Andrew S. Tanenbaum -6 SAP 87.6M -7 [ ] -8 04 04 048 04 048-9 4 3 a b c -0 - - OSI TCP/IP OSI TCP/IP OSI TCP/IP n -4 n( p) p = ( p) -5 OSI mailto:wdg98@63.net
-7 n m h [ ] hn/(hn+m)*00% [ OSI TCP/IP ] -8 TCP UDP - GB 68Gb 0km x Km 80 x 68/80x Gb/s 68/80x > 55 x < 6 Km -3-7 -8 CD CD 35mm NTSC VHS PAL 8.5* A4 mailto:wdg98@63.net
- g( t) = c + a sin( π nft) + n n= n= f ( t) = t T = f = T = a n = T 0 f ( t)sin( πnft) dt = πn b n = f ( t)cos(π nft) dt = 0 T 0 c = f ( t) dt = T 0 b n cos(πnft) -3 MHz bit 4Mbps -4 3log ( + 00) = 9.98 kbps 3kHz 3log = 6 kbps 6kbps -5 T S 6 H log ( + ) =.544 0H N H = 50000 S = 3 N 3 0log 0 ( ) = 93 db 50kHz T 93dB -6-7 c f = λ c df = dλ λ df c = dλ λ c f = λ λ mailto:wdg98@63.net 3
8 c = 3 0 λ = 0 6 m λ = 0. 0 6 = 0 7 m 8 3 0 7 f = 0 = 30 0 Hz = 30THz 6 (0 ) 0.µm 30THz -8 480 640 4 60 bps 44Mbps f = 4.4 0 8 c df c f = = λ dλ λ f λ f = = c 6 8 (.3 0 ) 4.4 0 6 =.5 0 m =.5 0 8 3 0 µm 6 44Mbps.5 0 µm -9 f f -0 3 c f = f λ λ λ f 3 - c f = λ λ cm f 30GHz λ 5m f 60MHz - GHz 30cm 5cm 80º 50km -3 0.00 o A = arctg = 0. 00057 00-4 0.5 6 3 60/3=0 0% 00 000000/4000=50 00 00*50=50000 mailto:wdg98@63.net 4
-5 π (/ ) = 0. 5π mm² 0km 3 0.5π (0 ) 0 000 = 0.5π 0 m³ 5708cm³ 9.0g/cm³ 9 5708 = 437 g 4 9 4kg 000 0 =.4 0 3 3.4 0 9 = 4. 0 9-6 CPU -7 4 00 400bps -8 0-9 -0 PCM 64kbps 64kbps 0Gbps 5650 - TDM FDM 00 FDM TDM µs 8000 4kHz 4kHz 8000-3 93 68 7*4 5 =93-68 5/93=3% -5 0 00000 /04 0 00000 /04 0.00-6 -7 a CCITT.048Mbps 3 8 5µs 30 4kHz 8*8000=64kbps mailto:wdg98@63.net 5
b DPCM 4 4kHz 4*8000=3bps c t s??? bit 4kHz *8000=8kHz -8 /4 0 A T/4 T 8 3 /x 3 T=3/x f =x/3-9 0 9 9 0 0 9 OC- 5.840Mbps 50Mbps 0ns -30 SONET 5µs 80 SONET 8000 PCM 80 SONET 90 9 8 80 8000 = 5840000 bps 5.84Mbps SONET STS- SONET STS- 3 3 6 87 87 9 8 8000 = 50000 bps SPE SONET SPE 50.Mbps 9 8 8000 = 576000 bps 0.576Mbps 49.536Mbps OC-3 3 OC- 49.546 3 = 48.608 Mbps -3 OC-3 c conactenation OC-3 3 OC- 55.5Mbps OC-3c 55.5Mbps OC-3c 3 OC- 3 70 9 OC-3c OC-3 49.760Mbps 48.608Mbps SPE 3 OC- 3 OC-3c 70 60 OC-3 58 OC-c OC-c *90=080 9 *3=36 080-36=044 SPE 043 9 OC-c 8 9 043 = 75096 8000 75096 8000 = 600768000 bps 600.768Mbps mailto:wdg98@63.net 6
OC-c 600.768Mbps -3 n/ n/4 n n n- / n+ /4 n n/ n 4( n ) -33 t = s t = s + x / d t = s + x/ b + kd t = x / b k p / b x p + ( k ) + kd b b x p x + ( k ) + kd < s + + kd b b b p s > ( k ) b -34 x / p ( p + h) x p ( p + h) x pb ( k )( p + h) b x ( p + h) + ( p + h)( k ) pb b p p ( p + h) x k + p b b p ( p + h) x k + p b b hx = k p = 0 mailto:wdg98@63.net 7
hx p > 0 p = k hx p = k N N N -35 nk + k n n n N + nk n N = kn + k n a N=6 n=4 k= 96 a N=6 n=4 k=3 44 N(N-)/ 0 mailto:wdg98@63.net 8 b N -36 3-37 a 3 3 7 3-38 n RAM 00ns 0.µs n n k bit T 8bit 8000 k bit RAM i i 0 n- j j RAM 0 4 RAM 4 4 RAM n 5µs 0.n = 5 n = 50 50-39 0*80=800bit 800bit -40 T 5µs -4 8*0=80 (8*300)*(0*300)=700 000 4bit 4*700000=8.8Mbit 8800kbit ISDN B 64kb/s 8800/64=450s FAX bit 4 FAX 4.4kb/s 64kb/s 450s 95% -4 ISDN NT ISDN
NT ISDN NT NT B+D NT NT NT OSI 3 NT PBX NT NT NT NT -43 3-44 6 8 3 5 - - - - ( 3 5 - - - -) - - 3-5 - ( 3 - - 5 - -) 3 5 - - - - 3 5 - - - - 4 8 - - 3-5 - 3 - - - - 5-3 - 5 - - - 3-5 - - -45 6 8 7 - - 6-4 5-7 6 - - - - 4 5 6-7 - - 5-4 6 5 - - 7 4 - - 5 4 6 7 - - - - 4 5 6 7 - - - - 4 8 4-5 - 6-7 - - - - - 4 6 5 7 - - - - 4 5 6 7 - - - - 4 5 6 7 mailto:wdg98@63.net 9
3-0.8 p = 0.8 0 0.07 p ( p) p ( p) p i p i ( ) p = E ip( p) i= i = p = 0.07 9.3 3- DLE STX A DLE DLE B DLE ETX 3-3 000000 3-4 00 000 0 00 6 6 6 / 3-5 3-6 Hamming 3-7 3-8 n k 0 4 4 4 C 4 4 nk C n C k C n C C 4 nk k n( n ) k( k ) = nk( nk )( nk )( nk 3) ( 3 4) 6( n )( k ) = ( nk )( nk )( nk 3) 3-9 x + x + mailto:wdg98@63.net 0
3-0 CRC CRC CRC CRC CRC 3-50% 50% 50% 4Mb/s 0.5µs (0 0 3 ) (0.5 0 6 ) = 60000 bit 60kb 50% 3-6 3000 = 8000 µs 8ms 6 T 64 33 64 8 (.536 0 ) 0. µs 8.33ms 8ms 36.33ms 36.33ms 36.33/ 0.33 = 0 0 7 3-4 3 A 7 B ack A ack 0~6 B 7 A r.rack=7 ack_expected=0 r.rack=7 next_frame_to_send_=7 3-5 NAK NONAK NAK NONAK NAK else NAK 3-6 mailto:wdg98@63.net
3-8 r.rack+<next_frame_to_send A 0 B B ACK ACK A 0 B NAK 0 A 0 r.rack+<next_frame_to_send 0 r.rack+<next_frame_to_send 3-9 0 6 7 7 0 0 6 7 7 0 3-0 µs 000bit ms 0ms s A B A B B NAK 3- MaxSeq=4 =4+=5 NrBufs<=5/=.5 NrBufs= 4 0 0 3 4 0 0 0 arrived[0] MaxSeq 3-7 4 70ms Mb/s 000bit ms t=0 t=ms t=7ms t=7ms t=54ms 54ms k ms k/54 a k= =/54=0.8% b k=7 =7/54=.9% c k=4 =4/54=0.74% 3-3 8 8 70ms 50kb/s 4000bit 3960+40 0.0*4000=80ms t=0 t=80ms t=70+80=350ms t=350+80=430ms t=430+70=700ms 700ms 8 80*8=040ms 0.0 3960 40 4000*0.0=40 NAK 40*/00=0.40 3960 80.4 80.4/(3960+80.4)=.99% 3-4 70ms 64kb/s 604ms mailto:wdg98@63.net
64ms 604/64=9 604ms 4096 4096/0.604=6.8kb/s 7 604ms 4096*7 4096*7/0.604=47.5kb/s 9 5 7 64kb/s 3-5 00 000km 00km 00km 0.5ms T 5µs 93 0.5ms 4 T 93*4=77bit 3-6 00-- 00-A 00- -A 0-- -- 0-0-- 000A A + 3-9 PPP HDLC bit PPP 3-30 PPP 3-7 LCP LCP 5 5 40 3-3 ( 0 ) = 4 0 mailto:wdg98@63.net 3 4 a=5 4 5 7 7 (4 0 ) = 0 0 OC-3 53 8 0 49.76 0 7 6 = 8978 365 4 3600
4- ALOHA 0.84 56Kb/ s = 0. 304 Kb/s 000/00=0b/s N =0304/0 030 030 N 030 4- ALOHA ALOHA ALOHA 4-3 00 =3600/8 0 000 00 0000 50 8000 50/8000=/60 4-4 a k G e Pr[ k] = k! k G 0 e G ALOHA e G e G = e G ALOHA e G 40ms 5 50 G= e = / e G k G k k b ( e ) e = ( e ) e = 0.35 ( 0.35) = 0.35 0. 865 c k k- k k p k = e G ( e G ) k E = kpk = ke k = k = G ( e G ) k = e G = e = 7.4 G 4-5 a p0 = e G = ln p 0 = ln 0. =. 3 G G b S = Ge G =. 3 e = 0. S =.3 0. = 0.3 c G> 4-6 mailto:wdg98@63.net 4
G G k E = kp = ke ( e ) = e k k = k = G E E- 4 G 4( e ) S = Ge G G G G D = 4( e ) S = Ge 4-7 Mok Ward 0 Mok Ward 0 N N- 4 0 0 3 0 8 3 0 5 7 4 6 9 3 0 0 0 8 0 5 3 7 4 6 9 9 0 9 6 4 8 5 7 0 3 4-8 B 0 7 C B D 3 5 7 3 3 3 5 7 3 mailto:wdg98@63.net 5
3 5 7 3 3 3 5 7 5 7 3 3 4-9 n n+ 0 n n i i / p n = n n C n ( ) n p = n n n ( ) = n n >> p n n = + + + L+ = n + p n C n n p n n+ = = = n n C n mailto:wdg98@63.net 6
n n = + n = n n-3 p = 3 n + n n M p n 3 i+ = n = n 3 i+ = ( n i) = n + i n+ i=0 3 i = n m = n i= 0 ( n i) (n + i) m = ( n )(n + ) n ( n ) i= 0 i mailto:wdg98@63.net 7 i 4-0 CSMA/CD 4- WDMA wave length division multiple access 0 3 4 GSM Global system for mobile communication 00 00kHz FDM TDM TDM 4-6 TDM 0ms 8 TDM
8 TDM 48bit 4.65ms TDM 57 4.65ms 4-3 A : (+ + + - - + - -) B :(+ + - + - - - +) C : (+ - + - - - + +) A + B + C 4-4 = ( + 3 + + 3 + ) S T m m i= S i T i T 0 i T i S T m m i= Si ( Ti ) = m m i= S i T ) = 0 i 4-5 + - 0 4-6 4 -+-3+--3++ ---++-++ /8= -+-3+--3++ --+-+++- /8=- -+-3+--3++ -+-+++-- /8=0 -+-3+--3++ -+----+- /8= A D B 0 C 4-8 0Mb/s 0MBaud 4-0 i i i ( ) i k- k ( k ) 0 pk = ( )[ L ( k ) ] = ( kp k ( k ) ) ( k )( k ) / 4- km / 00000 = 5 0 6 s 5µs mailto:wdg98@63.net 8
t =0µs CSMA/CD 0µs Gb/s 0µs 0 0 0 6 9 = 0000 0 000 bit 50 4-4 4 40 40 0 0ms 40% 6 40% 4 0% 0% 0 4-5 WHO_FOLLOWS WHO_FOLLOWS SET_SUCCESSOR 4-6 5Mb/s 00ns 00ns 00 0 3 00 = 40 m 40 4-7 6 8 8 8 4-8 0. 56 = 5.6 µs 0. 8 = 0.8 µs 0 =000/50 0/00=0.µs 6.5 =5.6+0.8+0. µs 4 4/6.5=8.5Mb/s 0Mb/s CSMA/CD 50 3Mb/s 4-9 4-30 40Mb/s 0ms 40000 5000 4-3 4-3 00km 0 km bit 00 / 00000 3 = 0 s ms 00Mb/s 0.0µs 000 80 0.0 000 8 = µs 0.08ms 3 0.0 4 8 =.9 µs.08ms +0.08+0.009 89bit 3 9bit 8000bit 89 /(.08 0 ) 7.6 0 6 7.6Mb/s mailto:wdg98@63.net 9
8% 4-33 D A D E E D E 4-35 4-36 /0 4-37 000 CPU 000 CPU 4-38 80.4 80.5 CPU µs s 300k =4096*00-5*000 300ms 800 800 800 300k 4-39 LAN 4-40 4-4 00 40ms 40/00 0.4ms 0ms 0 /(0 + 0.4) = 96% 96% mailto:wdg98@63.net 0
5-5- kill 5-3 5-4 5-5 000 5*8=40 ( 5 3) 4 00 = 9600-40000 - 9600-7 7 8 3600 8 5 5.7 0 - /(.5 0 ) = 6.7 0 6 40000 -.7-0 9600 6 3-0 9600 = 9.6 0 9.6 000 6.9 k 5-6 k 5-7 5-8 B 6 4 8 8 D 9 5 9 3 3 E 8 4 5 9 C 6 0 3 5 8 B B - D E B 5-9 8*50=400bit 400*=800b/s 800b/s 5-0 REGION CLUSTER ZONE 4800=5*6*0 6 0 0 6 5 5+6+0=5 5-3 mailto:wdg98@63.net
5 8 4 4 5-5 T 3 3 (n-)t / 5-6 3 p ( p) p 3 ( p) L = p + ( p) p + 3 ( p) = p 3p + 3 p 3p + 3 ( p) α = ( p) α ( α) ( α) α T = nα ( α) n= n = α = ( p) /( p) 3 H = L T = ( p 3p + 3) /( p) 5-7 0 00 000 5-8 04 5-9 5µs 00 000 48 8 48 = 384 bit 5 6 384 0 = 76.8 0 b/s 76.8Mb/s 5-0 6Mb/s 4/3 8Mb S = C /( M P) S M C P mailto:wdg98@63.net
6 (8 0 )/ 8 S = =.6 s 6 6 (6 0 ) / 8 ( 0 )/ 8 6Mb/s.6 s 5-? t MB 0?t MB 50?t MB +0? t=50?t?t=/40s 5ms 5-5-3 04 48 5-4 5-5 8 5-6 8 644 0 64 5-7 94.47..30 5-8 B 6 6 6 4 4096 0 4094 5-9 ARP IP HDLC PPP 5-30 RARP RARP ARP ARP 5-3 IP 5-33 IP - - ATM 5 5-34 5-35 IP IP LAN LAN ARP 60.80.40.0 mailto:wdg98@63.net 3
60.80.40.0 IP LAN LAN 5-36 * ps 00 ps 8 38 6 8 6 3.4 0 0 0 0 3.4 0 s 0 3 000 5-37 IP 5-38 IP 5-39 SETUP CONNECT 5-40 SETUP 4 7 CONNECT 4 4 8 5 5-4 VPI NY Danver VPI VCI 5-4 T L /T /( T L) 5 T=0µs L=µs 0 5 000 5-43 Generic Cell Rate Algorithm GCRA T L T PCR L T T N NT T d δ T N ( N )δ δ NT ( N ) T+L NT ( N ) δ = T + L L N = + T δ T=5µs L=5µs δ = 53 8/55.5. 73 µs N=.0 mailto:wdg98@63.net 4
:C C /4 8 54 55 55 55 0 /3 9 50 55 55 54 0 / 0 4 0 55 55 5 0 / 8 046 55 55 48 0 /0 6 4094 55 55 40 0 /9 3 3 890 55 55 4 0 /8 4 64 638 55 55 9 0 /7 5 8 3766 55 55 8 0 mailto:wdg98@63.net 5
6- LISTEN OK REJECT 6-6-3 a b 6-4 T T TPDUs k k TPDU TPDU T TPDUs T T T TPDU TPDU TPDU TPDU T TPDU 5 a 3768 00ms 0. 376.8s 376.8-60=37.8 b 40 4 t 4t 4t 0 ) 0( t 36.8 4t = 0( t 36.8) t = 536. 3 t = 536.3 t = 536.3 6-5 mailto:wdg98@63.net 6
x TPDU TPDU x y TPDU TPDU TPDU CONNECTION REQUEST TPDU TPDU CONNECTION ACCEPTED TPDU y y TPDU y TPDU z y TPDU y 6-6 3 A B B A A A B A A A A B A A B A B A B A A 6-7 - TPDU TPDU S TPDU S0 TPDU ACK TPDU TPDU ACK S0 TPDU mailto:wdg98@63.net 7
TPDU TPDU ACK ACK S TPDU 6-8 4 TPDU S0 S 8 3 ACK A W C 3 6 AC W AWC C AW C WA WAC WC A C A 6-8 8 AWC C AW C WA AW WA AC W W CA S TPDU AW WA 6-8 RECEIVE 6-9 n + n3 + n6 + n7 = listening n waiting n 3 sending n 6 receiving n 7 6-0 6-6- TPDU 6-3 TCP 6-4 p - q 6-5 TCP IP 65535 TCP 0 6555 TCP 6-6 LISTEN SYN RECD SYN SYN RECD 6-7 Nagle TCP mailto:wdg98@63.net 8
6-8 0 0 30 40ms 4 8 6 3 40ms min{4 3}=4KB 6-9 4 8 4 8K 6-0 TCP RTT TCP M RTT RTT = αrtt + ( α ) M 9 α = 0. RTT=30ms M=6 M=3 M3=4 RTT = 0.9 30 + ( 0.9) 6 = 9. 6 RTT = 0.9 30 + ( 0.9) 3 = 9.84 RTT = 0.9 30 + ( 0.9) 4 = 9.56 RTT 9.6ms 9.84ms 9.56ms 6-0ms*=0ms 0ms 50 65536 8 50 = 6. Mb/s 6./000 =.6% 6.Mb/s.6% 6- TPDU TPDU 30 30 TPDU 55 55 8 8/ 30 = 8738 b/s 8738b/s 6-3 IP IP IP UDP 6-3 8 04 Gb/s 000 µs 00km/ms 0.5ms 0.5ms 000 ms Mb/s 0.% 6-3 Gb/s ms Mb/s 04 ms 0.5ms 0.5ms RPC ms 000 6-33 ( 70000 0 + 730000 ) (70000 + 730000) = 0.73 ms mailto:wdg98@63.net 9
TPDU 730µs 6-34 64 8 *6= 0ns 5ns CPU 000/5=66.67MB/s 533Mb/s Gb/s Gb/s 64 9 6-35 0 75/8=9.375 75Tb/s 9.375 0 9 6 ( 0 ) /(9.375 0 ) 0 6 0 s 3 3 6-36 6 0 9 0 /(8 8) µs CPU 0.5µs 0.5µs 00MIPS 50 6-37 00km 0km 00µs 00µs K 89 89 00µs W 00 0 W = 89 4 / W = 89 /( 0 ) = 40 0 6 6 40Mb/s mailto:wdg98@63.net 30