What is the number of usable IP addresses in a 20-bit subnet?

To determine the number of usable IP addresses in a subnet, we first need to understand how the subnetting works. In a 20-bit subnet, the first 20 bits are used for the network portion, which leaves us with 12 bits available for host addresses.

The total number of addresses in the subnet can be calculated using the formula (2^{(number\ of\ host\ bits)}). For a 20-bit subnet, we have 12 host bits:

[

2^{12} = 4096

]

However, within this calculation, we must account for the fact that two addresses are reserved: one for the network address (the first address in the subnet) and one for the broadcast address (the last address in the subnet). Therefore, to find the number of usable addresses, we subtract these two reserved addresses from the total count:

[

4096 - 2 = 4094

]

This means there are 4094 usable IP addresses available in a 20-bit subnet, making the correct answer 4094.