(IEEE) Is the obvious answer ; no harshness meant in any way
Answer:
Classless Inter-Domain Routing
Explanation:
Classless Inter-Domain Routing (CIDR), pronounced “cider” or “sidder,” gets its name from the notion that it ignores the traditional A, B, and C class designations for IPv4 addresses and sets the network-host ID boundary wherever it wants to, in a way that simplifies routing across the resulting IP address spaces.