def emptyNet():

    "Create an empty network and add nodes to it."
    args=(sys.argv)
    no_of_hosts=int(args[1])
    no_of_Switches=int(args[2])

    print "no of hosts : "+no_of_hosts
    print "no of swithes : "+no_of_switches

    net = Mininet( controller=Controller )

    info( '*** Adding controller\n' )
    net.addController( 'c0' )

    info( '*** Adding hosts\n' )
    hosts=[]
    for i in range(no_of_hosts):
	hosts.append(net.addHost('h'+str(i+1)))

    info( '*** Adding switch\n' )
    switches=[]
    for i in range(no_of_hosts):
	switches.append(net.addSwitch('s'+str(i+1)))

    info( '*** Creating links\n' )
    for i in range(no_of_switches):
	if i+2 < no_of_switches:
		net.addLinks(switches[i],switches[i+2])
	if i%2 == 0 :
		t1=net.addLinks(switches[i],hosts[2*i])
		t2=net.addLinks(switches[i],hosts[2*i+2])
		t1.intf1.config(bw = 2)
		t2.intf1.config(bw = 2)
	else:
		k1=net.addLinks(switches[i],hosts[2*i-1])
		k2=net.addLinks(switches[i],hosts[2*i+1])
		k1.intf1.config(bw = 1)
		k2.intf1.config(bw = 1)

    info( '*** Starting network\n')
    net.start()

    info( '*** Running CLI\n' )
    CLI( net )

    info( '*** Stopping network' )
    net.stop()
def emptyNet():

    "Create an empty network and add nodes to it."
    args = (sys.argv)
    no_of_hosts = int(args[1])
    no_of_Switches = int(args[2])

    print "no of hosts : " + no_of_hosts
    print "no of swithes : " + no_of_switches

    net = Mininet(controller=Controller)

    info('*** Adding controller\n')
    net.addController('c0')

    info('*** Adding hosts\n')
    hosts = []
    for i in range(no_of_hosts):
        hosts.append(net.addHost('h' + str(i + 1)))

    info('*** Adding switch\n')
    switches = []
    for i in range(no_of_hosts):
        switches.append(net.addSwitch('s' + str(i + 1)))

    info('*** Creating links\n')
    for i in range(no_of_switches):
        if i + 2 < no_of_switches:
            net.addLinks(switches[i], switches[i + 2])
        if i % 2 == 0:
            t1 = net.addLinks(switches[i], hosts[2 * i])
            t2 = net.addLinks(switches[i], hosts[2 * i + 2])
            t1.intf1.config(bw=2)
            t2.intf1.config(bw=2)
        else:
            k1 = net.addLinks(switches[i], hosts[2 * i - 1])
            k2 = net.addLinks(switches[i], hosts[2 * i + 1])
            k1.intf1.config(bw=1)
            k2.intf1.config(bw=1)

    info('*** Starting network\n')
    net.start()

    info('*** Running CLI\n')
    CLI(net)

    info('*** Stopping network')
    net.stop()