[c-nsp] Network performance question - TCP Window issue?

[Klaus Kastens]

On Sun, 29 Apr 2012 18:04 +1030, CiscoNSP_list CiscoNSP_list wrote:
> 
> Performing wget or iperf I see the following (Have linux servers at each POP)
> 
> Pulling file from B->A  (A's linux server is on 10/100 port) I get 9.59M/s (So basically 100Mbit)
> Pulling file from C->B I get 8.30M/s, but it does fluctuate up+down considerably
> Pulling file from C->A I get a flatline at 2.16M/s (Multiple sessions and all attain this speed, but no faster and doesnt fluctuate)
> 
> 
> Im not seeing any excessive errors/drops nor any duplex issues on any of the switches

Did you run your iperf tests also with UDP? (The numbers don't look
like it.)

With TCP you won't see many drops on your switches, it will adjust - and
you will see less throughput.

With iperf available at all three sites I would run tests with UDP streams.
This won't find the maximum bandwith automatically, you have to set a
bandwidth for testing and see if you have any packet loss.

Keep in mind that your carrier might police on ethernet bandwidth,
iperf measures IP throuput.


 Best regards,
 Klaus Kastens

-- 
Klaus Kastens                                               NetUSE AG
Dr.-Hell-Str. 6, D-24107 Kiel,                                Germany
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