1. I Information Systems Technology Ross Malaga 5 "Part I Understanding Information Systems Technology" Copyright © 2005 Prentice Hall, Inc. 5-1 NETWORKING TECHNOLOGIES

2. Copyright © 2005 Prentice Hall, Inc. 5-2 LEARNING GOALS Describe the components of a telecommunications system. Compare and contrast the various types of transmission media Identify and explain the various types of computer networks. Identify and describe the role of the major hardware items used in networks. Describe the importance of networking protocols and identify the major ones used in business. Identify and describe the role of software used in networks. Describe the function of telecommunications services. Explain the importance of network planning and the major components of a network plan.

3. Copyright © 2005 Prentice Hall, Inc. 5-3 Bead Bar Consultant Networking Needs Meredith – How to build a network when there is no premises wiring? Suzanne – Need to connect all locations Leda – Connectivity would allow easier exchange of ideas with franchisees Mitch – Remote access to corporate network from anywhere Julia – Minimize costs and improve data collection and communications with all locations Miriam – Electronic sales data and marketing materials Rachel – Work flow systems to reduce paperwork Jim – Use of electronic forms instead of paper forms

4. Copyright © 2005 Prentice Hall, Inc. 5-4 Telecommunications Systems Purpose – to transmit data from one location to another –Voice data –Computer data –Video data –Any data Major components –Transmission media –Network topology –Data communications hardware –Protocols used in system –Network software –Telecommunications services

5. Copyright © 2005 Prentice Hall, Inc. 5-5 Data Format for Network Transmission Data inside computers is in digital form Networks transmit two forms of data –Analog – voice over telephone –Digital – data over ISDN telephone line Analog network cannot carry digital data –Most of existing telephone system is an analog network Conversion of digital data to analog format (when necessary) –Modulation Amplitude modulation Frequency modulation –Convert on one end of transmission; de-convert on other end –Modulation–demodulation, or modem for short

6. Copyright © 2005 Prentice Hall, Inc. 5-6 How Modems Work

7. Copyright © 2005 Prentice Hall, Inc. 5-7 Bandwidth The measure of capacity of transmission media Bits per second (bps) –Kilobits per second Modem communications over telephone lines –Megabits per second Most existing local area networks –Gigabits per second High speed data networks –Internet backbone

8. Copyright © 2005 Prentice Hall, Inc. 5-8 Network Media Physical media –Electrical signal Wire –Twisted pair »Phone System »LAN –Coaxial Signal interference –Optical signal Fiber optic cable –Thin glass fibers surrounded by coating –Uses lasers for light source –Very fast –Physical media require installation of cable Expensive Time consuming

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10. Copyright © 2005 Prentice Hall, Inc. 5-10 Network Media Wireless media –Radio frequency Low power radio waves Affected by electromagnetic interference Highly vulnerable to snooping Conflicting standards –IEEE 802.11a, b, and G Limited distance –Terrestrial microwave Tower Satellite –Geosynchronous – GEO –Medium earth orbit – MEO –Low earth orbit – LEO –Infrared Close proximity and “line of sight” location required

11. Copyright © 2005 Prentice Hall, Inc. 5-11 Media Types and Speed

12. Copyright © 2005 Prentice Hall, Inc. 5-12 Computer Networks Two or more computers that are connected for the purpose of sharing data –File sharing (e.g. MP3s) –E-mail –Database sharing Computer must be connected to the network media –Network interface card (NIC) –Each NIC has its own unique address Once connected to the network, the computer (or other device) becomes a network node

13. Copyright © 2005 Prentice Hall, Inc. 5-13 Transmitting Data in a Network Circuit switched network –Entire circuit from end to end must be open and available –Guarantees message goes through –Any one segment along the way goes down, the circuit is disabled Packet switched network –Message data divided into small pieces called packets, each with destination address and packet id –Special network hardware routes packets to destination where message is reassembled –More fault tolerant than circuit switched networks

14. Copyright © 2005 Prentice Hall, Inc. 5-14 Network Topologies The configurations of network components Widely used network topologies –Bus –Star –Ring –Mesh –Tree –Hybrid

15. Copyright © 2005 Prentice Hall, Inc. 5-15 Bus Network Topology Most simple network topology All devices connected to a common central cable Inexpensive Easily expanded If cable fails, the entire network will shut down Bus is topology used most widely in businesses

16. Copyright © 2005 Prentice Hall, Inc. 5-16 Bus Network Topology (Continued)

17. Copyright © 2005 Prentice Hall, Inc. 5-17 Star Network Topology Star topology is centered around central routing device called a hub All network nodes connect to the hub Easy to install and update If hub fails, network fails Hub can also be a bottleneck

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19. Copyright © 2005 Prentice Hall, Inc. 5-19 Ring Network Topology Each node connected to two other nodes in a ring Similar to the buss, but with the ends of the buss connected together More reliable than buss or star –If one node fails, data rerouted around failed node Expensive and difficult to install –Usually used by larger organizations who can afford the expense and to whom the reliability is very important

20. Copyright © 2005 Prentice Hall, Inc. 5-20 Ring Network Topology (Continued)

21. Copyright © 2005 Prentice Hall, Inc. 5-21 Mesh Network Topology Every node connected to every other node Fast Reliable –No hub or bus to fail –If one device goes down, it is the only node affected Expensive –Every node must be wired to every other node Difficult to add nodes –If there are 32 nodes in a mesh network and you wish to add a new node, how many new cables must you add?

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23. Copyright © 2005 Prentice Hall, Inc. 5-23 Tree Network Topology Combination of bus and star Two or more star networks connected using a bus for the backbone

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25. Copyright © 2005 Prentice Hall, Inc. 5-25 Hybrid Topologies Combine two or more of the other topologies Bus used for LANs and ring used for campus backbone linking LANs together

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27. Copyright © 2005 Prentice Hall, Inc. 5-27 Network Architecture Defines how network functions at a logical level Two primary types –Client-server –Peer-to-peer (P2P)

28. Copyright © 2005 Prentice Hall, Inc. 5-28 Client-server Network Architecture Nodes are either clients or servers Clients use services Servers provide services –Access to shared data –E-mail –Printing –FAX Client software on client node cooperates with server software on server node –WWW is largest client server application

29. Copyright © 2005 Prentice Hall, Inc. 5-29 Peer-to-Peer Network Architecture All nodes on the network are equal. Any node can be both a client and a server. Napster was an example of a P2P network used to share MP3 files. Windows printer and file sharing use P2P.

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31. Copyright © 2005 Prentice Hall, Inc. 5-31 Local Area Networks (LANs) Computer network where the nodes are all in close proximity –Department –Floor in office building –Small business building Provides access to shared resources –Servers –Printers –Databases –Internet access

32. Copyright © 2005 Prentice Hall, Inc. 5-32 Larger Networks Campus area network (CAN) –Connects LANs within a limited geographic area School Corporate campus Military installation Metropolitan area network (MAN) –Within a town or city Wide area network (WAN) –Two or more LANs that are geographically separate but linked through a public telephone network

33. Copyright © 2005 Prentice Hall, Inc. 5-33 Data Communications Hardware NIC Hub Modem Router – special hardware in packet switched networks that determines optimal routing path for packets Gateway – converts data from one standard to another; allows connections of disparate networks

34. Copyright © 2005 Prentice Hall, Inc. 5-34 Protocols An agreed upon set of rules that govern communications in a network TCP/IP –The protocol suite for the Internet –Transmission Control Protocol (TCP) Provides a reliable byte-stream transfer service between two endpoints on an internet –Internet Protocol (IP) Defines a delivery mechanism for packets of data sent between all systems on an Internet –Widely used by business, even for internal networks

35. Copyright © 2005 Prentice Hall, Inc. 5-35 Protocols (Continued) Ethernet –A set of rules for constructing message in a local network –Most widely used protocol for transmitting data over LANs –Listen before talk –Simple –Inexpensive –Flexible –Collisions High message volume greatly reduces transmission speed

36. Copyright © 2005 Prentice Hall, Inc. 5-36 Protocols (Continued) Token Ring –Also a set of rules for constructing message in a local network –Only one node “talks” at a time –Complex –Expensive –More fault tolerant than Ethernet –No collisions Transmission speed unaffected by message volume

37. Copyright © 2005 Prentice Hall, Inc. 5-37 Network Software Network operating system –Novell NetWare –Microsoft Windows Server 2003 Network management software –Helps ensure security of network –Monitors performance –Helps administrators reconfigure network –Remote administration via push technology Network monitoring software –Packet sniffers – see data as it moves over network –Keystroke monitors – see what users are doing

38. Copyright © 2005 Prentice Hall, Inc. 5-38 Telecommunications Services Value Added Networks (VANs) –Proprietary networks built using common carriers –Provide enhanced services Video conferencing Electronic data interchange (EDI) Virtual Private Networks (VPNs) –Use encryption to provide a secure end-to-end connection over common carriers or the Internet –Remote access to internal networks w/o dialup Leased lines –High speed, long distance data transfer

39. Copyright © 2005 Prentice Hall, Inc. 5-39 Leased Line Comparisons

40. Copyright © 2005 Prentice Hall, Inc. 5-40 Bead Bar Consultant How can the Bead Bar use networking technologies? –Meredith – Wireless connections –Suzanne – Connect all studios to org. software –Leda – Remote access to org. software for franchisees –Mitch – Can we access from onboard ships, also? –Julia – Cost benefits of wireless networking –Miriam – Improved inventory control due to more rapid transmission of sales and inventory data –Rachel – Improved efficiency –Jim – Will we need a network administrator? How about new policies and procedures for using and accessing the network?

41. Copyright © 2005 Prentice Hall, Inc. 5-41 Learning Goals Summary In this chapter you have learned: The components of a telecommunications system To compare and contrast the various types of transmission media To identify and explain the characteristics of various types of computer networks To identify and describe the role of the major hardware items used in networks The importance of networking protocols and identify the major ones used in business To identify and describe the role of software used in networks The function of telecommunications services The importance of network planning and the major components of a network plan