The TCP Header is 20 bytes in size and consists of many fields of data.
The fields are:

Connection window reduced. Sent from the sender to the receiver to let it know the ECE was received and so it has slowed down.

Used to signal congestion when ECN is used.

Urgent pointer. Indicates a byte offset from the current sequence number, Where urgent data is to be found.

Acknowledgement number is valid. Set to 1 for nearly all packets, if it is 0 then there is no acknowledgement number set.

PUSHed data

Reset. Used to abruptly reset the connection.

Used to establish connections by the 3-way handshake

Used to flag a disconnect

	Created by danhamilt1 over 11 years ago

CNOS (TCP) Note on TCP Header, created by danhamilt1 on 13/04/2013.