Simplified and refactored examples/dynamicnet.py

Extended LinearTopo to support mulitple hosts per switch

examples/dynamicnet.py

-# -*- coding: utf-8 -*-
+#!/usr/bin/python
 
 """
     This script builds a network using mininet for using with
@@ -17,118 +17,28 @@
 
 """
 
-from os import environ
-from sys import argv
-from sys import exit
-from getopt import getopt
-from getopt import GetoptError
+from optparse import OptionParser
 
-from mininet.topo import Topo
+from mininet.topo import LinearTopo
 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__":
-
+def main():
     # Defines the log level
     setLogLevel('info')
 
     # parses command line arguments
-    parser = ArgParser(argv[1:])
-
-    # Build network topology
-    topo = MyTopo()
+    parser = OptionParser()
+    parser.add_option('-H', dest='hosts', default=5,
+                      help='Number of hosts per switch')
+    parser.add_option('-S', dest='switches', default=2,
+                      help='Number of switches')
+    (options, args) = parser.parse_args()
 
-    # 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
+    # Build network topology (see mininet/topo.py)
+    topo = LinearTopo(int(options.switches), int(options.hosts))
 
     # Creates the Network using a remote controller
     net = Mininet(topo,
@@ -140,3 +50,6 @@ def usage(self):
     CLI(net)
     # Stop the network
     net.stop()
+
+if __name__ == "__main__":
+    main()

mininet/topo.py

@@ -236,23 +236,30 @@ def __init__(self, k=2, **opts):
                          port1=0, port2=(k - h + 1))
 
 class LinearTopo(Topo):
-    "Linear topology of k switches, with one host per switch."
+    "Linear topology of k switches, with n hosts per switch."
 
-    def __init__(self, k=2, **opts):
+    def __init__(self, k=2, n=1, **opts):
         """Init.
-           k: number of switches (and hosts)
+           k: number of switches
+           n: number of hosts per switch
            hconf: host configuration options
            lconf: link configuration options"""
 
         super(LinearTopo, self).__init__(**opts)
 
         self.k = k
+        self.n = n
 
         lastSwitch = None
         for i in irange(1, k):
-            host = self.addHost('h%s' % i)
+            # Add switch
             switch = self.addSwitch('s%s' % i)
-            self.addLink( host, switch)
+            # Add hosts to switch
+            for j in irange(1, n):
+              hostNum = (i-1)*n + j
+              host = self.addHost('h%s' % hostNum)
+              self.addLink(host, switch)
+            # Connect switch to previous
             if lastSwitch:
-                self.addLink( switch, lastSwitch)
+                self.addLink(switch, lastSwitch)
             lastSwitch = switch