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103 Cards in this Set
- Front
- Back
Topology
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the way that networks are arranged, constructed and connected
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Node
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an endpoint or switching point in a group of devices that can communicate with each other
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telecommunications
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communications via electronic, electromagnetic or photonic means over a distance.
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Telecommunications gives you 4 things:
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-shared resources
-act centrally when decentrally located -communication -shared information |
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Point to Point
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a simple network in which both nodes are computers
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Physical topology
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how wires are run from node to node
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Electrical topology
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how the network operates as a result of protocol and central node connectivity
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channel
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a communications path between nodes
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LAN (local area network)
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connectivity among two or more nodes closely located, and connecting people within an organization; are privately owned and are not regulated
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WAN (wide area network)
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networks that cover wide geographical areas. go beyond cities and extend globally. the next extreme is a GAN (global)
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Network Interface Card (NIC)
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a circuit card in a microcomputer that provides the electrical interface to a network
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hub
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passive device that provides a central point of contact for a network. it connects the nodes with shared bandwidth
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switch
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active device that provides a central point of contact for a network; it connects the nodes and provides dedicated bandwidth
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Packet
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unit of digital data with a set number of bytes including some that act as an address code.
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protocol
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standard that governs interaction; an agreed upon format for transmitting data between two devices
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Physical Topology
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the way the cabling ofa network is actually laid out
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Electrical Topology
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how the network operates as a result of protocol and central node connectivity
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UPS
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device that protects from power surges and continues providing power in case of short-term power outages
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bus network
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multipoint network w/ no master/slave. all nodes are equal but one may have NOS on it
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ring network
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a network where each node is connected to two adjacent nodes. token passing protocol is used (802.5)
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star network
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all circuits radiate from a central node, point to point. used in low-speed/low-cost data networks
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Multistation Access Unit (MAU)
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the hub in a ring network
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collision
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occurs when two nodes transmit at the same time
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collision avoidance
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a protocol that makes collisions of packets on a channel impossible; ex: CSMA/CA, token passing, polling
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collision detection
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the ability to detect and react to a collision of packets on a channel for ex. CSMA/CD
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csma/cd
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uses carrier sense to determine if the channel is quiet, collision can still occur
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network
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two or more nodes connected by one or more channels; consists of a pattern of paths and associated equipment
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hub
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network equipment that connects multiple nodes with shared bandwidth; passive device
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switch
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active device that provides centra point of contact for a network; connects nodes and provides dedicated bandwidth
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SNMP(simple network management protocol)
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allows remote devices to be managed rom a central office
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bridge
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intelligent devices that connect networks using same protocol allowing separation for security and congestion control
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translating bridge
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connect two LANs that use different data link protocols
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transparent bridge
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connect two LANs that use the same protocols
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router
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hardware or software that directs messages toward their destination, often from one network to another
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gateway
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intelligent device that connects networks that use different protocols, thus requiring protocol conversion
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path
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route between any two nodes
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4 Benefits of Network
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1. cost saving
2. sharing of resources 3. user interface 4. encourages management control |
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Physical Topology of of LAN
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always a star for ease of installation and maintenance
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TCP/IP
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IP is responsible for moving packets of data between nodes; TCP is responsible for verifying delivery from client to server
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Hierarchy of Networks
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PAN
TAN LAN MAN WAN GAN |
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PAN
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on or near the person; ex. bluetooth, earphones
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LAN
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homogeneous users; 1 mile radius; people within an organization; privately owned and nonregulated
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MAN
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city sized area; gives a city competitive advantage; ex. fiber using token-passing (FDDI)
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WAN
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heterogeneous users; widely dispersed; can extend globally; requires intermediary machines; extreme of WAN is GAN
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VAN
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special form of WAN; offers added intelligence like speed translation & data handling; Nonregulated
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Data Transmission Forms
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Synchronous & Asynchronous
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Synchronous
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block of data based; send a group of characters at a time, called a packet
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Asynchronous
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character based; sends a character at a time
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Asynchronous error checking
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Uses parity bits at end of 8bit string, Pbit contains 0 or 1 to make the addition of all bits = even. if odd, the data has been corrupted
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Synchronous data packet
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composed of header, data/body, and trailer (w/ BCC data for error checking)
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Synchronous packet picture
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[Header|data characters|Trailer(w/BCC)]
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Integrity
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if the data that was transmitted has not been corrupted by noise
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page of text
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2000 characters
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Cyclical Redundancy Checking
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synchronous data error checking; divides data by constant "K" and places remainder in BCC field. This number is recreated when received to make sure data is not corrupt
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Data Channel Reliability
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1. noise free channel
2. good error detection 3. correct and retransmit bad data 4. redundancy in data to self correct |
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Network Attributes
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RAPS
R- reliability A-accessibilitiy P-performance S-security |
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RTR
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resiliency through redundancy is what we ultimately want out of our network, given we have the RAPS attributes
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Power for Network Equipment attributes
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CARW
C-continuity 24*7 A-accessibility R-regulation W-waveform |
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convergence
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is the bringing together of two or more technologies; ex. video and text; major cause of need for greater bandwidth
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need for bandwidth growth each year
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300%
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Industry convergence
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video, data, voice
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Compression
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reduction of hte size of a file or stream, resulting in less required bandwidth
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DSL
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technology that provides digital communications over twisted pair copper
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ADSL
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digital technology on POTS lines providing high bandwidth; circuit is digitized and divided into telephone and one or more digital channels
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Carr's Axiom
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You can do a lot with a little!
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How you can do a lot with a little
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-convergence drives bandwidth
-compression reduces need -simple data/text is low bandwidth -always include future growth when installing -limited bandwidth may suffice when installing |
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T1 Bandwidth
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1.544 Mbps; 24 DS0 channels
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convergence
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combination of two or more media, such as text video; driving force behind bandwidth
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DS0 Bandwidth
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64Kbps
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ISP (internet service provider)
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retail point of access to the Internet backbone, Company who privdes Internet access to users.
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broadband
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transmission equipment and media that can support a wide bandwidth.
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ISDN (integrated services digital network)
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Digital switching and transmission systems with high data rate channels, high speed and high quality using digital. digital telephone, composed of multiple channels
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ADSL (asymmetric digital subscriber line)
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digital technology on POTS lines providing high bandwidth; circuit is digitized and divided into one or more data and telephone channels
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PDN (packet data network)
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provides connectivity to many points geographically; uses virtual circuits and datagrams
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PAD (packet assembler/disassembler)
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device that receives the total data block; break it into packets adds addressing; error-checking; places the packet onto network
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X.25
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a standard for packet-switched networks
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BISDN (broadband integrated services data network)
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ISDN above T1 that has ISDN specific services; use of 2 broadband technologies SONET and ATM to provide high bandwidth connectivity
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Frame relay
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an ISDN frame-mode service based upon fast packet switching.
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STS1/OC1
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51.84 Mbps;
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SONET (Synchronous optical network)
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high-speed, high reliability serial digital transmission over optical fiber cable
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ATM (asynchronous transfer mode)
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switching technology used by BISDN. connects cells at very high speeds. can have 5 byte header and 48 byte payload
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Internet means
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connectivity; a network of networks
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WWW
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interface; the graphical user interface to the internet
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hyptertext
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text with pointer to other text and media
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hypermedia
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involves images, sound, animation in addition to text
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tags
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commands inserted to specify how the document should be formatted
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SGML (standard generalized makrup language)
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a system for organizing and tagging elements ofa document.
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HTML
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authoring language that is used like a word processor to created documents on the WWW
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XML
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pared down version of SGML, allows authors to customize tags, enabling definitions.
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HTTP (HyperText Transfer Protocol)
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the software capability that provides the graphical users interface for the WWW
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MAE (metropolitan area ethernet)
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major access point to the Internet backbone (east, west and central)
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URL (uniform resrouce locator)
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global addresses of documents and other resources on the WWW
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intranet
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private implementation of internet technologies within an organization
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Demands of Business Today
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1. shortened product lifecycles
2. increased cost pressures 3. quality and customer service 4. changing markets 5. new business models |
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MIME (multipurpose internet mail extensions)
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an Internet Standard for the format of e-mail
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Reasons Internet have had a dramatic impact on Business
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PURCS
P-performance U-universal communication R-reliability C-cost S-standards |
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E commerce
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links enterprises, consumers, and communities through electronic transactions, and the electronic and physical exchange of goods, services , info and capital
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portal
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a web site or service that offers a broad array of resources and services from a single point of entry
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authentication
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process of determining whether someone/thing is infact what it declares itself to be
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authorization
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ability to determine if the person accessing is allowed to do so
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clarity of interface
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users understand and are comfortable with the interface
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security
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ensures that neither the user nor anyone else can inappropriately access, view, copy, change or destroy data in the system.
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privacy
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added security provided for assets, especially information of a personal nature
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