def topology():
    "Create a network with some docker containers acting as hosts."
    edgefile = os.path.join(RESULTS_FOLDER, "./substrate.edges.empty.data")
    nodesfile = os.path.join(RESULTS_FOLDER, "./substrate.nodes.data")
    CDNfile = os.path.join(RESULTS_FOLDER, "CDN.nodes.data")
    startersFile = os.path.join(RESULTS_FOLDER, "starters.nodes.data")
    solutionsFile = os.path.join(RESULTS_FOLDER, "solutions.data")
    service_edges = os.path.join(RESULTS_FOLDER, "./service.edges.data")
    switch = partial( OVSSwitch, protocols='OpenFlow13')

    topo = loadTopo(edgefile, nodesfile, CDNfile, startersFile, solutionsFile,service_edges)

    c = RemoteController('c', '0.0.0.0', 6633)
    # topodock=  loaddocker(os.path.join(RESULTS_FOLDER, "./substrate.edges.data"), os.path.join(RESULTS_FOLDER, "./substrate.nodes.data"))
    info('*** Start Containernet\n')
    net = Containernet(topo=topo, controller=c, link=TCLink,switch=switch)
    for host in net.hosts:
        if host.name in topo._cmd:
            for cmd in topo._cmd[host.name]:
                print("send cmd")
                print((host.sendCmd(cmd)))



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

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

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

    def stop(self):

        # stop the monitor agent
        if self.monitor_agent is not None:
            self.monitor_agent.stop()

        # stop emulator net
        Containernet.stop(self)

        # stop Ryu controller
        self.stopRyu()

    def __init__(self, controller=RemoteController, monitor=False,
                 enable_learning = True,   # in case of RemoteController (Ryu), learning switch behavior can be turned off/on
                 dc_emulation_max_cpu=1.0,  # fraction of overall CPU time for emulation
                 dc_emulation_max_mem=512,  # emulation max mem in MB
                 **kwargs):
        """
        Create an extended version of a Containernet network
        :param dc_emulation_max_cpu: max. CPU time used by containers in data centers
        :param kwargs: path through for Mininet parameters
        :return:
        """
        self.dcs = {}

        # make sure any remaining Ryu processes are killed
        self.killRyu()
        # make sure no containers are left over from a previous emulator run.
        self.removeLeftoverContainers()

        # call original Docker.__init__ and setup default controller
        Containernet.__init__(
            self, switch=OVSKernelSwitch, controller=controller, **kwargs)


        # Ryu management
        self.ryu_process = None
        if controller == RemoteController:
            # start Ryu controller
            self.startRyu(learning_switch=enable_learning)

        # add the specified controller
        self.addController('c0', controller=controller)

        # graph of the complete DC network
        self.DCNetwork_graph = nx.MultiDiGraph()

        # initialize pool of vlan tags to setup the SDN paths
        self.vlans = range(4096)[::-1]

        # link to Ryu REST_API
        ryu_ip = '0.0.0.0'
        ryu_port = '8080'
        self.ryu_REST_api = 'http://{0}:{1}'.format(ryu_ip, ryu_port)

        # monitoring agent
        if monitor:
            self.monitor_agent = DCNetworkMonitor(self)
        else:
            self.monitor_agent = None

        # initialize resource model registrar
        self.rm_registrar = ResourceModelRegistrar(
            dc_emulation_max_cpu, dc_emulation_max_mem)

    def stop(self):

        # stop the monitor agent
        if self.monitor_agent is not None:
            self.monitor_agent.stop()

        # stop emulator net
        Containernet.stop(self)

        # stop Ryu controller
        self.killRyu()

        # flag to indicate the topology has been stopped
        self.exit = True

 def addDocker(self, label, **params):
     """
     Wrapper for addDocker method to use custom container class.
     """
     self.DCNetwork_graph.add_node(label, type=params.get('type', 'docker'))
     return Containernet.addDocker(
         self, label, cls=EmulatorCompute, **params)

 def addSwitch( self, name, add_to_graph=True, **params ):
     """
     Wrapper for addSwitch method to store switch also in graph.
     """
     if add_to_graph:
         self.DCNetwork_graph.add_node(name)
     return Containernet.addSwitch(self, name, protocols='OpenFlow10,OpenFlow12,OpenFlow13', **params)

 def addExtSAP(self, sap_name, sap_ip, **params):
     """
     Wrapper for addExtSAP method to store SAP  also in graph.
     """
     # make sure that 'type' is set
     params['type'] = params.get('type','sap_ext')
     self.DCNetwork_graph.add_node(sap_name, type=params['type'])
     return Containernet.addExtSAP(self, sap_name, sap_ip, **params)

 def removeLink(self, link=None, node1=None, node2=None):
     """
     Remove the link from the Containernet and the networkx graph
     """
     if link is not None:
         node1 = link.intf1.node
         node2 = link.intf2.node
     assert node1 is not None
     assert node2 is not None
     Containernet.removeLink(self, link=link, node1=node1, node2=node2)
     # TODO we might decrease the loglevel to debug:
     try:
         self.DCNetwork_graph.remove_edge(node2.name, node1.name)
     except:
         LOG.warning("%s, %s not found in DCNetwork_graph." % ((node2.name, node1.name)))
     try:
         self.DCNetwork_graph.remove_edge(node1.name, node2.name)
     except:
         LOG.warning("%s, %s not found in DCNetwork_graph." % ((node1.name, node2.name)))

    def addSwitch( self, name, add_to_graph=True, **params ):
        """
        Wrapper for addSwitch method to store switch also in graph.
        """

        # add this switch to the global topology overview
        if add_to_graph:
            self.DCNetwork_graph.add_node(name, type=params.get('type','switch'))

        # set the learning switch behavior
        if 'failMode' in params :
            failMode = params['failMode']
        else :
            failMode = self.failMode

        s = Containernet.addSwitch(self, name, protocols='OpenFlow10,OpenFlow12,OpenFlow13', failMode=failMode, **params)

        return s

def topology():

    "Create a network with some docker containers acting as hosts."

    net = Containernet(controller=Controller)

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

    info('*** Adding docker containers\n')
    d1 = net.addDocker('d1', ip='10.0.0.251', dimage="mpeuster/stress", cpuset_cpus="0,1")
    d1.sendCmd("./start.sh")

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

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

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

    def addSwitch( self, name, add_to_graph=True, **params ):
        """
        Wrapper for addSwitch method to store switch also in graph.
        """

        # add this switch to the global topology overview
        if add_to_graph:
            self.DCNetwork_graph.add_node(name)

        # set the learning switch behavior
        if 'failMode' in params :
            failMode = params['failMode']
        else :
            failMode = self.failMode

        s = Containernet.addSwitch(self, name, protocols='OpenFlow10,OpenFlow12,OpenFlow13', failMode=failMode, **params)

        # set flow entry that enables learning switch behavior (needed to enable E-LAN functionality)
        #LOG.info('failmode {0}'.format(failMode))
        #if failMode == 'standalone' :
        #    LOG.info('add NORMAL')
        #    s.dpctl('add-flow', 'actions=NORMAL')

        return s

    def createNet(
            self,
            nswitches=1, nhosts=0, ndockers=0,
            autolinkswitches=False):
        """
        Creates a Mininet instance and automatically adds some
        nodes to it.
        """
        self.net = Containernet( controller=Controller )
        self.net.addController( 'c0' )

        # add some switches
        for i in range(0, nswitches):
            self.s.append(self.net.addSwitch('s%d' % i))
        # if specified, chain all switches
        if autolinkswitches:
            for i in range(0, len(self.s) - 1):
                self.net.addLink(self.s[i], self.s[i + 1])
        # add some hosts
        for i in range(0, nhosts):
            self.h.append(self.net.addHost('h%d' % i))
        # add some dockers
        for i in range(0, ndockers):
            self.d.append(self.net.addDocker('d%d' % i, dimage="ubuntu:trusty"))

def tfTopo():
    net = Containernet( topo=None, controller=RemoteController, switch=OVSKernelSwitch )

    net.addController( 'c0', RemoteController, ip="127.0.0.1", port=6633 )

    #Arguments
    opts, args = getopt.getopt(sys.argv[1:], "", ["flows=", "dos="])
    for o, a in opts:
        if o == "--flows":
            number_of_flows=int(a)
            print "Flows: ",a
        elif o in ("--dos"):
            number_of_dos=int(a)
            print "DoS: ",a

# Hosts 
    h1 = net.addHost('h1', ip='10.0.0.1', mac='00:00:00:00:00:01')
    h2 = net.addHost('h2', ip='10.0.0.2', mac='00:00:00:00:00:02')
    h3 = net.addHost('h3', ip='10.0.0.3', mac='00:00:00:00:00:03')
    h4 = net.addHost('h4', ip='10.0.0.4', mac='00:00:00:00:00:04')
    h5 = net.addHost('h5', ip='10.0.0.5', mac='00:00:00:00:00:05')
    h6 = net.addHost('h6', ip='10.0.0.6', mac='00:00:00:00:00:06')
    h7 = net.addHost('h7', ip='10.0.0.7', mac='00:00:00:00:00:07')
    h8 = net.addHost('h8', ip='10.0.0.8', mac='00:00:00:00:00:08')
    h9 = net.addHost('h9', ip='10.0.0.9', mac='00:00:00:00:00:09')
    h10 = net.addHost('h10', ip='10.0.0.10', mac='00:00:00:00:00:10')

    p1 = net.addHost('p1', ip='10.0.1.1', mac='00:00:00:00:01:01', cls=Docker, dimage='gmiotto/click',mem_limit=1024*1024*10, cpu_quota=pop_cpu_percentage*100,cpu_period=10000)
    p2 = net.addHost('p2', ip='10.0.1.2', mac='00:00:00:00:01:02', cls=Docker, dimage='gmiotto/click',mem_limit=1024*1024*10, cpu_quota=pop_cpu_percentage*100,cpu_period=10000)
    p3 = net.addHost('p3', ip='10.0.1.3', mac='00:00:00:00:01:03', cls=Docker, dimage='gmiotto/click',mem_limit=1024*1024*10, cpu_quota=pop_cpu_percentage*100,cpu_period=10000)
    p4 = net.addHost('p4', ip='10.0.1.4', mac='00:00:00:00:01:04', cls=Docker, dimage='gmiotto/click',mem_limit=1024*1024*10, cpu_quota=pop_cpu_percentage*100,cpu_period=10000)
    p5 = net.addHost('p5', ip='10.0.1.5', mac='00:00:00:00:01:05', cls=Docker, dimage='gmiotto/click',mem_limit=1024*1024*10, cpu_quota=pop_cpu_percentage*100,cpu_period=10000)
    p6 = net.addHost('p6', ip='10.0.1.6', mac='00:00:00:00:01:06', cls=Docker, dimage='gmiotto/click',mem_limit=1024*1024*10, cpu_quota=pop_cpu_percentage*100,cpu_period=10000)

    #Switches
    s1 = net.addSwitch('s1')
    s2 = net.addSwitch('s2')
    s3 = net.addSwitch('s3')
    s4 = net.addSwitch('s4')
    s5 = net.addSwitch('s5')
    s6 = net.addSwitch('s6')
    s7 = net.addSwitch('s7')
    s8 = net.addSwitch('s8')
    s9 = net.addSwitch('s9')
    s10 = net.addSwitch('s10')

    #PoP Hosts
    net.addLink(p1,s1, cls=TCLink, delay=pop_link_delay,bw=pop_link_bw,loss=pop_link_loss)
    net.addLink(p1,s1)

    net.addLink(p2,s2, cls=TCLink, delay=pop_link_delay,bw=pop_link_bw,loss=pop_link_loss)
    net.addLink(p2,s2)

    net.addLink(p3,s3, cls=TCLink, delay=pop_link_delay,bw=pop_link_bw,loss=pop_link_loss)
    net.addLink(p3,s3)

    net.addLink(p4,s4, cls=TCLink, delay=pop_link_delay,bw=pop_link_bw,loss=pop_link_loss)
    net.addLink(p4,s4)

    net.addLink(p5,s5, cls=TCLink, delay=pop_link_delay,bw=pop_link_bw,loss=pop_link_loss)
    net.addLink(p5,s5)

    net.addLink(p6,s6, cls=TCLink, delay=pop_link_delay,bw=pop_link_bw,loss=pop_link_loss)
    net.addLink(p6,s6)

    #Normal Hosts
    net.addLink(h1,s1, cls=TCLink, delay=host_switch_delay,bw=host_switch_bw,loss=host_switch_loss)
    net.addLink(h2,s2, cls=TCLink, delay=host_switch_delay,bw=host_switch_bw,loss=host_switch_loss)
    net.addLink(h3,s3, cls=TCLink, delay=host_switch_delay,bw=host_switch_bw,loss=host_switch_loss)
    net.addLink(h4,s4, cls=TCLink, delay=host_switch_delay,bw=host_switch_bw,loss=host_switch_loss)
    net.addLink(h5,s5, cls=TCLink, delay=host_switch_delay,bw=host_switch_bw,loss=host_switch_loss)
    net.addLink(h6,s6, cls=TCLink, delay=host_switch_delay,bw=host_switch_bw,loss=host_switch_loss)
    net.addLink(h7,s7, cls=TCLink, delay=host_switch_delay,bw=host_switch_bw,loss=host_switch_loss)
    net.addLink(h8,s8, cls=TCLink, delay=host_switch_delay,bw=host_switch_bw,loss=host_switch_loss)
    net.addLink(h9,s9, cls=TCLink, delay=host_switch_delay,bw=host_switch_bw,loss=host_switch_loss)
    net.addLink(h10,s10, cls=TCLink, delay=host_switch_delay,bw=host_switch_bw,loss=host_switch_loss)

    net.addLink(s7, s1, cls=TCLink, delay=inter_switch_delay,bw=inter_switch_bw,loss=inter_switch_loss) #s7-s1
    net.addLink(s7, s2, cls=TCLink, delay=inter_switch_delay,bw=inter_switch_bw,loss=inter_switch_loss) 
    net.addLink(s1, s2, cls=TCLink, delay=inter_switch_delay,bw=inter_switch_bw,loss=inter_switch_loss) 
    net.addLink(s1, s8, cls=TCLink, delay=inter_switch_delay,bw=inter_switch_bw,loss=inter_switch_loss) 
    net.addLink(s1, s3, cls=TCLink, delay=inter_switch_delay,bw=inter_switch_bw,loss=inter_switch_loss) 
    net.addLink(s1, s6, cls=TCLink, delay=inter_switch_delay,bw=inter_switch_bw,loss=inter_switch_loss) 
    net.addLink(s8, s3, cls=TCLink, delay=inter_switch_delay,bw=inter_switch_bw,loss=inter_switch_loss) 
    net.addLink(s2, s5, cls=TCLink, delay=inter_switch_delay,bw=inter_switch_bw,loss=inter_switch_loss) 
    net.addLink(s2, s4, cls=TCLink, delay=inter_switch_delay,bw=inter_switch_bw,loss=inter_switch_loss) 
    net.addLink(s3, s5, cls=TCLink, delay=inter_switch_delay,bw=inter_switch_bw,loss=inter_switch_loss) 
    net.addLink(s3, s4, cls=TCLink, delay=inter_switch_delay,bw=inter_switch_bw,loss=inter_switch_loss) 
    net.addLink(s4, s9, cls=TCLink, delay=inter_switch_delay,bw=inter_switch_bw,loss=inter_switch_loss) 
    net.addLink(s4, s6, cls=TCLink, delay=inter_switch_delay,bw=inter_switch_bw,loss=inter_switch_loss) 
    net.addLink(s5, s6, cls=TCLink, delay=inter_switch_delay,bw=inter_switch_bw,loss=inter_switch_loss) 
    net.addLink(s5, s10, cls=TCLink, delay=inter_switch_delay,bw=inter_switch_bw,loss=inter_switch_loss) 
    net.addLink(s9, s6, cls=TCLink, delay=inter_switch_delay,bw=inter_switch_bw,loss=inter_switch_loss) 
    net.addLink(s10, s6, cls=TCLink, delay=inter_switch_delay,bw=inter_switch_bw,loss=inter_switch_loss) 

    net.start()

    for host in net.hosts:
        if "h" in host.name:
            host.cmd('ethtool -K %s-eth0 tso off' % host.name)
#.........这里部分代码省略.........

 def start(self):
     # start
     for dc in self.dcs.itervalues():
         dc.start()
     Containernet.start(self)

    def addLink(self, node1, node2, **params):
        """
        Able to handle Datacenter objects as link
        end points.
        """
        assert node1 is not None
        assert node2 is not None
        LOG.debug("addLink: n1=%s n2=%s" % (str(node1), str(node2)))
        # ensure type of node1
        if isinstance( node1, basestring ):
            if node1 in self.dcs:
                node1 = self.dcs[node1].switch
        if isinstance( node1, Datacenter ):
            node1 = node1.switch
        # ensure type of node2
        if isinstance( node2, basestring ):
            if node2 in self.dcs:
                node2 = self.dcs[node2].switch
        if isinstance( node2, Datacenter ):
            node2 = node2.switch
        # try to give containers a default IP
        if isinstance( node1, Docker ):
            if "params1" not in params:
                params["params1"] = {}
            if "ip" not in params["params1"]:
                params["params1"]["ip"] = self.getNextIp()
        if isinstance( node2, Docker ):
            if "params2" not in params:
                params["params2"] = {}
            if "ip" not in params["params2"]:
                params["params2"]["ip"] = self.getNextIp()
        # ensure that we allow TCLinks between data centers
        # TODO this is not optimal, we use cls=Link for containers and TCLink for data centers
        # see Containernet issue: https://github.com/mpeuster/containernet/issues/3
        if "cls" not in params:
            params["cls"] = TCLink

        link = Containernet.addLink(self, node1, node2, **params)

        # try to give container interfaces a default id
        node1_port_id = node1.ports[link.intf1]
        if isinstance(node1, Docker):
            if "id" in params["params1"]:
                node1_port_id = params["params1"]["id"]
        node1_port_name = link.intf1.name

        node2_port_id = node2.ports[link.intf2]
        if isinstance(node2, Docker):
            if "id" in params["params2"]:
                node2_port_id = params["params2"]["id"]
        node2_port_name = link.intf2.name


        # add edge and assigned port number to graph in both directions between node1 and node2
        # port_id: id given in descriptor (if available, otherwise same as port)
        # port: portnumber assigned by Containernet

        attr_dict = {}
        # possible weight metrics allowed by TClink class:
        weight_metrics = ['bw', 'delay', 'jitter', 'loss']
        edge_attributes = [p for p in params if p in weight_metrics]
        for attr in edge_attributes:
            # if delay: strip ms (need number as weight in graph)
            match = re.search('([0-9]*\.?[0-9]+)', params[attr])
            if match:
                attr_number = match.group(1)
            else:
                attr_number = None
            attr_dict[attr] = attr_number


        attr_dict2 = {'src_port_id': node1_port_id, 'src_port_nr': node1.ports[link.intf1],
                      'src_port_name': node1_port_name,
                     'dst_port_id': node2_port_id, 'dst_port_nr': node2.ports[link.intf2],
                      'dst_port_name': node2_port_name}
        attr_dict2.update(attr_dict)
        self.DCNetwork_graph.add_edge(node1.name, node2.name, attr_dict=attr_dict2)

        attr_dict2 = {'src_port_id': node2_port_id, 'src_port_nr': node2.ports[link.intf2],
                      'src_port_name': node2_port_name,
                     'dst_port_id': node1_port_id, 'dst_port_nr': node1.ports[link.intf1],
                      'dst_port_name': node1_port_name}
        attr_dict2.update(attr_dict)
        self.DCNetwork_graph.add_edge(node2.name, node1.name, attr_dict=attr_dict2)

        return link

 def removeDocker( self, label, **params ):
     """
     Wrapper for removeDocker method to update graph.
     """
     self.DCNetwork_graph.remove_node(label)
     return Containernet.removeDocker(self, label, **params)

def tfTopo():
 net = Containernet( topo=None, controller=RemoteController, switch=OVSKernelSwitch )

 net.addController( 'c0', RemoteController, ip="127.0.0.1", port=6633 )

 # Hosts 
 h1 = net.addHost('h1', ip='10.0.0.1', mac='00:00:00:00:00:01')
 h2 = net.addHost('h2', ip='10.0.0.2', mac='00:00:00:00:00:02')
 h3 = net.addHost('h3', ip='10.0.0.3', mac='00:00:00:00:00:03', cls=Docker, dimage='gmiotto/click',mem_limit=1024*1024*10)
 h4 = net.addHost('h4', ip='10.0.0.4', mac='00:00:00:00:00:04')
 h5 = net.addHost('h5', ip='10.0.0.5', mac='00:00:00:00:00:05')

 #Switches
 s1 = net.addSwitch('s1')
 s2 = net.addSwitch('s2')
 s3 = net.addSwitch('s3')
 s4 = net.addSwitch('s4')
 s5 = net.addSwitch('s5')

 net.addLink(h3,s3)
 net.addLink(h3,s3)

 net.addLink(s1,s2)
 net.addLink(s2,s3)
 net.addLink(s3,s4)
 net.addLink(s4,s5)
 
 net.addLink(h1,s1)
 net.addLink(h2,s2)
 net.addLink(h4,s4)
 net.addLink(h5,s5)
 


 net.start()

 for host in net.hosts:
     if "h" in host.name:
         host.cmd('ethtool -K %s-eth0 tso off' % host.name)
 #call("echo  %s "% 'ha',shell=True)
 
 CLI(net)
 net.stop()

    def __init__(self, controller=RemoteController, monitor=False,
                 enable_learning=False, # learning switch behavior of the default ovs switches icw Ryu controller can be turned off/on, needed for E-LAN functionality
                 dc_emulation_max_cpu=1.0,  # fraction of overall CPU time for emulation
                 dc_emulation_max_mem=512,  # emulation max mem in MB
                 **kwargs):
        """
        Create an extended version of a Containernet network
        :param dc_emulation_max_cpu: max. CPU time used by containers in data centers
        :param kwargs: path through for Mininet parameters
        :return:
        """
        # members
        self.dcs = {}
        self.ryu_process = None
        #list of deployed nsds.E_Lines and E_LANs (uploaded from the dummy gatekeeper)
        self.deployed_nsds = []
        self.deployed_elines = []
        self.deployed_elans = []
        self.vlan_dict = {}

        # flag to indicate if the topology has been stopped (e.g. by api call)
        self.exit = False

        # always cleanup environment before we start the emulator
        self.killRyu()
        cleanup()

        # call original Docker.__init__ and setup default controller
        Containernet.__init__(
            self, switch=OVSKernelSwitch, controller=controller, **kwargs)

        # default switch configuration
        enable_ryu_learning = False
        if enable_learning :
            self.failMode = 'standalone'
            enable_ryu_learning = True
        else:
            self.failMode = 'secure'

        # Ryu management
        if controller == RemoteController:
            # start Ryu controller
            self.startRyu(learning_switch=enable_ryu_learning)

        # add the specified controller
        self.addController('c0', controller=controller)

        # graph of the complete DC network
        self.DCNetwork_graph = nx.MultiDiGraph()

        # initialize pool of vlan tags to setup the SDN paths
        self.vlans = range(1, 4095)[::-1]

        # link to Ryu REST_API
        ryu_ip = 'localhost'
        ryu_port = '8080'
        self.ryu_REST_api = 'http://{0}:{1}'.format(ryu_ip, ryu_port)
        self.RyuSession = requests.Session()

        # monitoring agent
        if monitor:
            self.monitor_agent = DCNetworkMonitor(self)
        else:
            self.monitor_agent = None

        # initialize resource model registrar
        self.rm_registrar = ResourceModelRegistrar(
            dc_emulation_max_cpu, dc_emulation_max_mem)
        self.cpu_period = CPU_PERIOD

#!/usr/bin/python
"""
This topology is used to test the compatibility of different Docker images.
The images to be tested can be found in 'examples/example-containers'.
They are build with './build.sh'
"""
from mininet.net import Containernet
from mininet.node import Controller
from mininet.cli import CLI
from mininet.link import TCLink
from mininet.log import info, setLogLevel
setLogLevel('info')

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

info('*** Adding docker containers\n')
d1 = net.addDocker('d1', dimage="ubuntu:trusty")
d2 = net.addDocker('d2', dimage="containernet_example:ubuntu1404")
d3 = net.addDocker('d3', dimage="containernet_example:ubuntu1604")
d4 = net.addDocker('d4', dimage="containernet_example:ubuntu1804")
d5 = net.addDocker('d5', dimage="containernet_example:centos6")
d6 = net.addDocker('d6', dimage="containernet_example:centos7")

info('*** Adding switches\n')
s1 = net.addSwitch('s1')

info('*** Creating links\n')
net.addLink(d1, s1)
net.addLink(d2, s1)

 def removeExtSAP(self, sap_name, **params):
     """
     Wrapper for removeExtSAP method to remove SAP  also from graph.
     """
     self.DCNetwork_graph.remove_node(sap_name)
     return Containernet.removeExtSAP(self, sap_name)