# Cisco CCNA mock exam questions sample test – Question 410

.You are the network administrator for your company. You have been assigned the task of configuring an appropriate IP addressing scheme in the network.
Assuming that the network address is 192.16.100.0/28, what will be the number of hosts per network in this scenario?

A. 2
B. 6
C. 14
D. 30

Explanation:
In this scenario, there will be 14 hosts per network. The formula for calculating the number of hosts on a subnet is 2n – 2, where n is the number of host bits in the summary mask. The
n can be calculated by subtracting host bits from the total number of bits in a subnet mask (32). In this case, n would be 32 – 28 = 4. Therefore, the formula to calculate the number of
bits in this scenario would be:
2(32 -28) – 2 = 24 – 2 = 14 hosts
You always subtract 2 from 2n because the all-zero-bit address is reserved for the network address (called the network ID) and the all-one-bit address is reserved for the broadcast
The 192.16.100.0/28 network address would not have 30 hosts per network. The 192.16.100.0/27 network address would actually yield 30 hosts per network. In this case, n would be
32 – 27 = 5, so the number of host bits in the subnet mask would be 32 – 2, which is equal to 30.
The 192.16.100.0/28 network address would not have 6 hosts per network. The 192.16.100.0/29 network address would yield 6 hosts per network. In this case, n would be 32 – 29 = 3,
so the number of host bits in the subnet mask would be 8 – 2, which is equal to 6.
The 192.16.100.0/28 network address would not have 2 hosts per network. The 192.16.100.0/30 network address would yield 2 hosts per network. In this case, n would be 32 – 30 = 2,
so the number of host bits in the subnet mask would be 4 – 2, which is equal to 2.
Objective:
Network Fundamentals
Sub-Objective:
Configure, verify, and troubleshoot IPv4 addressing and subnetting
References:
Cisco > Technology Support > IP > IP Routing > Design Technotes > IP Addressing and Subnetting for New Users > Document ID: 13788 > Understanding IP Addresses