TCP Header

+-----------------------------------+-----------------------------------+
|                                   |                                   |
|     16-bit source port number     |  16-bit destination port number   |
|                                   |                                   |
+-----------------------------------+-----------------------------------+
|                                                                       |
|                         32-bit sequence number                        |
|                                                                       |
+-----------------------------------------------------------------------+
|                                                                       |
|                      32-bit acknowledgement number                    |
|                                                                       |
+--------+--------------+-+-+-+-+-+-+-----------------------------------+
| 4-bit  | reserved     |U|A|P|R|S|F|                                   |
| header |              |R|C|S|S|Y|I|          16-bit window size       |
| length |   6 bits     |G|K|H|T|N|N|                                   |
+--------+--------------+-+-+-+-+-+-+-----------------------------------+
|                                   |                                   |
|        16-bit checksum            |        16-bit urgent pointer      |
|                                   |                                   |
+-----------------------------------+-----------------------------------+
|                                                                       |
/                          options (if any)                             /
|                                                                       |
+-----------------------------------------------------------------------+
|                                                                       |
|                                                                       |
/                                                                       /
\                                 data                                  \
/                                                                       /
|                                                                       |
|                                                                       |
+-----------------------------------------------------------------------+