(CCNA) Network Address

Number of hosts that can be on that network: (2^n)-2, n means numbers of host bits.

The reason we subtract 2 is because all 1s within the host portion of an IP address is a broadcast address for that network and cannot be assigned to a specific host. All 0s within the host portion indicates the network ID and again, cannot be assigned to a specific host.



Reference: www.cisco.com