diff --git a/src/emuvim/api/zerorpc/network.py b/src/emuvim/api/zerorpc/network.py
index 5a353fe..116d13b 100644
--- a/src/emuvim/api/zerorpc/network.py
+++ b/src/emuvim/api/zerorpc/network.py
@@ -71,7 +71,10 @@
         logging.debug("RPC CALL: network chain start")
         try:
             c = self.net.setChain(
-                vnf_src_name, vnf_dst_name, vnf_src_interface, vnf_dst_interface, weight=weight)
+                vnf_src_name, vnf_dst_name,
+                vnf_src_interface=vnf_src_interface,
+                vnf_dst_interface=vnf_dst_interface,
+                weight=weight)
             return str(c)
         except Exception as ex:
             logging.exception("RPC error.")
@@ -84,7 +87,11 @@
         logging.debug("RPC CALL: network chain stop")
         try:
             c = self.net.setChain(
-                vnf_src_name, vnf_dst_name, vnf_src_interface, vnf_dst_interface, cmd='del-flows', weight=weight)
+                vnf_src_name, vnf_dst_name,
+                vnf_src_interface=vnf_src_interface,
+                vnf_dst_interface=vnf_dst_interface,
+                cmd='del-flows',
+                weight=weight)
             return c
         except Exception as ex:
             logging.exception("RPC error.")
diff --git a/src/emuvim/cli/network.py b/src/emuvim/cli/network.py
index 5b0aa51..6b196a3 100755
--- a/src/emuvim/cli/network.py
+++ b/src/emuvim/cli/network.py
@@ -37,8 +37,8 @@
             #args.get("datacenter"),
             vnf_src_name,
             vnf_dst_name,
-            vnf_src_interface,
-            vnf_dst_interface,
+            vnf_src_interface=vnf_src_interface,
+            vnf_dst_interface=vnf_dst_interface,
             weight=weight)
         pp.pprint(r)
 
@@ -52,8 +52,8 @@
             #args.get("datacenter"),
             vnf_src_name,
             vnf_dst_name,
-            vnf_src_interface,
-            vnf_dst_interface,
+            vnf_src_interface=vnf_src_interface,
+            vnf_dst_interface=vnf_dst_interface,
             weight=weight)
         pp.pprint(r)
 
diff --git a/src/emuvim/dcemulator/net.py b/src/emuvim/dcemulator/net.py
index 54d578d..4028a26 100755
--- a/src/emuvim/dcemulator/net.py
+++ b/src/emuvim/dcemulator/net.py
@@ -224,15 +224,15 @@
             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']
-            #vnf_source_interface = 0
+            #logging.info('vnf_src_if: {0}'.format(vnf_src_interface))
 
         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:
-                #logging.info("{0},{1}".format(link_dict[link],vnf_source_interface))
+                #logging.info("here1: {0},{1}".format(link_dict[link],vnf_src_interface))
                 if link_dict[link]['src_port_id'] == vnf_src_interface:
                     # found the right link and connected switch
-                    #logging.info("{0},{1}".format(link_dict[link]['src_port_id'], vnf_source_interface))
+                    #logging.info("conn_sw: {2},{0},{1}".format(link_dict[link]['src_port_id'], vnf_src_interface, connected_sw))
                     src_sw = connected_sw
 
                     src_sw_inport = link_dict[link]['dst_port']
@@ -243,7 +243,6 @@
             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_dest_interface = 0
 
         vnf_dst_name = vnf_dst_name.split(':')[0]
         for connected_sw in self.DCNetwork_graph.neighbors(vnf_dst_name):
@@ -259,6 +258,8 @@
         # get shortest path
         #path = nx.shortest_path(self.DCNetwork_graph, vnf_src_name, vnf_dst_name)
         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=weight)
         except:
             logging.info("No path could be found between {0} and {1}".format(vnf_src_name, vnf_dst_name))
@@ -291,16 +292,6 @@
                 index_edge_out = 0
                 switch_outport = self.DCNetwork_graph[current_hop][next_hop][index_edge_out]['src_port']
 
-            # take into account that multiple edges are possible between 2 nodes
-            index_edge_in = 0
-
-
-            #switch_inport = self.DCNetwork_graph[current_hop][next_hop][index_edge_in]['dst_port']
-
-            #next2_hop = path[path.index(current_hop)+2]
-            #index_edge_out = 0
-            #switch_outport = self.DCNetwork_graph[next_hop][next2_hop][index_edge_out]['src_port']
-            #switch_outport = self.DCNetwork_graph[current_hop][next_hop][index_edge_out]['src_port']
 
             #logging.info("add flow in switch: {0} in_port: {1} out_port: {2}".format(current_node.name, switch_inport, switch_outport))
             # set of entry via ovs-ofctl
@@ -342,9 +333,9 @@
         ryu_of_port = '6653'
         ryu_cmd = 'ryu-manager'
         FNULL = open("/tmp/ryu.log", 'w')
-        self.ryu_process = Popen([ryu_cmd, ryu_path, ryu_path2, ryu_option, ryu_of_port], stdout=FNULL, stderr=FNULL)
+        #self.ryu_process = Popen([ryu_cmd, ryu_path, ryu_path2, ryu_option, ryu_of_port], stdout=FNULL, stderr=FNULL)
         # no learning switch
-        #self.ryu_process = Popen([ryu_cmd, ryu_path2, ryu_option, ryu_of_port], stdout=FNULL, stderr=FNULL)
+        self.ryu_process = Popen([ryu_cmd, ryu_path2, ryu_option, ryu_of_port], stdout=FNULL, stderr=FNULL)
         time.sleep(1)
 
     def stopRyu(self):
diff --git a/src/emuvim/examples/monitoring_demo_topology.py b/src/emuvim/examples/monitoring_demo_topology.py
index 20f3ba0..a5cf0b2 100755
--- a/src/emuvim/examples/monitoring_demo_topology.py
+++ b/src/emuvim/examples/monitoring_demo_topology.py
@@ -61,10 +61,12 @@
        These links can use Mininet's features to limit bw, add delay or jitter.
     """
     net.addLink(dc1, dc2, delay="10ms")
+    net.addLink(dc1, dc2)
     net.addLink("datacenter1", s1, delay="20ms")
     net.addLink(s1, dc3)
     net.addLink(s1, "datacenter4")
 
+
     """
     5. We want to access and control our data centers from the outside,
        e.g., we want to connect an orchestrator to start/stop compute