tracers+docs: Correcting compilation and installation of trace helpers
Also in this commit an example on how to use trace helpers, including
how to build graphs using R.
diff --git a/docs/source/examples.rst b/docs/source/examples.rst
index ddb4b26..ff36020 100644
--- a/docs/source/examples.rst
+++ b/docs/source/examples.rst
@@ -255,3 +255,77 @@
You can also run using visualizer module to verify that both bottleneck links are utilized::
./waf --run=ndn-congestion-alt-topo-plugin --visualize
+
+.. _trace example:
+
+Example of using trace helpers
+------------------------------
+
+This example (``ndn-tree-tracers.cc``) demonstrates basic usage of :ref:`trace classes`.
+
+In this scenario we will use a tree-like topology, where consumers are installed on leaf nodes and producer is in the root of the tree:
+
+.. aafig::
+ :aspect: 60
+ :scale: 120
+
+ /--------\ /--------\ /--------\ /--------\
+ |"leaf-1"| |"leaf-2"| |"leaf-3"| |"leaf-4"|
+ \--------/ \--------/ \--------/ \--------/
+ ^ ^ ^ ^
+ | | | |
+ \ / \ /
+ \ / \ / 10Mbps / 1ms
+ \ / \ /
+ | | | |
+ v v v v
+ /-------\ /-------\
+ |"rtr-1"| |"rtr-2"|
+ \-------/ \-------/
+ ^ ^
+ | |
+ \ / 10 Mpbs / 1ms
+ +--------\ /--------+
+ | |
+ v v
+ /--------\
+ | "root" |
+ \--------/
+
+The corresponding topology file (``topo-tree.txt``):
+
+.. literalinclude:: ../../examples/topologies/topo-tree.txt
+ :language: bash
+ :linenos:
+ :lines: 1-2,27-
+
+Example simulation (``ndn-tree-tracers.cc``) scenario that utilizes trace helpers:
+
+.. literalinclude:: ../../examples/ndn-tree-tracers.cc
+ :language: c++
+ :linenos:
+ :lines: 21-34,67-
+ :emphasize-lines: 7-11,63-67
+
+
+To run this scenario, use the following command::
+
+ ./waf --run=ndn-tree-tracers
+
+The successful run will create ``rate-trace.txt`` and ``aggregate-trace.txt`` files in the current directly, which can be analyzed manually or used as input to some graph/stats packages.
+
+For example, the following `R script <http://www.r-project.org/>`_ will build a number of nice graphs:
+
+.. image:: _static/root-rates.png
+ :alt: Interest/Data packet rates at the root node
+ :align: right
+
+.. image:: _static/root-5sec-counts.png
+ :alt: Interest/Data packet counts at the root node in 5-second intervals
+ :align: right
+
+.. literalinclude:: ../../examples/graphs/rate-graph.R
+ :language: r
+ :linenos:
+
+For more information about R and ggplot2, please refer to `R language manual <http://cran.r-project.org/manuals.html>`_, `ggplot2 module manual <http://docs.ggplot2.org/current/>`_.