km auditoriski vezbi 1
DESCRIPTION
KM Auditoriski Vezbi 1TRANSCRIPT
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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
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?
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
applicationtransportnetwork
linkphysical application
transportnetwork
linkphysical
applicationtransportnetwork
linkphysical
networklink
physical
data
data
data
transport
ack
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:
201419 -
applicationtransportnetwork
linkphysical
applicationtransportnetwork
linkphysical
applicationtransportnetwork
linkphysical
applicationtransportnetwork
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
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:
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
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1
2014 - 22
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?
, :
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
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: 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
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B . , n . . h , t . , B ?
8
2014 - 34
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: 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
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http://www.youtube.com/watch?v=Ve7_4ot-Dzs
Warriors of the net
2014 - 36