LAN & WAN (OCR AS Computer Science): Revision Note

LAN & WAN

What is a local area network (LAN)?

• LANs are networks that are contained within a  small geographical location 

• Typically, all the hardware used to make a LAN is owned by a single entity

  • This makes them more secure than WANs, which have connections owned by third-party companies

• A LAN is a network that is built using hubs and/or switches that connect several devices

• It is common for one hub or switch to be connected to a router, which will allow the LAN to connect  to other networks, such as the Internet

• A LAN can offer many advantages, such as:

  • Centralised management - A LAN allows centralised management of updates, backups and software installations

  • Security - A LAN can secure its devices with the use of firewalls, antivirus software and other security features to prevent unauthorised access

  • File Sharing and collaboration - A LAN allows users on the network to share resources such as printers and other peripherals. Users of the network can also collaborate and share files and folders

• Disadvantages of a LAN include:

  • If hardware fails, the network may not function properly or even at all

  • Networks are more prone to attacks than standalone computers

  • Access to data and peripherals can be slow depending on network traffic when compared to locally stored data and locally connected peripherals

  • Maintenance - LAN networks require maintenance to ensure that software is up to date. Upgrades and backups can be costly

What is a wide area network (WAN)?

• A wide area network (WAN) connects multiple local area networks (LANs) over a large geographical area

• A WAN allows users in different locations to share data and resources as if they were on the same network

• WANs usually use third-party connections such as leased lines, fibre, or satellite links

• These connections are provided by ISPs or telecommunications companies rather than owned by a single organisation

• For example, a company may connect its LANs in London and Manchester to create a WAN

Advantages of a WAN

• Enables communication and data sharing between offices or sites in different locations

• Allows access to central servers and shared databases from anywhere with a connection

Disadvantages of a WAN

• Typically slower than LANs due to greater transmission distances

• More expensive to set up and maintain because of leased lines or ISP costs

• More vulnerable to security risks as data travels across public networks