Сетевой уровень

1. Сетевой уровень

Занятие шестое
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2.

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3. Назначение сетевого уровня

The Network layer, or OSI Layer 3, provides services to
exchange the individual pieces of data over the network
between identified end devices. To accomplish this end-to-end
transport, Layer 3 uses four basic processes:
• Addressing
• Encapsulation
• Routing
• Decapsulation
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4. IPv4

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5. Формат пакета IPv4

Protocol: 01 ICMP; 06 TCP; 17 UDP
Длина пакета: 20-65535 байт.
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6. Иерархия IPv4

Формы записи маски: префиксная - /24,
десятичная - 255.255.255.0
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7. Кому узел может направить сообщение?

127.0.0.1
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8. Назначение шлюза по - умолчанию

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9. Маршрутизация

Маршрутизация – это способ направления сообщений по
различным сетям, посредством которого устройства доставляют
сообщения получателям.
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10. Понятие маршрутизации

The router will do one of three
things with the packet:
• Forward it to the next-hop
router
• Forward it to the destination
host
• Drop it
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11. Таблица маршрутизации (show ip route)

Destination network
Next-hop
Metric
Admin distance
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12. Таблица маршрутизации

Административная дистанция
Метрика
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13. Таблица маршрутизации для узлов

netstat -r
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14. Настройка маршрута по-умолчанию

Router1>enable
Router1# config terminal
Router1(config) #ip route 0.0.0.0 0.0.0.0 192.168.2.2
....
Router1#show ip route
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15. Статическая маршрутизация

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16. Динамическая маршрутизация

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17.

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