Final answer:
The network portion of the subnet mask represents the subnet ID, used to distinguish between different subnets within an IP network.
Step-by-step explanation:
A subnet mask is a 32-bit number created by setting host bits to all 0s and setting network bits to all 1s. In this way, the subnet mask separates the IP address into the network and host addresses. The “255” address is always assigned to a broadcast address, and the “0” address is always assigned to a network address. The part of the subnet mask that represents the subnet ID is the network portion. A subnet mask is used in IP networking to divide the IP address into a network identifier and a host identifier.
The network portion of the subnet mask is composed of all the consecutive leftmost bits set to '1', designating the specific subnet to which the host IP belongs. This portion can vary in length depending on the specific requirements of the network size and architecture. The host portion, on the other hand, is composed of the remaining bits set to '0', and it identifies a specific device or interface within the subnet.