5.role of CIDR notation in routing and how it helps the kernel make decisions

Let's say the host wants to send something on an ip address "10.23.2.132" which matches both the rules in a routing table, the default route and 10.23.2.0/24. Here, the kernel chooses the longest destination prefix that matches. This is where CIDR notation comes handy 10.23.2.0/24 matches and its prefix is 24 bits long. 0.0.0.0/0 i.e. the default address also matches but since the prefix length is 0 hence 10.23.2.0/24 takes priority.

CIDR (Classless Inter-Domain Routing) is crucial for modern network routing. It lets networks use flexible, varied-length prefixes instead of fixed "classes."

When your computer sends a packet the kernel looks at its routing table. If there are multiple ways to reach that address CIDR helps the kernel decide.

It uses the Longest Prefix Match (LPM) the kernel picks the route with the most matching bits. This ensures your data takes the most precise and efficient path, making routing smarter and more scalable.