7.1 PROTOCOL RULES & PROCEDURES TO GOVERN TRANSMISSION BETWEEN COMPONENTS IN A NETWORK *

7.2 ANALOG SIGNAL CONTINUOUS WAVEFORMCONTINUOUS WAVEFORM PASSES THRU SYSTEMPASSES THRU SYSTEM VOICE COMMUNICATIONSVOICE COMMUNICATIONS* Telecommunications, Networks

7.3 DIGITAL SIGNAL DISCRETE WAVEFORMDISCRETE WAVEFORM TWO DISCRETE STATES:TWO DISCRETE STATES: –1-BIT & 0-BIT –ON / OFF PULSE DATA COMMUNICATIONDATA COMMUNICATION USES MODEM TO TRANSLATE ANALOG TO DIGITAL, DIGITAL TO ANALOGUSES MODEM TO TRANSLATE ANALOG TO DIGITAL, DIGITAL TO ANALOG*

7.4 TELECOMMUNICATION SYSTEM COMPONENTS COMPUTERSCOMPUTERS TERMINALS (Input / output devices)TERMINALS (Input / output devices) COMMUNICATIONS CHANNELSCOMMUNICATIONS CHANNELS PROCESSORS (Modems; multiplexers; front-end processors)PROCESSORS (Modems; multiplexers; front-end processors) COMMUNICATIONS SOFTWARECOMMUNICATIONS SOFTWARE*

7.5 COMMUNICATION CHANNELS MEANS BY WHICH DATA ARE TRANSMITTED: TWISTED WIRES (Copper Wires) – phone linesTWISTED WIRES (Copper Wires) – phone lines COAXIAL CABLE: (Insulated Copper Wires) – Cable televisionCOAXIAL CABLE: (Insulated Copper Wires) – Cable television FIBER-OPTIC CABLE – high speed backbone, thousands of strands of clear glass fiber (hair),FIBER-OPTIC CABLE – high speed backbone, thousands of strands of clear glass fiber (hair), MICROWAVE – Terrestrial or SatelliteMICROWAVE – Terrestrial or Satellite*

7.6 SUPER CLEAR GLASS STRANDSSUPER CLEAR GLASS STRANDS FAST, LIGHT, DURABLEFAST, LIGHT, DURABLE BILLIONS OF BITS PER SECOND, FULL DUPLEX (10Gbps)BILLIONS OF BITS PER SECOND, FULL DUPLEX (10Gbps) EXPENSIVE, HARDER TO INSTALLEXPENSIVE, HARDER TO INSTALL OFTEN USED AS BACKBONE OF NETWORKSOFTEN USED AS BACKBONE OF NETWORKS* FIBER OPTICS SIGNALLASERCABLEPHOTODETECTORSIGNAL

7.7 TRANSMISSION SPEED: Bits per Second (BPS) or BaudTRANSMISSION SPEED: Bits per Second (BPS) or Baud BANDWIDTH: Capacity of Channel; Difference between Highest & Lowest FrequenciesBANDWIDTH: Capacity of Channel; Difference between Highest & Lowest Frequencies COMMUNICATIONS CHANNELS BROADBAND – High speed 1.5Mbps connection 1.5MB file 8 seconds to transmit

7.8 BPS: BITS PER SECOND KBPS: KILOBITS PER SECOND MBPS: MEGABITS PER SECOND GBPS: GIGABITS PER SECOND

7.9 Internet Connection Choices Device Upstream Speed Downstream Speed Cost per month Modem56Kbps56Kbps$20 Cable(Coax) 100Kbps to 500Kbps 1.5Mbps to 5Mbps $40 DSL (Twisted pair) 90Kbps to 640Kbps 144Kbps to 2.2Mbps $40-$100 T1 leased line 24 channels Mbps 1.544Mbps$1,100 T3 leased line 672 channels 44.7Mbps44.7Mbps$8,000 Satellite150Kbps 300Kbps to 900Kbps $70

7.10 OTHER SERVICES: DIGITAL SUBSCRIBER LINE (DSL): enhancing capacity over copper telephone linesDIGITAL SUBSCRIBER LINE (DSL): enhancing capacity over copper telephone lines CABLE MODEM: modem for cable TV for high-speed access to InternetCABLE MODEM: modem for cable TV for high-speed access to Internet T1 LINE: dedicated telephone connection, megabits per secondT1 LINE: dedicated telephone connection, megabits per second*

7.11 Internet Infrastructure Internet backbone – made up of many large networks (NSP’s) which interconnect Network Service Providers – own internet backbone. Examples are UUNet, CerfNet, SprintNet, IBM, WCOM NAP (Network Access Point) – Where NSP’s connect. ISP’s (Internet Service Providers) – Local and regional delivery subnetworks

7.12 NAP ISP Internet Network Architecture Backbone Regional ISP Local ISP

7.13 Circuit-Switched Networks Local and long distance telephone companies were early models in the 1950sLocal and long distance telephone companies were early models in the 1950s Single paths were created to connect two parties together, called circuit switchingSingle paths were created to connect two parties together, called circuit switching

7.14 Packet-Switched Networks The Internet uses Packet switchingThe Internet uses Packet switching –Files and messages are broken down into packets, which are electronically labeled with their origin and destination –The destination computer collects the packets and reassembles the data from the pieces in each packet –Each computer the packet encounters decides the best route towards its destination

7.15 Packet-Switched Network and Message Packets

7.16 The TCP/IP Internet Protocol Set of protocols developed by Vincent Cerf and Robert KahnSet of protocols developed by Vincent Cerf and Robert Kahn –Transmission Control Protocol (TCP) Controls the assembly of a message into smaller packets before transmission, and reassembles them once receivedControls the assembly of a message into smaller packets before transmission, and reassembles them once received –Internet Protocol (IP) Assigns sending and destination IPAssigns sending and destination IP address to each packet address to each packet Rules for routing packets from their source to their destinationRules for routing packets from their source to their destination

7.17 Routers – are packet switches. A router is connected between networks to route packets between them. Have updateable maps of the networks on the internet Determines the path for the packets

7.18 Open Architecture (Internet is based on this design Philosophy) Independent networks should not require any internal changes in order to be connected to the networkIndependent networks should not require any internal changes in order to be connected to the network Packets that do not arrive at their destination must be retransmittedPackets that do not arrive at their destination must be retransmitted Router computers do not retain information about the packetsRouter computers do not retain information about the packets No global control exists over the networkNo global control exists over the network

7.19 WAN – (Wide Area Network) Telecommunications network covering a large geographic area LAN – (Local Area Network) Connect computers (and devices) within a limited physical area (office, building, etc.)