CHAPTER 4 PG(76-79)

By: Hunza, Omar and Anum

NETWORK CONNECTIONS

By: Hunza Shah Bukhari

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.

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.

Dialup Dialup is a relatively old technology that connects

computers to a network using a standard telephone line. Computers are digitalTelephones 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.

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).

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.

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.

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

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.

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)

Speeds of typical network connectionsTechnology Used For Typical speedsWi-Fi LAN Up to 108 Mbps

Ethernet LAN 100 Mbps-10 Gbps

Fibre optic WAN Over 40 Gbps

WiMax WAN Up to 70 Mbps

Cable/ DSL WAN 10 Mbps-100 Mbps

Dialup WAN 56 Kbps

3G WAN 200 Kbps

4G WAN 5-20 mbps in use

Bluetooth PAN Up to 2 Mbps

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.

Protocols Rules for a network.

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.

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

Ports Ports identify the services from the

network To retrieve to a web page1. Connect to web server2. Computer connects to port 80 (standard

port used by HTTP

Ports are used so one computer can offer many services

Common ports are Port Service

25 SMTP (email)

80 HTTP (web)

110 POP (email)

53 DNS

443 HTTPS (web secure)

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

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

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

Pictures bibliography http://www.consentry.com/ http://aerva.com/blog/maximize-your-int

ernal-social-network-with-digital-signage/

http://flowingdata.com/2008/03/12/17-ways-to-visualize-the-twitter-universe/