I thought TCP header had 20byes On Thu, Nov 25, 2010 at 12:38 PM, Kingsley Charles < [email protected]> wrote:
> Hi all > > For the given below example, the fragment offset in the second packet > should be 185 right? The TCP header has not been considered while calcuating > the offset in the given below example. > > Snippet from http://www.tech-faq.com/packet-fragmentation.html > > A Packet Fragmentation Example > > If a 2,366 byte packet enters an Ethernet network with a default MTU size, > it must be fragmented into two packets. > > The first packet will: > > - Be 1,500 bytes in length. 20 bytes will be the IP header, 24 bytes > will be the TCP header, and 1,456 bytes will be data. > - Have the DF bit equal to 0 to mean "May Fragment" and the MF bit > equal to 1 to mean "More Fragments." > - Have a Fragmentation Offset of 0. > > The second packet will: > > - Be 910 bytes in length. 20 bytes will be the IP header, 24 bytes will > be the TCP header, and 866 bytes will be data. > - Have the DF bit equal to 0 to mean "May Fragment" and the MF bit > equal to 0 to mean "Last Fragment." > - Have a Fragmentation Offset of 182 (Note: 182 is 1456 divided by 8). > > > > With regards > Kings > > _______________________________________________ > For more information regarding industry leading CCIE Lab training, please > visit www.ipexpert.com > > -- Bruno Fagioli (by Jaunty Jackalope) Cisco Security Professional
_______________________________________________ For more information regarding industry leading CCIE Lab training, please visit www.ipexpert.com
