CISCO CCNA Exam – Q98

Given an IP address 172.16.28.252 with a subnet mask of 255.255.240.0, what is the correct network address?

A. 172.16.16.0
B. 172.16.0.0
C. 172.16.24.0
D. 172.16.28.0

Correct Answer: A

Explanation:
For this example, the network range is 172.16.16.1 – 172.16.31.254, the network address is 172.16.16.0 and the broadcast IP address is 172.16.31.255.

CISCO CCNA Exam – Q6

Refer to the exhibit.

CISCO CCNA Exam – Q6

Which subnet mask will place all hosts on Network B in the same subnet with the least amount of wasted addresses?

A. 255.255.255.0
B. 255.255.254.0
C. 255.255.252.0
D. 255.255.248.0

Correct Answer: B

Explanation:
310 hosts < 512 = 29 -> We need a subnet mask of 9 bits 0 -> 1111 1111.1111 1111.1111 1110.0000 0000 -> 255.255.254.0

CISCO CCNA Exam – Q5

Refer to the exhibit.

CISCO CCNA Exam – Q5

What is the most appropriate summarization for these routes?

A. 10.0.0.0 /21
B. 10.0.0.0 /22
C. 10.0.0.0 /23
D. 10.0.0.0 /24

Correct Answer: B

Explanation:
The 10.0.0.0/22 subnet mask will include the 10.0.0.0, 10.0.1.0, 10.0.2.0, and 10.0.3.0 networks, and only those four networks.

CISCO CCNA Exam – Q1

Refer to the exhibit.
ccna-exam-set-a-q1

Which three statements correctly describe Network Device A? (Choose three.)
A. With a network wide mask of 255.255.255.128, each interface does not require an IP address.
B. With a network wide mask of 255.255.255.128, each interface does require an IP address on a unique IP subnet.
C. With a network wide mask of 255.255.255.0, must be a Layer 2 device for the PCs to communicate with each other.
D. With a network wide mask of 255.255.255.0, must be a Layer 3 device for the PCs to communicate with each other.
E. With a network wide mask of 255.255.254.0, each interface does not require an IP address.

Correct Answer: B,D,E

Explanation:
If Subnet Mask is 255.255.255.128 the hosts vary from x.x.x.0 – x.x.x.127 & x.x.x.128- x.x.x.255, so the IP Addresses of 2 hosts fall in different subnets so each interface needs an IP an address so that they can communicate each other.
If Subnet Mask is 255.255.255.0 the 2 specified hosts fall in different subnets so they need a Layer 3 device to communicate.
If Subnet Mask is 255.255.254.0 the 2 specified hosts are in same subnet so are in network address and can be accommodated in same Layer 2 domain and can communicate with each other directly using the Layer 2 address.