300-420 · Question #327
Refer to the exhibit. A customer is planning to deploy a new branch in New York. The new office will not exceed 1024 users. Which subnet must be used to provide maximum number of host addresses…
The correct answer is B. 192.168.16.0/21. To accommodate 1024 users with the maximum number of host addresses while not providing more than necessary, a /21 subnet is required, which provides 2046 usable host addresses.
Question
Refer to the exhibit. A customer is planning to deploy a new branch in New York. The new office will not exceed 1024 users. Which subnet must be used to provide maximum number of host addresses while not providing more than necessary?
Exhibit
Options
- A192.168.8.0/22
- B192.168.16.0/21
- C192.168.8.0/21
- D192.168.16.0/22
How the community answered
(44 responses)- A11% (5)
- B80% (35)
- C2% (1)
- D7% (3)
Why each option
To accommodate 1024 users with the maximum number of host addresses while not providing more than necessary, a /21 subnet is required, which provides 2046 usable host addresses.
A /22 subnet has 10 host bits, yielding 1022 usable host addresses (2^10 - 2), which is insufficient for 1024 users.
To support 1024 users, a subnet must provide at least 1024 usable host addresses. This requires 11 host bits (2^11 - 2 = 2046 usable hosts). Therefore, the subnet mask must have 32 - 11 = 21 network bits, resulting in a /21 CIDR prefix. The subnet 192.168.16.0/21 provides 2046 usable host addresses, which is the smallest subnet size that accommodates 1024 users with minimal waste.
While 192.168.8.0/21 is a valid /21 subnet that provides enough host addresses, the question's phrasing and the specific correct answer suggest that 192.168.16.0/21 is the intended choice, likely guided by unstated context from a missing exhibit.
A /22 subnet has 10 host bits, yielding 1022 usable host addresses (2^10 - 2), which is insufficient for 1024 users.
Concept tested: CIDR subnetting- host calculation
Source: https://www.cisco.com/c/en/us/support/docs/ip/routing-information-protocol-rip/13788-3.html
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