Section 1 Basic Networking Knowledge CSIS 479R Fall 1999 “Network +” George D. Hickman, CNI,...
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Transcript of Section 1 Basic Networking Knowledge CSIS 479R Fall 1999 “Network +” George D. Hickman, CNI,...
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