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CSCI 1101 Intro to Computers
6. Local Area Networks
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A computer network is a collection of computers and other devices that communicate to share data, hardware and software.
Local area network (LAN) - a network located in a limited area. found in most businesses
Wide area network (WAN) - a network that covers a large geographical area
Local Area Networks
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A local area network makes a stand-alone computer a workstation on a network.
The workstation provides you with: your computer’s local resources
hard drive, software printer
access to network resources software storage space other printers
Benefits of Networking
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Network nodesinclude workstationsprinters, andservers.
Typical Network Resources
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You typically cannot use network resources until you log into the network. provide user ID and password
User account provides access to network accumulates information about network use tracks when you log in and out
Gaining Access to Networks
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Use these tips toselect a securepassword.
Password Considerations
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Workstation gains access to the server when the server hard drive is “mapped” to a drive letter.
Drive mapping - network term for assigning a drive letter to a network server disk drive. many use the letter F
Window’s Neighborhood Network is a utility that helps you see your workstation’s network drive mapping.
What is drive mapping?
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When you start a program that is stored on a LAN, the program is copied to your workstation’s RAM, then runs normally.
With proper licensing, many users on the same network can use the same program simultaneously, also known as sharing.
Sharing is effective because: less disk storage space required easier to update software less expensive
Executing programs on a Network
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Advantages to storing data files on a server: can access from any computer on network other network users can access files
option of restricting access
File locking - precaution that locks an open file so other users cannot open it at the same time
Where to store data files
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Default printer - printer you most frequently use
One way to select a different printer is to select a printer using the Printers dialog box.
Printer Issues
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A network interface card (NIC) is the key hardware component for connecting a computer to a local area network. small circuit board that sends data to and from
workstation to network
Different networks use different NICs. Popular network types include Ethernet and
Token Ring.
How to physically connect to a network
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Today’s networks use twisted-pair cable UTP (unshielded twisted pair STP (shielded twisted pair) looks similar to telephone cable has square plastic RJ-45 connector
Twisted-pair cable
Network Cabling
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Another option is coaxial cable resembles cable-TV cable round, silver BNC connector
Coaxial cable
More network cabling options
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Wireless networks use radio or infrared signals to transmit data from one network device to another. handy in environments where wiring is difficult to
install historical buildings
provide mobility good for temporary installations
Non-wired network connections
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On most of today’s networks, the cable from a workstation NIC connects to a network hub, a device that joins communication lines together.
A hub serves asa central connection pointfor workstation and servercables.
Making the connection
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When connected to a network, the device that processes your data depends on the types of servers. dedicated servers non-dedicated servers print servers application servers host computers
Where does the actual processing occur?
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Application server - computer that runs a specific application software package also referred to as client/server architecture
An application server splits processing between the workstation (client) and the network (server).
Client Server issues
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An application server typically runs database software and performs database functions as requested by the workstations.
Typical client/server work issues
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Some networks include a host computer, a minicomputer or a mainframe with attached terminals. all processing takes place on the host terminals only display results of processing also known as a time-sharing system Cyrix processing systems use this model
Terminal emulation software connects a microcomputer to a host
Centralized processing systems
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Today’s computers include software necessary to communicate with a network.
The software handles the communication between your workstation and the network server.
How networks communicate
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Network operating system (NOS) software manages network resources controls flow of data maintains security tracks user accounts
Network operating system has two components network server software network client software
Managing the network process
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Network server software (installed on file server) controls file access from the server’s hard disk manages print queue tracks user data
IDs and passwords
Network client software (installed on workstation) gathers login information handles drive mapping directs printouts to network printer
Network software components
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Most software designed for stand-alone computers can be installed on a network server.
Some software has built-in networking features that only appear when software is installed on network. ability to send a file to another network user
What can I run on a network?
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Using a single-user license for multiple users typically violates software’s copyright.
Software publishers offer a network license that allows use by multiple people on a network.
Network software licensing
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Groupware is application software that supports collaborative work by managing: schedules shared documents intra-group communications based on “information-centered model
Workflow software - automates the process of electronically routing documents from one person to another in a specified sequence based on a “process-centered model”
Group-based processing environments
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E-mail messages are stored on a server and forwarded to you when you want to read it.(store-and-forward technology)
How e-mail is communicated
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A gateway is an electronic link to other e-mail systems that allows you to send e-mail to people on other networks. transferred through the gateway
How e-mail gets to other systems
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Tips for using e-mail read mail regularly delete messages after you read them you don’t have to reply to every e-mail reply to one person instead of entire group think before you send don’t write anything confidential don’t get sloppy use proper netiquette
Managing e-mail effectively
