On Apr 25, 2006, at 9:16 PM, Rob wrote:
Hi,
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?
Thanks,
Rob.
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
I would suspect that a ping is not a valid test as it does not test
throughput and the send and reception phases have a large influence
on the out come. Ie, the time for the send and reception to take
place is long enough compared to the fast network that the results
are skewed. Try an ftp or other non-encrypted data transfer with a
large enough file that the startup and wind-down won't affect and
skew it. Probably still not a definitive test
btw, here is a test of my gbit network using your ping test
15 packets transmitted, 15 packets received, 0% packet loss
round-trip min/avg/max/stddev = 0.128/0.227/0.342/0.061 ms
---
Chad Leigh -- Shire.Net LLC
Your Web App and Email hosting provider
chad at shire.net
_______________________________________________
freebsd-questions@freebsd.org mailing list
http://lists.freebsd.org/mailman/listinfo/freebsd-questions
To unsubscribe, send any mail to "[EMAIL PROTECTED]"
