Just to reference for IP,TCP, UDP, ICMP header size..
Comparison of IPV4 and IPV6 header

IPV6 Header (protocol Number :41)

IPV4 Header (protocol Number: 4)

TCP Header (protocol number: 6)

UDP Header (protocol number :17)

ICMP Header (protocol number: 1)

http://nmap.org/book/tcpip-ref.html