Section 1 Basic Networking Section 1 Basic Networking KnowledgeKnowledge

CSIS 479R Fall 1999CSIS 479R Fall 1999

““Network +”Network +”

George D. Hickman, CNI, CNEGeorge D. Hickman, CNI, CNE

ObjectivesObjectives

Define computer networkingDefine computer networking Contrast the features of the computing Contrast the features of the computing

modelsmodels Compare LAN and WANCompare LAN and WAN Identify basic network elements and Identify basic network elements and

describe the role of clients, servers, describe the role of clients, servers, transmission media, and protocolstransmission media, and protocols

Identify the functions and features of the Identify the functions and features of the five basic network servicesfive basic network services

Objectives (con’t)Objectives (con’t)

Describe network file servicesDescribe network file services Describe network print servicesDescribe network print services Describe network message servicesDescribe network message services Describe network application servicesDescribe network application services Describe network database servicesDescribe network database services

Objectives (con’t)Objectives (con’t)

Identify the difference between centralized and Identify the difference between centralized and distributed network architecturesdistributed network architectures

Identify the term transmission media as it relates Identify the term transmission media as it relates to computer networksto computer networks

Identify the appropriate transmission media to Identify the appropriate transmission media to meet a stated business needmeet a stated business need

Identify the network connectivity devices and their Identify the network connectivity devices and their functionsfunctions

Identify the internetwork connectivity devices and Identify the internetwork connectivity devices and their functionstheir functions

Computer NetworkingComputer Networking

Networking is the sharing of information Networking is the sharing of information and servicesand services

Computer Networking provides the tools to Computer Networking provides the tools to allow computers to share information and allow computers to share information and resourcesresources

Computing ModelsComputing Models

Centralized computingCentralized computing– Mainframes and terminalsMainframes and terminals

Distributed computingDistributed computing– PCs do some processing, servers provide PCs do some processing, servers provide

processing or other servicesprocessing or other services Collaborative ComputingCollaborative Computing

– Multiple computers share the same taskMultiple computers share the same task– Screensavers in our labsScreensavers in our labs

Client/Server ComputingClient/Server Computing

Several Clients (PCs) are connected to a Several Clients (PCs) are connected to a serverserver

Clients request services from serversClients request services from servers Server performs some processing for clientServer performs some processing for client

Client/Network ComputingClient/Network Computing

Network-centric rather than Server-centricNetwork-centric rather than Server-centric Services are requested from the network, Services are requested from the network,

rather than from a specific serverrather than from a specific server Requires a Directory service, such as NDS Requires a Directory service, such as NDS

(Novell Directory Services)(Novell Directory Services)

LAN /WANLAN /WAN

Local Area NetworkLocal Area Network– Small group of computers interconnectedSmall group of computers interconnected

– Transmission measured in mbps (megabits/second)Transmission measured in mbps (megabits/second)

– Communication media usually owned by LAN ownerCommunication media usually owned by LAN owner

Wide Area NetworkWide Area Network– Geographically dispersedGeographically dispersed

– Transmission measured in kpbs (kilobits/second) Transmission measured in kpbs (kilobits/second)

– Communication media often leased from a providerCommunication media often leased from a provider

Special WANsSpecial WANs

Enterprise WANEnterprise WAN– Connects LANs of a single OrganizationConnects LANs of a single Organization

Global WANGlobal WAN– Crosses national boundaries (may or may not Crosses national boundaries (may or may not

cover entire globe)cover entire globe)– Internet is an exampleInternet is an example

Required Network ElementsRequired Network Elements

Individuals who need to Individuals who need to shareshare something something– Network ServicesNetwork Services

A method or A method or pathwaypathway for contacting each for contacting each otherother– Transmission mediaTransmission media

Communication rules to allow successful Communication rules to allow successful communication (2 way communication)communication (2 way communication)– Protocols like TCP/IP or IPX/SPXProtocols like TCP/IP or IPX/SPX

Network ServicesNetwork Services

ServersServers– Service providersService providers– Only Only provide servicesprovide services

ClientsClients– Service requestersService requesters– OnlyOnly request services request services

PeersPeers– Provide Provide and and request servicesrequest services

Peer-to-Peer NetworksPeer-to-Peer Networks

Distributed network services using peersDistributed network services using peers– Window 3.xWindow 3.x– Windows 95/98Windows 95/98– Windows NT WorkstationWindows NT Workstation– Windows NT ServerWindows NT Server– AppleTalkAppleTalk

Server-Centric NetworksServer-Centric Networks

Strictly defined rolesStrictly defined roles Clients request servicesClients request services Servers provide servicesServers provide services

– NetWareNetWare– Banyon VinesBanyon Vines– Open VMSOpen VMS

Transmission MediaTransmission Media

The pathway network signals takeThe pathway network signals take Often thought of as wires, but doesn’t need Often thought of as wires, but doesn’t need

to beto be– Fiber OpticFiber Optic– Radio (atmosphere is media)Radio (atmosphere is media)– Infrared (atmosphere is media)Infrared (atmosphere is media)

Guarantees message delivery path, but not Guarantees message delivery path, but not that messages will be understoodthat messages will be understood

ProtocolsProtocols

Rules that allow communicationRules that allow communication Can be one rule or a Can be one rule or a suitesuite of protocols or of protocols or

rulesrules TCP/IP is a protocol suiteTCP/IP is a protocol suite

Common Network ServicesCommon Network Services

File ServicesFile Services Print ServicesPrint Services Message ServicesMessage Services Application ServicesApplication Services Database ServicesDatabase Services

Network File ServicesNetwork File Services

Rapidly move files from place to placeRapidly move files from place to place Back up dataBack up data Efficient use of storage mediaEfficient use of storage media Handle multiple copies of same filesHandle multiple copies of same files

File Storage and Data MigrationFile Storage and Data Migration

Online StorageOnline Storage– Hard disks, etc. immediately available for useHard disks, etc. immediately available for use

Nearline StorageNearline Storage– Tape carousels, CD jukeboxesTape carousels, CD jukeboxes– Not immediately available, but no human Not immediately available, but no human

intervention neededintervention needed Offline StorageOffline Storage

– Not immediately available, human intervention Not immediately available, human intervention needed to useneeded to use

File Storage and Data MigrationFile Storage and Data Migration

File ArchivingFile Archiving Data MigrationData Migration BackupsBackups

– Moving data (often less-used or aged data in Moving data (often less-used or aged data in the case of migration) to offline, longer life, the case of migration) to offline, longer life, less expensive media. less expensive media.

File Update SynchronizationFile Update Synchronization

When the same file exists in two or more When the same file exists in two or more locations, they can become out of synclocations, they can become out of sync

Often occurs with laptops and portable Often occurs with laptops and portable devicesdevices

File Update Synchronization identifies File Update Synchronization identifies changes and manages file updates to changes and manages file updates to maintain file system integrity maintain file system integrity

Depends heavily on time stampsDepends heavily on time stamps

Network Print ServicesNetwork Print Services

Network Applications that manage access Network Applications that manage access to printers, fax machines, and copy to printers, fax machines, and copy equipmentequipment

Useful to limit the number of printers Useful to limit the number of printers required and to share specialized equipmentrequired and to share specialized equipment

Handling multiple simultaneous requests Handling multiple simultaneous requests (Queuing)(Queuing)

Network Message ServicesNetwork Message Services

Storing, accessing, delivering text, binary, Storing, accessing, delivering text, binary, graphic, digitized video, and audio data.graphic, digitized video, and audio data.

EmailEmail Integrated Email and voice mailIntegrated Email and voice mail Workgroup applicationsWorkgroup applications

Network Application ServicesNetwork Application Services

Network services thatNetwork services that run run software for software for clients.clients.

Different from file services because Different from file services because processingprocessing, not just files, is shared., not just files, is shared.

Specialization of serversSpecialization of servers– Client-server databaseClient-server database– PBXPBX

Network Database ServicesNetwork Database Services

Optimizes the computers that store, search, Optimizes the computers that store, search, and retrieve database recordsand retrieve database records

Control where data is stored geographicallyControl where data is stored geographically Organize data logically between Organize data logically between

organizational departmentsorganizational departments Provide data securityProvide data security Reduce database client access timeReduce database client access time

Distributed DataDistributed Data

Database is divided into smaller parts, often Database is divided into smaller parts, often managed by the department that owns the managed by the department that owns the datadata

DBMS makes the whole database appear as DBMS makes the whole database appear as a single, logical unit, and coordinates a single, logical unit, and coordinates changeschanges

ReplicationReplication

Multiple copies of data distributed Multiple copies of data distributed throughout networkthroughout network

Provides faster access when users can Provides faster access when users can access a closer copy of the databaseaccess a closer copy of the database

Provides fault tolerance since there is more Provides fault tolerance since there is more than one copy in the event of loss of the than one copy in the event of loss of the master copymaster copy

Requires a way of handling synchronizationRequires a way of handling synchronization

Synchronization MethodsSynchronization Methods

Master Database ReplicationMaster Database Replication– Changes can only be made to the master Changes can only be made to the master

databasedatabase– Replicas have read-only accessReplicas have read-only access

Local Database ReplicationLocal Database Replication– Changes can be made to the local copy of DBChanges can be made to the local copy of DB– All replicas must be able to communicate All replicas must be able to communicate

changes to all other replicaschanges to all other replicas

Transmission MediaTransmission Media

CharacteristicsCharacteristics– CostCost– Ease of installationEase of installation– CapacityCapacity– AttenuationAttenuation– Immunity from interference (EMI, RFI)Immunity from interference (EMI, RFI)– Signal captureSignal capture

Cable MediaCable Media

Twisted Pair cableTwisted Pair cable– Shielded or unshieldedShielded or unshielded– Category 1-5 (Cat 3, Cat 5 common for data)Category 1-5 (Cat 3, Cat 5 common for data)

Coaxial cableCoaxial cable– Like Cable TV cable, different resistanceLike Cable TV cable, different resistance

» 75 Ohm RG-6 Satellite TV, RG-59 Cable TV75 Ohm RG-6 Satellite TV, RG-59 Cable TV» 50 Ohm RG-8/11 Thick Ethernet RG-58 Thin Ethernet50 Ohm RG-8/11 Thick Ethernet RG-58 Thin Ethernet» 93 Ohm RG-62 ARCnet93 Ohm RG-62 ARCnet

Fiber Optic CableFiber Optic Cable– Glass or plastic fibersGlass or plastic fibers– EMI immune, allows faster transmission, greater lengthsEMI immune, allows faster transmission, greater lengths

Wireless MediaWireless Media

RadiowaveRadiowave– Shortwave, VHF and UHFShortwave, VHF and UHF

MicrowaveMicrowave– Terrestrial (earth-based) or SatelliteTerrestrial (earth-based) or Satellite

InfraredInfrared– Point to Point or BroadcastPoint to Point or Broadcast

Spread Spectrum RadioSpread Spectrum Radio

Direct sequence modulationDirect sequence modulation– Figure 1-23 on page 1-81Figure 1-23 on page 1-81– Signals send bits on rotating sequence on Signals send bits on rotating sequence on

various frequenciesvarious frequencies Frequency hoppingFrequency hopping

– Figure 1-24 on page 1-81Figure 1-24 on page 1-81– Signals send bytes (or other units) on rotating Signals send bytes (or other units) on rotating

sequence on various frequenciessequence on various frequencies

Transmission Media ConnectorsTransmission Media Connectors

Attach directly to the transmission mediaAttach directly to the transmission media Provide physical interface between Provide physical interface between

computing device and mediacomputing device and media Figures 1-26 and 1-27 on page 1-98Figures 1-26 and 1-27 on page 1-98

Network Interface CardNetwork Interface Card

A NIC is a NIC, not a NIC cardA NIC is a NIC, not a NIC card Some use an adapter to allow different Some use an adapter to allow different

media to attach (Transmission media media to attach (Transmission media adapter)adapter)

Designed for a specific useDesigned for a specific use– Don’t use a Token Ring NIC on an Ethernet Don’t use a Token Ring NIC on an Ethernet

LANLAN

ModemModem

Modulator/DEModulatorModulator/DEModulator Converts computer’s digital signals to Converts computer’s digital signals to

analog signals which can be used by analog signals which can be used by phone/other systemsphone/other systems

RepeatersRepeaters

Used to overcome attenuation and extend Used to overcome attenuation and extend transmission lengthstransmission lengths

AmplifierAmplifier type repeater amplifies all signals, type repeater amplifies all signals, including noiseincluding noise

Signal Regenerating RepeaterSignal Regenerating Repeater strips data strips data out and retransmits it so noise is less of an out and retransmits it so noise is less of an issueissue

HubsHubs

Sometimes called concentrators or multiport Sometimes called concentrators or multiport repeatersrepeaters

Active HubsActive Hubs– Regenerate or amplifies signalsRegenerate or amplifies signals– Can extend cable lengthCan extend cable length

Passive HubsPassive Hubs– Not a repeater (Cable TV splitter)Not a repeater (Cable TV splitter)

SwitchesSwitches– An Active hub that works like a bridge as wellAn Active hub that works like a bridge as well

BridgesBridges

Receives all signals on all segments they Receives all signals on all segments they are attached toare attached to

Determines destination of each signalDetermines destination of each signal Retransmits on other segments only those Retransmits on other segments only those

signals needing to “cross the bridge”signals needing to “cross the bridge” Used to divide traffic on heavily used Used to divide traffic on heavily used

networksnetworks

MultiplexersMultiplexers

Allows users to use the entire transmission Allows users to use the entire transmission media bandwidthmedia bandwidth

Combines two or more signals on a media Combines two or more signals on a media segmentsegment

Often called a MUXOften called a MUX

Internetwork Connectivity Internetwork Connectivity DevicesDevices

RoutersRouters» Connect two or more logically separate networksConnect two or more logically separate networks

» More processing intensive than bridges, so they don’t have as More processing intensive than bridges, so they don’t have as high of a throughput. (packets)high of a throughput. (packets)

» Provide Route SelectionProvide Route Selection

BroutersBrouters» Bridge & Router (Won’t drop unknown protocols)Bridge & Router (Won’t drop unknown protocols)

CSU/DSUCSU/DSU» Channel Service Unit/Digital Service UnitChannel Service Unit/Digital Service Unit

» Digital to digital “modem,” prepares signals for digital WAN Digital to digital “modem,” prepares signals for digital WAN linkslinks