- noun a system of organising IP addresses that is more compact and efficient than the older system, adding a slash and a new IP prefix number that represents a number of individual addresses. For example the old system used an IP address such as ‘22.214.171.124’ whereas CIDR would replace this with ‘126.96.36.199/12’. The IP Prefix number 12 represents 4,096 unique addresses, and the lower the number the more addresses are represented.
- acronym forclassless inter-domain routing
- A technique in which routers group routes together so as to reduce the information carried by the core routers. Also spelled classless interdomain routing. Its abbreviation is CIDR.