What numeric pattern separates the network ID from the host address?

• A. Subnet Mask
• B. Subnet
• C. IP Address
• D. Network Prefix

Answer: (A)

The boundary between the network part and the host part of an IPv4 address is determined by the subnet mask. This is a 32-bit pattern where ones indicate bits used for the network portion and zeros indicate bits used for the host portion. For example, with a mask of 255.255.255.0, the first three octets are the network portion and the last octet is the host portion. The network ID comes from applying this mask to the IP address (bitwise AND), which reveals the network portion, while the remaining bits form the host address.

The subnet mask is the specific pattern that actually separates those parts, whereas a subnet describes the group of addresses created by applying such a mask, and the network prefix is a way of expressing how many bits are allocated to the network portion (like /24). The full IP address is the combined network and host, so it isn’t the separator itself.