Cisco CCNA mock exam questions sample test – Question 368

.Which is the valid broadcast ID for the IP address 192.24.134.12 with a subnet mask of 255.255.255.128?

A. 192.24.134.127
B. 192.24.134.128
C. 192.24.134.129
D. 192.24.134.131


Correct Answer: A

Explanation:
192.24.134.127 is the valid broadcast ID for the IP address 192.24.134.12 with a subnet mask of 255.255.255.128. The valid range for the IP address 192.24.134.12 with a subnet
mask of 255.255.255.128 is 192.24.134.1 – 192.24.134.126. The subnet ID is 192.24.134.0.
Subnetting allows you to split single and large subnets defined by Class A, B, and C IP addresses into multiple subnets with smaller IP address host ranges. Subnetting allows efficient
use of IP addressing space, which has become a scarce resource.
To subnet an existing network, you will use host bits to split the IP address into multiple logical subnets. For example, if you use three bits of the host ID for subnetting, you have
created 23 = 2 x 2 x 2 = 8 subnets. Remaining bits of the host ID in decimal form will form the number of hosts on each subnet.
All other options are incorrect as these IP addresses fall in other subnets.
192.24.134.128 is the network ID for the next subnet created when using a mask of 255.255.255.128 on the class C network 192.24.134.0. The following network IDs are created
when you use a mask of 255.255.255.128 on the class C network 192.24.134.0:
192.24.134.0 – Valid range 192.24.134.1-192.24.134.126, 192.24.134.127 is the broadcast
192.24.134.128 – valid range 192.24.134.129-192.24.134.254, 192.24.134.255 is the broadcast
192.24.134.129 and 192.24.134.131 are both valid addresses in the second subnet created, that is, the 192.24.128.0 network.
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