Dynamic network creation using a remote controller

The script builds a network topology based on command line
arguments and uses a remote controller

examples/dynamicnet.py

+# -*- coding: utf-8 -*-
+
+"""
+    This script builds a network using mininet for using with
+a remote controller like POX.
+
+    The script receives from command line two arguments. The number
+of Switches and the number of Hosts per Switch. Then, it will build
+the network topology based on this arguments.
+
+    First of all, it build a topology and add the Switches to the network.
+After that, add the same number of Hosts for each Switch added. Lastly
+it make links between each switch.
+
+@author: Gustavo Pantuza
+@since: 18.07.2013
+
+"""
+
+from os import environ
+from sys import argv
+from sys import exit
+from getopt import getopt
+from getopt import GetoptError
+
+from mininet.topo import Topo
+from mininet.log import setLogLevel
+from mininet.net import Mininet
+from mininet.cli import CLI
+from mininet.node import RemoteController
+
+
+class MyTopo(Topo):
+    """ Topology Class Used in all classes to add network components """
+    def __init__(self, **opts):
+        super(MyTopo, self).__init__(**opts)
+
+
+class Switches():
+    """ Class to control switches addition """
+
+    def __init__(self, num, topo):
+
+        for i in xrange(num):
+            topo.addSwitch('s%s' % str(i))
+
+
+class Hosts():
+    """ Class to control host addition """
+
+    def __init__(self):
+        self._seq = 0
+
+    def add(self, num, switch, topo):
+        """ Adds hosts and its links """
+
+        for i in xrange(num):
+            host = topo.addHost("h%s" % str(self._seq))
+            topo.addLink(host, switch)
+            self._seq += 1
+
+
+class Links():
+    """ Create links between two switches """
+
+    def __init__(self, topo, switch0, switch1):
+
+        topo.addLink(switch0, switch1)
+
+
+class ArgParser(object):
+    """ Command line arguments parser class """
+
+    # possible command line options
+    OPTS = "s:h:"
+
+    def __init__(self, argv):
+        """ Tries to get options from command line """
+
+        try:
+            self.opts, self.args = getopt(argv, ArgParser.OPTS, ["help"])
+        except GetoptError:
+            self.usage()
+
+        self.switches = 2  # default value for the number of switches
+        self.hosts = 5  # default value for the number of hosts
+        self.parse()
+
+    def parse(self):
+        """ Parses the arguments and set values to the script execution """
+
+        for opt, args in self.opts:
+
+            if opt == "--help":
+                self.usage()
+            elif opt == "-s":
+                self.switches = int(args)
+            elif opt == "-h":
+                self.hosts = int(args)
+
+    def usage(self):
+        """ Prints how to usage the program """
+
+        print "python dinamicnet.py -s <Number-of-Switches>" \
+              " -h <hosts-per-switch>"
+        exit()
+
+
+if __name__ == "__main__":
+
+    # Defines the log level
+    setLogLevel('info')
+
+    # parses command line arguments
+    parser = ArgParser(argv[1:])
+
+    # Build network topology
+    topo = MyTopo()
+
+    # Adds Switches to network
+    Switches(parser.switches, topo)
+
+    # Adds Hosts to network
+    hosts = Hosts()
+    for i, switch in enumerate(topo.switches()):
+        hosts.add(parser.hosts, switch, topo)
+
+        try:  # Add links between switches
+            Links(topo, switch, topo.switches()[i + 1])
+        except IndexError:
+            break
+
+    # Creates the Network using a remote controller
+    net = Mininet(topo,
+                  controller=lambda a: RemoteController(a, ip='127.0.0.1'))
+
+    # Starts the network
+    net.start()
+    # Run the mininet client
+    CLI(net)
+    # Stop the network
+    net.stop()