Cisco CCNA mock exam questions sample test – Question 346

.DRAG DROP
Click the Exhibits button at the bottom of the page to examine a proposed network diagram. There are four proposed subnets, labeled A, B, C, and D. Subnet A will have 12 users,
subnet B will have 300 users, subnet C will have 118 users, and subnet D will have 61 users.
You are designing the IP addressing for this network. You are instructed not to waste IP addresses by making the subnets larger than necessary. Click and drag the correct network ID
from the left to the appropriate subnet on the right.

Select and Place:


Correct Answer:

Explanation:
Subnet A needs to support 12 users. The number of possible addresses in a subnet is determined by the number of host bits or zeros in the mask. The formula is 2n -2, where n is the
number of host bits. Therefore, to support 12 users efficiently, the subnet mask requires no more and no less than four host bits. When there are four host bits in the mask there 28
bits in the network portion. That is the case with 192.168.6.0/28.
Subnet B needs to support 300 users. To support 300 users without wasting addresses, the mask requires no more and no less than nine host bits. When there nine host bits in the
mask, there are 23 bits in the network portion. That is the case with 172.15.0.0/23.
Subnet C needs to support 118 users. To support 118 users without wasting addresses, the mask requires no more and no less than seven host bits. When there seven host bits in
the mask, there are 25 bits in the network portion. That is the case with 194.168.6.0/25.
Subnet D needs to support 61 users. To support 61 users without wasting addresses, the mask requires no more and no less than six host bits. When there six host bits in the mask,
there are 26 bits in the network portion. That is the case with 193.168.6.0/26.
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
Cisco > Technology Support > IP > IP Addressing Services > Design Technotes > Subnet Zero and the All-Ones Subnet > Document ID: 13711