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2! PSTN Internet 2/ 73

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twisted pair! 8 UTP100 m Cat310 MbpsCat5100 Mbps 2/ 73

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! 50Ω 50Ω 75Ω 75Ω 75Ω 2/ 73

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! 2 km 10 km 2/ 73

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! f(hz) 10 0 10 2 10 4 10 6 10 8 10 10 10 12 10 14 10 16 10 18 10 20 10 22 10 24 X γ 30km 3km 30m 3m 30mm 3mm 30µm 3µm f(hz) 10 4 10 5 10 6 10 7 10 8 10 9 10 10 10 11 10 12 10 13 10 14 10 15 10 16 AM FM TV Tnbm P101 Fig.2-11

Computer Networks v4 cs.sjtu 12/21/12! 36000km 270ms 540ms VSAT VSAT VSAT very small aperture satellite terminals

2! PSTN Internet

PSTN! PSTN Public Switched Telephone Network MODEM 10-12 10-5 10 7 11

! 1 km ~ 10 km

! Internet OVER Internet

! 1 km ~ 10 km

! PCM T1 E1 SONETSDH

PCMPulse Code Modulation! PCM PCM f (t)

! PCM T1 E1 SONETSDH

! 8000/ OVER 4000 HzNyquist4000 Hz 8000/ 2568 bit

! 256 192 128 64 0 t A B C D E F G H A B C D E F G H 188 244 240 144 80 72 122 200 10111100 11110100 11110000 10010000 01010000 01001000 01111100 11001000

! PCM T1 E1 SONETSDH

T1 1.544M b/s T124 8000/7 bit 7bit1 bit7b + 1b 56K + 8K 24 8 bit x 24 = 192 bitbit193 bit 193 bit x 8000/ = 1544000 bit/s = 1.544M b/s T1

! PCM T1 E1 SONETSDH

E1 2.048M b/s E132 8000/8 bit bit 32 8 bit x 32 = 256 bit 256 bit x 8000/ = 2.048M b/s E1

T1E1! T1 = 1.544M b/s E1 = 2.048M b/s T2 = T1 x 4 + = 6.312M b/s E2 = E1 x 4 + = 8.848M b/s T3 = T2 x 6 + = 44.736M b/s E3 = E2 x 4 + = 34.304M b/s T4 = T3 x 7 + = 274.176M b/s E4 = E3 x 4 + = 139.264M b/s

! PCM T1 E1 SONETSDH

SONET/SDH SONETSynchronous Optical Network ANSI T1.105 ~ 106 STS-1Synchronous Transport Signal OC-1Optical Carrier 125 µs810 B810 8b x 810B x 8000/ = 51.84M b/s SDHSynchronous Digital Hierarchy CCITT STM-1Synchronous Transport Module 155.52M b/s

SONETOCSTSSDH STM! 40M b/st1 ~ T3E1 ~ E3 SONETSDH (Mb/ SONET SDH s) OC STS STM 51.84 OC-1 STS-1 155.52 OC-3 STS-3 STM-1 466.56 OC-9 STS-9 STM-3 622.08 OC-12 STS-12 STM-4 933.12 OC-18 STS-18 STM-6 1244.16 OC-24 STS-24 STM-8 1866.24 OC-36 STS-36 STM-12 2488.32 OC-48 STS-48 STM-16 9953.28 OC-192 STS-192 STM-64 Tnbm P146 Fig. 2-37 SONET SDH!

! 1 km ~ 10 km

! crossbar 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7

! N/n n x k k N/n k x n n x k N n N X n k x n n x k N n N X n k x n n x k k x n

! time slot interchanger n n 0 1 2 3 4 5 6 7 4 7 6 3 0 5 2 1 n n nk RAM 7 1 6 2 5 5 4 0 3 3 2 6 1 7 0 4 n

! t A B C D A B C D A B C D

2! PSTN Internet

Internet! ADSL Internet over Cable

! ISP DHCP IP MODEM

! A G MODEMBF Codec / CDEH Medium-bandwidth trunk (Digital, fiber) Digital line H ISP 2 PC A Local loop (Analog) (Twisted pair) M Codec Toll office D Toll Toll B C office office E End office High-bandwidth trunk (digital, fiber) Tnbm P124 Fig. 2-23 G ISP 1 Codec M M M F M M MODEM pool

! 4k Hz

! ISP DHCP IP MODEM

MODEM! MODEM MOdulation and DEModulation MODEM Ø Ø RS-232RS-449

MODEM! 1000 2000 Hz V.32 6(1)b x 2400 = 14.4 kbps P129 Fig. 2-26(b) V.34 12 x 2400 = 28.8 kbps 14 x 2400 = 33.6 kbps V.90 ISP 33.6 kbpsisp56 kbps

Internet! ADSL Internet over Cable

ADSL! ADSL Asymmetric Digital Subscriber Line DSL ADSL DMT

DSL! DSLdigital subscriber line 4 khz 3UTP4 khz HDSL 1.544 ~ 2.048 Mbps2/43 ~ 4 km SDSL 1.544 ~ 2.048 Mbps13 km VDSL 13 ~ 52 Mbps1.5 ~ 2.3 Mbps 10.xx km ADSL 64 k ~ 1 Mbps512 k ~ 8 Mbps 13 ~5 km

ADSL! ADSL Asymmetric Digital Subscriber Line DSL ADSL DMT

ADSL! PC A C EF ADSL modem Internet A ADSL modem Ethernet D G B ATU-R C ' ATU-C ATU - CADSL Transmission UnitCentral ATU - RADSL Transmission UnitRemote E F ADSL modem B DG

ADSL! ADSL Asymmetric Digital Subscriber Line DSL ADSL DMT

DMT! DMTDiscrete MultiTone modulation 1.1MHz)2564312.5Hz 0 1 ~ 5250 4312.5Hz 0 1 2 3 4 5 6 7 8 9 251 252 253 254 255 Voice Upstream Downstream Tnbm P132 Fig. 2-28 DMTADSL

ADSL! Internet 80 90% voice 4k 4k 4k Upstream 64k 256k 1M Downstream 512k 1M 8M

Internet! ADSL Internet over Cable