diff --git a/p4src/checksums.p4 b/p4src/checksums.p4
index bc6eb06..b913ee4 100644
--- a/p4src/checksums.p4
+++ b/p4src/checksums.p4
@@ -21,12 +21,14 @@ control MyVerifyChecksum(inout headers hdr, inout metadata meta) {
 
 control MyComputeChecksum(inout headers  hdr, inout metadata meta) {
     apply {
+        bit<32> cksum = (bit<32>) hdr.ipv6.payload_length;
+
 		update_checksum (
 			hdr.icmp6.isValid(),
 			{
                 hdr.ipv6.src_addr,         /* 128 */
 				hdr.ipv6.dst_addr,         /* 128 */
-                (bit<32>) hdr.ipv6.payload_length,   /* 16 bit  -> should be 32 according to RFC2460 - also static number? */
+                cksum,                     /* 32 */
                 24w0,                      /* 24 0's */
                 PROTO_ICMP6                /* 8 */
             },