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ModemsUSB Ethernet modems
USB modems USB modem /, USB
Driver modem. Drivers
modem .
Ethernet modems
Ethernet modem /,
/.
mo ems outers t ernet
)
Ethernet /.
USB /, / ADSL , Ethernet modems ADSL .
USB / ADSL , Ethernet / ADSL .
USB modems
, Ethernet .
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Hardware
Hub
LAN
Gateways
LAN WAN
Router
Ip Internet
Modem
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Hardware
.
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LAN, WAN, MAN
LAN (Local Area Network)
.
LAN Ethernet.
WAN Wi e Area Networ
. WAN LAN.
MAN (Metropolitan Area Network)
.
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LAN
Ethernet Switch .
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.
Client - Server
Peer to Peer
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Internet IP
IP Internet.
Internet
( web browser).
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IPInternet Protocol Address
IP (Internet Protocol Address)
Internet.
,
IP ,
.
, IP
Internet .
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IPs IPs
IP (routers), ( ), (LAN - Local Area Network).
IP (PCs) .
(PCs)
IP
Internet.
IPs
IP
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IPs IP
IP ( 0 255) .
.
M 255.
255.
IP :
256*256*256*256=4.294.967.296
256 0 255 256.
32bit IPv4 0.0.0.0. 255.255.255.255. IPv6 128 bit.
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IPsIP Subnet Mask
network address host address ( ).
network address host address.
subnet mask IP:
..CCC.DDD
, . 143.233.91.9, 255.255.255.000 143.233.91.9/24.
24 network address 24 bits.
Subnet . .
, subnet mask "" .
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IPsPrivate & Public
IP
IP.
IP
.
TCP/IP LAN ,
.
IP :
10.0.0.0 10.255.255.255 172.16.0.0 172.31.255.255
192.168.0.0 192.168.255.255
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IPsStatic
IP
IP, .
IP
Internet.
IP;
Internet,
Internet .
web server ( ) o mail server ( e-
mail ).
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IPsDynamic
Ip
IP Internet IP.
IP Internet , .
IP :
ISPs IP Internet (.. dialup).
IP , .
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DNS
Domain Name System
Hostnames IP.
.
DNS .
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Noise Margin
Noise Margin dB.
(signal -
data ) (noise).
S/N (Signal/Noise).
6 dB .
12 .
- S/N 30dB
1000 .
12db ADSL
15,85 .
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Attenuation
Line attenuation dB.
( ) .
60-65 dB.
- attenuation (downstream) 10dB
DSLAM 90%
DSLAM 10%.
60db ADSL
1 DSLAM .