1 2 3 4 5 6 7 8  1 2 3 4 5 6 7 8  1 2 3 4 5 6 7 8  1 2 3 4 5 6 7 8
+----------------+----------------+----------------+----------------+
|major  | minor  |                |                |                |
|version| version|      type      |     seq_no     |   flags        |
+----------------+----------------+----------------+----------------+
|                                                                   |
|                            session_id                             |
+----------------+----------------+----------------+----------------+
|                                                                   |
|                              length                               |
+----------------+----------------+----------------+----------------+