Chapter 4 pg(76-79)

1. By: Hunza, Omar and Anum Chapter 4 pg(76-79)

2. By: Hunza Shah Bukhari Network Connections

3. Wired Connections • Many ways used to connect to computers • distance between the two computers, • the bandwidth required, • cost of the connection, • wireless or wired connection would be required. • Fibre optic cables are used to transfer data by sending light down an extremely thin glass tube. • Fibre optic connections travel at speeds of 40Gbps and each cable is able to contain multiple independent optical fibres. • They are also very expensive $70 per metre. • Fibre optics are used mainly for high speed connections for huge volumes of traffic.

4. Cable internet access • Cable internet access is the most common forms of broadband internet access at homes. • DSL (Digital Subscriber Line) connections are used with existing telephone networks. • A cable MODEM is used to convert the data for use over the network.

5. Dialup • Dialup is a relatively old technology that connects computers to a network using a standard telephone line. • Computers are digital • Telephones are analogue • MODEM (Modulator-Demodulator) to use the telephone network • The disadvantages for dialup are, • the relatively slow speed of 56 Kbps, • the telephone lines cannot be used for anything else when they are connected, • you have to pay for every minute you use making it very expensive.

6. Ethernet • Ethernet can be used in many ways. • Ethernet cables are used for many Local Area Networks (LANs). • Ethernet cables transfer data at high over short distances (less than 100 metres). • There many different Ethernets such as Fast Ethernet (100 Mbps) and 10 Gbit Ethernet (10 Gbps).

7. Wireless Connections • WiMax (Worldwide Interoperability for Microwave Access) is a wireless technology designed to transfer data over distances up to 50 kilometres. • Bandwidth is relatively high over 50 Mbps, but reduces with distance.

8. Wi-Fi (Wireless Fidelity) • Wi-Fi is a standard for wireless connecting devices in a small area, • such as an office • Wi-Fi devices connect to a wireless router, and from there to the internet. • Many areas such as hotels, cafes and shops now offer wireless hotspots to their customers, allowing Internet access while on the move.

9. Bluetooth • Bluetooth is a wireless technology used only for short distance or Personal Area Networks (PANs). • Bluetooth is often used to connect computers to mobile phones, cameras, game controllers, and other peripheral devices

10. 3G and 4G • 3G and 4G (3rd generation and 4th generation) are standards for wireless communication that operate using the mobile phone network. • 3G standard offers at least 200 kbps, 4G offers speed of at least several mbps.

11. Common mistake • Network speeds are measured in bits per second (bps), not bytes per second. This is a common source of confusion. • If your internet connection is 1 Mbps, the speed is not 1 megabyte per second, but 128 kilobytes per second (since there are 8 bits in a byte)

12. Speeds of typical network connections

13. Mac addresses • MAC stands for media access control. • This is a unique number which is built into every network device • It allows communication on physical networks.

14. Protocols • Rules for a network.

15. Internet Protocols • Monitors how devices are identified and how information is sent between them. • Each machine is given its own unique IP address • IP addresses contain four groups of digits which are separated by dots e.g. 192.169.2.5 • IP addresses can be given manually but in order to eliminate the conflict they are assigned by the DHCP • DHCP stands for dynamic host control protocols. • This is a program that keeps track of all IP addresses it has assigned • Private addresses are used on private networks such as LANs • The same private address can be used by other computers on other networks • Private network has a public IP address, which represents the entire network.

17. TCP • Transmission Control Protocol • This is to ensure that data is sent and received correctly • If data is lost on the network because of an error • TCP is responsible of making a request of resending the data • Both TCP and IP are a group of rules that monitor how data is sent in a network

18. Ports • Ports identify the services from the network • To retrieve to a web page • Connect to web server • Computer connects to port 80 (standard port used by HTTP

19. Ports are used so one computer can offer many services • Common ports are

20. The future of IP addresses • Current system uses 32 bit addresses • Total of 4.3 billion possible IP addresses • New addresses are being assigned at a rate of 243 million a year. • So there wont be new IP addresses for new users

21. Solution • The solution is to adopt a new standard called IPv6 • IPv6 uses 128 bit addresses giving a total of 4.3x10 to the power of 38 • Which will be enough for now

22. Articlehttp://www.pcmag.com/article2/0,2817,2413913,00.asp

23. Pictures bibliography • http://www.consentry.com/ • http://aerva.com/blog/maximize-your-internal-social-network-with-digital-signage/ • http://flowingdata.com/2008/03/12/17-ways-to-visualize-the-twitter-universe/