Local Area Network

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Local Area Network

• Andrew B. Vizcarra
• andrewv_at_admu.edu.ph
• http//www.math.admu.edu.ph/andrewv

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Course Outline

• Networking Fundamentals
• LAN Hardware and Software
• Network Design, Maintenance and Troubleshooting
• Network Security
• LAN Implementation and Others

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Grading System

• Attendance 10
• Midterms 30
• Finals 30
• Project/Research/Report 30
• TOTAL 100

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I. Networking Fundamentals
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What Is Networking?

• Networking is all about information
• every business runs on information
• more and more businesses, small and large, now
  rely on personal computers and networks to store
  their precious information
• The PC as an information tool
• word processing, accounting, graphics design,
  computerized reference, inventory tracking,
  simulation, numerical analysis

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What Is Networking?

• Exchanging information
• rarely a stand-alone environment
• The network
• computers connected over a network can make
  information exchange easier and faster

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PC Networks

• A number of personal computers and peripherals
  linked together by a cabling system through which
  the network components can communicate
• Offer the advantage of centralized file storage
  for data integrity and data backup
• Allow users to share data files and peripherals,
  and to communicate to each other via e-mail.

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LANLocal Area Network

• A data communication system allowing a number of
  independent devices to communicate directly to
  each other, within a moderately sized geographic
  area over a physical communications channel of
  moderate data rates
• Institute of Electrical and Electronics Engineers
  (IEEE) definition
• Connected by cabling
• May be organized on a workgroup or departmental
  basis and link to other LANs in the same building

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WANWide Area Networks

• Networks which consist of Local Area Networks in
  different geographical locations which
  communicate with each other by telephone
  landline, or by satellite

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Why Networking?

• Sharing information
• Sharing hardware resources
• Sharing software resources
• Preserving information
• Protecting information
• E-mail

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Some Problems

• You are an investment consultant. You have a PC
  in your home office. You have a printer, modem,
  fax machine, and scanner attached to your
  computer.
• Do you need a network?

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Some Problems

• You maintain the computers in a graphics design
  studio. The computers all have large hard drives
  to store files and optical disk drives with
  removal cartridges. Someone who wants to print
  an image takes a cartridge with the image stored
  on it over the computer with the printer.
• How would a network help this studio?

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Some Problems

• Your company is having a difficult time keeping
  information consistent because not all users have
  the most current version of the project reports
  on their computers hard drives. Also, important
  information has been lost because an individual
  consistently fails to back up his hard drive.
• How would you use a network to improve this
  situation?

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Some Problems

• Your company uses a lot of paper for inter-office
  memos because every morning the secretaries in
  your company must make hundreds of copies of the
  memos to distribute around the company.
• How could you use a network to reduce these costs
  in paper and productivity?

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LAN Background

• 1980s One User, One Computer
• Distributing and communicating information among
  individuals, each with an independent PC, is slow
  and prone to error
• By linking these individual computers over LANs,
  their usefulness and productivity have been
  increased enormously
• Internet and World Wide Web (WWW)

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Benefits of Networking

• More efficient management of resources
• Keep information reliable and up-to-date
• Speed up data sharing
• Allow workgroups to communicate more efficiently
• Help business service their clients more
  effectively
• Greatly expand a businesss marketing and
  customer service capability

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Who needs to network?

• Are you spending money on redundant hardware
  upgrades for each desktop machine?
• Are employees unable to share data because of
  software incompatibilities?
• Are support and training costs on the rise?
• Are a great many vendors servicing your
  information management needs in a piecemeal
  fashion?
• Are business bottlenecks created because people
  must wait for information before they can act?

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Who needs to network?

• Lost data because some individuals dont make
  backups as well as others
• An increasing number of files being transferred
  via floppy disks
• Routine business communication being conducted in
  an ad-hoc, haphazard fashion, or by arranging
  formal meetings to discuss everyday issues
• Important messages being passed via adhesive note
  pad, report margins, or scraps of paper, being
  lost or simply not noticed until it is too late

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Manpower needs

• Network administrator
• Database administrator
• Workgroup manager
• Support staff
• Maintenance contractor
• Webmaster or web site administrator

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Network Types
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Roles for computers in a LAN

• Clients
• Uses but do not provide network resources
• Peers
• Both use and provide network resources
• Servers
• Provide network resources

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Types of Networks

• 1. Server-based (client-server)
• an application component called a client issues
  requests for services
• another application component called a
  server/peer provides the requested service
• a LAN provides the means of transporting
  information back and forth between the client and
  the server component
• there can be multiple clients sharing the
  services of a single server, and the client
  applications need not be aware that processing is
  not being performed locally

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Server-based

• Advantages
• strong central security
• central file storage
• share hardware and software
• optimized dedicated servers
• less intrusive security (single password)
• easy manageability of a large number of users

• Disadvantages
• expensive dedicated hardware
• expensive network operating system
• a dedicated network administrator

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Types of Networks

• 2. Peer (peer-to-peer)
• no dedicated server or hierarchy among the
  computers
• use the network to share resources among
  independent peers
• every node sometimes participate in network
  management
• organized into workgroups

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Peer-to-peer

• Advantages
• no extra investment in server hardware
• easy setup
• no network administrator required
• ability of users to control resources sharing
• no reliance on other computers for their
  operation
• lower costs for small networks

• Disadvantages
• additional load on computers
• inability of peers to handle as many network
  connections as servers
• lack of central organization
• Requirement that users administer their own
  computers
• weak and intrusive security

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Types of Networks

• 3. Hybrid
• have all three types of computer operating on
  them
• have active domains and workgroups

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Peer vs. Server Security

• Share Level Security
• Server Level/File Level Security (access
  permission security)

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Some Problems

• You are installing a small network for a
  collections agency. There will be only five
  stations on the network. Cost is an issue, and
  the company would prefer not to dedicate an
  individuals time to maintaining a network.
  However, the agency is also concerned about
  keeping its data safe, and the users are not
  sophisticated computer users.
• In what way is a peer-to-peer network appropriate
  for this company? In what ways is it
  inappropriate?
• In what way is a server-based network appropriate
  for this company? In what ways is it
  inappropriate?

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Server Types

• File server
• Print server
• Applications server
• Message servers
• Database server

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File Server

• File transfer
• File storage and data migration
• online storage
• offline storage
• nearline storage
• Update synchronization
• File archiving

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Print Server

• Allow users to share printers
• Allow you to place printers where convenient
• Achieve better workstation performance by using
  high speed network data transfer, print queues,
  and spooling
• Allow users to share network fax services

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Application Server

• Allow client PCs to access and use extra
  computing power and expensive software
  applications that reside on a shared computer
• Used when efficiency or security requires a
  program to stay close to the data, and the data
  stays in one place

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Message Server

• Electronic mail
• Workgroup applications
• Object-oriented applications
• Directory services

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Database Server

• The clientend portion of the application runs on
  the client, providing an interface and handling
  less intensive functions, such as data requests
• The serverend portion of the application handles
  the intensive performance of database operations.
  

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Some Problems

• You network installation company uses Microsoft
  Access to keep track of customers, potential
  customers, and the various aspects of running a
  network installation job. The database has grown
  rather large, and as your company expands and
  more people access the database, the response
  time lags.
• How can you improve the performance of the
  database system?
• It is essential that your organization not lose
  data.
• What aspects of a dedicated file server will help
  keep your data safe?