A network segment (Subnet) is a way to divide IP addresses in a computer network. It is a contiguous subset of an IP address range used to divide multiple subnets in a network.
An IPv4 network segment is usually represented by an IP address and a subnet mask (or network mask), such as 192.168.0.0/24. This network segment means that the network address is 192.168.0.0, and the subnet mask is 255.255.255.0. The first 24 bits are used to identify the network part, and the last 8 bits are used to identify the host part. This network segment can accommodate 254 hosts (excluding network addresses and broadcast addresses).
The representation of IPv6 network segments is slightly different, using CIDR (Classless Inter-Domain Routing) prefix length. For example, 2001:db8::/48 indicates an IPv6 network segment, where the prefix length is 48 bits.
By dividing network segments, a large IP address space can be divided into multiple smaller subnets to meet the requirements of hosts in different subnets. Each subnet has its own network addresses and range of available host addresses.
Note that network administrators must carefully plan and configure network segments, ensure subnet masks match IP address ranges, and avoid IP address conflicts and overlaps.