A local area network (LAN) is a computer network that interconnects computers within a limited area such as a residence, school, laboratory, university campus or office building and has its network equipment and interconnects locally managed. By contrast, a wide area network (WAN), not only covers a larger geographic distance, but also generally involves leased telecommunication circuits or Internet links. For more info about Lemon Entrepreneurs visit:- www.lemon-school.com

1. What is Network
• Collection of computers, servers, mainframes, network devices, peripherals
• Connected to one another
• Allowing for data to be shared and used
• Biggest example of network – Internet (connecting the world)

2. Types of Network
• LAN (Local area network)
• WAN (Wide area network)
• WLAN (Wireless local area network)

3. Local Area Network
• Collection of independent computers
• Exchange information
• Over shared communication medium
• Confined to limited geographic area (Building or college)
• Can link from two to hundreds of computers
• Used by business and educational organization

4. Wide Area Network
• Connect multiple LANs that are geographically separate
• Accomplished by connecting the several LANs with dedicated leased lines
• By dial up phone lines, Satellite links, data packet carrier services
• Can be complex as hundreds of branch offices linked globally
• Routing protocol and filters minimize the expense of sending data over vast distances
• Medium and example – Internet

5. Wireless Local area network
• Use radio frequency technology to transmit and receive data over the air
• Minimizes the need for wired connection
• Gives user mobility (connection to LANs without physical connection with Cables)
• Gives flexibility and productivity (Entrepreneurs and Home users)
• Connect devices that may be physically difficult to reach with cable (with Internet )

6. What is Internet
• Global network of computers
• Which may be server or client
• Exchange information
• Defined as “Network of Networks”
• Linked through copper wires, wireless connections and other technologies
• World wide network of computers accessible to all
• Facilitate data communication services
• Full fledged conduit for any and all forms of information and commerce

7. What is Intranet
• Term Intranet is derived from two words:
“Intra” which means within and
“net” which means group of interconnected computers
• Private network utilizing Internet type tool
• Available only within the organization
• Provide easy access to corporate information for designated employees
• Security imposed by public key security, encryption key and firewall

8. Application of Intranet
• Sharing of companies policies/rules and regulation
• Access employees database
• Distribution of circulars and office orders
• Access product or customer data
• Sharing of information of common interest
• Submission of reports
• Corporate telephone directories
• Launching of personal or departmental home pages

9. What is Extranet
• Extranet is an Intranet for outside authorised users using internet technology
• Inter-organizational information system
• Commonly used by companies to share data in a secure fashion with business partners
• Internet tools are used to update extranet
• Example : Dealers have access to product files such as Product specification,images,Pictures
• Components of extranet are
TCI/IP protocols
E-mail
Web browser
External business partner

10. Benefits of extranet
• Improved quality
• Lower travel cost
• Lower administrative and overhead cost
• Reduction in paper work
• Delivery of accurate information on time
• Improved customer service
• Better communication
• Overall improvement in business effectiveness

11. Types of LAN Technology
• Ethernet
• Fast Ethernet
• Gigabit Ethernet
• 10 Gigabit Ethernet
• ATM
• POE
• Token Ring

12. Ethernet
• Most popular physical layer LAN technology in use today
• It defines
The number of conductors that are required for connection
The performance threshold that can be expected
Provides framework for data transmission
• Standard ethernet can transmit data at the rate of 10 Mega bit per second
• Strikes good balance between speed, cost and ease of installation
• Ability to support virtually all popular network protocols
• Ethernet standard popularly known as IEEE standard 802.3

13. Fast Ethernet
• Established for Ethernet networks that need higher transmission speed
• Raises Ethernet speed from 10 mbps to 100 mbps
• Minimal changes to the cable structure (Compared from Ethernet)
• Provides faster throughput for videos, multimedia, graphics, internet surfing
• Three types of fast Ethernet are
100 BASE-TX for use with level 5 UTP cable
100 BASE-FX for use with fibre optic cable
100 BASE-T4,utilizes an extra two wires for use with level-3 UTP cable
• 100 BASE –TX has become the most popular due to its close compatibility with 10 BASE-T
Ethernet cable

14. Gigabit Ethernet
• Developed to meet the need for faster communication
• With application such as multimedia and voice over IP
• Also known as “Gigabit-Ethernet-over-copper” or 1000 BASE-T
• GigE is a version of Ethernet that runs at a speed 10 times faster than 100 BASE-T
• Currently use as an Enterprise backbone

15. 10 Gigabit Ethernet
• Fastest and the most recent Ethernet standard
• Nominal rate of 10 Gigabits/s that makes it 10 times faster then Gigabit Ethernet
• Based entirely on the use of fibre optic cable
• Includes some elements of wide area routing

16. Power Over Ethernet (POE)
• Solution in which electrical current is running
• For networking hardware over the Ethernet category 5 cable
• Does not require an extra AC power cord at the product location
• Minimizes the amount of cable needed and leeds to cost sutting