IPv4 address
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... routing, although it must be stressed that
routability is in no way guaranteed with the allocation or
assignment of IPv4 addresses.
...
... 5. Due to the requirement to increase the utilization efficiency
of IPv4 address space, all assignments are made with the
assumption that sites make use of variable length subnet mask
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... classfull technologies for the purposes of administrative
convenience is generally insupportable due to the limited
availability of free IPv4 address space.
6. Regional registries ...
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7. Due to constraints on the available free pool of IPv4 address
space, the use of static IP address assignments (e.g., one
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... addressing may
ease some aspects of administration, the current rate of
consumption of the remaining unassigned IPv4 address space does
not permit the assignment of addresses for administrative ease.
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... registry to inform the organization
that the addresses have been returned to the free pool of IPv4
address space.
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