KM Auditoriski Vezbi 1

:

vs.

, ,

20142 -

-- .

(connectivity)

20143 -

:

:

20144 -

--point-to-point

multiple access

(switches) - (routers)

:

:

20145 -

. . .

(Bus) (full mesh)

S

(Star) (Ring) (Tree)

2014 - 6

:

:

: , , ,

: , , ,

Internet

= : , : ,

: :

> => !

:

20148 -

2014 - 9

R = (bps)

L = (bits)

a =

= La/R

La/R ~ 0:

La/R 1:

La/R > 1: , !

-

2014 - 10

(circuit switching)

(packet switching) ( )

(switching)

2014 - 11

(a) Circuit

switching

(b) Message

switching

(c) Packet

switching

? : vs.

:

201412 -

Hi

Hi

Got thetime?2:00

TCP connectionreq.

TCP connectionreply.

time

Get http://www.rpi.edu/index.htm

:

:

201413 -

(service) :

peer -to- peer :

201414 -

service interface

peer interface

Li+1 Li+1

LiLi

peer-to-peer

-- (end-to-end)

ISO OSI

201415 -

Application

Presentation

Session

Transport

Network

Datalink

Physical

Application

Presentation

Session

Transport

Network

Datalink

Physical

Network

Datalink

Physical

Physical medium

201416 -

Application

Presentation

Session

Transport

Network

Datalink

Physical

Application

Transport

Internetwork

Host to

Network

FTP

TCP

IP

Ethernet

Telnet HTTP

UDP

Packet

Radio

Point-to-

Point

TCP/IP Protocols OSI Ref ModelTCP/IP Model

?

201417 -

Telnet FTP NFS

Packet

radio

Coaxial

cable

Fiber

optic

Application

Transmission

Media

HTTP

(FTP File Transfer Protocol, NFS Network File Transfer, HTTP World Wide Web protocol)

Telnet FTP NFS

Packet

radio

Coaxial

cableFiber

optic

Application

Transmission

Media

HTTP

Intermediate

Layer (IP)

: --. . , .

:

2014 - 18

,

:

applicationtransportnetwork

linkphysical


linkphysical application

transportnetwork

linkphysical


linkphysical

networklink

physical

data

data

data

transport

ack

:

201419 -


linkphysical


linkphysical


linkphysical


linkphysical

networklink

physical

data

data

:

(header) ( )

,

201420 -

application

transport

network

linkphysical

application

transport

network

linkphysical

source destination

M

M

M

M

HtHtHnHtHnHl

M

M

M

M

HtHtHnHtHnHl

message

segment

datagram

frame

MM

:

201421 -

100%

1000%

10000%

100000%

1996 1998 2000 2002

Relative preformance increaseDWDM Link speed

x2/8 months

Router capacityx2.2/18 months

DRAM access rate x1.1/18 m

Internetx2/yr

Huge mismatches in technology trends (eg: DWDM

vs DRAM) must be planned for modular designs!

Moores lawx2/18 m

1

2014 - 22

?

, :

1. , , .

2. .

1

201423 -

n . . h . ( )?

2

201424 -

(1) ( + ) (2).

(1): n * h ( h

n)

(2):

M . , n*h ( 1).

nh / ( + nh).

:

201425 -

1024x768 3 /. . 56kbps ? 1Mbps ? 10Mbps ? 100Mbps ?

3

201426 -

Q = 1024 768 3 2,359,296 , 18,874,368 .

D , D = Q / t => t = Q / D.

56,000 bits/sec, 337.042 .

1,000,000 bits/sec, 18.874 .

10,000,000 bits/sec, 1.887 .

100,000,000 bits/sec, 0.189 .

201427 -

100 , . , TDM (Time Division Multiplexing) FDM (Frequency Division Multiplexing) ?

: . , . .. TDM .

, 100 , FDM. .

4

2014 - 28

?

.

, .

5

2014 - 29

x- k . s , d , p , b . ?

6

2014 - 30

t = s

t = s + x/b

t = s + x/b + kd

t = x/b

t = x/b + (k - 1)p/b + kd

s < (k - 1)p/b

2014 - 31

3 () . 7 . 18km/h. ( ) 150Mbps?

7

2014 - 32

: Dmin = 150 Mbps

n = 3

q = 7GB

V = 18 km/h

: Smin = ?

: t = Q / D, S = V * t, Q = n * q.

: S = V * t = V * (Q / D) = V * (n * q / D) < V * (n * q / Dmin)

S < 5.6km

2014 - 33

B . , n . . h , t . , B ?

8

2014 - 34

: Q0 = M B

D0 = B Bps

H0 = T0 = 0

Qn = M B

Hn = (n * h) B; Tn = (n * t) B

: Dn = ?

: t = t0 = Q0 / D0 = tn = (Qn + Hn + Tn ) / Dn

: Dn = (Qn + Hn + Tn ) / Q0 * D0 = B * (M + nh + nt ) / M

2014 - 35

http://www.youtube.com/watch?v=Ve7_4ot-Dzs

Warriors of the net

2014 - 36

Documents

KM Auditoriski Vezbi 1