Network layers

Network layer order (server to client)

Link, Internet, Transport, Application (LITA)

Network Protocol

A set of rules that defines how data is transmitted between devices / how devices communicate

MAC Address

A MAC Address (Media Access Control Address) is a unique identifier assigned to a device's network interface card (NIC). It is used to identify devices on a local network.

Application Layer

Handles interaction with network services, such as web browsing or emailing.

HTTP (AL)

Hyper text transfer protocol
Transfers data between web servers and browsers, e.g., retrieving web pages.

HTTPS (AL)

Hyper text transfer protocol secure
Adds encryption to HTTP for secure communication.

IMAP (AL)

Internet messaging access protocol
Used to retrieve emails from a server

SMTP (AL)

Simple mail transfer protocol
Used to send emails and transfer emails between servers.

FTP (AL)

File transfer protocol
Transfers files between client and server computers.

Transport Layer

Manages host-to-host communication and ensures data is correctly split into packets.

TCP (TL)

(Transmission Control Protocol): Ensures reliable delivery by retransmitting lost packets and reordering them.

• Sends an acknowledgment which doubles the signals sent (for the same amount of data sent)
• If ack not received, the packet is re-requested Suitable for tasks where information cannot be lost
  E.g. Used to send emails

UDP (TL)

(User Datagram Protocol): Faster but does not guarantee packet delivery or order.

• Does not handle unreceived data, allows information to be lost
• Suitable for time-sensitive tasks
  E.g. Used in Video Calls

Internet Layer

Routes packets across networks by adding IP addresses for senders and recipients.

IP addresses (IL)

Addresses used to identify senders and recipients in packet routing.

Link Layer

Handles the physical transmission of data, converting packets for transmission.

Ethernet (LL)

Transmits data as electrical signals over wired connections.

Wi-Fi (LL)

Transmits data as radio waves for wireless communication.

Device Drivers (LL)

Enable hardware interaction and function at the link layer.