4 Replies Latest reply on Apr 23, 2010 12:35 PM by stheriault

    Wan Killer for Capacity planning

      Hi,

      We are adding a new application on our WAN.  The vendor is telling me that they will be sending an extra 160MB (files) per hour over our WAN links.  I want to use WAN Killer to replicate the traffic over my 20Mbps link.  Can I use WAN Killer to simulate this traffic?  If so, how do I calculate it?

       

      Thanks.

        • Re: Wan Killer for Capacity planning

          Yes, you can use WAN killer to simulate this traffic.

          160MB per hour comes to about 372Kbps (less than 2% of your 20Mbps link's capacity), if you average the 160MB of file transfers over the course of the entire hour. The question is how "bursty" this transfer of 160MB will be.  Is it going to occur once per hour and saturate your WAN link or if it will trickle out over time?

          In the former case, you can use WAN killer to saturate your WAN link and verify that your new application's traffic is prioritized properly via QoS rules, etc.  In the latter case, you'll probably be just fine and can spare another 2% of your WAN link's capacity.  You may still want to verify that your WAN link isn't running near capacity already; a week's worth of data (depending on your business) should be sufficient.

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            • Re: Wan Killer for Capacity planning

              Thank you for your reply....

              Can you indicate to me how you calculated and got the result of 372Kbps from 160 MB per hour?  I'm having problems getting to that result.

               

              When using WAN Killer does that mean that I choose these parameters:

              Port - 9 discard - udp

              Packet size 1500

              Circuit bandwidth: 20480 Kbps (20Mbps)

              Generate data equivalent to x% of circuit bandwith: 2%

               

              Thank you very much

                • Re: Wan Killer for Capacity planning

                  Sure:

                  (160 MB per hour) x (1024 KB per MB) * (1024 B per KB) * (8 bits per byte) = 1342177280 bits per hour

                  (1342177280 bits per hour) / (3600 seconds per hour) = 372827 bits per second = 372Kbps

                  Again, assuming steady bandwidth consumption may not necessarily reflect how this application communicates across the WAN.  This new application is likely to do communication in bursts, which would consume, for brief periods, significantly more than 372Kbps.

                  You might also want to configure WAN Killer to reflect the same port number and L4 protocol that this new application would be using.

                    • Re: Wan Killer for Capacity planning

                      Thank you so much for the clarification.....

                      I will contact the vendor to get a better understanding of the communication in burst.

                      To do my capacity planning, with the tools I have, here is what I was thinking of doing:

                      1) Monitor my outgoing ports for a week.

                      2) Then use Wan killer for 8 hours with these settings:

                      20480 Kbps at 2%

                      3)Then compare my previous reports with the one with WanKiller working indicating that this does not include peaks during the day...

                       

                      Is there a better way of doing my capacity planning?  This is the only way I can see it.

                       

                      One again Thank you for all your help.