Depth resolution: the importance of IP subnets in modern network planning

How to use limited IPv4 efficiently as the number of Internet devices has increased explosively Address space has become a challenge for every network engineer. IP Subnetting and the unclassical inter-domain route (CIDR) are the core techniques for addressing this problem.

Why do you want to divide the subnet?

Reduction of broadcasting storms: By dividing large networks into smaller subnets, broadcast traffic can be limited to specific segments, significantly enhancing overall network performance.
Enhancing security: The subnet can serve as a secure border, with firewall strategies, and easily control access between different departments or services.
Optimizing the distribution of addresses: Avoid allocating a large Class B address to offices with only dozens of hosts, and by CIDR, you can assign IPs exactly as you want. Resources.

How can specific route and configuration be addressed?

Scene one: Two subnets can't communicate. The network addresses of the two hosts are first checked using the calculator. If they are not in the same subnet and there is no gateway to be installed, communication will inevitably fail. Scenario 2: DHCP address pool depleted. Checks the current mask settings. For example, from /24 Expand /23 , the number of hosts available can be doubled from 254 to 510 without changing the existing physical pounces.

Notes on key terms

CIDR (Classless Inter-Domain Routing)： Replaced traditional A/B/C network divisions with slashed numeric numbers (e.g., /24 ) indicates the length of the prefix and is more flexible.

Web address and radio address: The Internet address is the first IP of the subnet, which is used to mark the subnet itself; The address is the last one. IP for sending information to all hosts in the subnet. These two addresses are not normally assigned to the mainframe in the standard subnet.