Re: [Ilugc] Tools for simulating network issues
Hi Bala, On Mon, Jun 25, 2012 at 10:21 AM, Balachandran Sivakumar benignb...@gmail.com wrote: I guess the tc tool would be of use to you. You can do something like this: # tc qdisc add dev eth0 root netem delay 100ms for adding a 100ms delay to all packets. It can be deleted later. tc lets us do a lot of things. This was just an example. A wrapper script over tc should be able to do the job. Thanks. didn't know about tc. Looks like this will be useful for part of my needs (for atleast simulating latency). cheers, -Suraj -- Career Gear - Industry Driven Talent Factory http://careergear.in/ ___ ILUGC Mailing List: http://www.ae.iitm.ac.in/mailman/listinfo/ilugc
Re: [Ilugc] Tools for simulating network issues
Thanks. didn't know about tc. Looks like this will be useful for part of my needs (for atleast simulating latency). Just had a look at its manpages, I am happy to learn that at least learned that such a tool exists. http://manpages.ubuntu.com/manpages/lucid/man8/tc.8.html -- Regards, Balasubramaniam Natarajan www.etutorshop.com/moodle/ ___ ILUGC Mailing List: http://www.ae.iitm.ac.in/mailman/listinfo/ilugc
[Ilugc] Tools for simulating network issues
Hi, I'm looking for ways to simulate network issues. Specifically, the following scenarios: IP - packet loss TCP - connection establishment takes time - connection established, but server application is slow / unresponsive - piled up connections / running out of sockets The end goal is to expose learners to these problems and be able to show how tools like netstat or collectd's graphs will behave upon each scenario. I don't have multiple real machines, I have 8 VMs running inside a reasonably powerful quad core box. The box has only one network card. The learners do a graphical login to the box over LTSP and ssh into the various VMs. Theoretically, I do see a way to achieve these by developing relevant netfilter modules - however, I don't know if any ready made modules exist or how easy/time consuming it may be to develop a netfilter module, especially given I want the simulation to be highly controllable. Am I right in my approach? Any suggestions / pointers to tools will be helpful. thanks, -Suraj -- Career Gear - Industry Driven Talent Factory http://careergear.in/ ___ ILUGC Mailing List: http://www.ae.iitm.ac.in/mailman/listinfo/ilugc
Re: [Ilugc] Tools for simulating network issues
Hi Suraj, On Mon, Jun 25, 2012 at 10:15 AM, Suraj Kumar su...@careergear.in wrote: Hi, I'm looking for ways to simulate network issues. Specifically, the following scenarios: IP - packet loss TCP - connection establishment takes time - connection established, but server application is slow / unresponsive - piled up connections / running out of sockets I guess the tc tool would be of use to you. You can do something like this: # tc qdisc add dev eth0 root netem delay 100ms for adding a 100ms delay to all packets. It can be deleted later. tc lets us do a lot of things. This was just an example. A wrapper script over tc should be able to do the job. The end goal is to expose learners to these problems and be able to show how tools like netstat or collectd's graphs will behave upon each scenario. Nice way to teach :) Hope colleges do something like this. Thanks -- Thank you Balachandran Sivakumar Arise Awake and stop not till the goal is reached. - Swami Vivekananda Mail: benignb...@gmail.com Blog: http://benignbala.wordpress.com/ ___ ILUGC Mailing List: http://www.ae.iitm.ac.in/mailman/listinfo/ilugc
Re: [Ilugc] Tools for simulating network issues
Usually for a quick testing, I use FreeBSD-based live CD Frenzy as a VM (create a VM and assign the ISO image of the CD and boot directly from it with out installing anything) and use ipfw to simulate bandwidth, latency and packet loss. http://frenzy.org.ua/eng/ -- mks -- ___ ILUGC Mailing List: http://www.ae.iitm.ac.in/mailman/listinfo/ilugc
