© 2008 Prentice-Hall, Inc. 1 Technology in Action 1.

1 © 2008 Prentice-Hall, Inc.

Technology in ActionTechnology in Action

1


Technology in ActionTechnology in Action

Chapter 12Chapter 12

Behind the Scenes: Behind the Scenes: Networking and SecurityNetworking and Security


Chapter TopicsChapter Topics• Advantages of business networksAdvantages of business networks• Client/server vs. peer-to-peer networksClient/server vs. peer-to-peer networks• Classifications of client/server networksClassifications of client/server networks• Client/server network componentsClient/server network components• Types of serversTypes of servers• Network topologiesNetwork topologies• Types of transmission mediaTypes of transmission media• Network softwareNetwork software• Network adaptersNetwork adapters• Moving data in a client/server networkMoving data in a client/server network• Securing networksSecuring networks


Networking AdvantagesNetworking Advantages

• NetworksNetworks– Increase productivityIncrease productivity– Enable the sharing of Enable the sharing of

hardware resourceshardware resources– Enable the sharing of Enable the sharing of

softwaresoftware– Facilitate Internet Facilitate Internet

connectivityconnectivity


Client/Server NetworksClient/Server Networks

• Server-based networkServer-based network– Clients and serversClients and servers

• Data flows efficiently Data flows efficiently • Servers respond to Servers respond to

requests from clientsrequests from clients• Servers perform Servers perform

specific tasksspecific tasks• Scalable networkScalable network• CentralizedCentralized


Classifications of Classifications of Client/Server NetworksClient/Server Networks

• LANLAN– Local area networkLocal area network– Computers linked Computers linked

together over a together over a small geographic small geographic regionregion



• WANWAN– Wide area networkWide area network– Computers linked Computers linked

over large over large geographic geographic locationslocations

• MANMAN– Metropolitan area Metropolitan area

networknetwork– Computers linked Computers linked

together within a together within a city or countycity or county



• PANPAN– Personal area networkPersonal area network– Wireless devices connected in close proximity Wireless devices connected in close proximity

to each otherto each other

• IntranetIntranet– Private corporate networkPrivate corporate network– Protected by a firewallProtected by a firewall


Constructing Constructing Client/Server NetworksClient/Server Networks

• ServersServers• Network topologiesNetwork topologies• Transmission mediaTransmission media• Network operating Network operating

system (NOS)system (NOS)• Network adaptersNetwork adapters• Network navigation Network navigation

devicesdevices


Servers Servers

• Number and type of Number and type of servers depend on servers depend on network size and network size and workloadworkload

• Dedicated serverDedicated server– Performs one specific Performs one specific

functionfunction

• Authentication serverAuthentication server– Keeps track of network Keeps track of network

logins and services logins and services availableavailable

• File serverFile server– Stores and manages filesStores and manages files


Dedicated ServersDedicated Servers

• Print serverPrint server– Manages client-requested printing jobsManages client-requested printing jobs– Creates print queue (prioritizes print jobs)Creates print queue (prioritizes print jobs)

• Applications serverApplications server– Acts as a storage area for application softwareActs as a storage area for application software

• Database serverDatabase server– Provides clients with access to database Provides clients with access to database

informationinformation• E-mail serverE-mail server

– Processes and delivers incoming and outgoing Processes and delivers incoming and outgoing e-maile-mail


Dedicated ServersDedicated Servers

• Communications serverCommunications server– Handles communications between networks Handles communications between networks

including the Internetincluding the Internet– Often the only device on the network directly Often the only device on the network directly

connected to the Internetconnected to the Internet

• Web serverWeb server– Hosts a Web site available through Hosts a Web site available through

the Internetthe Internet


Network TopologiesNetwork Topologies

• The physical layout of computers, The physical layout of computers, transmission media, and other transmission media, and other componentscomponents

• Types of network topologiesTypes of network topologies– Bus topologyBus topology– Ring topologyRing topology– Star topologyStar topology– Hybrid topologyHybrid topology


Bus TopologyBus Topology• All nodes are connected in All nodes are connected in

sequence on a single cablesequence on a single cable• Used most often on Used most often on

peer-to-peer networkspeer-to-peer networks• Networked computers Networked computers

communicate with each communicate with each otherother

• One computer transmits One computer transmits data at a timedata at a time– Access methods avoid data Access methods avoid data

collisionscollisions– Data is transmitted in Data is transmitted in

“packets”“packets”


Ring TopologyRing Topology• Nodes are laid out in Nodes are laid out in

a ringa ring• Token (data packet) Token (data packet)

flows in one flows in one direction from direction from device to devicedevice to device

• Recent versions Recent versions have data transfer have data transfer rates up to 100 rates up to 100 MbpsMbps


Star TopologyStar Topology

• Nodes connect to a central Nodes connect to a central communications device communications device (switch)(switch)

• A node sends a signal to A node sends a signal to the switch, which the switch, which retransmits it to the retransmits it to the other nodesother nodes

• A node accepts only A node accepts only signal addressed to itsignal addressed to it


Avoiding Data CollisionsAvoiding Data Collisions on an Ethernet Network on an Ethernet Network


Transmission MediaTransmission Media

• The routes data takes to flow between The routes data takes to flow between devices on a networkdevices on a network

• Wired Wired

• WirelessWireless – Wireless Fidelity (Wi-Fi)Wireless Fidelity (Wi-Fi)– Uses radio wavesUses radio waves– 802.11 standard802.11 standard


Choosing a CableChoosing a Cable

• Maximum run lengthMaximum run length• Bandwidth Bandwidth • Bend radiusBend radius• Cable costCable cost

• Installation costsInstallation costs• Susceptibility to interferenceSusceptibility to interference• Signal transmission methodsSignal transmission methods

Comparison of Characteristics of Major Cable Types

Cable Characteristics Twisted Pair (Cat 6) Coaxial (ThinNet) Coaxial (ThickNet) Fiber-Optic

MaximumRun Length

328 feet (100 m) 607 feet (185 m) 1,640 feet (500m) Up to 62 miles (100 km)

Bandwidth 1,000 Mbps 10 Mbps 10 Mbps 100 Mbps to 2 Gbps

Bend Radius(Flexibility)

No limit 360 degrees/foot 30 degrees/foot 30 degrees/foot

Cable Cost Very low Low Moderate High

Installation Cost Very low Low Slightly higherthan ThinNet

Most expensive because of Installation training required

Susceptibilityto Interference

High Low Very low None (not susceptibleto EMI and RFI)


Twisted Pair CableTwisted Pair Cable

• Pairs of copper wire twisted Pairs of copper wire twisted around each otheraround each other

• Twists make the wires less Twists make the wires less susceptible to interferencesusceptible to interference

• Shielded twisted pair (STP)Shielded twisted pair (STP)– Layer of foil shieldingLayer of foil shielding

• Unshielded twisted pair (UTP)Unshielded twisted pair (UTP)– Cat 5E: Bandwidth 200 MbpsCat 5E: Bandwidth 200 Mbps– Cat 6: Bandwidth 1 GbpsCat 6: Bandwidth 1 Gbps– No foil layerNo foil layer

UTP

STP


Coaxial CableCoaxial Cable

• Four componentsFour components– Copper coreCopper core– Nonconductive insulating materialNonconductive insulating material– Braided metalBraided metal– Plastic coverPlastic cover


Fiber-Optic CableFiber-Optic Cable

• Components includeComponents include– Glass or plastic fibersGlass or plastic fibers– CladdingCladding– Outer jacketOuter jacket

• Uses light impulses Uses light impulses to transmit datato transmit data

• Immune to Immune to interferenceinterference


Wireless MediaWireless Media802.11 Standard802.11 Standard

• Wi-Fi, short for Wireless FidelityWi-Fi, short for Wireless Fidelity– 802.11b – 802.11b – first cost-effective wireless devices.– 802.11a, 802.11g – bandwidth increased to 54 802.11a, 802.11g – bandwidth increased to 54

MbpsMbps– Super G – bandwidth to 108 MbpsSuper G – bandwidth to 108 Mbps– 802.11n – 802.11n – will support higher throughput and

greatly increased range


Network Operating Systems (NOS)Network Operating Systems (NOS)

• Provide the protocol that Provide the protocol that controls the communication controls the communication between devices on the between devices on the networknetwork

• Major network operating Major network operating systemssystems– Windows Server 2003Windows Server 2003– UNIXUNIX– Novell NetWareNovell NetWare


Network AdaptersNetwork Adapters

• Devices that enable computers to Devices that enable computers to communicate on a networkcommunicate on a network

• Network interface cards (NICs)Network interface cards (NICs)• Three functionsThree functions

– Generate network transmission Generate network transmission signalssignals

– Create data packetsCreate data packets– Act as information gatekeepersAct as information gatekeepers

• Ethernet compliantEthernet compliant• Wireless NICsWireless NICs


Network Navigation DevicesNetwork Navigation Devices

• Media Access Control Media Access Control (MAC) address(MAC) address– Six two-digit numbers Six two-digit numbers

(01:40:87:44:79:A5)(01:40:87:44:79:A5)– Physical address of Physical address of

network adapternetwork adapter– Internal network Internal network

identificationidentification

• Repeaters and HubsRepeaters and Hubs– Amplify signals and Amplify signals and

retransmit themretransmit them


Network Navigation DevicesNetwork Navigation Devices

• Switches and Switches and BridgesBridges– Send data on a Send data on a

specific route specific route through the networkthrough the network

– Bridges send data Bridges send data between collision between collision domainsdomains

• RoutersRouters– Send information Send information

between two between two networksnetworks


Network Security ThreatsNetwork Security Threats

• Human Errors and MistakesHuman Errors and Mistakes– Accidents and mistakesAccidents and mistakes

• Malicious Human ActivityMalicious Human Activity– Current and former employees hacking or Current and former employees hacking or

planting virusesplanting viruses

• Natural Events and DisastersNatural Events and Disasters– Hurricanes, floods, fireHurricanes, floods, fire


Network SecurityNetwork Security

• AuthenticationAuthentication– User ID and password used to access the networkUser ID and password used to access the network– Use of a possessed object for accessUse of a possessed object for access

• Access privilegesAccess privileges– Enable access to certain network systemsEnable access to certain network systems

• Physical protection measuresPhysical protection measures– Restrict physical access to sensitive network Restrict physical access to sensitive network

equipmentequipment– Magnetic card readersMagnetic card readers– Biometric access devicesBiometric access devices


Network SecurityNetwork Security

• FirewallsFirewalls– Prevent access to the network by Prevent access to the network by

unauthorized usersunauthorized users– Composed of software and/or hardwareComposed of software and/or hardware– Screen and validate data packetsScreen and validate data packets– Bastion host/proxy serverBastion host/proxy server


Network Firewall LayoutNetwork Firewall Layout


Chapter 12 Summary QuestionsChapter 12 Summary Questions

• What are the advantages of a business What are the advantages of a business network?network?



• How does a client/server network differ How does a client/server network differ from a peer-to-peer network?from a peer-to-peer network?



• What are the different classifications of What are the different classifications of client/server networks?client/server networks?



• What components are needed to construct What components are needed to construct a client/server network?a client/server network?



• What do the various types of servers do?What do the various types of servers do?



• What are the various network topologies?What are the various network topologies?



• What types of transmission media are What types of transmission media are used in client/server networks?used in client/server networks?



• What software needs to be running on What software needs to be running on computers attached to a client/server computers attached to a client/server network?network?



• How do network adapters enable How do network adapters enable computers to participate in a client/server computers to participate in a client/server network?network?



• What devices assist in moving data What devices assist in moving data around a client/server network?around a client/server network?



• What measures are employed to keep What measures are employed to keep large networks secure?large networks secure?

© 2008 Prentice-Hall, Inc. 1 Technology in Action 1.

Documents

Transcript of © 2008 Prentice-Hall, Inc. 1 Technology in Action 1.