CIDRnotaatiolla

CIDRnotaatiolla refers to a notation system used to express IP address blocks and routing prefixes, derived from Classless Inter-Domain Routing (CIDR). It combines an IP address with a prefix length to indicate which portion of the address defines the network. The standard form is an IP address followed by a slash and a number, such as 192.0.2.0/24 for IPv4 or 2001:db8::/32 for IPv6.

The prefix length specifies how many leading bits of the address are fixed as the network portion. In IPv4, a /24 indicates a network with 256 addresses, while longer prefixes yield smaller networks; in IPv6, a /64 is common and designates a large contiguous network. CIDRnotaatiolla enables route aggregation and more flexible allocation than older classful methods, reducing the size of routing tables and improving scalability across the Internet.

Usage spans multiple areas including internet routing, subnet planning, firewall rules, and access control lists. Network operators assign address blocks using CIDRnotaatiolla to optimize address space and routing efficiency, while network devices parse the notation to determine forwarding decisions or filter criteria.

Examples include 203.0.113.0/24 for a IPv4 subnet and 2001:db8:abcd:0012::/64 for an IPv6 subnet. The notation supports both fixed-length networks and variable-length subnet masks, enabling precise traffic control and scalable address management.

See also: CIDR, subnet mask, VLSM, route aggregation, IPv4, IPv6.