Cidr — Test 1

Correct Answer: A. A. Number of bits in the network
Explanation: The CIDR value represents the number of bits in the network. These CIDR values are represented by ‘/’ at the end of the network Id.

Correct Answer: B. B. Class c
Explanation: The IP address 192.168.10.5/24 represents Class C because the CIDR value of Class C is 24; i.e. Class C has 24 bits in the network portion.

Correct Answer: A. A. True
Explanation: Yes, as CIDR value represents the number of bits in the network, hence it can also be used to calculate the number of bits in the host portion doing so will also determine the subnet mask of the IP address. Hence CIDR value affects the subnet mask of an IP address.

Correct Answer: B. B. 1993
Explanation: The CIDR system was introduced in 1993 along with the IPv4 standard. During 1988, 1998 and 2006 IANA, APIPA and new IPv4 standards were introduced respectively.

Correct Answer: B. B. False
Explanation: Private IPs are assigned by IANA. CIDR values are used to calculate the subnet mask and range of a given IP address. CIDR values are used by network administrators to create and manage different subnets. Private IPs, on the other hand, are used by companies to create their network.

Correct Answer: A. A. 16
Explanation: Given, CIDR value = 28 IP address = 192.13.67.0 (Class C) The default number of bits in the network portion = 24 Let n be the number of bits added to the network portion of the given IP address n = CIDR value – Default number of bits in the network portion n = 28 – 24 n = 4 Number of Subnets = 2n = 24 Number of Subnets = 16

Correct Answer: C. C. 126
Explanation: Given, CIDR value = 25 IP address = 172.16.0.0 (Class B) Total number of bits in an IP address = 32 Let n be the number of bits in the host portion of the given IP address n = Total number of bits in an IP address – CIDR value n = 32 – 25 n = 7 Number of Hosts = 2n – 2 = 27 – 2 Number of Hosts = 128 -2 Number of Hosts = 126 Since Network IP and Broadcast IP cannot be assigned to any host we remove those 2 IPs.

Correct Answer: D. D. 64
Explanation: Given, CIDR value = 26 IP address = 192.168.10.0 (Class C) Total number of bits in an IP address = 32 Let n be the number of bits in the host portion of the given IP address n = Total number of bits in an IP address – CIDR value n = 32 – 26 n = 6 Total number of valid IPs in a subnet = 2n = 26 Total number of valid IPs in a subnet = 64.