4 CSMA/CDMACMAC CSMA/CDMAC

4.1 (LAN) ()

Topology

1-,

2,

3()

4.2 10Mbps100Mbps1Gbps10Gbps 4.2.1 4.2.2 4.2.3

4.2.1 1. DIX Ethernet V2 IEEE 802.3 DIX Ethernet V2 IEEE 802.3 802.3 DIX Ethernet V2

802 LLC (Logical Link Control) MAC (Medium Access Control) TCP/IP DIX Ethernet V2 802.3 802 LLC 802.2

4.2.1 2. (adapter) NIC (Network Interface Card) / IP

CPUI/O

4.2.1 3. CSMA/CD B D C D A EB D B

B D D A, C E

4.2.1 CSMA/CDCarrier Sense Multiple Access with Collision Detection /

A B B B A B ( B A ) A

AB1km1km5 s

4.2.1 4. 2 2

2 k k 10 k = Min[, 10] [0,1,, (2k 1)] r r 16

51.2 s 10 Mb/s 512 bit 64 64

64 64 64 64

ABt

4.2.2

BNC T MAUMDIDB-15BNC RJ-45

250 m750 m 1 2 3

1RJ-45EthernetPROM 2Hub8101224310BASE2RJ-45

RJ45RJ45

10BASE2 5 mm ( 50 W) MAU MDI AUI BNC T BNC

10BASE2BNCBNC

CSMA/CD

10BASE-T (hub)100

CSMA/CD

4.2.3 N p 2 L (bit) C (b/s) L/C = T0 (s)

4.2.3 Smax

N a a Smax

a =1 ABABt = T0ABABt = 3T0t = 4T0t = 2T0ABt = 5T0 a = 4

a = 0.01 a = 0.01 ABABt = t = 0.5ABt = 100ABt = 100.5

4.3 MACIEEE802

MAC MACLLC MAC LLC()

4.3.1 MAC MACROM648 IEEE63125024224=16777216

100110101 01111011 00010010 00000000 00000000 00000001 OUI EUI-48 AC-DE-48-00-00-80 EUI-48 1 6 I/G I/G 2 3 4 5 6 1 2 3 4 5 610101100 11011110 01001000 00000000 00000000 10000000802.5802.6802.3802.4

1A-24-F6-54-1B-0E00-00-A2-A4-2C-0220-60-8C-C7-75-2A08-00-20-47-1F-E420-60-8C-11-D2-F6

MAC MAC MAC MAC . unicast broadcast multicast

4.3.2 MAC MAC DIX Ethernet V2 IEEE 802.3 MAC V2

V2 MAC MAC MAC IP 6 6

V2 MAC MAC MAC IP 2 MAC

V2 MAC MAC MAC IP = 64 18 46 MAC 64 46 ~ 1500 FCS 4

V2 MAC MAC MAC IP 8 7 MAC MAC

MAC FCS 46 ~ 1500 MAC 64 ~ 1518 MAC

9.6 s 96 bit 9.6 s

4.4

4.4.2 MAC MAC

1 2 B A1112MAC1MAC3MAC52MAC2MAC42MAC6AB

MAC 10 Mb/s 100 Mb/s

MAC MACMAC ()

Bridge MAC Bridge Bridge MAC

IPMAC 1IPMAC 2 1 2ABIP-HMAC-HMAC-TDL-HDL-T DLRMACDLRLANLAN

CSMA/CD

(transparent bridge)

(1) x () MAC (2) MAC d(3)(5)(3) MAC d = x() d (4) (6)(5) x (6) MAC (8)(7)(7) (8) (1)

B1B2LAN1LAN2LAN3LAN4 AB AH HLAN3AH B1B2 AH

LANLANLAN

MAC MAC MAC MAC x A x A

() ()

ABCDEFHIJG123456789123456789ABCDEFHJLanBridge

(source route)

LANLAN1LAN1241

1990 (switching hub)(switch)

132456

10 Mb/s N (10 Mb/s) N 10 Mb/s N N10 Mb/s

10BASE-T100 Mb/s100 Mb/s100 Mb/s

8881818881887

!MACMAC

4.5 VLAN VLAN VLAN

A4B1VLAN3C3B3VLAN1VLAN2C1A2A1A3C2B2 VLAN1, VLAN2 VLAN3

A4B1VLAN3C3B3VLAN1VLAN2C1A2A1A3C2B2 B1 VLAN2 B2 B3

A4B1VLAN3C3B3VLAN1VLAN2C1A2A1A3C2B2B1 A1, A2 C1 B1 ()

4 VLAN (tag) 802.3MAC 66246 ~ 15004/ FCS/ = 802.1Q 1 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 VID 2 2 4 VLAN 4CFI

4.6.1 100BASE-T 10BASE-T100BASE-T100BASE-T100Mb/s 100Mb/s10BASE-T100BASE-TMACIEEE802.3 CSMA/CDCSMA/CD

4.6.1 100BASE-T 100BASE-T CSMA/CD MAC 802.3 100 m 9.6 s 0.96 s

4.6.1 100BASE-T IEEE802.3u1100BASE-TX2UTP5STP2100BASE-FX23100BASE-T44UTP35

4.6.2 1 Gb/s 802.3 CSMA/CD CSMA/CD 10BASE-T 100BASE-T

4.6.2 11000BASE-X802.3z) 1000BASE-SX SX 1000BASE-LX LX 1000BASE-CX CX21000BASE-T 802.3ab) 4 5 UTP

(carrier extension) a a = C/L 100 m 64 512

MAC MAC 512 MAC 512 MAC FCSMAC = 64 MAC = 512

1500 #1 RRRRRRRR #2 RRRR #3 RRR #4 512 1500

1 Gb/s 100 Mb/s

4.6.3 10 MAC

4.6.3 10 10 10 Mb/s100 Mb/s 1 Gb/s 10 802.3 10 10 CSMA/CD

LAN PHY 10.000 Gb/s 10Gbps802.3MAC101G10Gbps10Gbps10/100/1000Mbps

WAN PHY9.95328Gb/s9.58464Gb/s 10GOC-19210GMAC Gb/s SONET/SDHOC-192/STM-64 10 OC-192/STM-64 9.95328 Gb/s

4.7 100VG-AnyLAN VGAny 100 Mb/s MAC

4.7 FDDI IEEE 802.5MAC100 Mb/s10002 km()100 km200 km4500

4.7 ABDCABDCFDDI

4.8 4.8.1 4.8.2 802.11 4.8.3 802.11 MAC

4.8.1 BSS ESS BSSAB AP AP DS

802.x

BSS BSS BSS BSS AP AP DS ESS ESS 802.11 A B

AP AEDCBF

4.8.2 802.11 802.11 FHSS DSSS IR 802.11a 5 GHz OFDM 6, 9, 12, 18, 24, 36, 48 56 Mb/s 802.11b 2.4 GHz 5.5 11 Mb/s

4.8.3 802.11 MAC CSMA/CD CSMA/CD

1ABCD A C B B

2 B A C D C D B A C D ADCB

CSMA/CA CSMA/CD CSMA CSMA Collision Avoidance 802.11 CSMA/CA CSMA/CA

802.11 MAC MAC BSS MAC DCF(Distributed Coordination Function)(CSMA/CA) PCF(Point Coordination Function)802.11b802.11aIEEE 802.11

802.11 MAC 802.11 MAC DCF CSMA PCF

IFS IFS (InterFrame Space)

SIFS(Short) 28 s SIFS ACK CTS MAC AP PCF AP

PIFS SIFS PCF PCF PIFS SIFS (slot) 50 s78 s

DIFS IFS DCF DIFS PIFS DIFS 128 s

SIFSPIFSDIFS 1 SIFSPIFSNAVDIFS ACKSIFS

CSMA/CA 802.11 MAC DIFS SIFS ACK ACK

(Virtual Carrier Sense) MAC

MAC NAV (Network Allocation Vector) NAV

DIFS 802.11

i 22 + i 1 8 ( 2 ) 2 16 ( 4 )

ACBDE A RTS (Request To Send)

CTSACBDECTS B CTS (Clear To Send) RTS CTS A CTS

ACBDECABCARTSCBCTSABCB

CTSACBDECTSDDARTSBCTSDBADABBAERTSCTSEDABE

BCARTSARTSACTSBCRTS

RTS CTS ACK DIFSRTSSIFSNAVRTSDIFSACK CTSSIFSSIFSNAVCTSNAV

P135 4-124-23