As you start to migrate more devices toward OpenFlow, it becomes increasingly important to monitor the links. We discussed various monitoring tool options in Chapter 7, Network Monitoring with Python – Part 1 and Chapter 8, Network Monitoring with Python – Part 2. Next we can easily integrate monitoring for the migrated devices. We will show the built-in topology viewer that came with Ryu (http://ryu.readthedocs.io/en/latest/gui.html). For easier demonstration, I have used the same Mininet topology we saw earlier in the chapter, but have changed the controller port back to 6633 in chapter13_mininet_3.py:
net = Mininet( controller=RemoteController, switch=OVSKernelSwitch )
c1 = net.addController('c2', controller=RemoteController,
ip='127.0.0.1', port=6633)
Launch the Mininet topology and the Gui Topology application:
# Mininet...
