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Revision as of 03:59, 12 March 2017 by Tomh (Talk | contribs) (patch requirement)

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As part of their Google Summer of Code 2017 applications to ns-3, we require that students produce a patch for ns-3. This will allow us to gauge your ability to dive into source code, understand it, make a modification, and proceed to build and verify if your modification works.

A patch in this regard can be at least one of the following:

  • If you already have contributed a patch for ns-3 in the past, point us to the relevant commits in our code repository or the bug tracker issue, and your patch requirement is satisfied.
  • If not the above, either complete the minimum requirement test given below, or pick a bug in our Bugzilla that does not already have a patch pending, and try to fix it.

Minimum requirement patch

Setting up the environment

Perform the following steps (you may want to review our Installation page):

  • Download the ns-3.26 release, or clone it from Mercurial:
 $: hg clone


 $: wget
  • Verify if you can build ns-3 and run the program to be patched
 $: ./waf configure --disable-python --enable-examples
 $: ./waf build
 $: ./waf --run tcp-bulk-send


The example program 'examples/tcp/' should be modified to output the evolution of the TCP congestion window, in the direction of the file transfer (node 0 to 1), in a time-series format. Currently, the example will print out:

 $: ./waf --run tcp-bulk-send
 Total Bytes Received: 564248

Your patch to this program alone (i.e. do not change ns-3.26 TCP code in any way) should output something like this:

 $: ./waf --run tcp-bulk-send
 0.011856s 536
 0.033024s 1072
 0.062768s 1608
 0.092512s 2144
 9.98802s 286760
 Total Bytes Received: 564248

Hint: Tracing of the TCP 'CongestionWindow' trace source can be used, either by obtaining a pointer to the socket being used by the BulkSendApplication, or by using a config path to connect to the trace source. For tutorial on tracing, see:

What to submit

  • A patch to that accomplishes the objectives. In your application, point us to a publicly available URL where you've hosted the patch (like a "gist" on for instance). See also some guidelines here about formatting patches for review. If you need help with this step, contact the ns-3 Org Admin (Tom Henderson) for advice.