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.

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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 .