TCP
- Transmission Control Protocol
- connection-based protocol.
- Multiplexación: Función que permite que los host receptores seleccionen la aplicación correcta para los datos recibidos, esto se realiza a través del numero de puerto
- Recuperación de errores: Permite numerar los datos con una secuencia y establecer un proceso de reconocimiento de los datos recibidos, lo que proporciona fiabilidad.
- Control de flujo usando ventanas: proceso que permite que dos dispositivos acuerden de forma dinámica el intercambio de datos.
- Establecimiento y terminación de conexiones: Proceso de establecimiento de sesiones donde se coordinan números de secuencia y acuses de recibo. Además permite finalizar la comunicación entre 2 entidades.
- Transferencia de datos ordenada y segmentación: Permite fraccionar la información para enviarla y reordenarla al momento de recibirla.
- Uso en Aplicaciones: Es ampliamente utilizado en aplicaciones que requieren una entrega fiable de datos, como navegadores web, correo electrónico, y transferencia de archivos.
- URG:
Indicates that the urgent pointer filed is significant. The urgent pointer indicates that the incoming data is urgent, and that a TCP segment with the URG flag set is processed immediately without consideration of having to wait on previously sent TCP segments. - ACK:
Acknowledgement flag indicates that the acknowledgement number is significant. It is used to acknowledge the receipt of a TCP segment. - PSH:
Push flag asking TCP to pass the data to the application promptly. - RST:
Reset flag is used to reset the connection. Another device, such as a firewall, might send it to tear a TCP connection. This flag is also used when data is sent to a host and there is no service on the receiving end to answer. - SYN:
Synchronize flag is used to initiate a TCP 3-way handshake and synchronize sequence numbers with the other host. The sequence number should be set randomly during TCP connection establishment. - FIN:
The sender has no more data to send.
Advantages and Disadvantages
| Advantages of TCP | Disadvantages of TCP |
|---|---|
| Guarantees the accuracy of data. | Requires a reliable connection between the two devices. If one small chunk of data is not received, then the entire chunk of data cannot be used. |
| Capable of synchronising two devices to prevent each other from being flooded with data. | A slow connection can bottleneck another device as the connection will be reserved on the receiving computer the whole time. |
| Performs a lot more processes for reliability. | TCP is significantly slower than UDP because more work has to be done by the devices using this protocol. |
- This request contains something called a SYN (short for synchronise) bit, which essentially makes first contact in starting the connection process.
- The server will then respond with a packet containing the SYN bit, as well as another "acknowledgement" bit, called ACK.
- Finally, your computer will send a packet that contains the ACK bit by itself, confirming that the connection has been setup successfully.
If the server is respond with an RST.
- Could be closed, filtered, blocked by the Firewall or another reason.
