Using the traditional classful subnetting convention that excludes the…

Concept

In classful IPv4 addressing, a Class B network has a /16 default prefix, leaving 16 bits in the host field. Borrowing bits for a subnet identifier increases the subnet count while reducing the bits available within each subnet.

With s borrowed bits, the subnet field has 2s combinations. If h host bits remain, each subnet has 2h addresses; the network and broadcast addresses are not assignable to hosts.

Application

1. A Class B address begins with 16 host bits.

2. Borrowing 6 bits leaves 16 − 6 = 10 host bits.

3. The 6-bit subnet field provides 26 = 64 bit combinations. Under the historical convention used by this item, the all-zero and all-one subnet numbers are excluded, so 64 − 2 = 62 subnets are counted.

4. Each subnet contains 210 = 1024 addresses. Removing the network and broadcast addresses gives 1024 − 2 = 1022 usable host addresses.

Cross-check

A /16 prefix plus 6 borrowed bits gives /22, so 32 − 22 = 10 host bits remain. This independently confirms 1024 addresses and 1022 usable hosts per subnet. Modern subnetting permits all 64 subnet numbers; the offered answer reflects the older exclusion convention.

Therefore, under the convention used by the offered choices, the result is 62 subnets and 1022 usable hosts per subnet.