Subject: Re: about topN within one day
From: Grzegorz Janoszka (grzesjan@onet.pl)
Date: Wed Sep 26 2001 - 09:28:22 CDT
On Wed, 26 Sep 2001, Eric Gauthier wrote: > Let me give you an example. Lets say that you move a constant 2.4Mbps > worth of traffic to AS xxx. Lets also say that, on average, you move > 1.5Mbps to AS yyy and 1.5 Mbps of traffic to AS zzz. Lets also say > that there are 9 other AS's who you move more than 2 Mbps to. > > Lets say that, in a particular 5 minute interval, the traffic to AS yyy > bursts up to 2.5 Mbps while AS zzz is at 1.0 Mbps and AS xxx stays at their > constant 2.4Mbps. Then, AS yyy becomes the 10th loudest speaker, > ends up at the bottom of the table, and AS xxx isn't listed. Now, > lets say in the 2nd 5 minute interval, AS yyy drops down to moving only > about 1.0 Mbps but AS zzz bursts up to 2.5 Mbps. Again, AS zzz becomes > the 10th loudest speaker, ends up at the bottom of the table, and AS xxx > isn't listed. If this alternated back and forth, then AS xxx would never > show up in the table but AS yyy and AS zzz would show up in alternating > tables. When you aggregate your information, then you'll have entries > for AS yyy and AS zzz but nothing for AS xxx - even though the average > throughput for AS xxx is 2.4 Mbps, for AS yyy is 1.75 Mbps, and for > AS zzz is 1.75 Mbps. > > Doing the aggregation like this is a nice way to get an idea of what's > going on, but it should be taken with a large grain of salt. I haven't checked it exactly (too much zzzzz ;-) ) but I agree. There is one solution: the bigger N in TopN - the better precision. -- Grzegorz Janoszka, Onet.pl S.A. -- Help mailto:majordomo@net.doit.wisc.edu and say "help" in message body Unsubscribe mailto:majordomo@net.doit.wisc.edu and say "unsubscribe flowscan" in message body Archive http://net.doit.wisc.edu/~plonka/list/flowscan/archive/
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