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NETWORKING. NETWORKS. Two or more computers communicating. TELECOMMUNICATIONS. Long distance communications. TOPOLOGY Bus Star Ring. Protocol Polling CSMA/CD Token Ring. LAN Characteristics. MAJOR FUNCTIONS. Make long distance communication seem local
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NETWORKS Two or more computers communicating TELECOMMUNICATIONS Long distance communications
TOPOLOGY Bus Star Ring Protocol Polling CSMA/CD Token Ring LAN Characteristics
MAJOR FUNCTIONS • Make long distance communication seem local • Standardize network interface • Standardize procedures for sending information • Govern error transmission • Govern security • Govern integrity of data
NETWORK COMPONENTS • Computers • Media • Software • Network connections • Satellites • Microwave • stations • Multiplexer – combines many data streams into a single stream
Additional Media Type • Electromagnetic waves • A type of radio wave • Used by satellites • Used by portable computers
MICROWAVE STATIONS Needs a direct sight line SATELLITES
WAN TOPOLOGIES 1. Point to Point 2. Multidrop 3. Mesh 4. Star
Point to Point Direct Connection Between Computers
Advantage No Waiting Disadvantage Expensive to connect Adding new computer
Multidrop Hierarchical Between Concentrator
Advantage No Waiting Direct connections Disadvantage May find delays if going outside the predefined connections Adding new computer
Star Central Point Time Sharing Host
Advantage Centralized control (security) Disadvantage Centralized control (delays)
Mesh Individual Routes Needs a router
Advantage No Waiting Disadvantage Connections (solutions – servers)
Other types of NETWORKS Public access networks (government) VAN – value added network (extra feature – faxes) Private area networks (Sears) Public Data Network (TYMNET)
Wide Area NetworksEnvironments PSTN PSN DDN ISDN DSL
TYPES of Lines • Private • Direct • Expensive • Tie line • Dedicated without the use of the PSTN • Exchanges • Foreign/private • 800 numbers
DDNdata digital network Only transmits DIGITAL information
PSNpacket switching network Sends information in groups called PACKETS
ISDNintegrated servicesdigital network Sends only digital signals Transmits HIGH VOLUME of data Can use the Internet while using the phone line – use of two phone lines
DSLDigital Subscriber Line Translates digital signals to analog Transmits HIGHER VOLUME of data than ISDN Spreads analog signal over a wide range of frequencies