How to verify speed of a 1Gb/s network?

Rob spamrefuse at
Wed Apr 26 03:16:07 UTC 2006


How can I verify that a 1Gb/s network is indeed
operating at its optimal speed? I tried this:

[master]$ ping -s 65507 node
65515 bytes from node: icmp_seq=0 ttl=64 time=1.97 ms
65515 bytes from node: icmp_seq=1 ttl=64 time=1.95 ms
65515 bytes from node: icmp_seq=2 ttl=64 time=1.94 ms
65515 bytes from node: icmp_seq=3 ttl=64 time=1.97 ms

(I tried many times, over a long period of time
to get these typical values).
>From this I conclude that it takes about 1.95 ms
for 65515 x 8 bits to go forth and back between
master and node.

Ideally, on a 1Gbit/s network, the time should be:
  65515 x 8 x 2 / (10243) = 0.98 ms
(x 2 for the roundtrip signal forth and back
and 10243 is the 1G of the network)

May I now conclude that the real-time is about
two times the ideal-time? I wonder if this indicates
a problem of the network?
And is this a proper test of this Gbit/s network?


PS: I verified my calculation method for two
computers here on a 100Mbit/s network, from which
I get:
   time with ping: 12.4 ms
   ideal calculated time: 10 ms
which is an acceptable difference.

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