Classless Inter-Domain Routing
<networking> (CIDR) /sid*r/ A technique that summarises a block of
Internet addresses in a routing table as an address in dotted decimal notation
followed by a forward slash and a two-digit decimal number giving the number of
leading one bits in the subnet mask. For example, 123.123.123.0/24 specifies a
subnet mask of 11111111.11111111.11111111.00000000 (binary), implying the block
of addresses 123.123.123.0 through 123.123.123.255.
CIDR is "classless" because it is not limited to the subnet masks specified by
Internet address classes A, B and C.
According to RFC 1519, CIDR was implemented to distribute Internet address space
more efficiently and to provide a mechanism for IP route aggregation. This in
turn reduces the number of entries in IP routing tables, enabling faster, more
efficient routing, e.g. using routing protocols such as OSPF. CIDR is supported
by BGP4.
See also RFC 1467, RFC 1518, RFC 1520.
(2006-01-26)
Nearby terms:
Classic-Ada « classical logic « Classic C «
Classless Inter-Domain Routing » class library »
class method » Class Oriented Ring Associated
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