THE INTERNET ADDRESS

                            WHAT IS IP ADDRESS???????

- IP address is a number that uniquely identifies each computer or device connected to the internet.


                             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 adress consists of 4 groups of number and each separated by a period.
- The number in each group is between 0 and 255.
- Each group is 8 bits long.
- Commonly written in decimal
- Example ;- 128.35.0.72

5 CLASSES OF IP ADDRESS

CLASS A : for government/large companies

CLASS B : for medim companies

CLASS C : for small companies

CLASS D : for multicasting

CLASS E : for future use

                                                                       IPV 4

- consists of 32 bits 

                                                          - written in decimal numbers

                                               IPV 6

                                                        -  from 32 bits increased to 128 bits
                                                          - written in hexadecimal numbers



                                                             DOMAIN NAME 

                                                        - The text version of ip address.
                                        - first portion of ip address is to identifies the network.
                                            - last portion is to identifies the specific computer.



                                                   TLDS 

internet service provider

                                INTERNET SERVICE PROVIDER (ISP)

                 - A company that provides internet connections and services to individuals and                                      organizations.


                                               ACCESS PROVIDER (ASP)
             
                - A business that provides individuals and organization access to the internet for free or for                    a fee.

RENSPOSIBILITIES 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.
   * provides 24 hour custom,er service and technical support.




                                          EXAMPLE OF ISP IN MALAYSIA

THE INTERNET CONNECTION

                               
                              TYPE OF INTERNET CONNECTION


                                                      DIAL-UP CONNECTION


1. CONVENTIONAL DIAL UP

     - to connect to the internet, PC has to dials its modem and connects to a modem attached to a         computer belonging to your ISP.
         - it is slower but cheaper, must be ties up to the telephone lines
         - example :- Jaring, TMNet

   2. ISDN

         - typically uses two phone lines to transfer data.
         - requires a special ISDN modem.
         - doesn't tie up phone line
         - faster but pricey


                  ADVANTAGES                                                   DISADVANTAGES                           
               * more secure because doesn't                               * slow connection speed
                 always ties up to the telephone                            * inconvenience because you must
                 line.                                                                         always to dial up to connect
                                                                                                 to the internet.
              * lower price                                                           * always be ties up to the telephone
                                                                                                 line


                                                          DIRECT CONNECTION


    1. DSL (DIGITAL SUBSCRIBER LINE)

       
                  - transmit over telephone lines but does not tie up to the telephone line
                  - fast, direct internet access via standard telephone line
                  - requires DSL modem
                  - example :- streamyx


2. FIBER TO THE PREMISES (FTTP)

                  - provide high speed internet access to house and business user by using fiber optic cable.


3. FIXED WIRELESS

  
                 - uses radio transmission towers rather than satellites
                 - provides high speed internet connections using a dish shaped antenna to communicate via                    radio signals.
                 - example;- YTL communication

4. CELLULAR RADIO NETWORK

                 - can be access via mobile phone or devices
                 - offers high speed internet connection to devices with built in compatible technology or                        computers with wireless modems.
                - Example ;- celcom, maxis


5.CABLE INTERNET SERVICE

                - provides high speed internet access through the cable television network via cable                               modem.


6. WI- FI
             

               - provide high speed internet connections to compatible or properly quipped wireless                              computers and devices.
               - streamyx with wifi


7. SATELLITE INTERNET SERVICE
 

               - provide high speed internet connections via satellite



FACTOR THAT YOU MUST CONSIDER TO CHOOSE THE RIGHT INTERNET CONNECTION


1. PRICE - the most affordable one is WIFI and low cost.
2. SECURITY LEVEL - different connection have different security level.
3.AVAILABILITY - not all services are available on all locations.

INTRODUCTION TO THE INTERNET

                                             
                                          INTERNET 

               Internet is a worldwide collection of works that links millions of businesses, government agencies, educational institutions, and individuals.

                        EVOLUTION OF THE INTERNET

The internet originated as APRANET and have two main goals:

→Allow scientist at different physical locations to share information and work together.

→Function  even if part of the network were disabled or destroyed by a disaster.

INTERNET2

→Internet2 is not a new internet but it is a Researcg and Development project.

→to ensure the internet in the future can handle tomorrow's application.

                               ADVANTAGES AND DISADVANTAGES OF INTERNET

ADVANTAGES	DISADVANTAGES
Software download: -You can freely download software like utilities, games, music, videos, movies, etc from the internet.	Virus threat :         - Computers attached to internet are more prone to virus attacks.
Online services:      -you can book ticket,hotel,flight online.	Social disconnect : - antisocial
E-mail:    - people can sent messages. It is delivered instantly to people anywhere in the world, unlike traditional mail that takes a lot of time.	Dangers involved when children using the internet: -Exposed children talking to harmful person and promote them to watch pornography.
Information resources: -Can find any information on almost any kind of subject that you are looking for by using Google,Yahoo,etc	Theft of personal information:                                - your personal information can be        accessed by an irresponsible people.

INTRANET 

⇨An intranet 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.    

ADVANTAGES	DISADVANTAGES
commercial or confidental data is kept secure in the organization.	High financial cost
Email remain private and may also be encrypted	Connections between an intranet and the internet potentially compromises security by allowing virus infections or system hacking.
High bandwith. No connection limits unlike the internet.	Staff need training
Reliable. The company will have dedicated IT personnal to keep things running smoothly.	Information overload

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 eletronic data interchange (EDI)	Expensive to implement
Share product catalogs exlusively with trade partners.	Security can be concern
Collaborate with other companies on joint development efforts.
Jointly develop and use training programs with other companies.

CLASSIFICATION OF NETWORK

                                                 
                                      CLASSIFICATION OF NETWORK 

                                                   LAN 

  💣A LAN is a network that connects computers and devices in a limited geographical area. As an example is a home and school computer laboratory.
  💣 The simplest form of LAN is to connect two computers together or connection of the computers and devices in the office or home.
  💣A network which consists of less than 500 interconnected devices across several buildings, is still  recognized as a LAN.
                                                    
                                                          CHARATERISTICS

⇨ they are used within small areas (such as in building)
⇨ limited to specific geographical area less than 2km supporting high speed networks.
⇨ they provide access for many devices.
⇨ they offer high speed communication
⇨ they use LAN specific equipment such as hubs, switches, and network interface cards.

                                                            ADVANTAGES
⇢ easy to share devices and data
⇢ cost of LAN setup is low
⇢ sharing of resources such as printers hence cost effective

                                                         DISADVANTAGES

⇢ a good LAN is required to be on all the times
⇢ each computer and devices become another point of entry for undersirables.
⇢ if all computers running at once, can reduce speed for each.
⇢ area covered is limited.


                                                   MAN 

🏢 MAN is high speed network that connects local area networks (LAN) in a metropolitan area such       as city or town.
🏢 Handles the bulk of communications activity across that region.
🏢 A MAN is optimized be owned for a larger geographical area than a LAN , ranging from several         blocks of buildings to entire cities.
🏢 A MAN might be owned and operated by a single organization, but it usually will be used by               many individuals and organizations.
🏢 MAN can span up to 50km,devices used are modem and eirw/cable.
🏢 Example of MAN : Traffic light monitoring system, cable network TV 


                                                             CHARATERISTICS

➤ It generally covers towns and cities.
➤Transmission medium used for MAN are optcal fibres, cables etc
➤They use devices such as routers, telephone, switches, and microwave antennas such as parts of           their communication infrastructure.


                                                               ADVANTAGES
➤Efficiency and shared access
➤All the computer owning residents of the area have equal ability to go on line.


                                                            DISADVANTAGES

➤ It can be costly

➤ security problems

➤ the connection can lag or become quite slow.

                                             WAN 

🌏 A WAN ia a neywork that covers a large geographic area (such as city, country, or the world)             using a communications channel that combines many types of media such as telephone lines,               cables, and radio waves.
🌏The example is INTERNET

                                                          CHARATERISTICS

🌏They can covers a very large geograhical area ( states,countries,continents)
🌏They usually communicate at slower speeds compared to LAN  and MAN 
🌏Communication medium use satelite, public telephone networks whic are onnected by routers.
🌏Routers forward packets from one to another a route from the sender to the receiver.


                                                           ADVANTAGES

🌏Messages can be sent very quickly to anyone else on the network.
🌏Everyone on the network can use the same data. This avoids problems where some users may have     older information than others.
🌏Share information/files over a larger area. 

                                                        DISADVANTAGES

🌏Setting up a network can be an expensive and colicated experience.
🌏Security problems because exposed to virusesand hackers
🌏Maintenance problems. Large enteprises will dedicate personnel to maintaining their WAN.



                               👻 COMPARISON BETWEEN LAN , MAN AND WAN 👻

Network Topology

                       
                      What is network topology?!?!

    ✌  Network topology refers to the layout of the computers and devices in a                                       communications network.
    ✌ It refers to both the physical and logical layout of a network.
    ✌ Physical topology is the arragement of cabling in a network while logical topology           is the pathway of data transmission between the computers.

                                                  🌟 STAR TOPOLOGY🌟

🌠Star topology means all the computers and other devices on the network connect to a central device thus forming a star.
🌠Two types of devices that provide a common central connection point to all the other devices on the network are hub and a switch. 

                                                            ADVANTAGES

1. If one device fails, only that devices is affected.
2. Devices can be added to or removed from network with little or no discruption.
3. Easy to troubleshoot and isolate problem.

                                                       DISADVANTAGES

1. If the hub/switch fails, the entire network cannot be function.
2. Requires more cable than most of the other topologies.
3. More expensive because cost of the hub/switch.

                                   🚌BUS TOPOLOGY🚌

🚏 Bus network consists of a single central cable (backbone) to which all computers and other devices connect.
🚏 Bus topology uses coaxial cable as a backbone.
🚏 The bus is the physical cable that connects the computers and other devices. 
🚏 The bus in a bus network transmit data, instructions, and information as a series of a signal.
🚏 Those signals are sent in all directions.
🚏 Each devices is connected to the single bus cable trough T-connector.
🚏 A terminator is required at each end of the bus cable to prevent the signal from bouncing back and forth on the bus cable. 

                                                                   ADVANTAGES
1. Inexpensive and easy to install.
2. Computers and other devices can be attached or detached at any point on the bus without disturbing the rest of the network.
3. Failure of one device usually does not affect the rest of the bus network.

                                                               DISADVANTAGES

1. There might be discruption when computer or other devices are added or removed.
2. Because all system on the network connect o a single canle or backbone, a break in the cable will prevent all systems from accesing the network.
3. It is difficult to identify the problem if the entire network shut down.


                              ⊚ RING TOPOLOGY ⊚

⚫ On a ring network, a cable forms a closed loop (ring) with all computer and devices arranged along the ring.
⚫ Data transmitted on a ring network travels from device around the entire ring, in one direction either clockwise or anticlockwise.
⚫ Token passing is one method for sending data around the ring. 
⚫ Only the device with the token is allowed to send data.
⚫ All others device must wait for the token to come to them.

                                                                ADVANTAGES

1. The transmission of data is relatively simple as packets travel in one direction only.
2. Cable faults are easily located, making troubleshooting easier. 
3. The uses of token passing enables all devices in a ring topology to share the network resources fairly. 



                                                            DISADVANTAGES

1. A failure in any cable or device breaks the loop and can take down the entire network.
2. Data packets must pass through every computer therefore, this makes it slower.
3. A ring network can span a larger distance than a bus network, but it is more difficult to install.

NETWORK ARCHITECHTURE

                                     
                     WHAT IS NETWORK ARCHITECTURE ?!?!

👤 Network architecture is the configuration of computers, devices and media on a network. 


        💚 CATEGORIES OF NETWORK ARCHITECTURE💚

👀 PEER TO PEER NETWORK

             👶  A simple , inexpensive network that typically connects fewer than 10 computers. Each                          computer called a peer that has equal responsibilities and capabilities. 
             👶  Each computer stores files on its own storage devices
             👶  Peer to peeer networks are ideal for very small business and home users.
             👶 Some operating system, such as windows include a peer to peer networking utility that                         allows users to set up a peer to peer network.
             👶 Each node is a computer on the network which acts and communicates with other peers to                   make a portion of their resources, such as processing power, disk storage or network                             bandwidth.

👀  CLIENT/SERVER NETWORK
                 

             👶  One or more computers act as a server, and  the other computers on the network request                        services from the server.
            👶 Server called as a host computer controls access to the hardware, software and the other                      resources on the network and provide a centralized storage area for programs,data and                          information.
            👶 The clients are other computers and mobile devices on the network that rely on the server                    for its resources.
            👶 Client/server architecture works when the client computer sends a resources or process                        request to the server over the network connection,which is then processed and delivered o                    the client.


   💀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,data or information with other computers on the peer-to-peer network.
Size	For medium and network.	For small network fewer than 10 computers.
Operating system	Needs a specific operating system suc 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.
Impementation	Big corporations or organizations with high security data.	Small business and home users.