_______ is when the networking portion borrows bits from the host portion.

• A. Subnetting
• B. CIDR
• C. Supernetting
• D. Aggregation

Answer: (A)

Subnetting is the process of extending the network portion of an address by borrowing bits from the host portion to create smaller subnets. By moving the boundary between network and host bits, you increase the number of networks while reducing the number of hosts available in each subnet. For example, taking a /24 network like 192.168.1.0 and using a /27 mask (255.255.255.224) splits it into eight subnets, each with 32 addresses (30 usable hosts). CIDR is the overarching approach that allows variable-length masks, but the act described—creating multiple subnets by using more network bits—is specifically subnetting. Supernetting and aggregation, in contrast, combine subnets into a larger block or summarized route, not the creation of subnets.