Fix: Added gevent monkey patch to fix issue that blocks

[osm/vim-emu.git] / src / emuvim / dcemulator / net.py

diff --git a/src/emuvim/dcemulator/net.py b/src/emuvim/dcemulator/net.py
index a08a9e1..58c2bff 100755 (executable)
--- a/src/emuvim/dcemulator/net.py
+++ b/src/emuvim/dcemulator/net.py
@@ -1,51 +1,62 @@
-"""
-Copyright (c) 2015 SONATA-NFV and Paderborn University
-ALL RIGHTS RESERVED.
-
-Licensed under the Apache License, Version 2.0 (the "License");
-you may not use this file except in compliance with the License.
-You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-Unless required by applicable law or agreed to in writing, software
-distributed under the License is distributed on an "AS IS" BASIS,
-WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-See the License for the specific language governing permissions and
-limitations under the License.
-
-Neither the name of the SONATA-NFV [, ANY ADDITIONAL AFFILIATION]
-nor the names of its contributors may be used to endorse or promote
-products derived from this software without specific prior written
-permission.
-
-This work has been performed in the framework of the SONATA project,
-funded by the European Commission under Grant number 671517 through
-the Horizon 2020 and 5G-PPP programmes. The authors would like to
-acknowledge the contributions of their colleagues of the SONATA
-partner consortium (www.sonata-nfv.eu).
-"""
+# Copyright (c) 2015 SONATA-NFV and Paderborn University
+# ALL RIGHTS RESERVED.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+# Neither the name of the SONATA-NFV, Paderborn University
+# nor the names of its contributors may be used to endorse or promote
+# products derived from this software without specific prior written
+# permission.
+#
+# This work has been performed in the framework of the SONATA project,
+# funded by the European Commission under Grant number 671517 through
+# the Horizon 2020 and 5G-PPP programmes. The authors would like to
+# acknowledge the contributions of their colleagues of the SONATA
+# partner consortium (www.sonata-nfv.eu).

 import logging
 import logging

-
-import site

 import time
 import time

-from subprocess import Popen

 import re
 import requests
 import re
 import requests

-
+import os
+import json
+import networkx as nx
+from subprocess import Popen
+from gevent import monkey

 from mininet.net import Containernet
 from mininet.net import Containernet

-from mininet.node import Controller, DefaultController, OVSSwitch, OVSKernelSwitch, Docker, RemoteController
+from mininet.node import OVSSwitch, OVSKernelSwitch, Docker, RemoteController

 from mininet.cli import CLI
 from mininet.link import TCLink
 from mininet.clean import cleanup
 from mininet.cli import CLI
 from mininet.link import TCLink
 from mininet.clean import cleanup

-import networkx as nx

 from emuvim.dcemulator.monitoring import DCNetworkMonitor
 from emuvim.dcemulator.node import Datacenter, EmulatorCompute
 from emuvim.dcemulator.resourcemodel import ResourceModelRegistrar
 
 from emuvim.dcemulator.monitoring import DCNetworkMonitor
 from emuvim.dcemulator.node import Datacenter, EmulatorCompute
 from emuvim.dcemulator.resourcemodel import ResourceModelRegistrar
 

+# ensure correct functionality of all gevent based REST servers
+monkey.patch_all(sys=True)
+
+# setup logging

 LOG = logging.getLogger("dcemulator.net")
 LOG.setLevel(logging.DEBUG)
 
 LOG = logging.getLogger("dcemulator.net")
 LOG.setLevel(logging.DEBUG)
 

+# default CPU period used for cpu percentage-based cfs values (microseconds)
+CPU_PERIOD = 1000000
+
+# default priority setting for added flow-rules
+DEFAULT_PRIORITY = 1000
+# default cookie number for new flow-rules
+DEFAULT_COOKIE = 10
+
+

 class DCNetwork(Containernet):
     """
     Wraps the original Mininet/Containernet class and provides
 class DCNetwork(Containernet):
     """
     Wraps the original Mininet/Containernet class and provides


@@ -55,7 +66,10 @@ class DCNetwork(Containernet):
     """
 
     def __init__(self, controller=RemoteController, monitor=False,
     """
 
     def __init__(self, controller=RemoteController, monitor=False,

-                 enable_learning = True,   # in case of RemoteController (Ryu), learning switch behavior can be turned off/on
+                 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):
                  dc_emulation_max_cpu=1.0,  # fraction of overall CPU time for emulation
                  dc_emulation_max_mem=512,  # emulation max mem in MB
                  **kwargs):


@@ -68,6 +82,12 @@ class DCNetwork(Containernet):
         # members
         self.dcs = {}
         self.ryu_process = None
         # 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.installed_chains = []

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


@@ -77,10 +97,18 @@ class DCNetwork(Containernet):
         Containernet.__init__(
             self, switch=OVSKernelSwitch, controller=controller, **kwargs)
 
         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
         # Ryu management
         if controller == RemoteController:
             # start Ryu controller

-            self.startRyu(learning_switch=enable_learning)
+            self.startRyu(learning_switch=enable_ryu_learning)

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


@@ -89,7 +117,7 @@ class DCNetwork(Containernet):
         self.DCNetwork_graph = nx.MultiDiGraph()
 
         # initialize pool of vlan tags to setup the SDN paths
         self.DCNetwork_graph = nx.MultiDiGraph()
 
         # initialize pool of vlan tags to setup the SDN paths

-        self.vlans = range(4096)[::-1]
+        self.vlans = range(1, 4095)[::-1]

 
         # link to Ryu REST_API
         ryu_ip = 'localhost'
 
         # link to Ryu REST_API
         ryu_ip = 'localhost'


@@ -106,6 +134,7 @@ class DCNetwork(Containernet):
         # initialize resource model registrar
         self.rm_registrar = ResourceModelRegistrar(
             dc_emulation_max_cpu, dc_emulation_max_mem)
         # initialize resource model registrar
         self.rm_registrar = ResourceModelRegistrar(
             dc_emulation_max_cpu, dc_emulation_max_mem)

+        self.cpu_period = CPU_PERIOD

 
     def addDatacenter(self, label, metadata={}, resource_log_path=None):
         """
 
     def addDatacenter(self, label, metadata={}, resource_log_path=None):
         """


@@ -113,7 +142,8 @@ class DCNetwork(Containernet):
         """
         if label in self.dcs:
             raise Exception("Data center label already exists: %s" % label)
         """
         if label in self.dcs:
             raise Exception("Data center label already exists: %s" % label)

-        dc = Datacenter(label, metadata=metadata, resource_log_path=resource_log_path)
+        dc = Datacenter(label, metadata=metadata,
+                        resource_log_path=resource_log_path)

         dc.net = self  # set reference to network
         self.dcs[label] = dc
         dc.create()  # finally create the data center in our Mininet instance
         dc.net = self  # set reference to network
         self.dcs[label] = dc
         dc.create()  # finally create the data center in our Mininet instance


@@ -127,33 +157,34 @@ class DCNetwork(Containernet):
         """
         assert node1 is not None
         assert node2 is not None
         """
         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
         # ensure type of node1

-        if isinstance( node1, basestring ):
+        if isinstance(node1, basestring):

             if node1 in self.dcs:
                 node1 = self.dcs[node1].switch
             if node1 in self.dcs:
                 node1 = self.dcs[node1].switch

-        if isinstance( node1, Datacenter ):
+        if isinstance(node1, Datacenter):

             node1 = node1.switch
         # ensure type of node2
             node1 = node1.switch
         # ensure type of node2

-        if isinstance( node2, basestring ):
+        if isinstance(node2, basestring):

             if node2 in self.dcs:
                 node2 = self.dcs[node2].switch
             if node2 in self.dcs:
                 node2 = self.dcs[node2].switch

-        if isinstance( node2, Datacenter ):
+        if isinstance(node2, Datacenter):

             node2 = node2.switch
         # try to give containers a default IP
             node2 = node2.switch
         # try to give containers a default IP

-        if isinstance( node1, Docker ):
+        if isinstance(node1, Docker):

             if "params1" not in params:
                 params["params1"] = {}
             if "ip" not in params["params1"]:
                 params["params1"]["ip"] = self.getNextIp()
             if "params1" not in params:
                 params["params1"] = {}
             if "ip" not in params["params1"]:
                 params["params1"]["ip"] = self.getNextIp()

-        if isinstance( node2, Docker ):
+        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
             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
+        # see Containernet issue:
+        # https://github.com/mpeuster/containernet/issues/3

         if "cls" not in params:
             params["cls"] = TCLink
 
         if "cls" not in params:
             params["cls"] = TCLink
 


@@ -172,7 +203,6 @@ class DCNetwork(Containernet):
                 node2_port_id = params["params2"]["id"]
         node2_port_name = link.intf2.name
 
                 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
         # 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


@@ -190,44 +220,100 @@ class DCNetwork(Containernet):
                 attr_number = None
             attr_dict[attr] = attr_number
 
                 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,
         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_id': node2_port_id, 'dst_port_nr': node2.ports[link.intf2],

                       'dst_port_name': node2_port_name}
         attr_dict2.update(attr_dict)
                       'dst_port_name': node2_port_name}
         attr_dict2.update(attr_dict)

-        self.DCNetwork_graph.add_edge(node1.name, node2.name, attr_dict=attr_dict2)
+        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,
 
         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_id': node1_port_id, 'dst_port_nr': node1.ports[link.intf1],

                       'dst_port_name': node1_port_name}
         attr_dict2.update(attr_dict)
                       'dst_port_name': node1_port_name}
         attr_dict2.update(attr_dict)

-        self.DCNetwork_graph.add_edge(node2.name, node1.name, attr_dict=attr_dict2)
+        self.DCNetwork_graph.add_edge(
+            node2.name, node1.name, attr_dict=attr_dict2)
+
+        LOG.debug("addLink: n1={0} intf1={1} -- n2={2} intf2={3}".format(
+            str(node1), node1_port_name, str(node2), node2_port_name))

 
         return link
 
 
         return link
 

-    def addDocker( self, label, **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 BaseException:
+            LOG.warning("%s, %s not found in DCNetwork_graph." %
+                        ((node2.name, node1.name)))
+        try:
+            self.DCNetwork_graph.remove_edge(node1.name, node2.name)
+        except BaseException:
+            LOG.warning("%s, %s not found in DCNetwork_graph." %
+                        ((node1.name, node2.name)))
+
+    def addDocker(self, label, **params):

         """
         Wrapper for addDocker method to use custom container class.
         """
         """
         Wrapper for addDocker method to use custom container class.
         """

-        self.DCNetwork_graph.add_node(label)
-        return Containernet.addDocker(self, label, cls=EmulatorCompute, **params)
+        self.DCNetwork_graph.add_node(label, type=params.get('type', 'docker'))
+        return Containernet.addDocker(
+            self, label, cls=EmulatorCompute, **params)

 
 

-    def removeDocker( self, label, **params ):
+    def removeDocker(self, label, **params):

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

-    def addSwitch( self, name, add_to_graph=True, **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 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)
+
+    def addSwitch(self, name, add_to_graph=True, **params):

         """
         Wrapper for addSwitch method to store switch also in graph.
         """
         """
         Wrapper for addSwitch method to store switch also in graph.
         """

+
+        # add this switch to the global topology overview

         if add_to_graph:
         if add_to_graph:

-            self.DCNetwork_graph.add_node(name)
-        return Containernet.addSwitch(self, name, protocols='OpenFlow10,OpenFlow12,OpenFlow13', **params)
+            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 getAllContainers(self):
         """
 
     def getAllContainers(self):
         """


@@ -256,11 +342,204 @@ class DCNetwork(Containernet):
         # stop Ryu controller
         self.killRyu()
 
         # stop Ryu controller
         self.killRyu()
 

-

     def CLI(self):
         CLI(self)
 
     def CLI(self):
         CLI(self)
 

-    def setChain(self, vnf_src_name, vnf_dst_name, vnf_src_interface=None, vnf_dst_interface=None, **kwargs):
+    def setLAN(self, vnf_list):
+        """
+        setup an E-LAN network by assigning the same VLAN tag to each DC interface of the VNFs in the E-LAN
+
+        :param vnf_list: names of the VNFs in this E-LAN  [{name:,interface:},...]
+        :return:
+        """
+        src_sw = None
+        src_sw_inport_name = None
+
+        # get a vlan tag for this E-LAN
+        vlan = self.vlans.pop()
+
+        for vnf in vnf_list:
+            vnf_src_name = vnf['name']
+            vnf_src_interface = vnf['interface']
+
+            # check if port is specified (vnf:port)
+            if vnf_src_interface is None:
+                # take first interface by default
+                connected_sw = self.DCNetwork_graph.neighbors(vnf_src_name)[0]
+                link_dict = self.DCNetwork_graph[vnf_src_name][connected_sw]
+                vnf_src_interface = link_dict[0]['src_port_id']
+
+            for connected_sw in self.DCNetwork_graph.neighbors(vnf_src_name):
+                link_dict = self.DCNetwork_graph[vnf_src_name][connected_sw]
+                for link in link_dict:
+                    if (link_dict[link]['src_port_id'] == vnf_src_interface or
+                            link_dict[link]['src_port_name'] == vnf_src_interface):  # Fix: we might also get interface names, e.g, from a son-emu-cli call
+                        # found the right link and connected switch
+                        src_sw = connected_sw
+                        src_sw_inport_name = link_dict[link]['dst_port_name']
+                        break
+
+            # set the tag on the dc switch interface
+            LOG.debug('set E-LAN: vnf name: {0} interface: {1} tag: {2}'.format(
+                vnf_src_name, vnf_src_interface, vlan))
+            switch_node = self.getNodeByName(src_sw)
+            self._set_vlan_tag(switch_node, src_sw_inport_name, vlan)
+
+    def _addMonitorFlow(self, vnf_src_name, vnf_dst_name, vnf_src_interface=None, vnf_dst_interface=None,
+                        tag=None, **kwargs):
+        """
+        Add a monitoring flow entry that adds a special flowentry/counter at the begin or end of a chain.
+        So this monitoring flowrule exists on top of a previously defined chain rule and uses the same vlan tag/routing.
+        :param vnf_src_name:
+        :param vnf_dst_name:
+        :param vnf_src_interface:
+        :param vnf_dst_interface:
+        :param tag: vlan tag to be used for this chain (same tag as existing chain)
+        :param monitor_placement: 'tx' or 'rx' indicating to place the extra flowentry resp. at the beginning or end of the chain
+        :return:
+        """
+
+        src_sw = None
+        src_sw_inport_nr = 0
+        src_sw_inport_name = None
+        dst_sw = None
+        dst_sw_outport_nr = 0
+        dst_sw_outport_name = None
+
+        LOG.debug("call AddMonitorFlow vnf_src_name=%r, vnf_src_interface=%r, vnf_dst_name=%r, vnf_dst_interface=%r",
+                  vnf_src_name, vnf_src_interface, vnf_dst_name, vnf_dst_interface)
+
+        # check if port is specified (vnf:port)
+        if vnf_src_interface is None:
+            # take first interface by default
+            connected_sw = self.DCNetwork_graph.neighbors(vnf_src_name)[0]
+            link_dict = self.DCNetwork_graph[vnf_src_name][connected_sw]
+            vnf_src_interface = link_dict[0]['src_port_id']
+
+        for connected_sw in self.DCNetwork_graph.neighbors(vnf_src_name):
+            link_dict = self.DCNetwork_graph[vnf_src_name][connected_sw]
+            for link in link_dict:
+                if (link_dict[link]['src_port_id'] == vnf_src_interface or
+                        link_dict[link]['src_port_name'] == vnf_src_interface):  # Fix: we might also get interface names, e.g, from a son-emu-cli call
+                    # found the right link and connected switch
+                    src_sw = connected_sw
+                    src_sw_inport_nr = link_dict[link]['dst_port_nr']
+                    src_sw_inport_name = link_dict[link]['dst_port_name']
+                    break
+
+        if vnf_dst_interface is None:
+            # take first interface by default
+            connected_sw = self.DCNetwork_graph.neighbors(vnf_dst_name)[0]
+            link_dict = self.DCNetwork_graph[connected_sw][vnf_dst_name]
+            vnf_dst_interface = link_dict[0]['dst_port_id']
+
+        vnf_dst_name = vnf_dst_name.split(':')[0]
+        for connected_sw in self.DCNetwork_graph.neighbors(vnf_dst_name):
+            link_dict = self.DCNetwork_graph[connected_sw][vnf_dst_name]
+            for link in link_dict:
+                if link_dict[link]['dst_port_id'] == vnf_dst_interface or \
+                        link_dict[link]['dst_port_name'] == vnf_dst_interface:  # Fix: we might also get interface names, e.g, from a son-emu-cli call
+                    # found the right link and connected switch
+                    dst_sw = connected_sw
+                    dst_sw_outport_nr = link_dict[link]['src_port_nr']
+                    dst_sw_outport_name = link_dict[link]['src_port_name']
+                    break
+
+        if not tag >= 0:
+            LOG.exception('tag not valid: {0}'.format(tag))
+
+        # get shortest path
+        try:
+            # returns the first found shortest path
+            # if all shortest paths are wanted, use: all_shortest_paths
+            path = nx.shortest_path(
+                self.DCNetwork_graph, src_sw, dst_sw, weight=kwargs.get('weight'))
+        except BaseException:
+            LOG.exception("No path could be found between {0} and {1} using src_sw={2} and dst_sw={3}".format(
+                vnf_src_name, vnf_dst_name, src_sw, dst_sw))
+            LOG.debug("Graph nodes: %r" % self.DCNetwork_graph.nodes())
+            LOG.debug("Graph edges: %r" % self.DCNetwork_graph.edges())
+            for e, v in self.DCNetwork_graph.edges():
+                LOG.debug("%r" % self.DCNetwork_graph[e][v])
+            return "No path could be found between {0} and {1}".format(
+                vnf_src_name, vnf_dst_name)
+
+        LOG.debug("Creating path between {0} and {1}: {2}".format(
+            vnf_src_name, vnf_dst_name, path))
+
+        current_hop = src_sw
+        switch_inport_nr = src_sw_inport_nr
+
+        cmd = kwargs.get('cmd')
+
+        # iterate through the path to install the flow-entries
+        for i in range(0, len(path)):
+            current_node = self.getNodeByName(current_hop)
+
+            if path.index(current_hop) < len(path) - 1:
+                next_hop = path[path.index(current_hop) + 1]
+            else:
+                # last switch reached
+                next_hop = vnf_dst_name
+
+            next_node = self.getNodeByName(next_hop)
+
+            if next_hop == vnf_dst_name:
+                switch_outport_nr = dst_sw_outport_nr
+                LOG.debug("end node reached: {0}".format(vnf_dst_name))
+            elif not isinstance(next_node, OVSSwitch):
+                LOG.info("Next node: {0} is not a switch".format(next_hop))
+                return "Next node: {0} is not a switch".format(next_hop)
+            else:
+                # take first link between switches by default
+                index_edge_out = 0
+                switch_outport_nr = self.DCNetwork_graph[current_hop][next_hop][index_edge_out]['src_port_nr']
+
+            # set of entry via ovs-ofctl
+            if isinstance(current_node, OVSSwitch):
+                kwargs['vlan'] = tag
+                kwargs['path'] = path
+                kwargs['current_hop'] = current_hop
+                kwargs['switch_inport_name'] = src_sw_inport_name
+                kwargs['switch_outport_name'] = dst_sw_outport_name
+                kwargs['skip_vlan_tag'] = True
+                kwargs['pathindex'] = i
+
+                monitor_placement = kwargs.get('monitor_placement').strip()
+                # put monitor flow at the dst switch
+                insert_flow = False
+                # first node:
+                if monitor_placement == 'tx' and path.index(current_hop) == 0:
+                    insert_flow = True
+                # put monitoring flow at the src switch
+                # last node:
+                elif monitor_placement == 'rx' and path.index(current_hop) == len(path) - 1:
+                    insert_flow = True
+                elif monitor_placement not in ['rx', 'tx']:
+                    LOG.exception(
+                        'invalid monitor command: {0}'.format(monitor_placement))
+
+                if self.controller == RemoteController and insert_flow:
+                    # set flow entry via ryu rest api
+                    self._set_flow_entry_ryu_rest(
+                        current_node, switch_inport_nr, switch_outport_nr, **kwargs)
+                    break
+                elif insert_flow:
+                    # set flow entry via ovs-ofctl
+                    self._set_flow_entry_dpctl(
+                        current_node, switch_inport_nr, switch_outport_nr, **kwargs)
+                    break
+
+            # take first link between switches by default
+            if isinstance(next_node, OVSSwitch):
+                switch_inport_nr = self.DCNetwork_graph[current_hop][next_hop][0]['dst_port_nr']
+                current_hop = next_hop
+
+        return "path {2} between {0} and {1}".format(
+            vnf_src_name, vnf_dst_name, cmd)
+
+    def setChain(self, vnf_src_name, vnf_dst_name,
+                 vnf_src_interface=None, vnf_dst_interface=None, **kwargs):

         """
         Chain 2 vnf interfaces together by installing the flowrules in the switches along their path.
         Currently the path is found using the default networkx shortest path function.
         """
         Chain 2 vnf interfaces together by installing the flowrules in the switches along their path.
         Currently the path is found using the default networkx shortest path function.


@@ -274,41 +553,68 @@ class DCNetwork(Containernet):
         :param cookie: cookie for the installed flowrules (can be used later as identifier for a set of installed chains)
         :param match: custom match entry to be added to the flowrules (default: only in_port and vlan tag)
         :param priority: custom flowrule priority
         :param cookie: cookie for the installed flowrules (can be used later as identifier for a set of installed chains)
         :param match: custom match entry to be added to the flowrules (default: only in_port and vlan tag)
         :param priority: custom flowrule priority

+        :param monitor: boolean to indicate whether this chain is a monitoring chain
+        :param tag: vlan tag to be used for this chain (pre-defined or new one if none is specified)
+        :param skip_vlan_tag: boolean to indicate if a vlan tag should be appointed to this flow or not

         :param path: custom path between the two VNFs (list of switches)
         :return: output log string
         """
         :param path: custom path between the two VNFs (list of switches)
         :return: output log string
         """

-        cmd = kwargs.get('cmd')
-        if cmd == 'add-flow':
-            ret = self._chainAddFlow(vnf_src_name, vnf_dst_name, vnf_src_interface, vnf_dst_interface, **kwargs)
-            if kwargs.get('bidirectional'):
-                if kwargs.get('path') is not None:
-                    kwargs['path'] = list(reversed(kwargs.get('path')))
-                ret = ret +'\n' + self._chainAddFlow(vnf_dst_name, vnf_src_name, vnf_dst_interface, vnf_src_interface, **kwargs)

 
 

-        elif cmd == 'del-flows':
-            ret = self._chainAddFlow(vnf_src_name, vnf_dst_name, vnf_src_interface, vnf_dst_interface, **kwargs)
+        # special procedure for monitoring flows
+        if kwargs.get('monitor'):
+
+            # check if chain already exists
+            found_chains = [chain_dict for chain_dict in self.installed_chains if
+                            (chain_dict['vnf_src_name'] == vnf_src_name and
+                             chain_dict['vnf_src_interface'] == vnf_src_interface and
+                             chain_dict['vnf_dst_name'] == vnf_dst_name and
+                             chain_dict['vnf_dst_interface'] == vnf_dst_interface)]
+
+            if len(found_chains) > 0:
+                # this chain exists, so need an extra monitoring flow
+                # assume only 1 chain per vnf/interface pair
+                LOG.debug('*** installing monitoring chain on top of pre-defined chain from {0}:{1} -> {2}:{3}'.
+                          format(vnf_src_name, vnf_src_interface, vnf_dst_name, vnf_dst_interface))
+                tag = found_chains[0]['tag']
+                ret = self._addMonitorFlow(vnf_src_name, vnf_dst_name, vnf_src_interface, vnf_dst_interface,
+                                           tag=tag, table_id=0, **kwargs)
+                return ret
+            else:
+                # no chain existing (or E-LAN) -> install normal chain
+                LOG.warning('*** installing monitoring chain without pre-defined NSD chain from {0}:{1} -> {2}:{3}'.
+                            format(vnf_src_name, vnf_src_interface, vnf_dst_name, vnf_dst_interface))
+                pass
+
+        cmd = kwargs.get('cmd', 'add-flow')
+        if cmd == 'add-flow' or cmd == 'del-flows':
+            ret = self._chainAddFlow(
+                vnf_src_name, vnf_dst_name, vnf_src_interface, vnf_dst_interface, **kwargs)

             if kwargs.get('bidirectional'):
                 if kwargs.get('path') is not None:
                     kwargs['path'] = list(reversed(kwargs.get('path')))
             if kwargs.get('bidirectional'):
                 if kwargs.get('path') is not None:
                     kwargs['path'] = list(reversed(kwargs.get('path')))

-                ret = ret + '\n' + self._chainAddFlow(vnf_dst_name, vnf_src_name, vnf_dst_interface, vnf_src_interface, **kwargs)
+                ret = ret + '\n' + \
+                    self._chainAddFlow(
+                        vnf_dst_name, vnf_src_name, vnf_dst_interface, vnf_src_interface, **kwargs)

 
         else:
             ret = "Command unknown"
 
         return ret
 
 
         else:
             ret = "Command unknown"
 
         return ret
 

-
-    def _chainAddFlow(self, vnf_src_name, vnf_dst_name, vnf_src_interface=None, vnf_dst_interface=None, **kwargs):
+    def _chainAddFlow(self, vnf_src_name, vnf_dst_name,
+                      vnf_src_interface=None, vnf_dst_interface=None, **kwargs):

 
         src_sw = None
 
         src_sw = None

-        dst_sw = None

         src_sw_inport_nr = 0
         src_sw_inport_nr = 0

+        src_sw_inport_name = None
+        dst_sw = None

         dst_sw_outport_nr = 0
         dst_sw_outport_nr = 0

+        dst_sw_outport_name = None

 
         LOG.debug("call chainAddFlow vnf_src_name=%r, vnf_src_interface=%r, vnf_dst_name=%r, vnf_dst_interface=%r",
                   vnf_src_name, vnf_src_interface, vnf_dst_name, vnf_dst_interface)
 
 
         LOG.debug("call chainAddFlow vnf_src_name=%r, vnf_src_interface=%r, vnf_dst_name=%r, vnf_dst_interface=%r",
                   vnf_src_name, vnf_src_interface, vnf_dst_name, vnf_dst_interface)
 

-        #check if port is specified (vnf:port)
+        # check if port is specified (vnf:port)

         if vnf_src_interface is None:
             # take first interface by default
             connected_sw = self.DCNetwork_graph.neighbors(vnf_src_name)[0]
         if vnf_src_interface is None:
             # take first interface by default
             connected_sw = self.DCNetwork_graph.neighbors(vnf_src_name)[0]


@@ -323,6 +629,7 @@ class DCNetwork(Containernet):
                     # found the right link and connected switch
                     src_sw = connected_sw
                     src_sw_inport_nr = link_dict[link]['dst_port_nr']
                     # found the right link and connected switch
                     src_sw = connected_sw
                     src_sw_inport_nr = link_dict[link]['dst_port_nr']

+                    src_sw_inport_name = link_dict[link]['dst_port_name']

                     break
 
         if vnf_dst_interface is None:
                     break
 
         if vnf_dst_interface is None:


@@ -340,6 +647,7 @@ class DCNetwork(Containernet):
                     # found the right link and connected switch
                     dst_sw = connected_sw
                     dst_sw_outport_nr = link_dict[link]['src_port_nr']
                     # found the right link and connected switch
                     dst_sw = connected_sw
                     dst_sw_outport_nr = link_dict[link]['src_port_nr']

+                    dst_sw_outport_name = link_dict[link]['src_port_name']

                     break
 
         path = kwargs.get('path')
                     break
 
         path = kwargs.get('path')


@@ -348,29 +656,46 @@ class DCNetwork(Containernet):
             try:
                 # returns the first found shortest path
                 # if all shortest paths are wanted, use: all_shortest_paths
             try:
                 # returns the first found shortest path
                 # if all shortest paths are wanted, use: all_shortest_paths

-                path = nx.shortest_path(self.DCNetwork_graph, src_sw, dst_sw, weight=kwargs.get('weight'))
-            except:
+                path = nx.shortest_path(
+                    self.DCNetwork_graph, src_sw, dst_sw, weight=kwargs.get('weight'))
+            except BaseException:

                 LOG.exception("No path could be found between {0} and {1} using src_sw={2} and dst_sw={3}".format(
                     vnf_src_name, vnf_dst_name, src_sw, dst_sw))
                 LOG.debug("Graph nodes: %r" % self.DCNetwork_graph.nodes())
                 LOG.debug("Graph edges: %r" % self.DCNetwork_graph.edges())
                 for e, v in self.DCNetwork_graph.edges():
                     LOG.debug("%r" % self.DCNetwork_graph[e][v])
                 LOG.exception("No path could be found between {0} and {1} using src_sw={2} and dst_sw={3}".format(
                     vnf_src_name, vnf_dst_name, src_sw, dst_sw))
                 LOG.debug("Graph nodes: %r" % self.DCNetwork_graph.nodes())
                 LOG.debug("Graph edges: %r" % self.DCNetwork_graph.edges())
                 for e, v in self.DCNetwork_graph.edges():
                     LOG.debug("%r" % self.DCNetwork_graph[e][v])

-                return "No path could be found between {0} and {1}".format(vnf_src_name, vnf_dst_name)
+                return "No path could be found between {0} and {1}".format(
+                    vnf_src_name, vnf_dst_name)

 
 

-        LOG.info("Path between {0} and {1}: {2}".format(vnf_src_name, vnf_dst_name, path))
+        LOG.debug("Creating path between {0} and {1}: {2}".format(
+            vnf_src_name, vnf_dst_name, path))

 
         current_hop = src_sw
         switch_inport_nr = src_sw_inport_nr
 
 
         current_hop = src_sw
         switch_inport_nr = src_sw_inport_nr
 

-        # choose free vlan if path contains more than 1 switch
+        # choose free vlan

         cmd = kwargs.get('cmd')
         vlan = None
         if cmd == 'add-flow':
         cmd = kwargs.get('cmd')
         vlan = None
         if cmd == 'add-flow':

-            if len(path) > 1:
+            if kwargs.get('tag'):
+                # use pre-defined tag
+                vlan = kwargs.get('tag')
+            else:

                 vlan = self.vlans.pop()
 
                 vlan = self.vlans.pop()
 

-        for i in range(0,len(path)):
+        # store the used vlan tag to identify this chain
+        if not kwargs.get('monitor'):
+            chain_dict = {}
+            chain_dict['vnf_src_name'] = vnf_src_name
+            chain_dict['vnf_dst_name'] = vnf_dst_name
+            chain_dict['vnf_src_interface'] = vnf_src_interface
+            chain_dict['vnf_dst_interface'] = vnf_dst_interface
+            chain_dict['tag'] = vlan
+            self.installed_chains.append(chain_dict)
+
+        # iterate through the path to install the flow-entries
+        for i in range(0, len(path)):

             current_node = self.getNodeByName(current_hop)
 
             if i < len(path) - 1:
             current_node = self.getNodeByName(current_hop)
 
             if i < len(path) - 1:


@@ -383,8 +708,8 @@ class DCNetwork(Containernet):
 
             if next_hop == vnf_dst_name:
                 switch_outport_nr = dst_sw_outport_nr
 
             if next_hop == vnf_dst_name:
                 switch_outport_nr = dst_sw_outport_nr

-                LOG.info("end node reached: {0}".format(vnf_dst_name))
-            elif not isinstance( next_node, OVSSwitch ):
+                LOG.debug("end node reached: {0}".format(vnf_dst_name))
+            elif not isinstance(next_node, OVSSwitch):

                 LOG.info("Next node: {0} is not a switch".format(next_hop))
                 return "Next node: {0} is not a switch".format(next_hop)
             else:
                 LOG.info("Next node: {0} is not a switch".format(next_hop))
                 return "Next node: {0} is not a switch".format(next_hop)
             else:


@@ -392,30 +717,44 @@ class DCNetwork(Containernet):
                 index_edge_out = 0
                 switch_outport_nr = self.DCNetwork_graph[current_hop][next_hop][index_edge_out]['src_port_nr']
 
                 index_edge_out = 0
                 switch_outport_nr = self.DCNetwork_graph[current_hop][next_hop][index_edge_out]['src_port_nr']
 

-
-           # set of entry via ovs-ofctl
-            if isinstance( current_node, OVSSwitch ):
+            # set OpenFlow entry
+            if isinstance(current_node, OVSSwitch):

                 kwargs['vlan'] = vlan
                 kwargs['path'] = path
                 kwargs['vlan'] = vlan
                 kwargs['path'] = path

+                kwargs['current_hop'] = current_hop
+                kwargs['switch_inport_name'] = src_sw_inport_name
+                kwargs['switch_outport_name'] = dst_sw_outport_name

                 kwargs['pathindex'] = i
 
                 if self.controller == RemoteController:
                 kwargs['pathindex'] = i
 
                 if self.controller == RemoteController:

-                    ## set flow entry via ryu rest api
-                    self._set_flow_entry_ryu_rest(current_node, switch_inport_nr, switch_outport_nr, **kwargs)
+                    # set flow entry via ryu rest api
+                    self._set_flow_entry_ryu_rest(
+                        current_node, switch_inport_nr, switch_outport_nr, **kwargs)

                 else:
                 else:

-                    ## set flow entry via ovs-ofctl
-                    self._set_flow_entry_dpctl(current_node, switch_inport_nr, switch_outport_nr, **kwargs)
-
-
+                    # set flow entry via ovs-ofctl
+                    self._set_flow_entry_dpctl(
+                        current_node, switch_inport_nr, switch_outport_nr, **kwargs)

 
             # take first link between switches by default
 
             # take first link between switches by default

-            if isinstance( next_node, OVSSwitch ):
+            if isinstance(next_node, OVSSwitch):

                 switch_inport_nr = self.DCNetwork_graph[current_hop][next_hop][0]['dst_port_nr']
                 current_hop = next_hop
 
                 switch_inport_nr = self.DCNetwork_graph[current_hop][next_hop][0]['dst_port_nr']
                 current_hop = next_hop
 

-        return "path {2} between {0} and {1}".format(vnf_src_name, vnf_dst_name, cmd)
-
-    def _set_flow_entry_ryu_rest(self, node, switch_inport_nr, switch_outport_nr, **kwargs):
+        flow_options = {
+            'priority': kwargs.get('priority', DEFAULT_PRIORITY),
+            'cookie': kwargs.get('cookie', DEFAULT_COOKIE),
+            'vlan': kwargs['vlan'],
+            'path': kwargs['path'],
+            'match_input': kwargs.get('match')
+        }
+        flow_options_str = json.dumps(flow_options, indent=1)
+        LOG.info("Installed flow rule: ({}:{}) -> ({}:{}) with options: {}"
+                 .format(vnf_src_name, vnf_src_interface, vnf_dst_name, vnf_dst_interface, flow_options))
+        return "success: {2} between {0} and {1} with options: {3}".format(
+            vnf_src_name, vnf_dst_name, cmd, flow_options_str)
+
+    def _set_flow_entry_ryu_rest(
+            self, node, switch_inport_nr, switch_outport_nr, **kwargs):

         match = 'in_port=%s' % switch_inport_nr
 
         cookie = kwargs.get('cookie')
         match = 'in_port=%s' % switch_inport_nr
 
         cookie = kwargs.get('cookie')


@@ -423,9 +762,16 @@ class DCNetwork(Containernet):
         cmd = kwargs.get('cmd')
         path = kwargs.get('path')
         index = kwargs.get('pathindex')
         cmd = kwargs.get('cmd')
         path = kwargs.get('path')
         index = kwargs.get('pathindex')

+        mod_dl_dst = kwargs.get('mod_dl_dst')

 
         vlan = kwargs.get('vlan')
 
         vlan = kwargs.get('vlan')

-        priority = kwargs.get('priority')
+        priority = kwargs.get('priority', DEFAULT_PRIORITY)
+        # flag to not set the ovs port vlan tag
+        skip_vlan_tag = kwargs.get('skip_vlan_tag')
+        # table id to put this flowentry
+        table_id = kwargs.get('table_id')
+        if not table_id:
+            table_id = 0

 
         s = ','
         if match_input:
 
         s = ','
         if match_input:


@@ -439,31 +785,58 @@ class DCNetwork(Containernet):
         if priority:
             flow['priority'] = int(priority)
 
         if priority:
             flow['priority'] = int(priority)
 

+        flow['table_id'] = table_id
+

         flow['actions'] = []
 
         # possible Ryu actions, match fields:
         # http://ryu.readthedocs.io/en/latest/app/ofctl_rest.html#add-a-flow-entry
         if cmd == 'add-flow':
             prefix = 'stats/flowentry/add'
         flow['actions'] = []
 
         # possible Ryu actions, match fields:
         # http://ryu.readthedocs.io/en/latest/app/ofctl_rest.html#add-a-flow-entry
         if cmd == 'add-flow':
             prefix = 'stats/flowentry/add'

-            if vlan != None:
+            if vlan is not None:

                 if index == 0:  # first node
                 if index == 0:  # first node

-                    action = {}
-                    action['type'] = 'PUSH_VLAN'  # Push a new VLAN tag if a input frame is non-VLAN-tagged
-                    action['ethertype'] = 33024   # Ethertype 0x8100(=33024): IEEE 802.1Q VLAN-tagged frame
-                    flow['actions'].append(action)
-                    action = {}
-                    action['type'] = 'SET_FIELD'
-                    action['field'] = 'vlan_vid'
-                    # ryu expects the field to be masked
-                    action['value'] = vlan | 0x1000
-                    flow['actions'].append(action)
-                elif index == len(path) -1:  # last node
-                    match += ',dl_vlan=%s' % vlan
-                    action = {}
-                    action['type'] = 'POP_VLAN'
-                    flow['actions'].append(action)
+                    # set vlan tag in ovs instance (to isolate E-LANs)
+                    if not skip_vlan_tag:
+                        in_port_name = kwargs.get('switch_inport_name')
+                        self._set_vlan_tag(node, in_port_name, vlan)
+                    # set vlan push action if more than 1 switch in the path
+                    if len(path) > 1:
+                        action = {}
+                        # Push a new VLAN tag if a input frame is
+                        # non-VLAN-tagged
+                        action['type'] = 'PUSH_VLAN'
+                        # Ethertype 0x8100(=33024): IEEE 802.1Q VLAN-tagged
+                        # frame
+                        action['ethertype'] = 33024
+                        flow['actions'].append(action)
+                        action = {}
+                        action['type'] = 'SET_FIELD'
+                        action['field'] = 'vlan_vid'
+                        # ryu expects the field to be masked
+                        action['value'] = vlan | 0x1000
+                        flow['actions'].append(action)
+
+                elif index == len(path) - 1:  # last node
+                    # set vlan tag in ovs instance (to isolate E-LANs)
+                    if not skip_vlan_tag:
+                        out_port_name = kwargs.get('switch_outport_name')
+                        self._set_vlan_tag(node, out_port_name, vlan)
+                    # set vlan pop action if more than 1 switch in the path
+                    if len(path) > 1:
+                        match += ',dl_vlan=%s' % vlan
+                        action = {}
+                        action['type'] = 'POP_VLAN'
+                        flow['actions'].append(action)
+

                 else:  # middle nodes
                     match += ',dl_vlan=%s' % vlan
                 else:  # middle nodes
                     match += ',dl_vlan=%s' % vlan

+            if mod_dl_dst:
+                action = {}
+                action['type'] = 'SET_FIELD'
+                action['field'] = 'eth_dst'
+                action['value'] = mod_dl_dst
+                flow['actions'].append(action)
+

             # output action must come last
             action = {}
             action['type'] = 'OUTPUT'
             # output action must come last
             action = {}
             action['type'] = 'OUTPUT'


@@ -475,7 +848,8 @@ class DCNetwork(Containernet):
 
             if cookie:
                 # TODO: add cookie_mask as argument
 
             if cookie:
                 # TODO: add cookie_mask as argument

-                flow['cookie_mask'] = int('0xffffffffffffffff', 16)  # need full mask to match complete cookie
+                # need full mask to match complete cookie
+                flow['cookie_mask'] = int('0xffffffffffffffff', 16)

 
             action = {}
             action['type'] = 'OUTPUT'
 
             action = {}
             action['type'] = 'OUTPUT'


@@ -485,7 +859,14 @@ class DCNetwork(Containernet):
         flow['match'] = self._parse_match(match)
         self.ryu_REST(prefix, data=flow)
 
         flow['match'] = self._parse_match(match)
         self.ryu_REST(prefix, data=flow)
 

-    def _set_flow_entry_dpctl(self, node, switch_inport_nr, switch_outport_nr, **kwargs):
+    def _set_vlan_tag(self, node, switch_port, tag):
+        node.vsctl('set', 'port {0} tag={1}'.format(switch_port, tag))
+        LOG.debug("set vlan in switch: {0} in_port: {1} vlan tag: {2}".format(
+            node.name, switch_port, tag))
+
+    def _set_flow_entry_dpctl(
+            self, node, switch_inport_nr, switch_outport_nr, **kwargs):
+

         match = 'in_port=%s' % switch_inport_nr
 
         cookie = kwargs.get('cookie')
         match = 'in_port=%s' % switch_inport_nr
 
         cookie = kwargs.get('cookie')


@@ -503,9 +884,10 @@ class DCNetwork(Containernet):
             match = s.join([match, match_input])
         if cmd == 'add-flow':
             action = 'action=%s' % switch_outport_nr
             match = s.join([match, match_input])
         if cmd == 'add-flow':
             action = 'action=%s' % switch_outport_nr

-            if vlan != None:
-                if index == 0: # first node
-                    action = ('action=mod_vlan_vid:%s' % vlan) + (',output=%s' % switch_outport_nr)
+            if vlan is not None:
+                if index == 0:  # first node
+                    action = ('action=mod_vlan_vid:%s' % vlan) + \
+                        (',output=%s' % switch_outport_nr)

                     match = '-O OpenFlow13 ' + match
                 elif index == len(path) - 1:  # last node
                     match += ',dl_vlan=%s' % vlan
                     match = '-O OpenFlow13 ' + match
                 elif index == len(path) - 1:  # last node
                     match += ',dl_vlan=%s' % vlan


@@ -520,14 +902,19 @@ class DCNetwork(Containernet):
 
         node.dpctl(cmd, ofcmd)
         LOG.info("{3} in switch: {0} in_port: {1} out_port: {2}".format(node.name, switch_inport_nr,
 
         node.dpctl(cmd, ofcmd)
         LOG.info("{3} in switch: {0} in_port: {1} out_port: {2}".format(node.name, switch_inport_nr,

-                                                                                 switch_outport_nr, cmd))
+                                                                        switch_outport_nr, cmd))

 
     # start Ryu Openflow controller as Remote Controller for the DCNetwork
     def startRyu(self, learning_switch=True):
         # start Ryu controller with rest-API
 
     # start Ryu Openflow controller as Remote Controller for the DCNetwork
     def startRyu(self, learning_switch=True):
         # start Ryu controller with rest-API

-        python_install_path = site.getsitepackages()[0]
-        ryu_path = python_install_path + '/ryu/app/simple_switch_13.py'
-        ryu_path2 = python_install_path + '/ryu/app/ofctl_rest.py'
+
+        # ryu default learning switch
+        # ryu_learning_app = python_install_path + '/ryu/app/simple_switch_13.py'
+        # custom learning switch that installs a default NORMAL action in the
+        # ovs switches
+        dir_path = os.path.dirname(os.path.realpath(__file__))
+        ryu_learning_app = dir_path + '/son_emu_simple_switch_13.py'
+        ryu_rest_app = 'ryu.app.ofctl_rest'

         # change the default Openflow controller port to 6653 (official IANA-assigned port number), as used by Mininet
         # Ryu still uses 6633 as default
         ryu_option = '--ofp-tcp-listen-port'
         # change the default Openflow controller port to 6653 (official IANA-assigned port number), as used by Mininet
         # Ryu still uses 6633 as default
         ryu_option = '--ofp-tcp-listen-port'


@@ -535,10 +922,13 @@ class DCNetwork(Containernet):
         ryu_cmd = 'ryu-manager'
         FNULL = open("/tmp/ryu.log", 'w')
         if learning_switch:
         ryu_cmd = 'ryu-manager'
         FNULL = open("/tmp/ryu.log", 'w')
         if learning_switch:

-            self.ryu_process = Popen([ryu_cmd, ryu_path, ryu_path2, ryu_option, ryu_of_port], stdout=FNULL, stderr=FNULL)
+            # learning and rest api
+            args = [ryu_cmd, ryu_learning_app, ryu_rest_app, ryu_option, ryu_of_port]

         else:
             # no learning switch, but with rest api
         else:
             # no learning switch, but with rest api

-            self.ryu_process = Popen([ryu_cmd, ryu_path2, ryu_option, ryu_of_port], stdout=FNULL, stderr=FNULL)
+            args = [ryu_cmd, ryu_rest_app, ryu_option, ryu_of_port]
+        self.ryu_process = Popen(args, stdout=FNULL, stderr=FNULL)
+        LOG.debug('starting ryu-controller with %s' % args)

         time.sleep(1)
 
     def killRyu(self):
         time.sleep(1)
 
     def killRyu(self):


@@ -559,22 +949,24 @@ class DCNetwork(Containernet):
             url = self.ryu_REST_api + '/' + str(prefix) + '/' + str(dpid)
         else:
             url = self.ryu_REST_api + '/' + str(prefix)
             url = self.ryu_REST_api + '/' + str(prefix) + '/' + str(dpid)
         else:
             url = self.ryu_REST_api + '/' + str(prefix)

+
+        LOG.debug('sending RYU command: %s, payload: %s', url, data)

         if data:
             req = self.RyuSession.post(url, json=data)
         else:
             req = self.RyuSession.get(url)
 
         if data:
             req = self.RyuSession.post(url, json=data)
         else:
             req = self.RyuSession.get(url)
 

-

         # do extra logging if status code is not 200 (OK)
         if req.status_code is not requests.codes.ok:
         # do extra logging if status code is not 200 (OK)
         if req.status_code is not requests.codes.ok:

-            logging.info(
+            LOG.info(

                 'type {0}  encoding: {1} text: {2} headers: {3} history: {4}'.format(req.headers['content-type'],
                                                                                      req.encoding, req.text,
                                                                                      req.headers, req.history))
             LOG.info('url: {0}'.format(str(url)))
                 'type {0}  encoding: {1} text: {2} headers: {3} history: {4}'.format(req.headers['content-type'],
                                                                                      req.encoding, req.text,
                                                                                      req.headers, req.history))
             LOG.info('url: {0}'.format(str(url)))

-            if data: LOG.info('POST: {0}'.format(str(data)))
-            LOG.info('status: {0} reason: {1}'.format(req.status_code, req.reason))
-
+            if data:
+                LOG.info('POST: {0}'.format(str(data)))
+            LOG.info('status: {0} reason: {1}'.format(
+                req.status_code, req.reason))

 
         if 'json' in req.headers['content-type']:
             ret = req.json()
 
         if 'json' in req.headers['content-type']:
             ret = req.json()


@@ -583,9 +975,9 @@ class DCNetwork(Containernet):
         ret = req.text.rstrip()
         return ret
 
         ret = req.text.rstrip()
         return ret
 

-

     # need to respect that some match fields must be integers
     # http://ryu.readthedocs.io/en/latest/app/ofctl_rest.html#description-of-match-and-actions
     # need to respect that some match fields must be integers
     # http://ryu.readthedocs.io/en/latest/app/ofctl_rest.html#description-of-match-and-actions

+

     def _parse_match(self, match):
         matches = match.split(',')
         dict = {}
     def _parse_match(self, match):
         matches = match.split(',')
         dict = {}


@@ -594,9 +986,27 @@ class DCNetwork(Containernet):
             if len(match) == 2:
                 try:
                     m2 = int(match[1], 0)
             if len(match) == 2:
                 try:
                     m2 = int(match[1], 0)

-                except:
+                except BaseException:

                     m2 = match[1]
 
                     m2 = match[1]
 

-                dict.update({match[0]:m2})
+                dict.update({match[0]: m2})

         return dict
 
         return dict
 

+    def find_connected_dc_interface(
+            self, vnf_src_name, vnf_src_interface=None):
+
+        if vnf_src_interface is None:
+            # take first interface by default
+            connected_sw = self.DCNetwork_graph.neighbors(vnf_src_name)[0]
+            link_dict = self.DCNetwork_graph[vnf_src_name][connected_sw]
+            vnf_src_interface = link_dict[0]['src_port_id']
+
+        for connected_sw in self.DCNetwork_graph.neighbors(vnf_src_name):
+            link_dict = self.DCNetwork_graph[vnf_src_name][connected_sw]
+            for link in link_dict:
+                if (link_dict[link]['src_port_id'] == vnf_src_interface or
+                        link_dict[link]['src_port_name'] == vnf_src_interface):
+                    # Fix: we might also get interface names, e.g, from a son-emu-cli call
+                    # found the right link and connected switch
+                    src_sw_inport_name = link_dict[link]['dst_port_name']
+                    return src_sw_inport_name