What is IPv4?
Internet Protocol version 4 (IPv4) is a 32-bit digital address used to assist with the routing of packets in a network.
You can think of an IP address as you would a street address. Here's a quick example of a local network address setup:
10.11.0.0/16 gives us a total of 65,536 addresses (only 65,534 are usable, 10.11.0.0 and 10.11.255.255 are reserved) Let's say we have 3 classrooms, the computers that are for non-faculty use will route their traffic through the faculty computer which will be connected to a managed switch. This switch is where the 3 classrooms traffic meets to be routed to and from the internet. Classroom 1 can use 10.11.1.0/24 for a total of 256 addresses (only 254 are usable, 10.11.1.0 and 10.11.1.255 are reserved) Classroom 2 can use 10.11.2.0/24 for a total of 256 addresses (only 254 are usable, 10.11.2.0 and 10.11.2.255 are reserved) Classroom 3 can use 10.11.3.0/24 for a total of 256 addresses (only 254 are usable, 10.11.3.0 and 10.11.3.255 are reserved) The faculty computer behaves like a gateway for the non-faculty computers, thus the faculty computers will have the lowermost non-reserved IP addresses: Classroom 1 Faculty will use 10.11.1.1 Classroom 2 Faculty will use 10.11.2.1 Classroom 3 Faculty will use 10.11.3.1 Every computer will then use each subsequently non-reserved IP address. Let's say you're working as the network security manager and you are noticing unusually high traffic from the following IP address: 10.11.2.7 This means that the offending traffic is coming from the 7th non-faculty computer in classroom 2. You can scale this to a total of 65,534 devices on the local network at any given moment if need be.
Knowing how a network is set up and which rooms correspond to which IP address range can make it easier to maintain control over a relatively large network with hundreds to thousands of concurrent hosts.