diff --git a/p4app/controller.py b/p4app/controller.py
index dad028c..3f678df 100644
--- a/p4app/controller.py
+++ b/p4app/controller.py
@@ -194,7 +194,7 @@ class L2Controller(object):
             dev    = "{}-eth0".format(host)
             net    = v6route['net']
             ipaddr = "{}/{}".format(net[1],net.prefixlen)
-            router = net[self.info['switch_suffix']]
+            router = str(net[self.info['switch_suffix']])
 
             self.config_v6_host(host, str(net), str(ipaddr), dev, router)