1. Chapter 3

2.  LANs, WANs, Virtual networks  Advantages of a client-server network  Network components – describing their purpose and justifying their use  Importance of Standards & The Use of Protocols

3.  The characteristics of: ◦ Local Area Networks ◦ Wide Area Networks ◦ Virtual Networks

6.  Computers are connected in a local geographical location. Eg up to ½ sq miles  Workstations have either physical or wireless network connections  Organisation owns the cabling.  Peripherals are often shared.  Software and data can be shared.

7.  Increasingly, more and more households how have more than one computer or laptop.  Data is now being shared across these devices including music and video streaming.  Printers are shared across the network also.  Media can also be streamed to devices like Xbox 360 and PS3 consoles. ◦ This allows people to stream music from their PC and play it through their console while playing a game!

8. Switch/Router connected to Internet Wireless Access Point (WAP)

9.  Computers are connected across a wider area compared to LAN. ◦ The geographical locations are far apart.  The internet is a fantastic example of a WAN.  Computers are able to connect to one another through the internet.

10.  Some systems might need WAN connections as well as LAN connections.  Examples include: ◦ University campuses spread over large areas ◦ The medical network (allows medical records to be accessed from all over the country) ◦ ATM machines, Lottery machines ◦ Large global businesses

11.  Computers are not close together.  External equipment may be needed to connect computers together: ◦ Telephone lines ◦ Satellite ◦ Mobile Phones  Specialist equipment is needed to connect to the WAN e.g. Router or modem.

12. Router

13. Is a WAN network... But is made up of lots of single computers and LAN networks. LAN 1 LAN 2

14.  There may be many computers connected in a LAN but they can be fooled into thinking that their network is much smaller.  This is accomplished by using virtual networks to limit what computers another computer can see on the network.

15. The computers surrounded with red do not know the blue computers exist. The switch ‘hides’ the blue computers from the red computers.

16. This example shows how computers might be connected using a virtual network across a WAN. The red computers communicate with each other and are unaware of the blue computers.

17.  Identify three characteristics of a LAN  Identify two characteristics of a WAN  Describe the purpose of a Virtual Network  Identify four services offered by an ISP

18.  Identify three characteristics of a LAN -within a local geo area, owns its cables, shared peripherals  Identify two characteristics of a WAN – covers large geo area, uses external cabling eg tel lines, leased lines, mobiles  Describe the purpose of a Virtual Network – to create a network of computers which operate like a single LAN even though computers maybe from different LANs or WANs,  Identify four services offered by an ISP