Data Communications Networking Devices - 4th Ed.pdf

852 __________________________________________________________________________ INDEXModems cont.)testing 427±30throughput issues 461±2transmission mode 373transmission technique 373±4transmitter section 356±8types 373±80using modem indicators 423±7voice/data capability 380voice/data operation 463±5wraparound unit 430Modulation 277, 363±5combined techniques 367±8techniques 369±72Modulators 358Monitor bit 338Morse code 39Multicast address 322Multichannel cable 777Multidrop line routing analysis837±42Multi-line controller MLC) 698Multiple access unit MAU) 308Multiple fallback switches 747Multiplexers 626±86comparison with other devices 627device support 627evolution 626sizing 823±6, 826±8utilization 180±1, 651Multiplexingeconomics 640±2techniques 627±40versus line-sharing 707versus packet switching 183±4Multipoint lines 33Multiprotocol Transport NetworkingMPTN) 597±8Multistation Access Unit MAU)276±7, 328±9cabling and device restrictions329±34Name server 223±4Narrowband ISDN N-ISDN) 153National Bureau of Standards NBS)62National Institute of Standards andTechnology NIST) 62National standards organizations59±63NCP Packet Switching InterfaceNPSI) 587Near End CrossTalk NEXT) 287±8Negative acknowledgement NAK)character 55, 123NetWare IPX 571Network Addressable Units NAUs)238Network Control Program NCP) 237Network control system NCS) 430Network frame rate determination843±6Network graph 553Network interface card NIC) 302,305Network layer 73Network nodes NNs) 248Network redistribution 611±12Network terminating unit NTU) 6,517Network-to-Node Interface NNI)259Nodes 676Non-data symbols 335±7Non-redundant main ring paths 329North Americabinary 7 zero code suppressionB7ZS) 527binary 8 zero substitution B8ZS)527±8framing formats on T1 lines 520±5NT1 network termination 1) 162NT2 network termination 2) 163Null NUL) character 121Null compression 758NWay autosensing logic 317Off hook OH) indicator 425Of®ce Channel Unit OCU) 507One-time passwords 807Open Systems Interconnection OSI)layers 71±4see also speci®c layersReference Model 59, 64, 70±4data ¯ow 74Operating mode and character display26Optic ®ber cables, electromagneticnon±susceptibility 773Optical cables, types 770Optical ®bers 768±9bandwidth 773electrical isolation 774security 774signal attenuation 774splicing 775types 769weight and size 774see also ®ber optic transmissionsystems, dedicated cablesystemOptical modem 771±2Optical multiplexers 772, 777±8Packet assembler/disassemblersPADs) 686±92applications 687±8PC based utilization 691types 688X.3 parameters 688±92Packet ®ltering 808±10Packet switching networks 183±201architecture 186±7call establishment 190±1construction 184delay problems 192±3¯ow control 191ITU recommendations 184±5packet format and content 188±9packet formation 187±8see also fast packet switchingPacketized Ensemble Protocol PEP)503Parallel bridging 560±2Parallel interface extenders 529±33application examples 532±3components 532operation 531Parametric detectors 662Parity checking 48±9®le transfer problems 50±1undetected errors 49±50Passwordcombinations 781±2one-time 807shortcomings 779±81static 806Path control layer 241Path costs 554±5Pattern substitution 759Payload Type Identi®er PTI) 261Permissive arrangement 114Phase modulation 365Phase-shift keying PSK) 365Physical layer 72, 75±117, 241, 257,312±13subdivision 300Plugs 111±17Point of presence POP) 14Point-to-point lines 32Poisson distribution 826, 828, 830,831, 835±6Poisson formula 826±9Poll and select line discipline 33±4Polling process 709Port-based switching 608±9Port selectors 715±16, 722±30computer site operations 723±4costs 727±8features 728±9line-switching network 729±30load balancing 728operation 723±4types of devices 722±3usage decisions 724±6Port-sharing units 711±16operation 713±15usage 713±15with modem-sharing units 715Positive acknowledgement ACK)communications controlcharacter 54Preamble ®eld 321Presentation layer 73, 242±3Private key encryption 791Programmable arrangement 115Protective ground GND, Pin 1) 82±3Protocol converters 720±1, 730±5applications 734±5character versus block modeoperation 733±4conversion categories 731±2data code/speed conversion 731device functionality conversion732±3device operation conversion 732operation 731