Ccna routing and Switching Complete Study Guide

R1

R2

No worries—solving this is easier than it looks initially. The question actually has 

the summary address listed in it: 192.168.144.0/20. You already know that /20 is 

255.255.240.0, which means you’ve got a block size of 16 in the third octet. Starting at 

144, which is also right there in the question, makes the next block size of 16 equal 160. 

You can’t go above 159 in the third octet, so the IP addresses that will be forwarded are 

192.168.144.1 through 192.168.159.254.

Okay, last one. In Figure 5.14, there are five networks connected to router R1. What’s 

the best summary address to R2?

f I g u r e   5 .14     Summarization example 5

What is the best summary to R2?