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OSI



 LAN

MAN 10

^km

WAN









1_ Local Area Network

_ Metropolitans Area Network _ Switch

_ Wide Area Network _ Client Server _ Server

7_ Link _ Medium

_ Guided – Unguided _ Node

_ Packet 11 _ Cell











 ISO

ISO/OSI IBM

SNA

DARPA TCP/IP





_ header - trailer

_ Topology _internetworking

_ Host _ protocol _ Architecture

_ Flow control

8_ Segmentation & Reassembling







OSI Open System Interconnection

Layer Function

7. Application

Allows user interaction and generation of data to be transmitted. Programs communicate with other programs at this level so it includes file transfers and transactions.

6.Presentation

Manages the way data is formatted or encoded for transfer. It may place data in an ASCII or EBCDIC format.

5. Session Oversees dialogue between users. Establishes and oversees logical relationships set up between users.

4. Transport

Maintains quality of communication. Acts as the traffic cop making sure flow is orderly. Ensures message validity and integrity.

3. Network Establishes a communication route between devices on different local networks.

2. Data Link

Puts messages together out of the stream of bits coming in and out of the wire or other media. It also governs data flow.

1. Physical The medium that carries data.

OSI

TCP/IP Transmission Control Protocol / Internet Protocol

DARPA

ARPANET

Telnet FTP

SMTP

SNMP , DNS

HTTP, NNTP

OSI TCP

UDP

_ Domain

_ Transportation Control Protocol _ User Datagram Protocol

IP IP

IP

ATM

ATM ATM

BISDN

ATM

AT&T , CNET ATM

CCITT ATM

ATM

ISDN 2 ATM

ISDN (N-

ISDN) (B-ISDN)

ATM B-ISDN

ISDN ISDN

ATM

B D

D B ۀ B

PRI B

D

ISDN

ISDN ATM

ATM STM

N-ISDN STM

ATM

ATM

S(t)

B(t) )}

( {

)}

( ) max{

( E S t

t t S

B 

B

32 100-1

10-1 15-5/1 150-15

ۀ

2-1

STM ATM

ۀ

ATM

ATM

OSI ATM

ATM

ATM AAL

ATM

SONET

AAL OSI

ATM

ۀ

BW1

BW2

BW3<BW1+BW2

●

●

●

●

●

●

●

1_ISI: Inter Symbol Interference

N dB Log S SNR 

HZ KHZ

HZ

KHZ

HZ HZ

SNR

m

m M 

M Log B C   B

) N / S ( BLog

C  

C B

S/N

Transmisson Media

Shield

bps

C C Kbps

64

Crosstalk

LAN Mbps

Mbps CATV

FDM

Mbps

T , T , FT , FT

Mbps T

T

T T

T

T

kbps FT T DS-O

DS-O .

64  N

T N=12

T , FT Yankee Group

T

44.736 Mbps T

FT T

●

●

●

●

1-Geostationary orbit

…

k C

MAN

GHZ

GHZ

●

●

●

T GHZ , T

NBI

1_Mainframe

●

●

● SCADA

●

●

●

MHZ MHZ

MHZ MHZ

Yagi dB

● FDM

1ATM(Automatic Teller Machine)

KHZ KHZ

● WDM

FDM

FDM

● TDM

1Time slot

DS T

4000 2 4000HZ

T

₁

T T

Switching

circuit switch

(packet switching)

o

o o o

o o o (virtual circuit switching)

ISDN

o o o

1_Campus Area Network

o

o

Data Link layer

●

●

●

●

Connectionless

Connection Oriented

Connection Req.

Disconnection Req.

DLE ETX , STX

DLE

FEC ARQ



k r

r n 2

ⁿ

2

^k

h

min

d h

min

d c

h

min

Overhead Data n

n-k k

c

h r

n

r

h

min

CRC

n K k

/n h

min

BCH

 ARQ

Stop & Wait

Sliding Window

N GO back N

ACK

ACK time out

ACK

ACK

t

frame

(bps) capacity

) ( Channel

bit Size Frame t

_frame



t

prop

speed n

propagatio ce t

_prop

dis tan



t

proc

T=2 t

prop

+ t

frame

+ 2 t

proc

t

frame

frame prop proc

t a t a t

U



 

 0

1 2

1

a

LAN MB

Mbps

b

sec /  m U

km sec

/  m

Kpbs U

w

w

w w=2

ⁿ

N ACK

ACK

ACK ACK

n

ACK

ACK

w

ACK ACK

P











 

 

 ATM

CER ۀ CLR

CIR CER

CLR CIR

FEC FEC

ARQ ATM

ARQ

ATM

5µs/Km

ۀ CCITT

SG-XVIII

ATM

LAN

LAN IEEE 802

LAN

LAN

Topology LAN

_ Bus

_ Ring _ Star _ Tree

.

Multipiont

token

terminator

MAN DQDB , FDDI

Token

HUB

Media Access Control

MAC

IEEE 802 LAN

[CSMA/CD , P-CSMA , 1-CSMA] ,

CSMA , Slotted ALOHA , ALOHA

ALOHA

ALOHA

ACK ACK

S



 Q

! ) ] (

[ K

e k G

P

G K r









k k P

r

[k]





2t

frame

S G









G S

ALOHA

P

_o





CSMA Carrier Sense Multiple Access

CS t

prop

LAN ACK

ALOHA

CSMA

CSMA

t

^frame

t

^frame

CSMA P

CSMA P

1-P

P P

 n



CSMA/CD CSMA

Detect

Collision

N N d

d d



N N

OR

N Log d

d



2

%

100

CSMA

Datagram

Bellman-Ford

Dijkestra

ATM

ATM UNI NNI

(a ATM

(b ATM

S T TA

UNI ۀ NNI

ۀ

ATM DQDB

ATM (GFC) 2

VPI3 VCI4

ATM

ATM

CAC2

(VP) VC

ۀ

CLP 3

ATM ۀ

PT ۀ

RES HEC

ATM

) (  )

( 

C(bps)





 c



 c

 c



 c

 

D.G. Kendall C,B,A

A/B/C

A

 G

B G

M D

C M/M/2

 t )

t ( o t  

  )

t ( o 

 t

 t )

t ( o t   



 

k

T



^



 



^

T T

) K ( KP )

K ( E

K





 

^





   

 T









^











































^





^



 



 





M/M/1 )

t t ( P

_n

 

t n t  



^{(1 )(1 ) . ( )}



⁽⁾



^{(1 ) ( )}



⁽⁾



^{(1 ( )) 0( )}



) ( )

(t t p t t t t t o t p ₁ t t t o t P ₁ t t t t

p_n   _n 



 



 







    _n



 



    _n



 



  

 t ))

t ( o ( 



t



 t )

(

o

) ( )

( ) ( ) ) (

(

1

1

t p t

p t dt p

t dp

n n

n

n

     



 



n







 ) p p

_

p

_

x

(  

_n



_n



_n

n

 n



S

2

n

p p

p p ) ( p p

p

_n



_n



_n



ⁿ



ⁿ



 











p



^





n

p

n

0 1

1 lim

_

1

_



 

 p

_{n n}





^







0

0

1

n

p 

n

 1

 p

p  

 1



 p

ρ ρ<1



 

n )

1 ( 

 



ⁿ

p

n

p p   p p







 

 

 

^



p

np p )

n ( E

n n

p



 



 



 



 

P

B

P

B

) P ( 

_B



 )

P ( 

 







 

 









_

( P ) P N

P P ) P P (

) P ( ) P

(

_N ^N

N B



B



 



P ) P P (

) p ( ) p p

(

_N ^N

N

 



 





_{ }





P k

p

k











 



 



 



 

_N^N_^ _N^N_{ N}^N_

P

) P . (

P ) P P ( P

P P

 













 















 

 ) 1 (

) ) (

( T E

n T E

E