2.1 Network configuration file

As mentioned above, you need to specify a network configuration file when you run a simulation. This configuration file specifies each node in the network along with all of its interfaces and their respective addresses, as well as all the links that exist between each node and other nodes in the network.

We use the network from Figure 2 to illustrate how network configuration files are built. Interface 1 on node R1 is connected to interface 1 on node R2, and interface 2 on node R1 is connected to interface 1 on node R3. The network configuration file for this network is the following:

# Configuration for Router 1
Router 1 {
     1  1.1.1.1  255.255.255.255
     2  1.1.2.1  255.255.255.255
     1:1 2:1
     1:2 3:1
}

# Configuration for Router 2
Router 2 {
     1  1.1.1.2  255.255.255.255
     2:1 1:1
}

# Configuration for Router 3
Router 3 {
     1  1.1.2.2  255.255.255.255
     3:1 1:2
}

As usual, lines that start with a ``#'' are comments and will be ignored by the simulator. Each interface on each router has its own IP address and netmask. The notation X:Y refers to interface Y on node X. Thus, the line ``1:1 2:1'' in the configuration entry for node R1, shown above, specifies that interface 1 on R1 should be connected to interface 1 on R2. Note that in this configuration, R2 and R3 are actually end points, not routers. However, the simulator requires the word ``Router'' for each node in the configuration file.

This sample configuration file is provided in $PDIR/template/network3.cfg. You can modify the sample or create your own configuration for testing purposes.