Designing Cisco Enterprise Networks (ENSLD) — Question 123
An engineer is designing an IPv4 addressing plan for an enterprise with 1000 branches. Each branch requires a prefix for data and a prefix for voice. Each prefix must accommodate up to 128 hosts, and prefixes must facilitate summarization at aggregation points in the network. The security team requires a simple method for identifying voce prefixes. Which allocation does the engineer recommend from the RFC1918 address space?
Answer options
- A. /24 prefixes for data from 10.0.0.0/15 and /24 prefixes for voice from 172.16.0.0/15
- B. /24 prefixes for data from 10.0.0.0/8 and /24 prefixes for voice from the next contiguous /24 prefix per site
- C. /25 prefixes for data from 10.0.0.0/8 end /25 prefixes for voice from the next contiguous /25 prefix per branch
- D. /24 prefixes for data from 10.0.0.0/8 and /24 prefixes for voice from 172.16.0.0/12
Correct answer: B
Explanation
Option B is the correct choice because it provides a /24 prefix for data and allocates the next contiguous /24 prefix for voice, which allows for efficient summarization and meets the host requirements. The other options either do not satisfy the host capacity requirements or do not ensure contiguous prefix allocation, which is necessary for effective summarization.