What is TCP/IP ?

1. ? 1

1-1 1

1-2. 2

2. 3

2-1. 3

2-1-1. 3

2-1-2. 5

2-1-3. 11

2-1-4. 18

2-2. 20

2-2-1. Signaling 20

2-2-2. 22

2-2-3. (TOPOLOGY) 27

2-2-4. 31

2-3. 32

2-3-1. (Twisted Pair) 32

2-3-2. TP (TP cable) 32

2-3-3. (Coaxial cable) 33

2-3-4. (Fiber Optics) 35

2-4. 37

2-4-1. (SDM : Space division Multiplexing) 37

2-4-2. (FDM : Frequency Division Multiplexing) 37

2-4-3. (TDM : Time Division Multiplexing) 37

2-4-4. (STDM : Statistical Time Division Multiplexing) 37

2-5. 38

2-5-1. CSMA/CD 38

2-5-2. TOKEN PASSING 39

2-6. LAN 41

2-6-1. EtherNet 41

2-6-2. Fast EtherNet 43

2-6-3. Gigabit EtherNet 45

2-6-4. Token Ring 47

2-6-5. FDDI (Fiber Distributed Data Interface) 48

2-6-6. VLAN (Virtual LAN) 50

2-7. Switching 55

2-7-1. (Circuit Switching) 57

2-7-2. (Packet Switching) 59

3. 62

3-1. 62

3-1-2. 62

3-1-3. 63

3-2. 64

3-2-1. (fragmentation packetization and reassembly) 64

3-2-2. (encapsulation) 64

3-2-3. (connection control) 65

3-2-4. (flow control) 65

3-2-5. (error control) 65

3-2-6. (synchronization) 65

3-2-7. (sequence) 65

3-2-8. (addressing) 65

3-2-9. (multiplexing) 66

3-2-10 66

3-3. 67

3-3-1. / (direct/indirect) 67

3-3-2. / (monolithic/structured) 68

3-3-3. / (symmetric/asymmetric) 68

4. OSI 7 70

4-1. OSI 7 (OSI 7 Layer) 70

4-2. Layer 1 - Physical Layer 74

4-3. Layer 2 - Data Link Layer 76

4-3-1. EtherNet 81

4-3-2. Ehernet MAC 81

4-3-3. Ethernet 84

4-4. Layer 3,4 - Network, Transport Layer 89

4-4-1. Layer 3 - Transport Layer 90

4-4-2. Layer 4 - Transport Layer 99

4-5. Layer 5,6,7 - Session, Presentation, Application Layer 103

5. Internetworking 104

5-1. Internetworking ? 104

5-2 104

5-2-1 104

5-2-2. 106

5-3. 108

5-3-1. (REPEATER) 108

5-3-2. (BRIDGE) 109

5-3-3. (HUB) 111

5-3-4. (SWITCHING HUB) 112

5-3-5 (ROUTER) 113

5-3-6. RAS 115

5-3-7. DCE 115

5-4. 116

5-4-1. RIP 116

5-4-2. OSPF 116

5-4-3. HDLCSDLC 1175-4-4. BGP 117

5-4-5. LAP-DB 1195-4-6. IGRPEIGRP 120

5-5. 121

5-5-1. (GateWay) 121

5-5-2. 122

What is NetWork ?

1. ?

1-1

.

.

.... ( ), e-Mail, , , ,

NFS PC copy .

. , ...

.

.

' ' . .

? .

. .

.

.

.

SUN "Network is computer. Computer is network."

.

, ' '

.

.

What is NetWork ?

1-2.

, , .

.

.

.

(Back Bone) .

.

.

.

.

.

.

.

.

What is NetWork ?

2.

2-1.

.

.

.

2-1-1.

.

.

, node, link, station . node

, link .

station Teminal . Teminal , FAX

.

FDDI ? Fiber Distributed Data Interface.

100Mbps LAN .

What is NetWork ?

, ,

.

.

, , , .

. ,

Cable LAN

. LAN

,

. , , , ,

. LAN twisted pair

cable ,

(logical channel)

. ,

What is NetWork ?

2-1-2.

(Terminal)

communication .

TTY Mode Termianl

Intelligent Terminal .

(DTE : Data Teminal Equipment)

CCITT( ),EIA( ), ISO(

) . (DCE : Data Circuit Terminating

Equipment) ,

.

25pin, 37/9pin 15pin

.

, , .

. FAX TV .

DSU .

(DTE : Data Terminal Equipment) .

, , , , .

What is NetWork ?

( , )

.

.

, HDLC

DCE .

Terminal

1.

( , ) 2 (

) ,

2.

Terminal .

.

(CCU:Communication Control Unit) .

, ETB(End of Transmisson

Block), EXT(End of Text)

,

.

What is NetWork ?

(Terminal Interface)

(1)

(DTE) (interface) .

(Protocol) . DTE/DCE

DTE/DCE

.

. 56Kbps Modem . v.90

56Kbps 3Com X2 Roackwell

K56Flex . 56Kbps Modem

.

.

ISO(International Organization for Standardization:

) ITU-T(International Telecommunication Union: ) .

(2) DTE/DCE

DTE/DCE Interface( ) DTE(Date Terminal Equipment)

DCE(Data Circuit Terminating Equipment)

Protocal

.

DTE (CCU:Communication Control Unit)

. 2

.

Modem DSU . Modem DSU

CCITT (DCE) .

DTE DCE

DTE/DCE .

,

.

What is NetWork ?

(1) CCITT (Consultative Comittee on International Telegaphy and Telephony)

CCITT 1959 ITU( :International Telecommunication

Union) . CCITT

.

, , , , , .

(2) ISO (International Standard Organization)

ISO 1947 80 . ISO 150

,

. TC(Technical Committee)97

TC97 15 SC(Sub-Committee) . SC

SC6 SC6 3

.

(3) EIA(Electronic Industries Association)

EIA 1924 RMA(Radio Manufacture Association) EIA

. TR-30(Data Transmission)

. TR-30 2 TR-30.1 ,

TR-30.2 .TR-30 1962 RS-232

.

(4) FTSC (Federal Telecommunication Standards Committee)

FTSC ,

CCITT,ISO , FTSC

.

(FED-STD-1005,FED-STD-1006 )

FIPS

.

(5)Bell System

Bell .

Bell

.

CCITT CCITT

X V .

What is NetWork ?

A CCITT

B

C

D

E ,

F

G,H,J

M.N

O

P

Q

R1,R2

R,S,T,U

V

K,L

X

Z

[CCITT ]

V.1 2

V.2

V.3 CCITT No.5

V.4 7

V.5

(600,1200,2400,9600bps )

V.6

(600,1200,2400,3600,9600bps )

V.15

V.20

V.22 ( ) 1200bps

V.22BIS 1200bps

V.23 600/1200

V.24

V.25

V.26 4 2400bps

V.26BIS 2400/1200bps

V.27 4800bps

V.27BIS 4800bps

V.27TER 4800/2400bps

What is NetWork ?

V.29 9600bps

V.35 60-108kHZ 48kbps

V.36 60-108kHZ 48kbps

V.37 60-108kHZ 72kbps

V.41

V.50

[CCITT V ]

X.1

X.2

X.3 ,

X.4 CCITT No.5

X.20 DTE,DCE

X.20BIS V.21 DTE,DCE

X.21 DTE DCE

X.21BIS V DTE PDN

X.24 DTE DCE

X.25 DCE DTE

X.28 PDN DTE/DCE

X.29 DTE PAD

X.40 (Primary group)

X.50

[CCITT X ]

What is NetWork ?

2-1-3.

.

. .

.

4 ? 6

. 5 10

. ,

.

. 1

.

( , )

( )

.

.

(Circuit Switching)

.

(SDM : Space division Multiplexing)

.

SDM (Space division Multiplexing)

What is NetWork ?

(TDM : Time Division Multiplexing)

(Multiplexor) .

Time Switch Time Switch

Time Slot . .

TDM (Time Division Multiplexing

.

. PCM

.

.

.

( ) DSU(Digital Service Unit)

. X.21 DTE, DCE .

(Packet Switching)

1960

( )

. 1960

. ARPA

. ARPA

.

.

What is NetWork ?

. , .

.

Packet Switching

A B . A B

, .

. , .

(store and forward)

B .

B

. B

. B .

, ,

,

.

Virtual Circuit( ) .

.

.

.

. Datagram(

) .

. ,

.

.

.

What is NetWork ?

, deadlock .

8 - 16 .

.

.

,

What is NetWork ?

, .

,

, (Packet Switch)

(Packet MultipleXer:PMX) .

.

(Packet mode Terminal) ,

. (None Packet mode Terminal)

, .

, .

( ) .

(TDM: Time Division Multiplex) (STDM:

Statistic Time Division Multiplex) . TDM

STDM

.

TDM

TDM

TDM

( ) . ,

. 64Kbps 4 TDM

.

64kbps 4 256kps

What is NetWork ?

64kbps . TDM

. .

.

.

TDM . TDM

(Time Slot)

. TDM

. , TDM

.

STDM

STDM TDM

.

STDM

STDM 4

9.6Kbps 128Kbps . STDM

. STDM

. STDM

. STDM .

STDM . , STDM

Queueing STDM

. STDM

What is NetWork ?

. STDM

. STDM , Queuing

.

. STDM 128Kbps .

What is NetWork ?

2-1-4.

. ( ,

) PCM .

.

.

2 . .

, , .

0 carrier 1 carrier .

0 1

. 0 1 .

2 , 4 , 8 .

0 1

. NRZ. ,

.

? +V, -V .

AMI(Alternate Mark Inversion) .

0 0 [V] 1 +[V] -[V]

. .

What is NetWork ?

(1)

. 128

-256 , (BCC) .

polling selectiing system contention syetem .

=> => => .

(2) HDLC

HDLC High level Data Link Control procedure ,

ATM, ISDN

. HDLC

. HDLC CRC(Cyclic Redundancy Check code)

check . .

.

.

.

.

,

, DSU, CSU

.

.

. PCM ,

SDNS MUX MX13 . PCM 56Kbps

. SDNS MUX HSM (High

Speed Modem) 128K ~ 768Kbps

. MX13 PCM SDNS MUX T1/E1

T1/E1 Screen Cable .

Screen Cable O/R (Optical Repeater)

P-O/R , HDSL (High bit rate Digital Subscriber

Line) .

What is NetWork ?

2-2.

2-2-1. Signaling

Broadband

TV ,

(FDM:Frequency Division Multiplex)

, . (Coaxial Cable)

(Fiber Cable) .

TV .

,

.

.

.

BaseBand

LAN .

(FDM:Frequency Division Multiplex)

, (TDM:Time Divisional Multiplexing) .

(Attenuation )

.

Table 2.1

What is NetWork ?

ps., Data Channel

.

. Twisted Pairs,

, , Bandwidth .

.

.

Bandwidth 10310MHZ

300MHZ Bandwidth Twisted Pairs 1 2MHZ

Bandwidth . GHZ Bandwidth .

Bandwidth

. Bandwidth

. bps(bit per

second) . 1.54Mbit .

1.54Mbps Bandwidth .

Bandwidth .

What is NetWork ?

2-2-2.

Peer To Peer

Peer-to-Peer 2.1

. ,

. Peer to Peer Client Server

, ,

.

. Peer-to-Peer

, .

Client/Server .

Client/Server

.

Figure 2.1 Peer to Peer Network

What is NetWork ?

Peer to Peer 1.

Lan Card

NIC(Network Interface Card) NIU(Network Interface Unit) .

. LAN

, LAN ,

. (ISA, EISA,

PCI, PCMCIA ), (AUI, TP, BNC ) ( , )

. .

Peer to Peer 2.

HUB

(HUB) , (Repeter)

. .

.

.

(AUI, BNC, TP ) , TP(Twisted Pair)

. 10Base-T, 100Base-Tx, 100Base-Fx 100VG-AnyLAN

. SNMP(Simple Network Management Protocol) (Dummy)

(Intelligent) , (Stackable)

. , (Switching) .

What is NetWork ?

Peer to Peer 3.

UTP

UPT (Pair)

. LAN EIA/TIA-568 . USOC(Universal Service Order

Codes) RJ-45/RJ-11 . USOC Bell Operation Company

FCC .

(FCC Part 68, Subpart F, Section 68502) USOC

EIA/TIA-568

.

4 (2Pair) .

LAN 8 (4Pair)

. EIA/TIA-568

RJ-45 . UTP

.

Peer to Peer 3.

UTP RJ-45

. RJ-45 UTP ,

RJ-45 UTP .

What is NetWork ?

Client/Server

(Server) ' ' .

PC

, . Lan Client Server .

Figure 2.2 Client / Server

Client/Server

.

(terminal) .

, . (Dummy),

(Intelligent) .

2.2

LAN .

.

Client/Server .

, DB(Data Base), .

. , PC

, PC .

What is NetWork ?

Host Terminal

, ,

Client/Server

.

.

CPU , . Telnet hitel

PC

.

What is NetWork ?

2-2-3. (TOPOLOGY)

. Point-to-Point Star Ring .

.

.

.

Figure 2.3

Star Topology

,

Point-to-Point .

,

. ,

,

. , (Star) 2.4

(Concentrator) (Point-to-Point)

, (Station) .

, .

Figure 2.4 Star Topology

What is NetWork ?

Bus Topology

(Bus) 2-5

. , , ,

. (Backbone)

. T Point-to-Point ,

(Adapter) (Terminator)

. (Baseband) ,

, Bus Topology

, ,

.

, CSMA/CD . .

Figure 2.4 BUS Topology

What is NetWork ?

Ring Topology

(Ring) . 2.5

, ,

. FDDI(Fiber Distributed Data Interface)

. FDDI 1987 ANSI X3T9.5 .

,

LAN .

,

. Point-to-Point .

, .

.

. (Checking) (Recovery) ,

FDDI(Fiber Data Distributed Interface) .

Figure 2.5 Ring Topology

What is NetWork ?

Tree Topology

.

.

Figure 2.6 Tree Topology

What is NetWork ?

2-2-4.

LAN(Local Area Network)

LAN ,

. LAN

(Point-to-point) . LAN(Local Area Network)

,

.

. .

ps., LAN 1973 5 22 , PARC(Palo Alto Research Center) Computer

Science Dr. Robert M. Metcalfe (Ethernet) .

, Metcalfe 'DARPA(Defense

Advanced Research Projects Agency)' ,

'ALOHA NET' . .

MAN (Metropolitan Area Network)

MAN(Metropolitan Area Network) LAN LAN

LAN , MAN

LAN .

MAN . LAN

, WAN .

WAN (Wide Area Network)

WAN(Wide Area Network) , , ( )

. LAN MAN . WAN

.

VAN (Value Added Network)

VAN WAN, MAN

.

What is NetWork ?

2-3.

,

Bounded, Unbounded . Unbounded

, Bounded .

2-3-1. (Twisted Pair)

Twisted Pair

.

.

, .

.

. (1-10Mbps) ,

. PC .

2-3-2. TP (TP cable)

2.7 TP . TP

, UTP(Unshielded Twisted Pair)

STP(Shielded Twisted Pair) . 100M ,

(Category) 1 5

. 10Base-T 100Base-Tx .

, TP

. TP , STP .

Figure 2.7 The Structure of TP Cable

What is NetWork ?

3( CAT.3 CAT3 ) 10M , 5

100M . 6 , 5

. 2-2 . TP

.

Table 2.2 The Character of Category

3( CAT.3 CAT3 ) 10M , 5

100M . 6 , 5

. TP

.

2-3-3. (Coaxial cable)

,

, ,

. , LAN

.

500hm 750hm .

Ethernet 50hm . Baseband Broadband

3/8 , 1/2 . Baseband LAN

10-12Mbit .

Thick Thin . Thin

. 10Base-2 . Thick Thin

. 10Base-5

. 2.8 .

What is NetWork ?

Figure 2.8 Coaxial Cable

10Base-2 5 , , ,

. BNC

, T ,

(Terminator) .( 2.9 ) 10Base-2 200M

.

Figure 2.9 The Connection of Coaxial Cable

10Base-5 , 10Base-T 2

, (Transceiver) .

, AUI . AUI

.( 2.10 ) 10Base-5 500M .

Figure 2.10 The Connection of AUI Cable

What is NetWork ?

ps., ,

. . BNC

, T , T

. , BNC ,

. .

2-3-4. (Fiber Optics)

,

.

.

LED

.

.

, .

, .

.

. ,

. (3.3GHZ)

, . 1Gbit ,

1 1 . ,

.

,

. . 2.11

, 2.12 .

, 2Km, 20Km

.( , ATM 622M )

.

Figure 2.11 The Structure of Optical Cable

What is NetWork ?

Figure 2.12 The Structure of Connector

Table 2.3 .

Table 2.3 Cable Specification

What is NetWork ?

2-4.

2-4-1. (SDM : Space division Multiplexing)

. SDM

.

2-4-2. (FDM : Frequency Division Multiplexing)

Bandwidth

Sub-Channel .

Baseband Signal

(Carrier Signal)

.

2-4-3. (TDM : Time Division Multiplexing)

,

. FDM

TDM

. TDM

.

2-4-4.

(STDM : Statistical Time Division Multiplexing)

Channel Allocation TDM

.

. Port

TDM .

. TDM TDM STDM

ATM .

What is NetWork ?

2-5.

2-5-1. CSMA/CD

. Carrier Sense

.

.

Multiple Access .

Collision Detection .

CSMA/CD LAN ' ' .

CSMA

,

. IEEE 802.3 .

.(Carrier Sensing )

, . .

(Multiple Access )

.(Collision Detection)

.

Figure 2.13 CSMA / CD

What is NetWork ?

CSMA / CD

. .

. .

CSMA/CD

1980 2 IEEE(IEEE : Isntitute of Electrical and Electronics Engineers,

) 802 LAN . IEEE 802 ANSI(American National Standards Institute, )

, LAN

.

2-5-2. TOKEN PASSING

,

.

.

1. Token Ring

(Token Ring) LAN

.

, IEEE 802.5 .

.

Token Ring

. .

.

What is NetWork ?

Token Ring

. .

CSMA/CD . . .

Figure 2.14 Token Ring

2. Token bus

(Token Bus) LAN ,

. , (Dummy)

,

.

Token Bus

. . .

Token Bus

. CSMA/CD .

.

What is NetWork ?

2-6. LAN

2-6-1. EtherNet

Ethernet Contention LAN .

1970 CSMA/CD . CSMA/CD

1980 IEEE IEEE802.3

. LAN .

,

. .

10Mbps .

(10Base-5) . .

.

UTP .

.

EtherNet

IEEE 3 .

10Base-FL . .

10Base-5 500m . Thick 2.5m

.

10Base-2 Thin 200m .

10Base-T UTP , 100m .

EtherNet

CSMA/CD . (Node)

. (Broadcast)

. ,

What is NetWork ?

. CSMA/CD

.

. CSMA/CD

, .

.

UTP 10Mbps

. (Concentrator) . 10Mbps

. 100Mbps . 100Mbps

.

.

. (Dedicate) ,

. . ,

" " .

.

,

.

1518Byte 64Byte .

What is NetWork ?

2-6-2. Fast EtherNet

. MPEG 1.5Mbps .

MPEG-II 6Mbps .

10Mbps ,

. , 10Mbps

100Mbps . UTP

. LAN ,

100Mbps . 2.4 2.5 100M LAN

.

Table 2.4

Table 2.5

What is NetWork ?

100Mbps

. CSMA/CD

. IEEE 802.3 .

10 .

10Base-T 5 UTP .

, , , IBM, , SVC

.

LAN .

, , SVC,

.

Figure 2.15 The Architecture of Fast EtherNet

,

(Virtual pipe) . ,

,

.

.

.

100Mbps

.

What is NetWork ?

2-6-3. Gigabit EtherNet

10Mbps 1000Mbps .

.

. UTP .

ATM .

,

. 2.6 , ,

.

Table 2.6

(Gigabit Ethernet) 1000Mbps

10/100

(Fast Ethernet) 2-3 10 . ,

100

.

LAN .

802.3(CSMA/CD) 802.3

, IP, IPX,

.

, .

CSMA/CD(Carrier Sense Multiple Access/Collision Detection)

(full duplex)

.

( ) . (UTP) 99 .

What is NetWork ?

Figure 2.16 The Architecture of Gigabit EtherNet

, , ,

.

NIC(Network Interface Card) 100Mbps

,

.

10 15% 40 50%

.

What is NetWork ?

2-6-4. Token Ring

Token Ring IBM , 4-16Mbps

DATA ,

. 2-5-2 ..

What is NetWork ?

2-6-5. FDDI (Fiber Distributed Data Interface)

FDDI 100Mbps passing LAN

.

FDDI(Fiber Distributed Digital Interfaces Networks) 1980 ANSI

LAN Token Ring 10

100Mbps 200Km .

Ethernet 10Mbps N/W .

Bandwidth ANSI , , ATM LAN

LAN FDDI

Figure 2.17 The Architecture of FDDI

FDDI fiber( ) Dual Ring( ) .

FDDI Ring SMT(Station ManagemenT)

SMT FDDI Ring Link Backup ring

. FDDI Ethernet

MTU . FDDI 100Mb/s Token-passing,

Dual-ring LAN . Dual Ring Architectur data Ring

Ring . FDDI

. Single Mode Multi Mode . Single

Laser , Multi LED . , Laser

.

What is NetWork ?

Figure 2.18 The Architecture of FDDI

What is NetWork ?

2-6-6. VLAN (Virtual LAN)

(VLAN : Virtual LAN) LAN

LAN . LAN

.

2.19 A B

. A

B .

Figure 2.19 The Architecture of Virtual Lan

.

.

,

. , , FDDI

, .

,

.

,

, .

,

.

.

What is NetWork ?

.

, ,

, . 2.19

, ,

.

Figure 2.19 The Congestion of Network

,

. 2.20 ,

, .

, 2.21

, 3 .

.

.

Figure 2.20 The bottleneck between Router

What is NetWork ?

Figure 2.21 The avoid of bottleneck between Router

4 .

.

(Polysy-based) .

, .

. A , B

.

.

. ( 2.22 ) Port

,

. ,

.

Figure 2.22 The Port-Based Virtual LAN

What is NetWork ?

MAC MAC MAC

. MAC

. ( 2-23 ) MAC

, .

Figure 2.23 The MAC-Based Virtual LAN

(TCP/IP, IPX/SPX, Netbeui )

. ( 2.24)

,

.

.

Figure 2.24 The Protocol-Based Virtual LAN

What is NetWork ?

IP IPX

, IP . ( 2.25 )

, .

.

.

3 .

Figure 2.25 The Network-Based Virtual LAN

What is NetWork ?

2-7. Switching

(Circuit

Switching) (Packet Switching) .

LAN 95 10

.

. .

LAN LAN

.

.

95 LAN .

. (dedicated-bandwidth)

(switched) LAN

.

LAN

. 10Mbps

PC 10Mbps .

, , . LAN

.

(circuit) . (packet)

LAN ,

, FDDI LAN . (cell) ATM

LAN WAN .

Figure 2.26 The Model of Switched Network

What is NetWork ?

.

LAN .

(virtual) LAN .

LAN 3 (IP)

.

.

What is NetWork ?

2-7-1. (Circuit Switching)

.

.

, . ,

.

,

. CODE, FPORMAT, SPEED, PROTOCOL ,

Station - .

' '(PSTN:Public-Switched Telephone Network; ) .

1:1

.

PSDN(Public-Switched Data Network)

.

1:1

.

Circuit Switching Network .

Figure 2.27 The Circuit Switching Concept

A C A ,

C B, D, E, F .

' ...' B, D, E, F

.

'Closed Circuit' .

What is NetWork ?

.

, A C ,

.

,

. , B, D, E, F

.

Circuit Switching Null-Modem . PC

Null-Modem , DOS FX

NC Link, 95 .

What is NetWork ?

2-7-2. (Packet Switching)

.

IDLE TIME .

.

.

.

(Store and

Forward) .

IEEE LAN ' ' ' '

. circuit switched network

.

.

Figure 2.28 The Packet Switching Concept

A C B D

?

.

packet

What is NetWork ?

. , ,

, .

A F 0 A

1 B 2 C A 0, 6, 12, 18, 24, 30, 36,

42, 48, 54 . TDMA(Time Division Multiple

Access) . .

A C 100 10

1 circuit switching 10

(A ).

Figure 2.29 Packet Segmentation

packet switching network A 6

(9 6) + 1 = 55 .

Figure 2.30 Data transfer time

5.5

. A

.

A F

.

( A F )

(DTE:Data Terminal Equipment) ,

What is NetWork ?

access control 'Random Access' 'Token'

.

Random access ALOHA, CSMA/CD .

random access CSMA/CD .

Token token ring, token bus .

: ( ) . bps(bit per second) 100bps 100 . Mbps .

Mbps

64kbps .

: .

. 64kbps

.

64kbps ADSL 64kbps

(ADC) . Mbps

.

LAN : Local Area Network . , WAN

.

WAN : Wide Area Network. LAN LAN . DTE : (terminal) .

, , DTE .

ALOHA , ALOHA 1970 random

access (

). center .

DTE .

DTE DTE

DTE

.

ALOHA 100 10

.

What is NetWork ?

3.

.

(communication protocol ) .

.

3-1.

.

. ,XXX ? , , YYY .. .

,

. .

,

. ,

.

3-1-2.

.

, 1970 .

ARRPA (Advanced Research Project Agency )

.

,

.

. ARPA

, CCITT

X.25 . X.25

,

.

.

What is NetWork ?

.

3-1-3.

-

.

.

.

.

.

.

.

CCITT ISO (

)

.

.

(OSI: Open System Interconnection) . OSI

.

What is NetWork ?

3-2.

,

.

3-2-1. (fragmentation packetization and reassembly)

,

.

(PDU : Protocol Data Unit) .

3-2-2. (encapsulation)

PDU . 3 .

: . : : .

Figure 3.1 Segmentation and Reassembly

Figure 3.2 Capsulation

What is NetWork ?

3-2-3. (connection control)

(connection establishment)

, (data transfer), (connection termination) 3

.

3-2-4. (flow control)

. / PDU

(ACK) .

ACK .

3-2-5. (error control)

PDU .

3-2-6. (synchronization)

2

. , , , 2

.

3-2-7. (sequence)

. , ,

.

3-2-8. (addressing)

, ,

.

What is NetWork ?

3-2-9. (multiplexing)

.

1:1 ,

(upward multiplexing) (downward multiplexing ) .

,

.

, ,

.

3-2-10

.

(priority): : (security) :

What is NetWork ?

3-3.

/ / /

.

3-3-1. / (direct/indirect)

.

(a) (point to point)

. (b) (multi point)

(a) . (a)

(b)

.

Figure 3.3 The Classification of Protocol

(c)

. (d)

catinet .

What is NetWork ?

3-3-2. / (monolithic/structured)

,

.

HDLC

.

,

.

,

.

.

OSI .

3-3-3. / (symmetric/asymmetric)

,

.

.

Figure 3.4 Each Protocol Layer

.

What is NetWork ?

.

.

What is NetWork ?

4. OSI 7

, ? OS

. ( )

. 95 ' '

,

. FTP, .

, ,

.

ISO(International Standards Organization) OSI(Open Systems

Interconnection) 7 Layer Reference Model .

4-1. OSI 7 (OSI 7 Layer)

1977 1983 .

IBM SNA DEC

DECNet .

OSI 7

.

.

OSI 7 .

7

Application Layer WWW, Telnet, NetBIOS,

FTPPresentation Layer

Session Layer

Tranport Layer TCP/IP

Network Layer

Data Link Layer

Physical Layer

Figure 4.1 OSI 7 Layers

What is NetWork ?

.

7 : Application Layer .

.

6 : Presentation Layer

.

5 : Session Layer . .

4 : Transport Layer .

.

3 : Network Layer

.

2 : Data Link Layer .

.

1 : Physical Layer .

7 , ,

. 1,2 3,4 ,

5,6,7 .

OS . DOS

OS OS

NOS(Network OS) . 3 NOS UNIX,

NetWare, Windows .

What is NetWork ?

ISO 7 ,

. 7

WAN TCP/IP

. , 1 2 Ethernet , 3 4

TCP/IP, NetBuei, IPX .

OSI 7 (OSI )

IEEE1394 . 5,6,7

' ' . Telnet, FTP, e-mail (SMTP, POP), News

(NNTP), NetBIOS .

LAN 1, 2 .

.

What is NetWork ?

OSI 7

OSI 7 Layer .

,

.

SendingApplication Layer (Layer 7) .

Presentation Layer (Layer 6) .

Session Layer (Layer 5) .

Transport Layer (Layer 4) ,

.

Network Layer (Layer 3) .

Data Link Layer (Layer 2) ,

.

Physical Layer (Layer 1) , ,

.

ReceivingPhysical Layer (Layer 1) , ,

.

Data Link Layer (Layer 2) .

Network Layer (Layer 3) .

Transport Layer (Layer 4) .

Session Layer (Layer 5) .

Presentation Layer (Layer 6) .

.

Application Layer (Layer 7) .

What is NetWork ?

4-2. Layer 1 - Physical Layer

.

.

. 10/90

10% 90% .

,

.

10Mbps (Ethernet) .

( )

( ) 1Mbps .

.

100Mbps .

.

(twisted pair line) . TP

.

. TP UTP(Unshielded TP)

STP(Shielded TP) TP STP UTP

. UTP 10Mbps , 100Mbps

.

Figure 4.2 , ,

.

.

0% .

.

What is NetWork ?

.

.( 2Mbps

)

1 RS-232 . RS-232 15m

9600bps 1 +3V , 0 -3V

. 12V . PC COM1 COM4

RS-232C . Ethernet 0V

-2V .

1 . ' (

)' . RS-232 1 1 (point-to-point) .

( ) .

.

Figure 4.3 a) Point to Point, b) BUS, c) Star, d) Ring

What is NetWork ?

4-3. Layer 2 - Data Link Layer

.

.

(

).

. , , .

(Transfer Control)

(asynchronous) (synchronous)

. ' '

, . PC

COM1-COM4 . ABC ABC

ASCII 41h, 42h, 43h . 414243h

414243h 2 10000001 10000010 10000011 .

.

.

.

(Asynchronous)

.

1 . ( 0) . . , ( 1) .

What is NetWork ?

.

9600 [bps] .. 1 over 9600 = 104 sec .

1 0 0

104 + 52(sampling ) = 156 sec 104 sec 8

, .

,

. 8MB

1MB .

, ,

. PC PC

. PC

PC .

(Synchronous)

' ' .

. , , .

.

.

. 1 01 0 10

1 0 0 1 (transition)

.

What is NetWork ?

DPLL(Digital Phase Locked Loop)

.

64

1518 . (Frame) (

). 10101010 7 10101011

.

.

, .

.

What is NetWork ?

(Error Control)

' ' .

. .

, 8 1

. A

(ascii code) 100 0001 0 100 0001 .

127 7

8 . vi, mail

7 .

1

. 1

. A 101 0001

0 101 0001 . 1 3

. 1

. ,

.

( , ).

9600 bps 104 sec ,

. (burst error)

( ) .

CRC(Cyclic Redundancy Check)

. PC CRC .

CRC

polynomial generator (CRC-16 1 1000 0000

0000 0101) -2 . CRC-16

16 .

.

CRC polynomial generator

. CRC

FCS(Frame Check Sequence) .

What is NetWork ?

(Flow Control)

. ( )

. 1 1

DTE

.

. ,

.

Ack .

Xon/Xoff .

(Multiple Access Control)

(Multiple Access Control) .

, , , DTE

. DTE

.

'Random Access' 'Token' Random Access

CSMA/CD .

What is NetWork ?

4-3-1. EtherNet

OSI 7 1, 2 LAN . IEEE 802.3

. 1, 2 2

LLC(Link Layer Contorl) MAC(Medium Access Contorl) . LLC

MAC . 2 MAC

.

MAU .

Figure 4.4 EtherNet

4-3-2. Ehernet MAC

MAC , ,

, .

.

64 1518 octet

Preamble

SFD

DA

SA

FCS

7 octet 1 octet 6 octet 6 octet 46 1500 octet 4octet

SFD : Start Frame Delimiter DA : Destination Address

SA : Source Address FCS : Frame Check Sequence

1 . (CSMA/CD

What is NetWork ?

.

10101010 7 ,

) ( , 10101011

, , .)

. 6 , 48 ,

. FCS 32 G(X) CRC

FCS CRC . , IEEE

. , MAC 24

, 24 .

00-20-AF-21-3C-80 00:20:AF:21:3C:80 24

. 3COM 00-60-8C, 00-20-AF, 00-A0-24

. 00-AA-00 .

. CRC .

2

.

. DA

CRC .

MAC . Random Access

CSMA/CD . MAC .

. . . (JAM) 32 .

. 16 .

.

.

.

.

SFD . , . , .

CRC . .

What is NetWork ?

,

.

Figure 4.5

What is NetWork ?

4-3-3. Ethernet

10Base2, 10Base5, 10BaseT . 10

Mbps 2 200m( 185m), 5 500m

. T Twited UTP .

10Base5 10Base2 10Base5 10Base2 .

.

10Base5 . 50

10Base2 Thick ( ).

Yellow .

.

Figure 4.6 10Base5

10Base5 ( 1cm

) .

10Base2 50 185m .

(10Base5 ) . 10Base2

Thin . BNC ( BNC

) . .

What is NetWork ?

Figure 4.7 10Base2

Thick Net Thin Net 50 ( )

.

. 1 0V, 0 -2.05V .

Thin Net 185m

, .

. ,

. .

.

.

10Base5 10Base2 2 , 3 .

.

.

round trip delay

.

.

What is NetWork ?

10BaseT

10BaseT . UTP

RJ-45 . STP TP

.

Figure 4.8 10BaseT

.

DTE PC

10BaseT .

100m . 4 ( ), 5 .

Figure 4.9 Hub 10BaseT

What is NetWork ?

...

1,2 ,

. .

, .

.

. CSMA/CD (

)

.

,

. FDDI .

1,2 .

XDSL, .

Modulator/DeModulator

. , TDMA

. 8000 , 8

24 .

.

24 1 ,

?

1 8000 , 8 8 8000 = 64000

8000 64000 24 + 8000 = 1544000,

1.544 [Mbps] .

1.544 [Mbps] ? T1

. .

.

, 64Kbps , T1 6 , 12

7 56kbps . 56kbps

.

, 56kbps .

, ADSL, HDSL ? DSL

What is NetWork ?

. .

DSL AD

. 1Mbps

AD DA

. , .

64Kbps

.

. TV

.

What is NetWork ?

4-4. Layer 3,4 - Network, Transport Layer

OSI 7 1, 2 . , 3~7

1, 2 MAC

. .

1,2

. .

10BaseT ,

. MAC

. ,

, fp

. 3, 4 .

,

. , 2

. ,

3 . , 2 , 3, 4

.

.

' ' . ' ' .

'

' ( ).

, . ,

.

3

.

(routing) . 3

. QoS(Quality of Service)

, .

, .

4 . 3

5 .

WinSock , .

4 .

3, 4 3, 4 TCP/IP

NetBEUI .

What is NetWork ?

4-4-1. Layer 3 - Transport Layer

IP(Internet Protocol) TCP/IP 3, 4 . ARPA

.

TCP/IP suite . TCP 4 , IP 3 . IP

.

IP

IP IP

. IP MAC

.( , )

IP 32 1 .

(netro.ajou.ac.kr)

11001010000111100000101110111011

10

2 11001010 00011110 00001011 10111011

16 CA. 1E. 0B. BB

10 202. 30. 11. 187

202.30.11.187 .

A , B , C

. A , C

.

1 8 9 16 17 24 25 32

A0 ID ID

0.H.H.H

127.H.H.H

B1 0 ID ID

128.N.H.H

191.N.H.H

C1 1 0 ID

ID

192.N.N.H

233.N.N.H

D1 1 1 0

234.0.0.0

239.255.255.255

Figure 4.10 IP Class

What is NetWork ?

4.10 ID , ID

. 0 . DTE

, IP IP

.

.

A 7 ID 24 ID

. B 14 ID 16 ID , C

21 ID 8 ID . A ARPANET

C . IP 192 233

C .

0 1 . 0

1

.

D MBONE

. ,

.

10000 B

. LG B 150.150.X.X

. 2 65536 .

10000 20 100

( ) .

. ID

.

IP 32 IP 1

ID ID , 0 ID .

150.150.50.214 255.255.255.0 /

IP AND .

IP150. 150. 50. 214

10010110 10010110 00110010 11010110

11111111 11111111 11111111 00000000

, 150. 150. 50. 0

What is NetWork ?

, C 127 ,

? .

255.255.255.128 128 IP .

IP

( ) . IP

IP .

, ?

.

202.30.11.187 C 255.255.255.0

. 202.30.11.187 202.30.11.44

202.30.0.11 .

.

.

IP . AND

.

202.30.11.187

1 1 0 0 1 0 1 0 0 0 0 1 1 1 1 0 0 0 0 0 1 0 1 1 1 0 1 1 1 0 1 1

AND

255.255.255.0

1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0

202.30.11.0

1 1 0 0 1 0 1 0 0 0 0 1 1 1 1 0 0 0 0 0 1 0 1 1 0 0 0 0 0 0 0 0

.

202.30.11.44 .

202.30.11.44

1 1 0 0 1 0 1 0 0 0 0 1 1 1 1 0 0 0 0 0 1 0 1 1 0 0 1 0 1 1 0 0

AND

255.255.255.0

1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0

202.30.11.0

1 1 0 0 1 0 1 0 0 0 0 1 1 1 1 0 0 0 0 0 1 0 1 1 0 0 0 0 0 0 0 0

' ' ' '

. 202.30.0.11

What is NetWork ?

202.30.0.11

1 1 0 0 1 0 1 0 0 0 0 1 1 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 1 1

AND

255.255.255.0

1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0

202.30.0.0

1 1 0 0 1 0 1 0 0 0 0 1 1 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

' ' 202.30.11.0 202.30.0.0

.

What is NetWork ?

IP

IP . IP

NIC(Network Information Center) . InterNIC IP

, - ,

. - NIC(APNIC) NIC

KRNIC . www.krnic.net .

KRNIC (ISP) IP ISP

. ISP IP IP

. ,

. ID

.

IP . .. PC

? winipcfg TCP/IP

. ' ' .

Figure 4.11 winipcfg

What is NetWork ?

IP .

? IP .

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

ID

D M

(TTL:Time To Live)

IP

IP

(65,546 )

Figure 4.12 IP Datagram

IP .

IP . 4 0100 .

6(IPV6 ) .

ISO QoS

. .

TTL . 8

256 .

.

1 1 1

IP 255 .

What is NetWork ?

, .

.

, .

4

4

3

3

2

2

1 1

Figure 4.13

,

. 4

.

.

RIP(Routing

Information Protocol) .

?

.

202.30.X.X 202.30.11.X 202.30.0.X

. 202.30.X.X 202.30.11.X

202.30.11.2 202.30.0.X 202.30.0.4 .

.

Figure 4.14

What is NetWork ?

202.30.11.187 202.30.11.44 202.30.0.11

.

?

. tracert ,

traceroute .

202.30.11.187 . 202.30.11.187 Netro

Linux telnet login traceroute . 150.150.50.214

.

Figure 4.15 traceroute

202.30.11.2 .

202.30.0.1 165.133.249.137 .

PC 202.30.11.187 tracert .

What is NetWork ?

Figure 4.16 tracert

134.75.68.2 202.30.0.4 202.30.11.187 .

tracert .

. KIX

. KRNIC

.

ARP(Address Resolution Protocol)

IP 3 ARP . IP SA DA

, MAC

. IP MAC ARP .

ARP

ARP .

What is NetWork ?

4-4-2. Layer 4 - Transport Layer

4 ' ' . IP

.

. .

. .

.

(connection-oriented)

(connectionless) .

. . TCP/IP

TCP UDP .

.

Figure 4.17 TCP and UDP Protocol

What is NetWork ?

TCP(Transmission Control Protocol) TCP Reliable Stream Service .

. ,

.

TCP

. IP IP .

,

.

TCP

TCP .

. TCP code

.

.

.

Open Listen . Open

Listen . TCP

Ack(acknowledge)

. Ack TCP (time out)

. time out

.

TCP ,

. . TCP

,

.

.

What is NetWork ?

TCP

TCP PDU(Protocol Data Unit)

. .

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

Ack

URG

Figure 4.18 TCP Segment (PDU)

TCP .

.

.

4.17 .

WWW 8080 . .

. Ack

. .

UDP(User Datagram Protocol)

UDP .

, , .

.

? , TCP

- .

, TCP

.

UDP .

What is NetWork ?

TCP/IP, ARP, UDP 3,4 . 3,4

.

- SLIP/PPP

1 1 ( , , )

IP . IP

SLIP(Serial Line Interface Protocol) PPP(Point to Point Protocol) .

SLIP .

. PPP TCP .

- NetBIOS/NetBEUI

DOS DOS BIOS Call .

BIOS Call

. IBM

NetBIOS .

. OSI 4, 5 .

IBM NetBIOS Extended User Interface NetBEUI

. NetBIOS int 2Fh API , NetBEUI

.

NetBIOS/NetBEUI Microsoft Enterprise Network ,

. , ' '

. 95 NT

NetBIOS .

. (UDP

). . TCP/IP 1.2

1.5 .

NetBEUI TCP/IP IPX NetBIOS . TCP/IP

NetBEUI NT 95 NetBEUI ,

TCP/IP .

- DLC(Data Link Control)

DLC IEEE802.2

. JetDirect HP

.

What is NetWork ?

4-5. Layer 5,6,7 - Session, Presentation, Application Layer

5,6,7

4 . 5,6 7

.

5

. ,

.

.

. .

.

C

16 , 32 .

.

. ( ) .

. telnet, FTP, SMTP, POP,

SNMP, WWW ' ' ' ' .

What is NetWork ?

5. Internetworking

5-1. Internetworking ?

(Internetworking)

. , LAN WAN .

,

. ,

, , .

.

(Repeater), (Bridge), (Router),

(Gateway) , . [

5.1] 4 OSI 7 .

,

.

.

Figure 5.1

5-2

5-2-1

.

. ,

What is NetWork ?

. .

5.4 ,

.

LAN LAN WAN .

LAN ,

, LAN .

, LAN

. LAN

" " .

, .

, .

" " .

.

,

.

.

.

.

Figure 5.2 ISDN

What is NetWork ?

,

.

,

.

, [ 5.2] ISDN

.

5-2-2.

5-2-1 ,

. 5-4

.

. ,

TCP/IP . IPX

, .

.

TCP/IP 'IP (Routing) '

.

(Forwarding) (Filtering) ,

. LAN , ,

3 ,

, .

LAN LAN

, .

. ,

. 3

, ,

.

.

LAN

(Destination) (Source)

, .

What is NetWork ?

.

3 ,

.

.

,

,

. ,

, ,

LAN .

(Bridging) LAN ,

.

[ 5.5] .

What is NetWork ?

5-3.

5-3-1. (REPEATER)

,

.

. ,

.

, ,

.

.

1 ,

, . ,

.

2 . 0.5

4 . 4

.([ 5.3] , [ 5.4]

OSI .)

Figure 5.3

Figure 5.4 OSI

What is NetWork ?

5-3-2. (BRIDGE)

,

, .

. , ,

.

, 2 .

, .

(Local) (Remote) ,

LAN , LAN LAN

WAN , LAN

. .

, .

, ([ 5.5]

, [ 5.6] OSI ).

Figure 5.5 Bridge

What is NetWork ?

Figure 5.6 Bridge OSI

What is NetWork ?

5-3-3. (HUB)

HUB . HUB

LAN

.

Dummy HUB ( )

SNMP(Simple Network Management Protocol)

Management Intelligent HUB .

LAN . LAN

. .(

CSMA/CD )

. HUB

.

LAN (Dedicated Medium Switching)

Switching HUB ( LAN Switch)

, Dedicate .

.

Figure 5.8 8

SH-1200M HUB

What is NetWork ?

5-3-4. (SWITCHING HUB)

,

.

LAN

.

.

Figure 5.9

Cisco Catalyst5000

What is NetWork ?

5-3-5 (ROUTER)

LAN WAN LAN

.

,

LAN , LAN WAN

, ,

. 3 .

, .

.

. (Static Routing)

(Dynamic Routing)

.

,

. (Brouter)

,

, .

.([ 5-10] OSI

, [ 5.11] 2501

Rustle 4501 .)

Figure 5.10

What is NetWork ?

Figure 5.11 Cisco 2501 Router, Rustle Router

Figure 5.12 Cisco 2501 Router

What is NetWork ?

5-3-6. RAS

RAS Remote Access Server Remote Access System ,

. RAS ,

RAS (Terminal Server)

(Communication Server) . RAS WAN

LAN . PC '

' ISP , ISP

RAS .

RAS PPP , , X.25, ISDN BRI PRI,

ATM, DS-3 PSTN WAN

.

. RAS

, RAS

, . ,

LAN . [ 5.13]

.

Figure 5.13

5-3-7. DCE

DCE WAN ,

WAN ,

.

DCE (MODEM)

DSU(Digital Service Unit), CSU(Channel Service Unit), HSM(High Speed Modem),

FDSU(Fractional DSU) . DSU 56/64Kbps , CSU

T1/E1 , FDSU HSM 768Kbps .

What is NetWork ?

5-4.

5-4-1. RIP

RIP(Routing Information Protocol) Distance-Vector

1980 . RIP (Hop) 15

, 15 .

. RIP

15 ,

.

RIP

. RIP 30

. 30

. RIP VLSM(Variable Length

Subnet Mask) . RIP

. RIP RIP Version II

. RIP II VLSM

RIP

. RIP IP IPX

, IPX RIP .

5-4-2. OSPF

OSPF(Open Shortest Path First) Link-State

. OSPF (Area) .

, . IP

. 1 ,

2 ( 0.0.0.0)

. .

OSPF RIP .

RIP . OSPF

(Path Cost) .

. '1' , '10'

. OSPF

.

OSPF VLSM ,

. . OSPF Version 1

What is NetWork ?

Version 2 Version 2 ,

OSPF .

5-4-3. HDLCSDLC

HDLC(High-level Data Link Control) ISO 1974

, , X.25

LAPB(Link Access Procedure, Balanced) ISDN

LAPD(Link Access Procedure, D-Channel) .

, .

SDLC(Synchronous Data Link Control) HDLC

, IBM .

HDLC , , ,

. ,

16 FCS(Frame Check

Sequence) .

.

, HDLC

.

HDLC , " HDLC" . SDLC

.

SDLC SDLC ' (Station)' .(

.) HDLC , ,

, SDLC .

, ,

. .

. .

.

5-4-4. BGP

BGP(Border Gateway Protocol) RFC 1105

, EGP(Exterior Gateway Protocol)

.

, BGP EGP . BGP

AS(Autonomous System) BGP

, AS BGP ,

What is NetWork ?

BGP AS AS

.

BGP ,

, . , BPG

, .

TCP .

BGP RIP (Distance Vector) ,

, AS

, (Counting to Infinity)

. BGP .

AS ?

AS Autonomous System , " "

. , " " "

" .

ISP(Internet Service Provider)

. ISP

.

ISP

. AS .

AS , ( , , ) ,

. AS

AS ,

EGP , IGP(Interior Gateway Protocol)

. IGP RIP OSPF , EGP BGP .

What is NetWork ?

5-4-5. LAP-DB

LAPD LAPB ISDN X.25 , HDLC

. ,

,

D .

LAPD , 2

.

. D (throughput)

,

D .

LAP 2 X.25 LAPB 2

, ' '(SAPI : Service Access Point Identifier), '

'(TEI : Terminal Endpoint Identifier) 2

. SAPI ,

, TEI

. 2 SAPI TEI , '

'(DLCI : Data Link Connection Identifier) .(

DLCI .)

LAPB Point-to-Point

LAPD . Point-to-Mutipoint

, .

Point-to-Point Point-to-Multipoint

. TEI '1' .

What is NetWork ?

5-4-6. IGRPEIGRP

IGRP(Interior Gateway Routing Protocol) EIGRP(Enhanced IGRP) (Cisco)

,

. RIP IGRP .

, , , . IGRP

(Load Balancing) . EIGRP IGRP

.

IGRP ' ' .

IGRP , . 'Opcode'

, . '1' (Update) , '2' (Request)

. ,

' ', 'Opcode', 'AS Number' .

(Entry) . , IP

1,500 .

' '(Edition)

.

. 'AS Number' . AS

. AS AS .

' ' ' (Major) ', '

(External) ' . IGRP

, , AS , AS .

IGRP ' (Checksum)' .

. 7

. ' ' 3 ,

(Metric) 5 , 5 ' '(Delay), ' '

, MTU( ) 'MTU' ,

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.

What is NetWork ?

5-5.

5-5-1. (GateWay)

(Gateway)

, OSI 7 .

. IBM SNA(System Network Architecture) X.25

.

,

.([ 5.14] )

Figure 5.14 GateWay

What is NetWork ?

5-5-2.

LAN

. LAN

, ,

. (Switching)

(Dedicated) LAN 3 ,

, LAN .

(KALPANA) LAN

, .

,

.

LAN LAN

, LAN ,

2 .

( MAC address) ,

, ,

.

. ,

, .

[ 5.15] " "

.

. ,

(Back-plan) ,

.

, LAN . ,

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3 4 .

LAN .

What is NetWork ?

Figure 5.15 LAN

3 3

3 . 3 IP

. IP 3

. .

. . , . (Cut-through),

,

.(Store & Forward)

What is NetWork ?

(Cut-through) ,

.

,

. , ,

, .

,

. ,

,

, .

, (Congestion)

. ,

(Store & Forward) .

What is NetWork ?

. ,

.

, ,

, , ,

.

,

. [ 5.16] LAN

. [ 5.17] [ 5-1]

.

,

.

Figure 5.16 , LAN

Figure 5.17 ,

What is NetWork ?

5.1 ,

What is NetWork ?

2 3

2 MAC 2

. , MAC

.

2 3 , .

2 MAC

. ,

, MAC

. LAN

LAN ,

.

2

. , ,

.

2 .

3 3 IP, IPX 3 .

2 , 3

IP ,

. IP 3

.

3 , IP 3

, .

RIP, OSPF IP/IPX

, IP/IPX .

, 3 . 3

, .

IP ,

. 3 .

3 .

3 . ,

2 .

3

. ,

3 .