Re: large RTT variation caused by bandwidth oscillation

From: Andrei Gurtov (gurtov@cs.helsinki.fi)
Date: Sun Jan 13 2002 - 11:12:22 EST


> Some questions about GPRS. What is the approximate bandwidth
> delay product in such network? What kind of network apps are
> supposed to run on it? It seems that interactive apps are out
> of questions. How often will those delay spikes happen? Thanks.

Bandwidth is 10-50 kbps, RTT about 800 ms. People use it for normal Internet
access. Frequency of delay spikes depends on many things. E.g. voice calls
to your mobile terminal suspend the data connection. Driving in Helsinki
seems to generate handovers (delay spikes) roughly every minute.

For more details please check
http://www.cs.helsinki.fi/u/gurtov/papers/icc01.html
http://www.cs.helsinki.fi/u/gurtov/papers/pwc01.html

Andrei



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