Tcp Tutorial-7

size which y can handle. This too is determined by both x and y during connection time.


So once x knows the maximum size of the datagram which y can handle, it breaks down the data into smaller chunks or datagrams. Each datagram has it's own TCP header which too is put by TCP. A TCP Header contains a lot of information, but the most important of it is the Source and Destination IP and Port numbers and yes also the sequence number.

************** HACKING TRUTH: Learn more about Ports, IP's, Sockets in the Net Tools Manual ************** The source which is your computer(x) now knows what the IP Addresses and Port Numbers of the Destination and Source computers are. It now calculates the Checksum value by adding up all the octets of the datagram and puts the final checksum value to the TCP Header. The different octets and not the datagrams are then numbered. An octet would be a smaller broken down form of the entire data. TCP then puts all this information into the TCP header of each datagram. A TCP Header of a datagram would finally look like -:


+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Source Port | Destination Port | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Sequence Number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Acknowledgment Number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

| Offset| Reserved |R|C|S|S|Y|I| Window |

| | |G|K|H|T|N|N| | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Checksum | Urgent Pointer | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | The Actual Data form the next 500 octets | | |