diff --git a/doc/plan.org b/doc/plan.org
index 51b51d0..b7e1c8b 100644
--- a/doc/plan.org
+++ b/doc/plan.org
@@ -66,6 +66,7 @@
 **** DONE Parse icmp
 **** DONE Parse icmpv6
 **** DONE Add (static) egress configuration
+**** TODO Calculate ICMP6 checksums
 **** TODO Make switch answer icmp6 echo request for
 **** TODO Make switch answer icmp echo request for
 **** TODO Add default route for v6 and v4 hosts
@@ -144,6 +145,29 @@ user@T:~# iptables  -t mangle -A PREROUTING \
 **** Static mappings
       - likely need table(s)
       - need tcp & udp translation
+**** ICMPv6
+Different lengths possible
+
+[20:35] line:~% ping -6 -s 20 ::1
+PING ::1(::1) 20 data bytes
+28 bytes from ::1: icmp_seq=1 ttl=64 time=0.045 ms
+28 bytes from ::1: icmp_seq=2 ttl=64 time=0.064 ms
+^C
+--- ::1 ping statistics ---
+2 packets transmitted, 2 received, 0% packet loss, time 1018ms
+rtt min/avg/max/mdev = 0.045/0.054/0.064/0.012 ms
+[20:36] line:~% ping -6 -s 80 ::1
+PING ::1(::1) 80 data bytes
+88 bytes from ::1: icmp_seq=1 ttl=64 time=0.053 ms
+88 bytes from ::1: icmp_seq=2 ttl=64 time=0.095 ms
+^C
+--- ::1 ping statistics ---
+2 packets transmitted, 2 received, 0% packet loss, time 1001ms
+rtt min/avg/max/mdev = 0.053/0.074/0.095/0.021 ms
+[20:36] line:~%
+
+Different checksum in most packets.
+
 ***** Hosts
 ****** Left side: IPv6
 ****** Right side: IPv4
@@ -157,6 +181,8 @@ user@T:~# iptables  -t mangle -A PREROUTING \
 **** RFC 6052: https://tools.ietf.org/html/rfc6052  IPv6 Addressing of IPv4/IPv6 Translators
 **** RFC 6586 for deployment experiences using Stateful NAT64.
 **** RFC 7757 Explicit Address Mappings for Stateless IP/ICMP Translation
+**** RFC 4443 ICMPv6 https://tools.ietf.org/html/rfc4443
+**** RFC 2460 IPv6 (Checksum https://tools.ietf.org/html/rfc2460#section-8.1)
 **** EAMT/Jool: https://www.jool.mx/en/eamt.html
 * Proposal / task description
 ** Task description for mystudies
diff --git a/p4src/checksums.p4 b/p4src/checksums.p4
index 5c58803..6fb70cb 100644
--- a/p4src/checksums.p4
+++ b/p4src/checksums.p4
@@ -21,38 +21,17 @@ control MyVerifyChecksum(inout headers hdr, inout metadata meta) {
 
 control MyComputeChecksum(inout headers  hdr, inout metadata meta) {
     apply {
-        /* 512 bit+ according to
-        https://en.wikipedia.org/wiki/Transmission_Control_Protocol#TCP_checksum_for_IPv4
-        */
-			update_checksum_with_payload(
-			hdr.ipv6.isValid(),
+		update_checksum (
+			hdr.icmp6.isValid(),
 			{
-                hdr.ipv6.src_addr, /* 128 */
-				hdr.ipv6.dst_addr, /* 128 */
-				meta.tcpLength,
-				24w0,
-				hdr.ipv6.next_header,
-				// TCP header
-				hdr.tcp.src_port,
-				hdr.tcp.dst_port,
-				hdr.tcp.seqNo,
-				hdr.tcp.ackNo,
-				hdr.tcp.data_offset,
-				hdr.tcp.res,
-				hdr.tcp.cwr,
-				hdr.tcp.ece,
-				hdr.tcp.urg,
-				hdr.tcp.ack,
-				hdr.tcp.psh,
-				hdr.tcp.rst,
-				hdr.tcp.syn,
-				hdr.tcp.fin,
-				hdr.tcp.window,
-				hdr.tcp.urgentPtr
-			},
-			hdr.tcp.checksum,
-			HashAlgorithm.csum16);
-
+                hdr.ipv6.src_addr,         /* 128 */
+				hdr.ipv6.dst_addr,         /* 128 */
+                hdr.ipv6.payload_length,   /* 16  -> should be 32 according to RFC2460 - also static number? */
+                24w0,                      /* 24 0's */
+                PROTO_ICMP6                /* 8 */
+            }
+            hdr.icmp6.checksum,
+            HashAlgorithm.csum16);
     }
 }