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networking Chapt. 3
terms
| Question | Answer |
|---|---|
| media | physical or atmospheric paths that signals follow |
| transmit | issue signals along a network medium such as a cable |
| transmission | process of transmitting or the progress of signals after they have transmitted |
| signaling methods | analog digital |
| volts | electrical current pressure |
| strength of a signal | is directly proportional to its voltage |
| transceiver | transmits and receives signals |
| voltage | strength of a signal |
| signals can be | current, light pulses, electromagnetic waves |
| analog signal properties | amplitude frequency wavelength phase |
| amplitude | height of the wave |
| amplitude | measure of a waves strength at any given time |
| frequency | number of times the amplitude cycles over fixed time |
| wavelength | distance between one peak and the next |
| phase | progress of wave over time in a relationship compared to a fixed point |
| hertz | one full wave per second |
| frequency expressed in | cycles per second |
| hertz | cycles per second |
| wavelength | distance between corresponding points on a wave cycle |
| analog signal benefit | more variable than digital signals so they can convey greater subtleties with less energy |
| analog signal drawback | voltage is varied and imprecise |
| noise | any type of interference that may degrade a signal |
| analog transmission | is more susceptible to transmission flaws |
| digital signals | composed of pulses of precise,positive voltages and zero voltages |
| one | pulse of positive voltages |
| in a data signal | multiple bytes are combined to form a message |
| eight bits | byte |
| digital transmission involves | sending and receiving only a pattern of ones and zeros |
| overhead | describes the nondata information that must accompany data for a signal to be properly routed and interpreted by a network |
| examples of overhead | data link layer header and trailer |
| examples of overhead | network layer addressing information |
| examples of overhead | transport layer flow control information |
| standards dictate | type of transmitter,communications channel,and receiver should be used |
| modem | modulator demodulator |
| data modulation | used to modify analog signals to make them suitable for carrying data over a communication path |
| modulation | simple wave |
| modulation | combined with another analog signal to produce a unique signal that gets transmitted from one node to another |
| simple wave | carrier wave |
| carrier wave | purpose is a messenger, help convey information |
| data wave | information |
| frequency modulation radio | data must travel along a particular frequency |
| modulation | used to make a signal conform to a specific pathway |
| am | a modulation technique in which the amplitude of the carrier signal is modified by the application of a data signal |
| fm | a method of data modulation in which the frequency of the carrier signal is modified by the application of a data signal |
| data transmission | direction in which the signals travel over the media |
| simplex | signals travel in only one direction |
| simplex | unidirectional communication |
| digital drawback | many pulses required to transmit same information |
| digital benefit | more reliable less noise interference |
| overhead | required for proper signal routing and interpretation |
| half duplex | signals travel in both directions but only one direction at a time |
| half duplex | walkie talkie |
| modem | accomplishes translation |
| data modulation | make data suitable for carrying over communication path |
| data modulation | data relies on digital transmission |
| carrier wave | combined with another analog signal |
| carrier wave | produces a unique signal |
| carrier wave | purpose is to convey information |
| information wave | data wave |
| data wave | added to a carrier wave |
| information wave | modifies one carrier wave property |
| full duplex | bidirectional transmission |
| full duplex transmission | telephone call |
| full duplex transmission | ethernet networks because they use multiple channels on the same medium |
| makes use of modulation | digital subscriber line |
| channel | distinct communication path between nodes |
| channels are seperated | physically and logically |
| full duplex capability | increases the speed in which data travels over the network |
| multiplexing | a form of transmission that allows multiple signals to travel simultaneously over one medium |
| full duplex | signals travel in both directions simultaneously |
| subchannels | the mediums channel is logically seperated into multiple smaller channels in order to carry multiple signals |
| multiplexer | a device that can combine many signals on a channel |
| channel | a lane on a highway.distinct way to communicate |
| multiplexer | required at the transmitting end of a channel |
| demultiplexer | at the receiving end |
| physical seperation | one wire for transmission and one for reception |
| demultiplexer | seperates the combined signals and regenerates them in their original form |
| networks rely on multiplexing to | increase the amount of data that can be transmitted in any given time or span over a given bandwidth |
| time division multiplexing | divides a channel into multiple intervals of time |
| tdm | time slots |
| subchannels | logical multiple smaller channels |
| multiplexing | travel simultaneously over one medium |
| mux | combines many signals |
| demux | seperates combined signals |
| tdm | assigns a seperate time slot to every node on the network,and,in that time slot,carries data from that node |
| time slots | reserved for their designated nodes regardless of whetehr or not the node has data to transmit |
| tdm | inefficient if the nodes on the network rarely send data |
| statistical multiplexing | the transmitter assignes slots to nodes according to priority and need |
| frequency division multiplexing | assigns a unique frequency band to each communications subchannel |
| wavelength division multiplexing | technology used with fiber optic cable which enables one fiber optic connection to carry multiple light signals simultaneously |
| dense wavelength division multiplexing | a multiplexing technique used over singlw mode or multimode fiber optic cable in which each signal is assigned a different wavelength for its carrier wave |
| wavelength division multiplexing | a multiplexing technique in which each single on a fiber optic channel is assigned a different wavelength, which equates to its own subchannel |
| analog | wave |
| digital | block |
| fdm | cell phones dsl |
| point to point transmission | one transmitter and one receiver |
| point to multipoint transmission | one transmitter and multiple receivers |
| broadcast transmission | one transmitter and multiple undefined receivers |
| nonbroadcast | one transmitter and multiple defined recipients |
| broadcast transmission | simple and quick; used on wired and wireless networks |
| important characteristics of data transmission | type of signaling and the direction in which it travels |
| important characteristics of data transmission | number of senders and receivers;the relationship between them |
| broadcast transmission | everyone can get the transmission whether or not they want it |
| data communication may involve | a single transmitter with one or more receivers |
| data communication may involve | multiple transmitters with one or more transceivers |
| throughput | capacity ot bandwith |
| throughput | amount of data transmitted during given time |
| throughput | expressed as quantity of bits transmitted per second |
| bandwidth | difference between highest and lowest frequencies medium can transmit |
| bandwidth | range of frequencies |
| bandwidth | measured in hertz |
| bandwidth | the width of your frequency band |
| baseband systems | can transmit only one signal ,or one channel,at a time |
| baseband | transmission form in which digital signals are sent thru direct current pulses applied to the wire |
| baseband | supports half duplex and full duplex |
| broadband | form of transmission in which signals are modulated as radio frequency analog waves that use different frequency waves |
| baseband | does not encode information as digital pulses |
| broadband | more expensive because of extra hardware |
| broadband | span longer didistances than baseband |
| emi | common source of noise |
| emi | waves that emanate from electrical devices or cables carrying electricity |
| type of emi | radio frequency interference |
| cross talk | a signal traveling on one wire or cable infringes on the signal traveling over an adjacent wire or cable |
| alien cross talk | cross talk occurs between two cables |
| next | near end cross talk |
| attenuation | loss of a signals strength as it travels away from the source |
| repeater | a device that regenerates a digital signal |
| regeneration | process of retransmitting a digital signal,repeats the pure signal,with no noise |
| latency | the delay between the transmission of a signal and its receipt |
| affects latency | length of the cable and intervening connectivity device |
| round trip time | length of time it takes for a packet to go from sender to receiver,then back from receiver to sender |
| to constrain the latency and avoid its associated errors | each type of cabling is rated for a maximum number of connected network segments |
| to constrain the latency and avoid its associated errors | each transmission method is assigned a maximum segment length |
| throughput is limited | by the signaling and multiplexing techniques used in a given transmission method` |
| baseband transmission | ethernet |
| factors that affect the final cost in choosing to use a certain type of media | cost of installation |
| factors that affect the final cost in choosing to use a certain type of media | cost of new system versus the old one |
| factors that affect the final cost in choosing to use a certain type of media | maintenance and support |
| factors that affect the final cost in choosing to use a certain type of media | cost of a lower transmission rate affecting productivity |
| factors that affect the final cost in choosing to use a certain type of media | downtime |
| near end cross talk | occurs near source |
| type of media least affected by noise | fiber optic cable |
| conduit | pipeline to contain and further protect cabling |
| the maximum segment length depends on | attenuation, latency, maximum network length |
| populated segment | part of a network that coontains end nodes |
| unpopulated segment | link segment |
| link segment | part of the network that does not contain end nodes but connects two networking devices such as routers |
| maximum distance a signal can travel and still be interpreted | is equal to a segments length |
| factors that determine the size and scalabiility of networking media | maximum nodes per segment |
| factors that determine the size and scalabiility of networking media | maximum segment length |
| factors that determine the size and scalabiility of networking media | maximum network length |
| amplifiers and repeaters | found in the physical layer of the osi model |
| repeater | device regenerates digital signals |
| amplifier | boosts analog signals |
| connectors | pieces of hardware that connects the wire to the network device |
| media converter | hardware that enables networks or segments running on different media to interconnect and exchange signals |
| physical media characteristics | throughput |
| physical media characteristics | cost |
| physical media characteristics | noise and immunity |
| physical media characteristics | connectors and media converters |
| causes of throughput limitation | laws of physics |
| causes of throughput limitation | noise |
| causes of throughput limitation | signaling and multiplexing techniques |
| causes of throughput limitation | devices connected to transmission medium |
| maximum nodes per segment dependency | attenuation and latency |
| sheath | jacket |
| attenuation | signal decaying over time |
| latency | time back and forth |
| sheath | protects the cable from physical damage |
| because of its shielding | most coaxial cable has a high resistance to noise |
| rg | radio guide |
| significane difference between cable types | lie in the materials used for their shielding and conducting cores |
| impedeance | resistance that contributes to controlling the signal |
| impedance | expressed in ohms |
| transmission characteristics | impedance attenuation throughput |
| awg | american wire gauge |
| coaxial cable | is used to guide radio frequencies in broadband transmission |
| awg size | size of the conducting core in a coaxial cable |
| coaxial cable is a central metal core | surrounded by insulator,braided metal sheilding,outer cover |
| rg 6 | deliver broadband cable internet service and cable tv |
| rg 6 | impedeance of 75 ohms and contains 18 awg conducting core |
| coaxial cable advantage | carries signals farther before amplifier is required |
| coaxial cable disadvantage over twisted pair | more expensive |
| rg 8 | provided the medium for the first ethernet network |
| rg 8 | impedeance of 50 ohms and contains 10 awg conducting core |
| rg 58 | impedeance of 50 ohms and contains 24 awg conducting core |
| rg 59 | impedeance of 75 ohms and contains a 20 or 24 awg conducting core |
| rg 58 | popular medium for ethernet lans |
| rg 59 | used for relatively short connections |
| the larger the awg size | the smaller the diameter of a piece of wire |
| types of connectors | f type and bnc |
| twisted pair cable | inexpensive, flexible,easy to install,scommadates everal topologies,spans msignificant distance before requitring repeater |
| twisted pair cable | accomodates several different topologies |
| more wire twists per foot | more resistance to cross talk,higher quality,more expensive |
| hundreds of different designs | twisted pait cable |
| tia/eia 568 | wiring standard specification |
| twisted pair categories | shielded and unshielded |
| twisted pair categories | Cat 3,5,5e,6,6a,7 |
| shielded twisted pair | individually shielded,each pair has a shield and then shielded as a whole |
| unshielded twisted pair | used most often |
| stp and utp | use registered jack 45 |
| telephone connections | use registered jack 11 |
| maximum segment length for stp and utp | 100 meters and 328 feet |
| patch cable | relatively short cable and had connectors at both ends |
| termination standards | tia/eia 568 a or b |
| tia 568 a or tia 568 b | defines a patch or a crossover cable |
| fiber optic cable | one or more glass or plastic fibers at its center core |
| data transmission | pulsing light sent from laser or light emittting diode thru central fibers |
| cladding | layer of glass or plastic surrounding core |
| fiber optic cable benefits | high throughput, high resistance to noise, |
| fiber optic cable benefits | excellent security,able to carry signals for a longer distance |
| fiber optic drawbacks | more expensive and requires special equipment to splice and connect |
| ferrule | short tube within a connector that encircles the fiber and keeps it properly aligned |
| optical loss | degradation of the light signal after it travels a certain distance away from its source |
| single mode fiber | consists of a narrow core of eight to ten microns in diameter |
| single mode fiber | laser generated light travels over one path |
| single mode fiber | light does not disperse as signal travels |
| single mode fiber | can carry signals many miles |
| multimode fiber | contains a core with a larger diameter than single mode fiber,usually fifty to 62.5 microns |
| multimode fiber | many pulses of light generated by a laser or led traveling at different angles |
| multimode fiber | greater attenuation than single mode fiber |
| multimode fiber | not suited to distances longer then a few miles,it is less expensive |
| fiber optic converter | required to connect multimode fiber networks to single mode fiber networks |
| serial | refers to a style of data transmission in which the pulses that represent bits follow one another along a single transmission line |
| serial | issued sequentially not simultaneously |
| physical layer standard | specifies signal voltage,signal timing,plus the characteristics of compatible interfaces |
| rs 232 | serial data transmission method |
| rs 232 connectors | db9,db 25,rj 45 |
| straight thru cable | connect two dissimiliar devices |
| crossover cable | connect two similiar devices |
| cable plant | hardware that make sup the enterprise cabling system |
| tia/eia joint 568 commercial building wiring standard | structured cabling |
| entranc facilities | designates where the telecommunications service provider accepts responsibility for the external connection |
| demarc | their network stops and ours starts |
| main distribution frame | first point of interconnection between an organizations LAN or WAN and a service providers facility |
| mdf | computer room or equipment room |
| cross connect facilities | the point where circuits interconnect with other circuits |
| punch down block | panel of data recepors into which twisted pair wire is inserted,punched down,to complete a circuit |
| intermediate distribution frame | junction point between the mdf and concentration of fewer connections |
| backbone wiring | the cables or wireless links that provide interconnection between entrance facilities and mdfs,mdf,idfs and telecommunications closet |
| telecommunications closet | contains connectivity for groups of connections in the area |
| horizontal wiring | wiring that connects workstations to the closest telecommunications closet |
| three possible cabling types for horizontal wiring | stp,utp or fiber optic cables |
| maximum allowable distance for horizontal wiring | 100 meters |
| work area | an area that encompasses all patch cables and horizontal wiring necesary to connect workstations,printers and other network devices from their nics to the telecommunications closet |
| bend radius | the radius of the maximum arc into which you can loop a cable before you will impair data transmission |
| plenum | the area above the ceiling tile or below the subflooring |
| two methods for transmitting data | analog and digital |
| tia/eia specifications for backbone cabling | utp single mode multi mode fiber |
| many network problems can be traced to | poor cable installation |
| multiplexing | allows multiple signals to travel simultaneously over one medium |
| analog | signal wave |
| digital | pulse,on off |
| zip cord cable | short fiber optic cable in which two strands are arranged side by side in conjoined jackets,enabling full duplex communication |
| console | the serial interface on the back of the connectivity device |
| 100 meters | 90 meters to telecommunications closet 10 meters to workstation |
Created by:
cgeaski
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