ndt-users list created

[Aaron Brown <>]

On Jan 14, 2010, at 7:27 AM, Ralf Hildebrandt wrote:

"The slowest link in the end-to-end path is a a 622 Mbps OC-12 subnet" -
but it's not! It cannot be, since the speed measured EXCEEDS the
theoretical limit of 622 Mbps!

TCP/Web100 Network Diagnostic Tool v3.5.12
click START to begin

** Starting test 1 of 1 **
Connecting to 'rispacs-perf.charite.de'
[rispacs-perf.charite.de/10.48.4.4] to run test
Connected to: rispacs-perf.charite.de  --  Using IPv4 address
Checking for Middleboxes . . . . . . . . . . . . . . . . . .  Done
checking for firewalls . . . . . . . . . . . . . . . . . . .  Done
running 10s outbound test (client-to-server [C2S]) . . . . . 914.9Mb/s
running 10s inbound test (server-to-client [S2C]) . . . . . . 802.35Mb/s
The slowest link in the end-to-end path is a a 622 Mbps OC-12 subnet
Information: Other network traffic is congesting the link

click START to re-test

The connection cannot be faster than its slowest link. But it is.
In my case it's Gigabit Hardware from desk to server (just 3 hops).

NDT attempts to guess the slowest link type by sending packets out, and seeing how the network affects them. Unfortunately, the network affects aren't a perfect tell for the type of link, and can sometimes misidentify the link like you're seeing.

Cheers,

Aaron

Winter 2010 ESCC/Internet2 Joint Techs

Hosted by the University of Utah - Salt Lake City, UT
January 31 - February 4, 2010

http://events.internet2.edu/2010/jt-slc/