diff --git a/doc/plan.org b/doc/plan.org
index 429f7e5..1ea4f22 100644
--- a/doc/plan.org
+++ b/doc/plan.org
@@ -432,9 +432,18 @@ DEBUG:main:INCOMING: <Ether  dst=33:33:ff:00:00:42 src=00:00:0a:00:00:01 type=0x
 
 **** Requirements
 *** Performance comparison
-*** Feature/Functionality difference / overview
+*** Feature/Functionality difference / overview / Challenges in P4
+**** ICMP6: checksum over payload
+     - variable length, up to 65k
+**** Synchronisation with the controller
+     - Double data type definition -> might differ
+     - TYPE_CPU for ethernet
+     - Port ingress offset (9 vs. 16 bit)
+
+
 **** Not included
      - DNS64 - has already been solved in a different domain
+
 *** References / Follow up
 **** RFC 2460 IPv6 (Checksum https://tools.ietf.org/html/rfc2460#section-8.1)
 **** RFC 3810 MLD2 https://tools.ietf.org/html/rfc3810
diff --git a/p4app/controller.py b/p4app/controller.py
index 707dcec..a1f13e6 100644
--- a/p4app/controller.py
+++ b/p4app/controller.py
@@ -35,10 +35,8 @@ class L2Controller(object):
         # Command line mapping
         self.modes = ['base', 'router']
 
-
         self.info={}
-        self.info['ndp_multicast'] = ipaddress.ip_network("ff02::1:ff00:0/104")
-
+        self.info['ndp_multicast'] = ipaddress.ip_network(u"ff02::1:ff00:0/104")
 
         self.address_suffix = 42
 
@@ -146,10 +144,15 @@ class L2Controller(object):
 
 
     def fill_tables(self):
-        self.controller.table_clear("v6_routing")
+        self.controller.table_clear("v6_networks")
         for v6route in self.v6_routes[self.mode]:
             net = self.prefix_to_net(v6route['net'], self.v6_mask)
-            self.controller.table_add("v6_routing", "set_egress_port", [net], [v6route['port']])
+            self.controller.table_add("v6_networks", "set_egress_port", [net], [v6route['port']])
+
+        for v6net in self.info['ndp_multicast']:
+            net = str(v6net)
+            self.controller.table_add("v6_networks", "controller_reply", [net])
+
 
         self.controller.table_clear("v4_routing")
         for v4route in self.v4_routes[self.mode]:
diff --git a/p4src/headers.p4 b/p4src/headers.p4
index 64c6c7f..a5f78bc 100644
--- a/p4src/headers.p4
+++ b/p4src/headers.p4
@@ -15,6 +15,7 @@ typedef bit<16>  mcast_t;
 const bit<16> TYPE_IPV4  = 0x0800;
 const bit<16> TYPE_IPV6  = 0x86DD;
 const bit<16> TYPE_CPU   = 0x4242;
+const bit<16> TYPE_DEBUG = 0x2323;
 
 
 const bit<8>  PROTO_ICMP = 1;
diff --git a/p4src/static-mapping.p4 b/p4src/static-mapping.p4
index 7facbd6..b15bbe6 100644
--- a/p4src/static-mapping.p4
+++ b/p4src/static-mapping.p4
@@ -18,13 +18,16 @@ control MyIngress(inout headers hdr,
 
     /********************** ACTIONS ***********************************/
 
-    /* As the name says */
     action drop() {
         mark_to_drop();
     }
 
-    /* As the name says */
-    action send_to_controller() {
+	action set_egress_port (port_t out_port) {
+        standard_metadata.egress_spec = out_port;
+	}
+
+    action controller_debug() {
+        hdr.ethernet.ethertype = TYPE_DEBUG;
         clone3(CloneType.I2E, 100, meta);
     }
 
@@ -33,8 +36,7 @@ control MyIngress(inout headers hdr,
         clone3(CloneType.I2E, 100, meta);
     }
 
-    /* Output PKG on correct ports (plural) */
-    action multicast_pkg(mcast_t mcast_grp) {
+    action multicast_pkg(mcast_t mcast_grp) {         /* Output PKG on correct ports (plural) */
         standard_metadata.mcast_grp = mcast_grp;
     }
 
@@ -54,7 +56,7 @@ control MyIngress(inout headers hdr,
             hdr.icmp6.type: exact;
         }
         actions = {
-            send_to_controller;
+            controller_debug;
             icmp6_neighbor_solicitation;
             NoAction;
         }
@@ -70,12 +72,12 @@ control MyIngress(inout headers hdr,
         }
         actions = {
 			multicast_pkg;
-            send_to_controller;
+            controller_debug;
             NoAction;
         }
         size = NDP_TABLE_SIZE;
         default_action = NoAction;
-//        default_action = send_to_controller;
+//        default_action = controller_debug;
     }
 
     /* Handle multicast registration of NDP */
@@ -85,12 +87,12 @@ control MyIngress(inout headers hdr,
         }
         actions = {
 			multicast_pkg;
-            send_to_controller;
+            controller_debug;
             NoAction;
         }
         size = NDP_TABLE_SIZE;
         default_action = NoAction;
-//        default_action = send_to_controller;
+//        default_action = controller_debug;
     }
 
     /********************** NDP support ***********************************/
@@ -103,12 +105,12 @@ control MyIngress(inout headers hdr,
         }
         actions = {
 			multicast_pkg;
-            send_to_controller;
+            controller_debug;
             NoAction;
         }
         size = NDP_TABLE_SIZE;
 //        default_action = NoAction;
-        default_action = send_to_controller;
+        default_action = controller_debug;
     }
 
 
@@ -130,28 +132,24 @@ control MyIngress(inout headers hdr,
         */
     }
 
+
+	/********************** ROUTING (egress definiton) TABLES ***********************************/
+
     table v6_addresses {
         key = {
             hdr.ipv6.dst_addr: exact;
-//            hdr.ipv6.next_header: exact;
         }
         actions = {
-//			icmp6_answer;
-            send_to_controller;
+            controller_debug;
             controller_reply;
             NoAction;
         }
         size = ADDRESS_TABLE_SIZE;
-//        default_action = send_to_controller;
         default_action = NoAction;
 
     }
 
-	/********************** ROUTING (egress definiton) TABLES ***********************************/
-	action set_egress_port (port_t out_port) {
-        standard_metadata.egress_spec = out_port;
-	}
-    table v6_routing {
+    table v6_networks {
         key = {
             hdr.ipv6.dst_addr: lpm;
         }
@@ -163,6 +161,7 @@ control MyIngress(inout headers hdr,
         default_action = NoAction;
     }
 
+
     table v4_routing {
         key = {
             hdr.ipv4.dst_addr: lpm;