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LAN. Eric Wong CS 147 Fall 2008. What is LAN?. LAN stands for Local Area Network A LAN is a network that connects multiple computers These computers may be in the same room, same building, or spread out throughout multiple buildings. LAN. Characteristics of LAN.
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LAN Eric Wong CS 147 Fall 2008
What is LAN? • LAN stands for Local Area Network • A LAN is a network that connects multiple computers • These computers may be in the same room, same building, or spread out throughout multiple buildings
Characteristics of LAN • A network of two or more computers • All computers in the network connected by cables or wi-fi • Does not require leased communication lines
Components of a network • Ethernet • Hubs • Individual Computers • Protocol • NICs • Network Software • Server
Ethernet • Uses Ethernet cables to physically connect computers to a network
Ethernet (cont) • May be wireless using radio waves for two-way communication • Ethernet protocol formally known as IEEE 802.3 • IEEE is the Institute of Electrical and Electronic Engineers
Ethernet (cont) • Called IEEE 802.3 because it was defined in February 1980
Hubs • A Junction Box with multiple ports for Ethernet cables to connect to • Sends all data it receives to every computer in the network • MAC (Medium Access Control) addresses
Hubs (cont) • Computers ignore all information that is addresses to a different MAC • Hubs use half-duplex mode • Each computer can only send or receive data at the same time • Can’t do both at once
Network Switch • Alternative to a Hub • Full Duplex Functionality • Nodes can receive and send data at the same time • Sends data to specific MAC addresses only instead of every computer
Network Switch (cont) • Superior to Network Hubs
Computers • Allows users to interface with the network • Computers on a network share resources and/or information
Protocol • Ethernet is a communications protocol • They define the rules that allow computers to communicate with each other • Protocol operations send signals to the desired network and attempts to find a connection
TCP/IP • Another common communication protocol in LANs • TCP stands for Transmission Control Protocol • IP stands for Internet Protocol • Also used for Internet connections
NIC • NIC stands for Network Interface Card • Installed into an empty slot on the motherboard • May be built into the motherboard • Ethernet cables connect from the Hub or Switch to the NIC
NIC (cont) • Every computer in a network has one • All NICs connected to the network must use the same architecture
Network Software • Software that uses all the hardware to create a networking environment • Allows administration of network • Many operating systems contain networking software • Also available from vendors
Server • Server performs a special service on the network • May be spread out over multiple computers • Typically one computer dedicated to server functions
Server (cont) • Server computer is built differently • Stores a majority of the data in a network
The Purpose of LAN • It allows shared file access between computers quickly • Share peripherals • Transfer data between computers at a high rate
Disadvantages • Computers must be physically close to each other • Security issues
Security • With Hubs, packet sniffers allow access to data intended for other computers • Viruses on one computer may threaten whole network
WAN • Stands for Wide-Area Network • Computer network on a much larger scale than LANs • Internet is an example of WAN.
Larger Networks • LANs may connect to other LANs or WANs to form an even larger network • Usually done with a router • Router receives data and forwards it to the correct location
Sources • Anissimov, Michael. "What is a Local Area Network." WiseGEEK. 18 Nov. 2008 <http://www.wisegeek.com/what-is-a-local-area-network.htm>. • Kayne, R. "What are Networking Hubs." WiseGEEK. 19 Nov. 2008 <http://www.wisegeek.com/what-are-networking-hubs.htm>. • Kayne, R. "What is Ethernet?" WiseGEEK. 19 Nov. 2008 <http://www.wisegeek.com/what-is-ethernet.htm>. • White, David. "What is TCP/IP." WiseGEEK. 18 Nov. 2008 <http://www.wisegeek.com/what-is-tcpip.htm>.
Sources (cont) • "What is Computer Networking." Senior Corps Tech Center. Corporation for National and Community Service. 20 Nov. 2008 <http://www.seniortechcenter.org/hardware_and_software/what_is_network.php>.