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CIDR 的用处

tag-icon • tag-icon networking routing ip-address
CIDR 的用处

可能重复：
什么是有类寻址？

多年来，我听说过“CIDR”这个词，但从未认真思考过它。今天早上，我仔细阅读了维基百科文章读完之后我明白了 CIDR 实际上只是一种用于网络（或在网络上）生成 IP 地址的算法。

这是公平的评价吗？还是我错过了大局？它还有其他主要用途吗？

提前致谢！

答案1

除了在互联网上的主要用途外，它的另一个主要用途是划分大型企业网络的私有 IP 地址范围

RFC1519说

Classless Inter-Domain Routing (CIDR):
         an Address Assignment and Aggregation Strategy

1.  Problem, Goal, and Motivation

   As the Internet has evolved and grown over in recent years, it has
   become evident that it is soon to face several serious scaling
   problems. These include:

      1.   Exhaustion of the class B network address space. One
           fundamental cause of this problem is the lack of a network
           class of a size which is appropriate for mid-sized
           organization; class C, with a maximum of 254 host
           addresses, is too small, while class B, which allows up to
           65534 addresses, is too large for most organizations.

      2.   Growth of routing tables in Internet routers beyond the
           ability of current software, hardware, and people to
           effectively manage.

      3.   Eventual exhaustion of the 32-bit IP address space.

   It has become clear that the first two of these problems are likely
   to become critical within the next one to three years.  This memo
   attempts to deal with these problems by proposing a mechanism to slow
   the growth of the routing table and the need for allocating new IP
   network numbers. It does not attempt to solve the third problem,
   which is of a more long-term nature, but instead endeavors to ease
   enough of the short to mid-term difficulties to allow the Internet to
   continue to function efficiently while progress is made on a longer-
   term solution.

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