why upload with adsl is faster than 100M ethernet ?

Mike McSpedon mmcspedon at arrow.com
Fri Oct 15 12:50:09 UTC 2004

I've used QCheck (freeware) for testing response time, TCP and UDP
performance, and packet loss. Works well. You need to install the enpoint on
the target machine. Check out:


-Mike McSpedon
Arrow Global Data Communications

-----Original Message-----
From: owner-nanog at merit.edu [mailto:owner-nanog at merit.edu]On Behalf Of
Alex Bligh
Sent: Friday, October 15, 2004 8:25 AM
To: Iljitsch van Beijnum; Joe Shen
Cc: NANGO; Alex Bligh
Subject: Re: why upload with adsl is faster than 100M ethernet ?

I can't remember what the tool is now, but there used to be a tool which
worked like ping but sent a udp stream at a given rate per second and told
you about packet drops, and also allowed for some parameter to be tweaked
to give stochastic variation in interpacket delay (i.e. massive jitter).
You could use this to show inadequate buffering on gigabit interfaces where
a 2Mb/s stream would get through, but if you wound up the jitter
sufficiently, a whole burst of packets would arrive together and a gigabit
interface with (deliberately) misconfigured buffers would then drop packets.


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