The Internet Address

What is IP Address?

• A number that uniquely identifies each computer or device connected to the Internet.
• IP addresses are also referred to as IP numbers and Internet addresses.
• IP address sometimes is called a dotted decimal number or dotted quad.

                                                         What is IP usage?

• A way to find specific server or computer on the internet or a network
• Provide identity to a computer in a network
• Identify for a particular device/machine on a particular network
• Allows transfers of files and e-mail

                                                       What is IP structure?

• IP addresses usually consists of four groups of number each separated by a period.
• The number in each group is between 0 and 255. It is 32 bit long ,each group is 8 bits long
• Commonly written in decimal for example, 128.35.0.72
• These four sections represent the machine itself and the network it is on
• The network portion is assigned.
• The host section is determined by the network administrator 

      5 Classes of IP address A B C D and E:

• Class A : reserved for governments/ large companies
• Class B : reserved for medium companies
• Class C :reserved for small companies

Internet Service Provider

Internet Service Provider(ISP) : 

• A company that provides Internet connections and service to individuals and oraganizations

Access Provider :

• A bussiness that provides individuals and organizations access to the Internet for free or for a fee.

Responsibilities of an ISP: 

-Providing and maintaining a connection to the Internet

-Support the hardware and software needed to service that connection

-To protect their site and network from external threats such as viruses, hacker attacks and other illegal activities

-Provide 24-hour customer service and technical support

Example of ISP in Malaysia

ISP : TMnet

Products : Streamyx,UniFi,TM Hotspot

ISP : Time

Product : TimeFibre Home Broadband,Time Broadband

ISP : Packet One Network

Products : P1

ISP : YTL Communications

Product : YES

Different types of internet connection

Two types of internet connection

• Dial-up connection
• Broadband Internet Connection/ Direct Connection

Conventional dial-up : To connect to the Internet, your computer dials its modem and connects to a modem attached to a computer belonging to your ISP.)

Broadband Internet Connection : Broadband or high-speed internet service has seen a rise in popularity over the last decade, becoming a standard communication service over its slower counter-part, dial-up Internet. You can use the broadband vs. dial-up chart on this page to learn the differences between each type of Internet connectivity and decide whether or not to move into the high-speed era.

BROADBAND VS. DIAL-UP

Criteria	Dial-up connection	Broadband
Speed	Slow, maximum speed is 56 kbps	Faster, can go up to several megabytes per second
Equip-ment	Less equipment compare to Broadband	More than dialup connection, change based on different broadband technology and speed for the example Fiber Optic Cable
Availa-bility	Dial-up can be accessed anywhere via a telephone line.	Broadband availability has become more and more widespread over the last few years in particular. satellite Internet is always an option for more rural areas that haven't been expanded to yet

Intranet and Extranet

Advantages and disadvantages of Intranet

   Definition of intranet : An intranet ( intra means within) is an internal network that uses internet technologies. Network which only available inside an organization or a company. Intranet generally make company information accessible to employees and facilitate working in groups. Simple intranet applications include electronic publishing of organization material such as telephone directories, event calendars and employee benefits information.

                         AdvantagesADVANTAGES

•Commercial or confidential data is kept secure within the organization

•Email remain private and may also be encrypted

•High bandwidth.No connection limits unlike the Internet.

•Reliable. The company will have dedicated IT 

personnel to keep things running smoothly.

     Disadvantages

•High financial cost incurred by the company when initially 
implementing the intranet

•Connections between an intranet and the Internet potentially
 compromises security, by allowing virus infections or system hacking.

•Staff needs training to ensure workers know how to use the system effectively.

•Information overload is another disadvantage because it reduces productivity. 

Advantages and disadvantages of Extranet

Definition of extranet: An extranet is the portion of a company’s network that allows customers or suppliers  of a company to access parts of an enterprise’s intranet. An extranet provides a secure, physical connection to the company’s network.

Advantages	Disadvantages
Exchange large volumes of data using electronic data interchange (EDI)	Extranets can be expensive to implement and maintain within an organization (e.g., hardware, software, employee training costs), if hosted internally rather than by an application service provider.
Share product catalogs exclusively with trade partners	Security of extranets can be a concern when hosting valuable or proprietary information.
Collaborate with other companies on joint development efforts
Jointly develop and use training programs with other companies

Overview Of The Internet (Advantages And Disadvantages Of The Internet)

Definition of the internet

The Internet is a worldwide collection of networks that links millions of businesses, government agencies, educational institutions, and individual.

• Internet is a world-wide global system of interconnected computer networks. Internet uses the standard Internet Protocol (TCP/IP).

• Every computer in internet is identified by a unique IP address.IP Address is a unique set of numbers (such as 110.22.33.114) which identifies a computer location

• A special computer DNS (Domain Name Server) is used to give name to the IP Address so that user can locate a computer by a name.

• For example, a DNS server will resolve a name http://www.tutorialspoint.com to a particular IP address to uniquely identify the computer on which this website is hosted. Internet is accessible to every user all over the world.

Advantages and disadvantages of internet

Advantages	Disadvantages
Software Downloads:	Virus threat:
You can freely download software like utilities, games, music, videos, movies, etc from the Internet.	Computers attached to Internet are more prone to virus attacks and they can end up into crashing your whole hard disk.
Online Services:	Social Disconnect:
Perform all your transactions online.	People now only meet on social networks.
Can book tickets for a movie, transfer funds, pay utility bills.	More and more people are getting engaged with virtual world and drifting apart from their friends and family.
Make a hotel or flight reservation right from your home.
E-mail:	Dangers involved when children using the Internet :
People can sent messages. It is delivered instantly to people anywhere in the world, unlike traditional mail that takes a lot of time.	When children talk to others online, they do not realize they could actually be talking to a harmful person. Plus, there are thousands of pornographic sites on the Internet that can be easily found.
Information resources:	Theft of Personal information:
Can find any information on almost any kind of subject that you are looking for by using search engines like Google, Yahoo, MSN, etc.	Your personal information such as your name, address, credit card, bank details and other information can be accessed by an irresponsible  people for their own benefit.

LAN,MAN and WAN

Differences between Lan(Local Area Network), Man(Metropolitan Area Network) and Wan(Wide Area Network)

• Lan(Local Area Network) : The simplest form of LAN is to connect two computers together or connection of the computers and devices in the office or home.
• Man(Metropolitan Area Network) : Connects local area networks(LAN) in a metropolitan area such as a city or town.Handles the bulk of communications activity across the region.
• Wan(Wide Area Network) :Cover a large geographic area using a communications channel that combines many types of media such as telephone lines,cables and radio waves.

Criteria	LAN	MAN	WAN
Area  of coverage	Network cover limited geographical area such as closely positioned group of buildings network , at home,network  inside computer laboratory and network in office building	A high speed network that connects Local Area Networks in a Metropolitan Area such as a cities or town	Network cover large geographical area such a countries,the continents or the world
Network size	Small size (in a building)	Larger size (in a cities or campus)	Largest size (different states or countries)
Speed	Fastest in data transferring and access time	Slower in data transferring and access time	Slowest in data transferring and access time
Example	Network inside the computer  lab, Network around school and Network inside your home	Surveillance system,Traffic light monitoring system and Cable Network TV	Car Navigation System, Video conference, Intelligent and Transportation System(ITS)
Communi-cation devices	Connected using modems,hubs, switch and router	Connected using modems,hubs, switch,router	The connection is made via satellite communication link or via internet
Cost	Less costly setup and maintenance	More costly setup and maintenance	Costliest setup and maintenance
Network ownership	Private Owned,controlled and manage by a single person or organization	Private- Owned and operated by a single entity such as a government or large corporation	Not owned up any one organization but exist under collective or distributed ownership

Network Topology

Network Topology

What is network topology?

• A network topology refers to the layout of the computers and devices in a communications network.  

What is physical topology and logical topology?

• Physical topology is the arrangement of a cabling.
• Logical topology is the path that data travels between computers on a network.

Different between Client-Server and Peer to Peer Network Architecture 

Topo logy	Definition	Advantages	Disadvantages
Bus	A bus network consists of a single central cable(backbone), to which all computers and other devices connect.	Inexpensive and easy to install	There might be disruption when computer or other devices are added or removed.
		Other devices can be attached or detached without disturbing the network	The break in the main cable(backbone) will prevent all systems from accessing the network.
		Failure of one device usually does not affect the rest of the network	It is difficult to identify the problem if the entire network shut down
Star	All the computers and other devices on the network connect to a central device, thus forming a star.	If one device fails,only that device is affected	If the hub or switch fails,the entire network will be inoperabled
		Devices can be added or removed from network with no disruption	Requires more cables than most of the other topologies
		Easy to troubleshoot and isolate problem	More expensive because of the cost of hub/switch
Ring	On a ring network, a cable forms a closed loop(ring) with all computers and devices arranged along the ring	Transmission of data is simple as packets travel in one direction only	A failure in any cable or device breaks the loop and can take down entire network
		Cable faults are easily located,making troubleshooting easier	Data packets must pass through every computer,thus make it slower.
		All devices in ring topology share the network resources fairly	More difficult to install than a bus network

Network Architecture

Network Architecture

Peer-to-Peer network and Client/Server network

What is network architecture?
The configuration of computers, devices and media on a network.

Differences between Client/Server and Peer-to-Peer network

Category	Client/Server	Peer-to-Peer
Definition	one or more computers act as a server, and the other computers on the network request services from the server.	Each computer, called a peer, has equal responsibilities and capabilities,sharing hardware(sucs as a printer),data or information with other computers on the peer-to-peer network.
Size	For medium and large network	For small network fewer than 10 computers
Operating System	Needs a specific operating system such as Windows Server 2008.	Does not need a specific operating system.
Training	Needs training	Does not need training
Set up	More difficult to set up	Easy to set up
Installation	More expensive to install	Less expensive to install
Implementation	Big corporations or organizations with high security data	Small businesses and home users