Optical Networks: A Practical Perspective - Part 84 pdf

800 INDEX bidirectional protection switching (continued) illustrated, 541 See also protection switching bidirectional systems, 303-305 direction illustration, 305 illustrated, 304 wavelengths, 304 bidirectional WDM systems, 686-688 amplifiers for, 688 asymmetric traffic and, 687 designing, 688 guard band, 688 illustrated, 686 implementation using, 687 unidirectional comparison, 686-688 birefringence, 57 bit error rates (BERs), 258-263, 264-265, 276 evaluating, 260 floor, 268,269 for high-speed optical communication systems, 250 impairments and, 284 measurement, 277, 509 for OOK direct detection receiver, 276 threshold setting and, 260 of uncoded system, 278 bit interleaved parity (BIP) code, 268 bit interleaving, 620-623 demultiplexing operation, 622-623 function illustration, 621 optical multiplexer, 622 bit rate, 29 aggregate, 604 bandwidth ratio, 30 distance product, 53, 54 four-wave mixing and, 90-91 maximum, 348 RZ/NRZ transmission and, 312 sensitivity as function of, 261 transparency, 420 bit stuffing, 274 blazed reflection gratings, 121,122, 227 blazing, 121 blocking model, 465,467-474 blocking probability, 467 computing, for lightpath requests, 470 conversion gain, 472, 473 Erlang-B formula and, 468 estimating, 467 full wavelength conversion and, 471,472 reduction, 468 blocking switches, 202 border gateway protocol (BGP), 392 Bragg gratings, 123-126 apodization, 124, 126 bandwidth, 126 fiber, 127 formation, 123 index distribution, 124 principle of operation, 124-126 reflection spectra, 125 uses, 123 See also gratings Bragg wavelength, 124 Brillouin gain coefficient, 325 Bronze service class, 567 BT Labs testbed, 654 bubble-based waveguide switches, 212, 213 buffering, 618, 635-649 implemented with feedback delay lines, 640 input, 635, 639 lack of good methods, 636 output, 637-639 recirculation, 639-641 bulk mechanical switches, 207-209 bulk micromachining, 211,212 burst switching, 649-650 cable network, 595 capital cost, 668 carriers capital cost, 668 long-haul, 688 metro, 699 new generation of, 668 operations cost, 668 scalable networks and, 669 SONET/SDH-based backbone network, 670 carriers carrier, 9 cascaded filters, 307-308 C-band, 66 chromatic dispersion in, 98 EDFAs in, 289 L-band vs., 689 long-haul networks, 689 See also L-band center frequency, 732 central office, 593 INDEX 801 channel spacing, 29, 336 FWM and, 91,332 increased, 332 unequal, 332, 347 chirped fiber Bragg gratings, 316-318 for compensating three wavelengths, 318 illustrated, 317 large chromatic dispersion, 317 uses, 317 See also dispersion compensation chirped Gaussian pulses, 69-74, 104, 356 broadening of, 70-74 illustrated, 70 propagation, 734-735 See also chromatic dispersion chirped RZ modulation, 343 chirp factor, 70 chirp RZ pulses, 100 chromatic dispersion, 36, 57, 68-76 absence of, 69 anomalous, 69 causes of, 309 in C-band, 98 chirped Gaussian pulses, 69-74 compensation, 38,267, 343 DM soliton systems, 341 for DSF, 331 EDFAs and, 38 fiber nonlinearities trade-off, 38, 49 length, 71, 72 management, 335 map, 315 material dispersion, 68, 69 nonzero-dispersion fiber (NZ-DSF), 93,316 normal, 69 origin, 57, 58 parameter, 74 profiles, 74-76, 309 pulse-broadening effect, 70, 71 pulse compression effect, 72, 73 reasons for, 68 slope, 75,343 slope, compensation, 318 for SMF, 331 system limitations, 72 total, 74, 315 total, variation of, 319 waveguide dispersion, 68 chromatic dispersion limits communication link length, 312 large source spectral width, 313-314 narrow source spectral width, 309-311 NRZ modulation, 309-311 RZ modulation, 311-314 for unchirped pulses, 312, 313 circuit emulation, 675 circuit-switched networks, 6-7 problem, 7 services, 7 circulators, 113 cladding, 33 electric/magnetic field vectors in, 59 materials, 50 refractive index, 60 Class I safety standard, 527, 530 Class IIIa safety standard, 527 Class IIIb safety standard, 527 client layers, 363-400 ATM, 363,381-388 ESCON, 363 Fibre Channel, 363 Gigabit Ethernet, 363 IP, 363, 388-395 protection, 563 SONET/SDH, 363, 364-381 types of, 363 clients, 403,404 clipping, 244-245 probability, 245 of subcarrier modulated signal, 244 clock, 251 clock recovery, 251,273 closest-to-finish, 648 Clos switch, 204-205 advantages, 205 illustrated, 205 three-stage, 204 coding gain, 269-270 of FEC code, 269 Reed-Solomon codes, 270 repetition code, 269-270 coherent crosstalk. See intrachannel crosstalk coherent detection, 263-265 idea behind, 263 improved receiver sensitivities, 264 coherent receivers, 263-265 advantages, 265 802 INDEX coherent receivers (continued) balanced, 278 heterodyne, 264 homodyne, 264 illustrated, 264 sensitivity, 265 in WDM system, 265 common object request broker (CORBA) model, 501 competitive LECs (CLECs), 4 compliant wavelength interface, 525 conduction band, 161 configuration management, 496, 519-526 adaptation management, 524-526 connection management, 520-524 equipment management, 519-520 See also network management congestion, 450, 454 connectionless services, 6, 8 connection management, 496, 520-524, 531 interaction with other layers, 522-524 interoperability, 520 route computation, 521-522 signaling network, 522 signaling protocol, 522 topology management, 521 See also configuration management; network management connection-oriented services, 6 constant bit rate (CBR), 387 contention resolution by delay lines, 656 optics (CRO), 657 recirculation buffering and, 640 wavelengths for, 641-645 Contention Resolution by Delay Lines (CORD) testbed, 656-657 conversion gain, 472,473 core, 33 electric/magnetic field vectors in, 59 materials, 50 multimode fiber, 33 single-mode fiber, 35 coupled mode theory, 110 couplers, 108-112 2 • 2, 108, 112, 226 in AWG, 142 conservation of energy, 111-112 coupling ratio, 136 illustrated, 108 lossless, 111 power transfer function, 110 principle of operation, 110-111 star, 108-109 uses, 109 wavelength-independent, 108-109 wavelength-selective, 108 coupling coefficient, 110 crossbar switch, 203-204 architecture, 203 fabrication, 204 illustrated, 204 cross-gain modulation (CGM), 219-220 advantages, 220 cross-phase modulation vs., 220-221 pulse distortion in, 220 SOA gain dependencies and, 219 cross-phase modulation (CPM), 83, 89-90, 220-223,323, 333 CGM vs., 220-221 effect in WDM systems, 90 illustrated, 221 intensity modulation conversion, 220 nonlinear dielectric polarization, 89 properties, 220 reducing, 90 in WDM systems, 90, 335, 338 See also nonlinear effects crosstalk, 165,299-308 in all-optical networks, 345 bidirectional systems, 303-305 forms of, 299 interchannel, 299 intrachannel, 299-301 Mach-Zehnder interferometers and, 137 in networks, 303 Raman amplifiers, 161 reducing, 165, 305-307 in SOAs, 165 of switches, 201 uses, 165 cutoff wavelength, 60, 192-193, 194 data communication network (DCN), 498, 512-513 realization methods, 513 signaling and, 512-513 transport methods, 512 datagram services, 8, 19 data link layers, 18-19, 382, 388 INDEX 803 DBR lasers, 181-183 sampled grating (SG), 183, 184-185 super-structure grating (SSG), 183, 184-185 two- and three-section, 181-183 See also lasers DC balance, 241 deadlock, 649 decision rules, 258 dedicated bandwidth, 594 dedicated protection, 540 defect condition, 510 defect indicators, 510-511 deflection index, 648 deflection routing, 637, 645-649 delay, 645-647 livelock, 649 small buffers, 649 throughput, 647-648 deflection rules, 648 degeneracy factor, 92 degree constraints, 451 delay, 645-647 differential group (DGD), 62, 320, 321 propagation, 647 queuing, 647 delay lines contention resolution by, 656 feedback, 636, 640 feed-forward, 636 required for different architectures, 644 demodulation, 239, 250-267 APD noise, 255 bit error rates, 258-263 coherent detection, 263-265 direct detection receiver, 253-254 equalization, 266-267 front-end amplifier noise, 254-255 ideal receiver, 252-253 optical preamplifiers, 255-258 as "photon counting," 252 timing recovery, 265-266 See also modulation demultiplexers, 115 AWG as, 140 with broad passband, 150 cost reduction, 365 misalignment, 345 MZI as, 137 optical packet, 659 depletion region, 163 design considerations, 341-348 all-optical networks, 345-346 dispersion compensation, 343 DM soliton systems, 338-341 fiber type, 341-342 interchannel spacing and number of wavelengths, 344-345 modulation, 343 nonlinearities, 323-335, 344 overall, 341-348 soliton systems, 336-338 transmit power and amplifier spacing, 342-343 transparency, 348 wavelength planning, 346-347 wavelength stabilization, 335-336 detectors, 192-199 front-end amplifier, 192, 197-199 photodetector, 192-197 dial up bandwidth, 521 dichroics, 113-114 dielectric, 63 dielectric polarization, 56, 82 linear, 82 nonlinear, 83, 84, 85, 89, 91 dielectric thin-film filter, 133-135 multiplexer/demultiplexer using, 135 TFF, 133 TFMF, 133, 135 three-cavity, 134 transfer functions, 134 dielectric waveguides, 63-64 differential group delay (DGD), 62, 320 average, 320 variation with time, 321 differential loss, 641 diffraction, 55, 117, 120 diffraction gratings, 120 diffraction pattern, 122-123 amplitude distribution, 123 intensity distribution, 123 Diff-Serv, 392 digital crossconnects (DCSs), 22, 380-381 ADM functions, 381 narrowband, 380 ports, 380 types of, 381 uses, 380 wideband, 380 804 INDEX digital subscriber loop (DSL), 591,597 modems, 597 technology, 11 digital wrapper overhead, 518-519 advantages/disadvantages, 519 uses, 519 See also optical layer overhead Dijkstra shortest-path-first algorithm, 391,581 dimensioning models, 464-482 maximum load, 475-482 statistical, 464-4 74 direct detection, 252 direct detection receiver, 253-254, 265,273 BER for, 276 pin, 285 directional couplers, 108 direct modulation, 38, 186-187 advantages, 187 disadvantages, 187 illustrated, 187 with NRZ systems, 343 See also modulation dispersion, 35, 49, 68, 308-323 chromatic, 36, 57, 68-76, 309 as cumulative effect, 308 forms of, 308 group velocity (GVD), 69, 731,733 importance, 101 intermodal, 35, 36, 52, 308 as limiting factor, 49 management, 314 material, 68, 69 polarization-mode (PMD), 62, 308, 320-323 waveguide, 60, 68, 69 See also chromatic dispersion dispersion compensating fibers (DCFs), 267, 315-316 disadvantages, 315-316 figure of merit (FOM), 316 total chromatic dispersion, 315 dispersion compensation, 314-319 chirped fiber Bragg gratings, 316-318 with DCFs, 267, 315-316 design considerations, 343 for each channel separately, 319 methods, 314 PMD, 321-322 slope, 318-319 dispersion fibers negative, 95-98 positive, 95-98 dispersion-managed solitons, 100-101,240 average chromatic dispersion, 341 average span dispersion, 339 constant BER contours, 340 peak transmit power, 339 performance comparison, 341 performance factors, 340 spans between amplifiers, 338 system design, 338-341 use of, 338 See also solitons dispersion parameter, 312 dispersion-shifted fibers (DSF), 75 chromatic dispersion for, 331 four-wave mixing (FWM) and, 331 WDM systems and, 684 distributed-feedback (DFB) lasers, 37, 169-171,224 advantages, 170 array of, 186 packaging, 170 reflections into, 170 SLM, 310 structure, 169 temperature sensitivity, 170 See also lasers distributed network control, 496 distribution networks, 593 double sideband (DSB) signals, 248 drop-and-continue function, 502, 556 dual homing, 556-558 deployment, 558 hub nodes, 556 illustrated, 557 duobinary modulation. See optical duobinary modulation dynamic WXCs, 116 edge-emitting lasers, 173 effective cross-sectional area, 78-79 effective index, 60, 68, 69 effective length, 78-79, 88 in amplified systems, 323-325 calculation, 78 as function of link length, 324 reducing, 324 INDEX 805 electric flux density, 56 electro-absorption (EA)modulators, 188 electronic regeneration, 25 electronic switches, 215-216 electro-optic switches, 213-214 element management system (EMS), 497-499, 512 communication, 498, 499 multiple, 498 views, 498-499 See also network elements; network management enhanced HFC, 598-599 architecture, 598 bandwidth, 598 bandwidth allocation, 599 evolution path, 599 See also access networks equalization electronic, 267, 273 gain, in EDFAs, 292-293 introducing at amplifier stages, 292 for PMD compensation, 321 structures, 266-267 equalization filter, 266-267 effect of, 267 illustrated, 267 equalizers, 251 equipment management, 519-520 deployment, 520 design, 519 inventory maintenance, 520 See also configuration management; network management erbium-doped fiber amplifiers (EDFAs), 37, 154-159, 224 advantages, 37, 289 bandwidth, 66 C-band, 289 chromatic dispersion and, 38 elements, 154 energy levels, 155 gain bandwidth, 289 gain equalization in, 292-293 gain flatness, 156-158 gain saturation in, 290-291 high input powers and, 290 illustrated, 154 L-band, 158-159, 289, 292 multistage designs, 158 nonflat gain spectrum, 38 passband flatness, 292 principle of operation, 154-156 pump, 517 Raman amplifiers vs., 159 SOAs vs., 161 two-stage, 158 in WDM communication systems, 157 See also optical amplifiers erbium-doped fluoride fiber amplifiers (EDFFAs), 157 Erlang-B formula, 468 error-correcting codes, 267, 273 Reed-Solomon codes, 270-272 repetition code, 269 error detection, 267-272 error propagation, 247 ESCON (enterprise serial connection) network, 12, 21,363,396-397, 400 data rate per channel, 396 limiting factors, 397 maximum interconnection distance and, 397 protocol throughput, 503 standards, 724-725 etalons, 118 Ethernet, 398 10-Gigabit, 389, 398 Gigabit, 363,389, 398 excessive loss, 110 excess noise factor, 255,275 excited state absorption, 157 expedited forwarding (EF) packets, 392 external cavity lasers, 171-172 disadvantages, 172 with fiber Bragg grating, 172 grating, 171, 172 structure, 171 tunable, 179-180 See also lasers external modulation, 38, 187-190 with DFB lasers, 314 lithium niobate, 188, 189, 190 for long-distance transmission, 311 semiconductor electro-absorption (EA), 188 types, 187-188 See also modulation 806 INDEX extinction ratio, 186, 200, 287-288 chirp reduction and, 310 power penalty, 288 reducing, 288 extra traffic, 546 eye diagram, 251 Fabry-Perot amplifier, 167 Fabry-Perot cavity, 167 Fabry-Perot filter, 227 power transfer function, 131,132 tuning, 133 Fabry-Perot (FP) laser, 168 array, 186 oscillation, 168 failures active component, 538 causes, 538 erroneous connections due to, 556 events, 538 human error, 538 IP network, 559 mean time between, 538 node, 538,553-554 simultaneous transmitter, 562 slow recovery from, 558 in TPONs, 604 See also protection Faraday rotator, 114 fast signaling channel, 498 fault management, 496, 507-519 alarm management, 510-512 example, 507 optical trace, 509 service restoration, 507 support, 503 See also network management feedback delay line architecture, 640 feedback shift register, 275 feed-forward delay line architecture, 636, 640 fiber Bragg gratings, 127 chirped, 316-318 external cavity lasers with, 172 optical add/drop elements, 128 temperature coefficient, 127 uses, 127 fiber cables, 11 fiber distributed data interface (FDDI), 39, 241 fiber gratings, 126-133 fiber, 127 long-period, 127-132 photosensitivity, 126 short-period, 126-127 tunability, 133 See also gratings fiber lasers, 166 fiber modes, 59-61 effective index, 60 fundamental, 59 propagation constant, 59 fiber nonlinearities. See nonlinear effects fiber to the building (FTTB), 600 fiber to the cabinet (FTTCab), 600 fiber to the curb (FTTC), 40, 592, 599-609 architecture, 600 feeder network, 600 optical network units (ONUs), 599-607 See also access networks fiber to the home (FTTH), 40, 599 fiber transmission technology, 11 Fibre Channel, 363,397 open fiber control (OFC) protocol, 528-530, 534 standards, 724-725 field-effect transistor (FET), 199 figure of merit (FOM), 316 filters, 115 acousto-optic tunable (AOTFs), 143-147, 230 applications, 116 cascaded, 307-308 dielectric thin-film, 133-135 equalization, 266-267 Fabry-Perot, 131,133,227 guiding, 337, 338 multilayer thin-film, 743-750 piezoelectric, 133 sliding-frequency guiding, 338 technology characteristics, 116-117 thin-film resonant cavity (TFF), 133 thin-film resonant multicavity (TFMF), 133, 135 transversal, 267 finite field, 271 first-order PMD, 322 first-passage model, 464-465,466 INDEX 807 fixed-wavelength conversion, 457 ring network with, 479 WA problem and, 459 flooding, 390-391 forward defect indicator (FDI) signal, 510-512 forward error correction (FEC), 268, 505 code performance measurement, 269 coding gain, 270 reasons for using, 268 in undersea transmission systems, 271 use of, 269 forwarding, 618 Fourier transforms, 55, 82, 728,732 four-wave mixing (FWM), 38, 76, 90-93, 104, 223-224, 323,329-333 advantages, 223 bit rate and, 90-91 channel spacing and, 91 dispersion-shifted fiber (DSF) and, 331 effect, 329 efficiencies, 331 illustrated, 224 intrachannel crosstalk manifestation, 331 limit computation, 356 maximum transmit power limitation, 332 nonlinear dielectric polarization, 91, 92 power enhancement, 223 power penalty, 330 in WDM systems, 332 See also nonlinear effects frame relay, 8 framing pulses, 620 Franz-Keldysh effect, 190 free spectral range (FSR), 132, 228 of AWG, 141 input/output waveguides and, 228 frequencies equal spacing, 346 microwave, 243,244 optical carrier, 242 frequency division multiplexing (FDM), 13 front-end amplifiers, 192, 197-199, 250 dynamic range, 198-199 equivalent circuits, 198 high-impedance, 197, 198, 199 noise, 254-255 transimpedance, 197, 198, 199 types of, 197 FRONTIERNET switch, 652-654 illustrated, 653 wavelength converters, 652 See also PPS testbeds full service, 592 full service access network standard, 604 full wavelength conversion, 457 blocking probability and, 471,472 ring network with, 478 WA problem and, 459 wavelength-routing networks, 464 full width half maximum (FWHM), 132, 145 fundamental mode, 59 fundamental solitons, 98, 739 pulse, 739 pulse illustration, 99 See also solitons gain amplifier cascades, 294 APD receivers, 260 clamping, 297 coding, 269-270 conversion, 472,473 EDFA, bandwidth, 289 equalization, in EDFAs, 292-293 FEC coding, 270 mode-locked lasers, 176 Reed-Solomon codes, 270 repetition code, 269-270 SBS, 79, 325, 326 SOA dependencies, 219 SRS bandwidth, 327 SRS coefficient, 81 unequal, effect of, 293 gain saturation in EDFAs, 290-291 optical amplifier illustration, 291 Gaussian distribution, 752-753 Gaussian random process, 756 geometrical optics approach, 50-55 intermodal dispersion and, 53 light propagation, 51 geometrical optics model, 33 illustrated, 35 light rays, 33 get operation, 500 Gigabit Ethernet, 363,389, 398 Gold service class, 567 Gordon-Haus jitter, 337 808 INDEX graded-index fibers, 53, 54 graph coloring, 461-462 grating circle, 142 grating coupler sampled reflector (GCSR) lasers, 183, 185 illustrated, 186 VGF, 185 grating equation, 121 grating external cavity lasers, 171 grating plane, 120 gratings, 118-122 apodized, 124 arrayed waveguide (AWG), 137, 139-143,606 Bragg, 123-126 diffraction, 120 examples, 119 fiber, 126-133 order, 121 pitch, 120, 121 principle of operation, 121-122 reflection, 119, 120 Stimax, 120 transmission, 119, 120 very long, 318 greedy algorithm, 476-477 grooming, 440 group velocity, 69, 731 dispersion (GVD), 69, 731,733 of pulse, 732 guaranteed bandwidth service, 655 guided rays, 52 guidelines for description of managed objects (GDMO), 501 guiding filters, 337-338 center frequency, 337 sliding-frequency, 338 half-wave plate, 114 head end, 593 header processing, 634-635 head-of-line (HOL) blocking, 639 helical LAN (HLAN) topology, 655 heterodyne receivers, 264 heterostructure, 163 high channel count multiplexer architectures, 148-151 multistage banding, 148-149 serial approaches, 148 single-stage, 148 higher-order nonlinear susceptibility, 741 higher-order solitons, 100 high-impedance front-end amplifier, 197, 199 high-level data link control (HDLC), 18, 388 high performance parallel interface (HIPPI), 397 hold-off time, 583 homodyne receivers, 264 homogeneity, 58 hops, 444 maximum number of, 444 minimum average number of, 446 horizontal partitioning, 496 hot-potato routing. See deflection routing hub topology, 442 architecture, 445 example, 444-445 illustrated, 442 number of wavelengths, 448 See also lightpath topologies hybrid fiber coax (HFC) networks, 592, 598 architecture, 598 enhanced, 598-599 illustrated, 596 ideal receiver, 252-253 imaging plane, 120 impedance, 743 concept, 745 input, 745 intrinsic, 743, 745 load, 745 incumbent LECs (ILECs), 3 induced electric polarization, 56 information model (IM), 499-500 attributes and functions, 499 classes of objects, 499 examples, 499-500 input buffering, 635, 639 input impedance, 745 insertion loss, 113,200-201 bulk mechanical switches, 209 uniformity, 200-201 integer linear program (ILP), 452 integrated services digital network (ISDN), 597 intensity-dependent refractive index, 85 interchannel crosstalk, 299, 301-303 power penalty, 301,303 sources, 301 See also crosstalk INDEX 809 interchannel spacing, 344-345 interdomain routing protocol, 392 lnterexchange carriers (IXCs), 3 interference, 117 interference length, 473 interferometric techniques, 220-223 interleaving, 271-272 depth, 272 multistage, 149-151 intermodal dispersion, 35, 36, 308 geometrical optics approach and, 53 graded-index fibers and, 54 link length and, 308 reducing, 52 time spread due to, 52 See also dispersion intermodulation products, 243 International Standards Organization (ISO), 16 International Telecommunications Union (ITU) equal frequency spacing, 346 fiber standards, 721 grid, 30, 31,439 layers within optical layer, 504 management standards, 722-723 optical networking standards, 722 SDH standards, 721-722 standards, 721-723 wavelength grid, 347 wavelength standardization, 346 See also standards Internet Protocol (IP), 7, 363,388-395 assured forwarding (AF) packets, 392 as common link layer, 674, 675 expedited forwarding (EF) packets, 392 explicitly routed paths, 393 forwarding, 390-392 label-switched router (LSR), 392-394 in layered hierarchy, 389 layering structures, 388 multiprotocol label switching (MPLS), 392-394 network failure, 559 over ATM over SONET, 20 over SONET, 19-20 over WDM, 388, 389 over WDM variants, 677-678 protection and, 558-559 QoS, 392 routing, 390-392 See also client layers; IP layer Internet service providers (ISPs), 3 interoperability, 530 intersymbol interference (ISI), 49, 246 deliberate introduction of, 246 from PMD, 321 intrachannel crosstalk, 299-301 causes of, 299 FWM manifestation as, 331 level, 301 power penalty, 300, 301 source illustration, 300 See also crosstalk intradomain routing protocol, 391 intraoffice connections, 375 intrinsic impedance, 743,745 ionization coefficient ratio, 255 IP layer as common link layer, 674, 675 maturity, 675 on top of optical layer, 676 QoS guarantees, 676 See also Internet Protocol (IP) isolators, 112-115, 227 insertion loss, 113 isolation, 113 parameters, 113 polarization-independent, 115 principle of operation, 113-115 uses, 112-113 isotropy, 57 Just-Enough-Time (JET)protocol, 649 KEOPS (Keys to Optical Packet Switching), 650-652 broadcast-and-select packet switch, 653 demonstrations, 650 predecessor, 650 switch controller, 651 wavelength-routing packet switch, 652 label distribution protocol with constrained routing (CR-LDP), 394 label-switched paths (LSPs), 392, 558-559 alternate, 559 failure, 394 packets, 393,558 label-switched router (LSR), 392-394, 524 label forwarding, 393 receiving packets, 392 . advantages/disadvantages, 519 uses, 519 See also optical layer overhead Dijkstra shortest-path-first algorithm, 391,581 dimensioning models, 46 4-4 82 maximum load, 47 5-4 82 statistical, 46 4-4 74. 114 fast signaling channel, 498 fault management, 496, 50 7-5 19 alarm management, 51 0-5 12 example, 507 optical trace, 509 service restoration, 507 support, 503 See also network management. 33 6-3 38 transmit power and amplifier spacing, 34 2-3 43 transparency, 348 wavelength planning, 34 6-3 47 wavelength stabilization, 33 5-3 36 detectors, 19 2-1 99 front-end amplifier, 192, 19 7-1 99