Year 10 Digi Tech - Supplementary Revision

What does TCP stand for?

Transmission Control Protocol

Steps in TCP

Connection Setup, Data Transfer, Error Check, Reordering Packets, Connection Close

Connection Setup

TCP ensures both devices are ready to talk to each other.

Data Transfer

TCP sends the data in packets.

Error Check

TCP checks for missing or damaged packets, and asks for them again.

Reordering Packets

TCP rearranges packets that are out of order into the right order.

Connection Close

Once everything’s sent and received, TCP closes the connection politely.

Examples of TCP

Web browsing, streaming videos and music, sending emails.

OSI Model

Seven-layer framework for network protocol services.

7 layers of the OSI Model

Application, Presentation, Session, Transport, Network, Data Link, Physical.

Application

What you actually see/use – like websites, emails, or apps.

Presentation

Makes sure data is in the right format, e.g. text, images.

Session

Starts and ends the connection between devices.

Transport

Breaks data into packets and checks they arrive correctly (uses TCP).

Network

Chooses the best path for data to travel (like a GPS for data).

Data Link

Moves data between devices on the same network (like Wi-Fi or cables).

Physical

Sends raw bits as electrical signals or light (e.g. through cables or radio waves).