What is the function of a subnet mask?

A subnet mask plays a crucial role in computer networking, specifically in defining the network and host portions of an IP address. By using a subnet mask, devices on a network can determine which other IP addresses are part of their local network and which addresses are part of different networks. This understanding allows for efficient routing of data packets and helps in segregating different subnetworks.

When an IP address is combined with a subnet mask, it helps identify the range of valid IP addresses that can exist within that specific subnet. This is essential for organizing and managing IP address allocation within a larger network, allowing devices to communicate effectively while also maintaining network security and traffic management.

In contrast, the other options do not accurately capture the primary function of a subnet mask. While speed of data transfer, data encryption, and user permissions are important aspects of network communication and security, they are not the direct function of a subnet mask in relation to IP addressing and network organization.