How to build a simple point to point star topology?

[Linh Vu]

Hi everyone, I'm new to ns3 and I have problem when building a point to point star topology.

I tried to make a simple network with 1 router and 2 nodes like the diagram:

#             n0      r      n1

#             |        _        |

#             ====|_|====

#                  router

So apparently, I want to create the network with the address of router is, for example, 10.1.1.1, and 2 nodes are 10.1.1.2 and 10.1.1.3.

However, since I have to put the pairs (router - node 0) and (router - node 1) in different NetDeviceContainer, then when I use  Ipv4InterfaceContainer to assign address. it appears that each  net device container has to have different network number ( like 10.1.1.0 and 10.1.2.0)...  Anyone can help me on this?

This is the code I did by myself

// Create 3 nodes: n0, n1 and router r

// router: c:[1]; no:  c[0], n1: c[2]; 

  NodeContainer c;

  c.Create (3);  

  NodeContainer n0r = NodeContainer (c.Get (0), c.Get (1));

  NodeContainer n1r = NodeContainer (c.Get (1), c.Get (2));

// install internet stack to 3 nodes

  InternetStackHelper internet;

  internet.Install (c);

// create p2p link

  PointToPointHelper p2p;

  p2p.SetDeviceAttribute ("DataRate", StringValue ("5Mbps"));

  p2p.SetChannelAttribute ("Delay", StringValue ("2ms"));

  NetDeviceContainer d0r = p2p.Install (n0r);

  NetDeviceContainer d1r = p2p.Install (n1r);

  

  NS_LOG_INFO ("====================Creating Topology=========================");

// assign ip address

  Ipv4AddressHelper ipv4;

  ipv4.SetBase ("10.1.1.0", "255.255.255.0");

  Ipv4InterfaceContainer i0r = ipv4.Assign (d0r);

  ipv4.NewAddress();

  Ipv4InterfaceContainer i1r = ipv4.Assign (d1r);