TCP packet
TCP packet format
Figure 27: TCP packet format
Table 5: Description on the 6 flag bits in the TCP header
Flag bit | Description |
|---|---|
URG | The urgent pointer is valid. |
ACK | The acknowledgement number is valid. |
PSH | The receiver passes the data to the application layer as soon as possible. |
RST | Reset the connection. |
SYN | Synchronize sequence numbers to initiate a connection. |
FIN | The sender has finished sending data. This field terminates a connection. |
TCP state transition
Figure 28: TCP state transition diagram
The protocols using TCP can be static or dynamic. Static protocols use fixed port numbers for interaction and dynamic protocols use negotiated port numbers.