What does a subnet mask do in a network?

What does a subnet mask do in a network?

• A. Identifies the device's MAC address
• B. Defines the network and host portions of an IP address
• C. Secures the network from unauthorized access
• D. Connects devices to the internet

Answer: (B)

A subnet mask plays a critical role in facilitating network communication by defining which portion of an IP address indicates the network and which part identifies the host within that network. In IP addressing, every device must be aware of its place within the overall network structure. The subnet mask accomplishes this by employing a binary representation that separates the two segments of the IP address. For example, consider an IP address of 192.168.1.10 with a subnet mask of 255.255.255.0. The subnet mask informs the device that the first three octets (192.168.1) represent the network part, while the last octet (.10) identifies the specific device or host. This arrangement enables routers and switches to efficiently manage traffic and data transmission within the network, ensuring that packets are appropriately directed to their destination. The other choices do not align with the primary function of a subnet mask. Identifying a device's MAC address involves different protocols and methods that operate at layer 2 of the OSI model, while securing the network relates to firewalls and authentication measures rather than segmentation of IP addresses. Lastly, connecting devices to the internet generally involves routers and gateways, and is not a direct function of the subnet mask itself.

A subnet mask plays a critical role in facilitating network communication by defining which portion of an IP address indicates the network and which part identifies the host within that network. In IP addressing, every device must be aware of its place within the overall network structure. The subnet mask accomplishes this by employing a binary representation that separates the two segments of the IP address.

For example, consider an IP address of 192.168.1.10 with a subnet mask of 255.255.255.0. The subnet mask informs the device that the first three octets (192.168.1) represent the network part, while the last octet (.10) identifies the specific device or host. This arrangement enables routers and switches to efficiently manage traffic and data transmission within the network, ensuring that packets are appropriately directed to their destination.

The other choices do not align with the primary function of a subnet mask. Identifying a device's MAC address involves different protocols and methods that operate at layer 2 of the OSI model, while securing the network relates to firewalls and authentication measures rather than segmentation of IP addresses. Lastly, connecting devices to the internet generally involves routers and gateways, and is not a direct function of the subnet mask itself.