4.3 ?????FDDI

1
??? ???

• 4.1 ???????
• 4.2 ???
• 4.3 ?????FDDI
• 4.4 ?????
• 4.5 ?????
• 4.6 ??
• 4.7 ?????
• 4.8 ?????

2
4.1 ???????
3
IEEE 802??????

• 802.1??????????????????????
• 802.2????????LLC??
• 802.3??CSMA/CD??????????????
• 802.5????????????????????
• 802.11??WLAN??????????????
• 802.15??WPAN??????????????
• 802.16??WMAN??????????????
• 802.20??WWAN??????????????

4
4.2 ???

• 4.2.1 CSMA/CD??
• 4.2.2 ???
• 4.2.3 ?????
• 4.2.4 ?????
• 4.2.5 ????
• 4.2.6 ???????

5
Bob Metcalfe ??
6
???????

• University of Hawaii ?ALOHA ??(1968)
• Xerox ? 2.94M ???(1973)
• Xerox, DEC and Intel ? 10M ???(DIX ??)(1980
  Ver11982 Ver2 )
• IEEE 802.3 ?? (1985)
• IEEE 802.3u Fast Ethernet ??(1995)
• IEEE 802.3z/ab Gigabit Ethernet ??(1999)
• IEEE 802.3ae 10G Ethernet??(2002)
• 100G/40G(2010?)

7
4.2.1 CSMA/CD??

• ALOHA
• pure ALOHA
• slot ALOHA
• CSMA
• CSMA/CD
• ???
• CSMA/CA
• ?????

8
ALOHA??(1)

• ALOHA???70?????????Norman Abramson???????,????????
  ??????????????
• ALOHA????
• ?ALOHA
• ??ALOHA
• ????
• ???????,????????
• ??????????????????

9
ALOHA??(2)

• ?ALOHA
• Norman Abramson
• ????????
• ????????18(1/2e)
• ??ALOHA
• Roberts( 1972?)
• ????????
• ????????36(1/e)

10
CSMA??

• ?ALOHA???,??????????????????????????,????????????
• ????????????????,????????????,?????????????CSMA(Ca
  rrier Sense Multiple Access)???
• CSMA???????
• 1-??CSMA
• ???CSMA
• P??CSMA

11
CSMA/CD??

• ?????????,???
• (1)??????
• (2)??????,?????????????
• (3)?????,??????,????????,?????????????
• (4)???????????????,????????,??????????,????(1)

12
CSMA/CD????
13
????
14
??????????

• ????
• Collision Window 2 ??????
• ??????????
• ??10Mbps????,64Bytes???????51.2µs??
• ????????????2500m?????????4?Repeater???????51.2µs
  

15
?????????

• ????????k??????????(Ti)????i1???
• Ti r 51.2µs
• ??r random(0 2i-1)

16
4.2.2 ???
17
????????(1)

• ???( Preamble ) 7????10101010
• ??????????????
• ???10101011
• ?????????
• ????6??
• ????( Unicast Address )
• ????(Multicast Address)01005e
• ????(Broadcast Address)? 1

18
?????????(2)

• ??? 6??
• ????,????
• Cisco?00-00-0c, IBM? 08-00-5A
• ??/??(Type/Length )2??
• ?????
• IP,0x0800(????2048)
• ARP,0x0806(????2054)
• IEEE802.3??

19
?????????(3)

• Data(????)01500 Bytes
• PAD(????)046 Bytes
• ????????64??,
• CRC??? 32?
• ??????G(X)X32X26X23X22X16 X11X10 X8X7
  X5X4X2X1?
• ????????????????????PAD

20
4.2.3 ?????
21
4.2.4 ?????
22
4.2.5 ????
23
4.2.6 ???????
24
4.3 ?????FDDI

• 4.3.1 ????
• 4.3.2 FDDI

25
4.3.1 ????
26
??????

• ?????
• ???16Mbps
• ??
• ??????

27
4.3.2 FDDI
28
DAS
29
????
30
FDDI??

• ????
• ???100Mbps
• ??
• ????????

31
4.4 ?????

• 4.4.1 ?????
• 4.4.2 ??????
• 4.4.3 ??????
• 4.4.4 100G/40G???

32
4.4.1 ?????
33
?????

• ??FDDI???
• 100Base-TX
• 100Base-FX
• ??????4?3?UTP??????
• 100Base-T4
• ???????,????2?3?UTP
• 100Base-T2

34
??????????
35
?????????

• ??????
• ????
• 100Base-T,??Hub?Switch??????,????????

36
?????????
37
4.4.2 ??????
38
???????????
39
??????????

• ????
• ???

40
??????????
41
4.4.3 ??????

• ??/?????
• ????????
• ?????QoS
• ??OAM

42
???????????
43
??????????
44
4.4.4 40G/100G???

• 2007?7? ,IEEE 802.3ba
• 40G
• 1m?????
• 10m??
• 100m????
• 100G
• 10m??
• 100m????
• 10km?40km????

45
4.5 ?????

• 4.5.1 ????
• 4.5.2 ???
• 4.5.3 MAC??
• 4.5.4 ?????
• 4.5.5 ??

46
4.5.1 ????

• ??BSS
• ?AP?BSS
• ?????ESS

47
??BSS
48
?AP?BSS
49
?????ESS
50
4.5.2 ???
51
4.5.3 MAC??

• 1? CSMA/CA????
• 2? ?????????
• 3???DCF
• 4?PCF??
• 5??????
• 6?????
• 7????

52
1?CSMA/CA??

• CSMA/CA???????
• ????????????, ???????
• (1)??????,????IFS(InterFrame Space)??,????????????
  ?,???????
• (2)?????,????????????????????
• (3)????????,??????IFS??,???????,??????????,???????
  ??????????,?????

53
CSMA/CA???????
54
??DATA?????ACK?
55
????

• ?CSMA/CA???,????????????DIFS,?????????????????????
  ,?????????????????IFS,?????????
• ????????,?????(0,CWindow)???????????????,????????
  ????????,??????????
• ?????????????????????????????

56
??????
57
????

• ?????????CWindow????????????,????(?????DATA??????A
  CK?,??????????)?????????,????????

58
2??????
59
?????
60
3???DCF
61
Collision Avoidance RTS-CTS exchange
A
B
AP
defer
time
62
802.11 frame addressing
Address 4 used only in ad hoc mode
Address 1 MAC address of wireless host or AP to
receive this frame
Address 3 MAC address of router interface to
which AP is attached
Address 2 MAC address of wireless host or AP
transmitting this frame
63
802.11 frame addressing
H1
R1
64
???
65
4?PCF??
66
????

• ?????????
• ??????????AP?????(probe response)????
• ??????????AP,??AP????????(association request)?
• ???AP?????(association response)?????

67
5??????

• ??????????SIFS(Short IFS)??DCF?????,SIFS???????CTS
  ???ACK???????PCF?????,????????????AP?
• ???PIFS(PCF IFS)?PIFS??SIFS,PIFS?????AP???????????
  ?,???AP????????????????????,???????????PCF???
• ???DIFS(DCF IFS)?DIFS??PIFS,??DCF?????????????????
  ???

68
6?????

• ?802.11?,AP????????????????,??AP????????
• ???AP?????????????,AP?????????????????????,???????
  ?,??AP????????

69
7????
70
4.5.4 ?????
71
4.5.5 ??

• ????
• ??
• ????
• ????
• ??
• WEP
• WPA
• ???WAPI

72
4.6 ??

• 4.6.1 ????
• 4.6.2 ?????
• 4.6.3 ?????VLAN

73
??????

• ???(Repeator)
• ???(Hub)
• ??(Bridge)
• ???(LAN Switch)
• ???(Router)
• ??(Gateway)

74
??????
75
4.6.1 ????
76
???????

• ??(Flooding)????
• ??MAC??????????(Forwarding)
• ??(Discard)

77
B2????
78
4.6.2 ?????
79
STP????

• (1)??????????(Root Bridge)???????????????
• (2)??????????????????????????????????????????????
  , ????????????????
• (3)?????????????????????????????????????????????,
  ????????????????

80
BPDU??
81
BPDU??

• ???BPDU?,????????
• ?BPDU??BPDU?????????,??BPDU???????????
• ?BPDU??BPDU???????????,???BPDU????????????

82
STP??
83
STP?????

• ????(blocking)????????BPDU?
• ????(listening)????????BPDU,???????????
• ????(learning)???????????
• ????(forwarding)??????????

84
4.6.3 VLAN

• ??VLAN???
• ?????????
• ?????,????????
• ???????
• ??VLAN?????????

85
???????????3?VLAN
86
VLAN??

• ????
• ??MAC??

87
??VLAN????

• VTP??
• ?VTP???,????????Server,Client ?Transparent

88
802.1Q
89
4.7 ?????

• ??????
• ??????

90
4.7.1 ??????
91
4.7.2 ??????
92
????
93
4.8 ?????

• ?????RPR(Resilient Packet Ring)?????????????????SD
  H?ATM??????????????????

94
??

• 5?6?8?9?10?11?12?18?19?24?26