Testing LFNs

David Andersen dga at cs.cmu.edu
Wed May 6 10:17:09 CDT 2009


set your system send and receive TCP buffers larger.  You're probably  
being limited by that.  With linux, make sure you have window auto- 
scaling enabled and have increased the maximum size it can grow to to  
at least 4MB.

Or test with UDP and blast as fast as you can so that you're not  
seeing TCP weirdness.

IOS includes a 'ttcp' command you can use on the router itself:

http://www.cisco.com/en/US/tech/tk801/tk36/technologies_tech_note09186a0080094694.shtml

   -Dave

On May 6, 2009, at 11:10 AM, Kaegler, Mike wrote:

> I have a new T3 thats 65msec long. I'd usually be using iperf to  
> test new
> links, but at 65msec, even at the maximum window size, I can only get
> 6-8mbit through. No combination of options I've been able to find  
> has gotten
> me more than 6mbit through this link. Should I just shotgun 9 copies  
> of it?
>
> Are there better ways to test these links? Can one verify this link  
> with
> just a pair of 7200s and linux machines on either side? Or is this  
> something
> one really needs "real" test hardware for? If 6mbit go through  
> clean, is
> there a real chance 44 will not?
>
> TIA,
> -mKaegler
>
>
> -- 
> Michael Kaegler, TESSCO Technologies: Engineering, 410 229 1295
> Your wireless success, nothing less. http://www.tessco.com/
>
>
>

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