[c-nsp] Prove it's not the network!

[Jason Berenson]

Eric,

As for the speed testing issue.  You could tell them to disconnect 
everything from the LAN side of the router and connect a laptop only.  
Have them run a speed test like that.  The idea that when no one else is 
using the connection the speed is a steady 1.5M might hit home at that 
point.

-Jason

Eric Gauthier wrote:
> Rick,
>
> This type of problem is one of the most difficult to diagnose.
> If you've exhausted all of your other avenues, then you might
> want to consider capturing the network traffic for this
> person's session during a time when its "slow".  This is a very
> labor intensive process, but it may be the only way to focus
> in on the "real" problem.  You will need to grab traffic from
> the end-user's network port so thta you can go through the
> entire session - DNS lookup, TCP setup, the Outlook/Exchange 
> login, the request for information, the response time of the 
> server, and the download rates, etc. - and build a timeline 
> for the transaction.  
>
> This won't, in itself, tell you what's wrong but it will tell 
> you how long each sub-component is taking.  From there, you
> should be able to figure out which one is causing the worst
> delay and then research it - be it the network or application.
>
> Eric Gauthier
> .....................................
> . Boston University
> . Network Systems Engineering Group
> . 111 Cummington St. Boston, MA 02215
> . 617-353-8218 ~^~ elg at bu.edu
> . http://www.bu.edu/nsg/
> .....................................
>
>
>
> On Tue, May 13, 2008 at 10:15:32AM -0500, Rick Martin wrote:
>   
>>  I know this is not really a Cisco specific question but it is
>> definitely in support of Cisco hardware. 
>>
>>  How do most of you folks prove that "the problem" is not the network?
>> We utilize CA Spectrum and eHealth for availability and statistical
>> analysis but in some instances that does not cut it. We don't typically
>> have much trouble proving that a T1 is serving up 1.5 meg of bandwidth.
>> Customers complain that their access is slow, we show that they are
>> using all available bandwidth and eventually sell them more bandwidth
>> and the problem is resolved.
>>
>>  The more difficult effort is when there is plenty of available
>> bandwidth and a particular application is slow (Outlook in the case I am
>> involved in now). This is a very high level political official and we
>> must come to a resolution. All tools we have available to us today
>> indicate that there is not a problem with the network. Typical
>> utilization on the T1 is about 500 to 600K peak during the day. Certain
>> management continues to point the finger at the network. We have used
>> Internet based speed tests that at times show less than 1.5Meg download
>> speeds, I explain the variables in the Internet and the particular tool
>> in use as well as local contention for the bandwidth etc to no avail,
>> once they see less than 1.5 meg speed the finger points to the network.
>> I still must somehow "prove" that the network is not the issue. 
>>
>>  I am interested in an Internet speed test like tool to install at the
>> core of our network that would provide a sustained upload or download
>> test that would run for longer periods of time than a regular speed
>> test. I would like to fill the pipe while graphing in Ehealth or as part
>> of the selected tool to prove that the contracted bandwidth is available
>> in both directions.
>>
>>  Any recommendations for products would be appreciated. We are currently
>> looking at SolarWinds WAN Killer and a traffic generator from Omnicore
>> LanTraffic V2. I am also open to different "types" of solutions to point
>> to where the problem is actually located. 
>>
>> Thanks in advance for any suggestions
>>
>> Rick Martin
>> Network Engineer
>> State of Arkansas, Department of Information Systems
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