Patch for GSOC Project : Framework for TCP Prague simulations in ns-3

src/point-to-point-layout/doc/bcube.rst

Index: src/point-to-point-layout/doc/bcube.rst
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+.. include:: replace.txt
+.. highlight:: cpp
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+BCube topology
+--------------
+
+BCube is a server-centric network topology designed to meet the requirements of 
+Modular Data Centres. It consists of servers with multiple network ports connected 
+to multiple layers of COTS (commodity off-the-shelf) mini-switches. Servers act as 
+not only end hosts, but also relay nodes for each other. BCube supports various 
+bandwidth-intensive applications by speeding-up one-to-one, one-to-several, and 
+one-to-all traffic patterns, and by providing high network capacity for all-to-all 
+traffic. BCube exhibits graceful performance degradation as the server and/or switch 
+failure rate increases. This property is of special importance for shipping-container 
+data centers, since once the container is sealed and operational, it becomes very 
+difficult to repair or replace its components.
+
+Construction of BCube
+---------------------
+
+BCube is a recursively defined structure. There are two types of devices in BCube: 
+Servers with multiple ports, and switches that connect a constant number of servers.  
+A BCube0 is simply n servers connecting to an n-port switch. A BCube1 is constructed 
+from n BCube0s and n n-port switches. More generically, a BCubek (k ≥ 1)) is constructed 
+from n BCubek−1s and n^k n-port switches. Each server in a BCubek has k + 1 ports, which 
+are numbered from level-0 to level-k. It is easy to see that a BCubek has N = n^(k+1) 
+servers and k + 1 level of switches, with each level having n^k n-port switches.
+
+The construction of a BCubek is as follows. We number the n BCubek−1s from 0 to n − 1 
+and the servers in each BCubek−1 from 0 to n^k − 1. We then connect the level-k port 
+of the i-th server (i ∈ [0, n^k − 1]) in the j-th BCubek−1 (j ∈ [0, n − 1]) to the j-th 
+port of the i-th level-k switch. The links in BCube are bidirectional. In ns-3, all the
+links  are created and configured using the associated ``PointToPointHelper`` object.
+
+The BCube construction guarantees that switches only connect to servers and never 
+directly  connect to other switches. As a direct consequence, we can treat the switches 
+as dummy crossbars that connect several neighboring servers and let servers relay traffic 
+for each other. 
+
+Using the PointToPointBCube
+----------------------------
+
+The PointToPointBCubeHelper object can be instantiated by following statement.
+  PointToPointBCubeHelper bcube (nLevels, nServers, pointToPointRouter);
+  where,
+  nLevels is number of levels (k)
+  nServers is number of servers (n)
+  pointToPointRouter is a ``PointToPointHelper`` object 
+
+Examples
+========
+.
+The BCube topology example is found at ``src/netanim/examples/bcube-animation.cc``.
+
+References
+**********
+
+Link to the Paper: https://www.microsoft.com/en-us/research/wp-content/uploads/2016/02/comm136-guo.pdf