Cisco CCNA mock exam questions sample test – Question 274

.What is the possible IP range that can be assigned to hosts on a subnet that includes the address 192.168.144.34/29?

A. 192.168.144.32 – 192.168.144.63
B. 192.168.144.33 – 192.168.144.38
C. 192.168.144.33 – 192.168.144.48
D. 192.168.144.28 – 192.168.144.40

Correct Answer: B

Explanation:
Range 192.168.144.33 – 192.168.144.38 is the correct answer. To determine the range of addresses that can be assigned in a subnet, you must first determine the network ID of the
subnetwork and the broadcast address of the subnetwork. All addresses that can be assigned to hosts will lie between these endpoints. The network ID can be obtained by
determining the interval between subnet IDs. With a 29-bit mask, the decimal equivalent of the mask will be 255.255.255.248. The interval between subnets can be derived by
subtracting the value of the last octet of the mask from 256. In this case, that operation would be 256 – 248 = 8. Therefore, the interval is 8.
The first network ID will always be the classful network you started with (in this case 192.168.144.0). Each subnetwork ID will fall at 8-bit intervals as follows:
192.168.114.0
192.168.144.8
192.168.144.16
192.168.144.24
192.168.144.32
192.168.144.40
We can stop at the 192.168.144.40 address because the address given in the scenario, 192.168.144.34, is in the network with a subnet ID of 192.168.144.32. Therefore, since the
broadcast address for this network will be 1 less than the next subnet ID (192.168.144.39), the valid range of IP addresses is 192.168.144.33 – 192.168.144.38. 192.168.144.39 will be
the broadcast address for the next subnet, and 192.168.144.40 will be the first valid address in the next subnet.
None of the other answers is the correct range.
Objective:
Network Fundamentals
Sub-Objective:
Apply troubleshooting methodologies to resolve problems
References:
Cisco > Technology Support > IP > IP Routing > Design TechNotes > IP Addressing and Subnetting for New Users > Document ID: 13788 > Understanding IP Addresses