Control Flags (6 bits)

Protocol: TCP TCP PCI

Field: control flags

Length: 6 bits

Contents: operation control flags.

1. URG: Urgent Pointer field significant

The urgent pointer field must be processed.

Urgent Pointer (2 bytes)

2. ACK: Acknowledgment field significant

The acknowledgment field bust be processed.

Acknowledgment Number (4 bytes)

3. PSH: Push Function

Data must be passed immediately to destination process.

3. RST: Reset the connection

Indicates that the connection will be closed.

3. SYN: Synchronize sequence numbers

Indicates request for connection setup.

The 'maximum segment size' option must be processed (if any).

Options (n bytes)

3. FIN: No more data from sender

Indicates finally the end of a connection.