4 Replies Latest reply on Jan 10, 2008 9:15 PM by Leon

    Does anyone know WAN simulation software?

    Leon SupportEmployee

       

      I am trying to simulate a low link (wan) environment, perhaps only 19.2kbps, the latency may be 200 ms.

       

       

      Is anyone familiar with such software? A free one will be great.

       

       

       

       

       

      Thanks,

       

       

      Leon

       

       

        • 1. Re: Does anyone know WAN simulation software?
          beau.gordon Employee

           

          Leon,

           

          I have tried to find free software that runs on Windows which emulates a WAN, but I have been unsuccessful . Most commercial network emulation products are marketed to software testers and they are able to charge a high price ( $400~ish on the low end). I have used a trial version of Shunra before with some success, but the trial is limited in the amount of delay and the bandwidth it is able to emulate.

           

           

          I think that there are several free tools that do this that run on Linux or FreeBSD.  I found this list during my evaluation:

           

           

          http://en.wikipedia.org/wiki/Network_emulation

           

           

          Good luck.  If you find something that does this it would be a great tool to know about.

           

           

          • 2. Re: Does anyone know WAN simulation software?
            Employee

            http://snad.ncsl.nist.gov/itg/nistnet/ -- it's pretty old, so you might not want to try it on the latest Ubuntu drop... got any old Debian Woody disks kicking around? That said, it works well.

            1 of 1 people found this helpful
            • 3. Re: Does anyone know WAN simulation software?
              tperkes Employee

              Leon,

               

              You can build your own WAN simulation device and it's not too complex. You can use either FreeBSD's dummynet feature or Linux's netem feature. I personally like using Linux because you have more control over the buffer size used. However, FreeBSD's dummynet is easier to configure but it has some limitations on queue depth.

               

              What you'll need (Linux):

              1. A PC with two NICs.

              2. A copy of Linux that uses the 2.6 kernel. I used Ubuntu Desktop 7.10. (www.ubuntu.com)

              3. Working knowledge of static IP routing.

              4. Two ethernet switchs or hubs.

               

              Summary of steps:

              1. Modify the kernel to allow IP forwarding. The sysctl command is used to accomplish this.

              2. Modify the routing tables to route traffic between the two subnets. The ip command is used to accomplish this.

              3. Modify the traffic queue on the NIC to use netem on the outbound interface. The tc command is used to accomplish.

              4. Modify the child traffic queue on the NIC to use the token bucket filter queuing discipline.

               

              Note: Information on how accomplish steps 2 - 4 can be found at www.linux-foundation.com under their respective sections.

              • 4. Re: Does anyone know WAN simulation software?
                Leon SupportEmployee

                 

                All the information is so helpful. But it seems I can only give "Help answer" to one person.

                 

                 

                 

                 

                 

                Thanks,

                 

                 

                Leon