Следует зарезервировать несколько больший диапазон, чтобы обеспечить добавление сайтов в будущем.
D.2.3 Большая локальная сеть
Наконец, предположим, что существует шесть больших локальных сетей. Мы хотим обеспечить соединение каждой из них с 500 хостами. Подойдет 7-битовая маска подсети (см. раздел D.1.1). Типичная 7-битовая подсеть содержит диапазон адресов, подобный следующим:
от 130.15.2.1 до 130.15.2.255
от 130.15.3.0 до 130.15.3.254
Если нужно 6 таких локальных сетей, можно применить 7-битовые маски к диапазону:
от 130.15.2.0 до 130.15.13.255
Лучше резервировать больший диапазон, чтобы учесть будущие потребности.
D.2.4 Резюме
Маски переменной длины поддерживают эффективное выделение IP-адресов. Первым шагом в их применении должен быть анализ сети и определение необходимых размеров. Затем выделяется диапазон номеров для использования с каждым размером маски. Полезно оставлять небольшие промежутки между диапазонами адресов, чтобы учесть будущее расширение сети.
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