diff --git a/tools/test/topos/ukRegion.py b/tools/test/topos/ukRegion.py
index a3a8696..ecbdf6a 100644
--- a/tools/test/topos/ukRegion.py
+++ b/tools/test/topos/ukRegion.py
@@ -16,26 +16,26 @@
         Topo.__init__(self)
 
         # add nodes, switches first...
-        DOVER = self.addSwitch('s1')
-        BRGHTN_A = self.addSwitch('s2')
-        BRGHTN_B = self.addSwitch('s3')
-        BRGHTN_C = self.addSwitch('s4')
-        LONDON_A = self.addSwitch('s5')
-        LONDON_B = self.addSwitch('s6')
-        LONDON_C = self.addSwitch('s7')
-        LONDON_D = self.addSwitch('s8')
-        LONDON_E = self.addSwitch('s9')
+        DOVER = self.addSwitch('s1', dpid='0000000000000010')
+        BRGHTN_A = self.addSwitch('s2', dpid='0000000000000021')
+        BRGHTN_B = self.addSwitch('s3', dpid='0000000000000022')
+        BRGHTN_C = self.addSwitch('s4', dpid='0000000000000023')
+        LONDON_A = self.addSwitch('s5', dpid='0000000000000031')
+        LONDON_B = self.addSwitch('s6', dpid='0000000000000032')
+        LONDON_C = self.addSwitch('s7', dpid='0000000000000033')
+        LONDON_D = self.addSwitch('s8', dpid='0000000000000034')
+        LONDON_E = self.addSwitch('s9', dpid='0000000000000035')
 
         # ... and now hosts
-        DOVER_host = self.addHost('h1')
-        BRGHTN_A_host = self.addHost('h2')
-        BRGHTN_B_host = self.addHost('h3')
-        BRGHTN_C_host = self.addHost('h4')
-        LONDON_A_host = self.addHost('h5')
-        LONDON_B_host = self.addHost('h6')
-        LONDON_C_host = self.addHost('h7')
-        LONDON_D_host = self.addHost('h8')
-        LONDON_E_host = self.addHost('h9')
+        DOVER_host = self.addHost('h1', mac='000000000010')
+        BRGHTN_A_host = self.addHost('h2', mac='000000000021')
+        BRGHTN_B_host = self.addHost('h3', mac='000000000022')
+        BRGHTN_C_host = self.addHost('h4', mac='000000000023')
+        LONDON_A_host = self.addHost('h5', mac='000000000031')
+        LONDON_B_host = self.addHost('h6', mac='000000000032')
+        LONDON_C_host = self.addHost('h7', mac='000000000033')
+        LONDON_D_host = self.addHost('h8', mac='000000000034')
+        LONDON_E_host = self.addHost('h9', mac='000000000035')
 
         # add edges between switch and corresponding host
         self.addLink(DOVER, DOVER_host)