1.3- Computer Networks, Connections and Protocols

A small block of data which is transported from one computer to another.

The part of the packet which contains the sender and destination addresses, the protocol being used and a packet number.

The part of the packet which contains the actual data which is being sent.

The address of the device where the initial message has been sent from.

The address of the device where the message is going to.

An agreement which must be made between two devices, before communicating over the internet.

The protocols in this layer determine how the data will be transferred in applications. Web browsers, email clients and file transfer protocols operate here.

The layer where the network hardware is located such as the network interface card and cabling. Ethernet and Wi-Fi run here.

This layer routes the packets across the network using the IP protocol

Sets up the communication between the two devices communicating data and breaks the data in to the agreed packet size. TCP and IP run here.

A numerical address assigned to a device communicating data across the internet. This address changes. IPv4 format is 4 bytes, IPv6 uses 16 bytes for more addresses.

When the receiving device detects that an error has occurred during the transmission of data. The data is then requested again.

A data network technology. A message is broken in to packets and then sent across a network using the most suitable routes between the source and destination

An insecure protocol used between a browser and web server. Hypertext Transfer Protocol transmits HTML web pages from web server to client

Secure version of HTTP, the traffic is encrypted between the browser and the web server for security. Now fairly standard

Transmission Control Protocol - this sets up and maintains a reliable connection between two computers, e.g. client’s browser and web server

This protocol describes how to route packets of data around networks. Short for Internet Protocol, it’s used by routers and switches to direct packets

Alternative email protocol to POP, the client can read emails but they stay on the server, short for Internet Mail Access Protocol

Protocol for transferring files to and from a file server. File Transfer Protocol

Rules for sending emails from client to server, and then server to server. Simple Mail Transfer Protocol

Used by client to download emails from mail server. Post Office Protocol is older and less useful than IMAP

Wireless connection standards are known by this 4-letter acronym, this describes how wireless devices connect

The protocols used at the lowest layer of a network, describing the rules for connecting hardware and cables

A set of agreed rules which allow two devices to communicate. SMTP, HTTPS and TCP are all examples