diff --git a/doc/plan.org b/doc/plan.org
index 00138b3..a9ae98c 100644
--- a/doc/plan.org
+++ b/doc/plan.org
@@ -203,6 +203,8 @@ multicast address of the target address."
 
 **** DONE Make switch answer icmp6 echo request for
 **** TODO Make switch answer icmp echo request for
+**** TODO Introduce mixed mode: switch: icmp6 echo reply, controller: NDP
+***** TODO try 1: reply seen, but checksum is incorrect
 **** DONE Add default route for v6  hosts
 p4@ubuntu:~/master-thesis$ mx h1 ip -6 r
 sudo: unable to resolve host ubuntu
@@ -290,6 +292,7 @@ user@T:~# iptables  -t mangle -A PREROUTING \
      - IPv6 in IPv4 mapped hosts are in 10.0.6.0/24
      - IPv4 default router = 10.0.0.42
 **** Neighbor discover protocol
+***** Initial log
      - Matching on prefix & ingress port, setting multicast
 
 Being forwarded:
@@ -463,6 +466,30 @@ DEBUG:main:INCOMING: <Ether  dst=33:33:00:00:00:02 src=00:00:0a:00:00:02 type=0x
 We are not using router advertisements, so we ignore RS packets
 DEBUG:main:INCOMING: <Ether  dst=33:33:00:00:00:02 src=00:00:0a:00:00:01 type=0x86dd |<IPv6  version=6 tc=0 fl=0 plen=16 nh=ICMPv6 hlim=255 src=fe80::200:aff:fe00:1 dst=ff02::2 |<ICMPv6ND_RS  type=Router Solicitation code=0 cksum=0xf72e res=0 |<ICMPv6NDOptSrcLLAddr  type=1 len=1 lladdr=00:00:0a:00:00:01 |>>>>
 
+***** Double table entries due to collision
+      - NDP: last 24 bit
+      - Switch has same ending address in different networks -> equal
+        last 24 bit
+      - results in trying to add multicast address multiple times
+
+Adding entry to exact match table v6_addresses
+match key:           EXACT-ff:02:00:00:00:00:00:00:00:00:00:01:ff:00:00:42
+action:              controller_reply
+runtime data:        00:01
+Invalid table operation (DUPLICATE_ENTRY)
+Adding entry to exact match table v6_addresses
+match key:           EXACT-ff:02:00:00:00:00:00:00:00:00:00:01:ff:00:00:43
+action:              controller_reply
+runtime data:        00:01
+Invalid table operation (DUPLICATE_ENTRY)
+Adding entry to exact match table v6_addresses
+match key:           EXACT-20:01:0d:b8:00:00:00:01:00:00:00:00:00:00:00:43
+action:              icmp6_echo_reply
+runtime data:
+Entry has been added with handle 5
+
+
+
 **** Static mappings
       - likely need table(s)
       - need tcp & udp translation
@@ -517,7 +544,6 @@ DEBUG:main:INCOMING: <Ether  dst=33:33:ff:00:00:42 src=00:00:0a:00:00:01 type=0x
 ****** Right side: IPv4
 ***** Included in the header
 
-
 **** Requirements
 *** Performance comparison
 *** Feature/Functionality difference / overview / Challenges in P4
diff --git a/p4src/static-mapping.p4 b/p4src/static-mapping.p4
index a84eca1..9d21e3a 100644
--- a/p4src/static-mapping.p4
+++ b/p4src/static-mapping.p4
@@ -63,7 +63,7 @@ control MyIngress(inout headers hdr,
         hdr.icmp6.type = ICMP6_ECHO_REPLY;
 
         meta.do_cksum = 1;
-        //meta.cast_length = (bit<32>) hdr.ipv6.payload_length;
+        meta.cast_length = (bit<32>) hdr.ipv6.payload_length;
     }
 
     /* this needs SESSIONS!!