Topic 3 - Networks

Computer system or software that requests a service from a server connected to the same network

A computer system or software that provides a service to other computer systems on the same network

Formed when 2 or more computers are linked together. Every computer on the network can send and receive data between themselves.

Hub - Connection point for all devices on a single network If data is sent on this, it gets sent to all devices connected to the ports of the hub which is inefficient Switch - Similar to a hub, but can identify which device is connected to which port making it more efficient since data can be sent only to the computer that needs it Router - Can connect multiple networks and acts as an intermediary between them

This is a globally connected network that uses the TCP/IP protocol to transmit data. It hosts the webpages that make up the World Wide Web.

Internet Service Providers run and provide networks that provide internet access.

Internet Exchanges. These connect all ISP and internet networks together.

Unit of information that is suitable for travel through a computer network

A file is grouped into packets of data. This file being transmitted through packet switching may be divided into multiple packets. Each packet can take different routes to the same destination based on network availability and guided by routers. Once all at the destination, they are reassembled together. Packet switching is more efficient

Header: Contains source and destination addresses, packet number, number of packets and protocol information Payload: Data itself Trailer: Error checking information (e.g. checksum)

This is used to manage traffic across networks. It controls the flow of data packets by checking its addresses and ensuring they are on the correct path to their destination. It also makes sure all transmission occurs securely.

Local Area Network. Covers a single building/less than 1km radius coverage

Several LANs connected together using multiple routers and covers a radius of more than 1km. An example of this is the Internet.

Virtual Local Area Network. This is when a physical LAN is split up into virtual networks using switches in a logical manner. This would make sense for example departments in a business. They increase the overall security and performance of the LAN.

Storage Area Network. This is a network of storage devices. Not accessible by LAN.

Wireless Local Area Network. This is essentially a LAN but devices are connected wirelessly by high-frequency data waves called Wi-Fi.

Pros: - No cables (reduced costs) - Can move devices around Cons: - Security - Obstructions like walls may slow down speeds

Personal Area Network. This connect devices in a user’s immediate area. This includes things life Wi-Fi hotspots and Bluetooth devices.

This is sort of like a private version of the internet. Intranet web pages are only accessible from computers on a particular network.

When an intranet system is accessible through an online portal.

• From your VPN client, you send all your URL requests to a VPN server • The VPN server makes a request to that internet resource on your behalf and then returns the response to you via the VPN client

• Connection with VPN server is secure thanks to encryption • The process of creating and maintaining an encrypted connection between the server and client is called tunneling

SSL or TSL

Encryption: Data is not able to be understood by attackers Tunneling: Data can be secured using protocols