Subnetting is the foundation for expanding local networks and the internet by allowing for more efficient use of limited IP addresses and reducing the size of routing tables stored in routers. It involves dividing IP networks into smaller physical networks called subnets to address the problems of running out of IP addresses and large routing tables. The document introduces subnetting and discusses the importance of understanding it for network administrators due to these issues, using three IP address classes - A, B and C - as examples.

1. SUBNETTING INTRODUCTIONDeveloped by Peter Smith

2. IntroductionSubnetting is the foundation underlying the expansion of both Local Networks & the Internet in today’s world.Subnetting has become essential knowledge for the Administrator of any network.Peter Smith2

3. IntroductionThere are 2 fundamental reasons why subnetting has so much importance in today’s networking environment:The world is running out of available IP addresses. Subnetting reduces the size of the routing tables stored in routers. Peter Smith3

4. IntroductionThere are only 3 usable IP address classes:Class AClass BClass CClass A networks have the highest number of available hosts.Class C networks have the fewest number of hosts.Peter Smith4