# Summary Route Drill 3

Like the other summary route drills, this post lists three practice problems. Each problem lists a set of subnet/mask pair for existing routes in some router. Your job: choose the subnet/mask pair to use as the best summary route that includes the addresses in all the routes in the original list. Here are some other useful links as well:

Imagine that each column of Table 1 lists subnet/mask combinations that exist as routes in some router’s IP routing table. Your job: find the subnet/mask combination that you would configure in a manual summary route to replace all those routes with one summary route. Choose the best summary – that is, the summary route that includes all addresses in all the subordinate subnets, while including as few extra addresses as is possible.

#### Table 1 – Three Problems: Find the Best Summary Route for Each

 Problem 1 Problem 2 Problem 3 10.7.56.0/21 172.20.201.0/24 192.168.8.100/30 10.7.32.0/20 172.20.196.0/22 192.168.8.108/30 10.7.52.0/22 172.20.184.0/21 192.168.8.116/30 10.7.72.0/23 172.20.180.0/23 192.168.8.124/30
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1. Toigonbai March 24, 09:58

1) 10.7.0.0/17
2) 172.20.128.0/17
3) 192.168.8.96/27

• CCENTSkills March 24, 18:25

Hi Toigonbai,
Thanks for the reply! I’ll get an answer post out this week. In the mean time, I’ll not comment, just to avoid spoiling the answers for the next person to come along and read the post.
Wendell

2. Davy March 25, 06:04

I’m with Toigonbai, summary routes are:

1) 10.7.0.0/17
2) 172.20.128.0/17
3) 192.168.8.96/27

3. Pankaj Patinge March 25, 07:07

Problem 1) 10.7.0.0/17
Problem 2) 172.20.128.0/17
Problem 3) 192.168.8.96/27

4. Pankaj Patinge March 26, 02:43

Problem 1) 10.7.0.0/17
Problem 2) 172.20.128.0/17
Problem 3) 192.168.8.96/27

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