CCENT/CCNA ICND1 100-101 Official Cert Guide

Practice Problem 2

Table I-4 Practice Problem 2: First Two Steps

For Problem 2, at Step 3, all the original masks are /23, so the initial mask will be one smaller, or /22. Finding the correct answer requires three passes through calculating a new subnet ID and mask, with the final answer shown in Table I-5.

Table I-5 Practice Problem 2: Multiple Passes Through Step 4 (Correct Answer Highlighted)

The best summary route will use subnet ID 172.21.96.0, mask /20.