyond normal processing times.
There is NO QOS through the Internet. Any QOS offered by a SOHO system is for internal traffic, and (at best) "who gets out first" at the WAN port. Once it hits the ISP, all bets are off.
Eschew Obfuscation! Espouse Elucidation!
Optimists are never pleasantly surprised.
Nov 4th, 2008: History is made: - Richie Daley becomes the first Mayor in history with his own pet President.