Summary Route Practice Set 1

Want proof you are ready for #CCNA? Try these route summary drills. The underlying skills require a fair amount of mastery of sub netting, so doing these drills can help prove you are ready for the toughest sub netting the CCNA has to offer.

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. Unsure as to what that means? Check out this post that explains more about route summarization.

Your task: 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 the 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 Route Summary Problems

 Problem 1 Problem 2 Problem 3 10.100.0.0/16 172.16.207.192/26 192.168.1.100/30 10.102.0.0/16 172.16.205.64/26 192.168.1.80/29 10.104.0.0/16 172.16.206.128/25 192.168.1.72/30 10.101.0.0/16 172.16.204.0/24 192.168.1.112/28
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1. Vannara Mao February 17, 09:13

Awesome! Thank you.

2. toigonbai February 17, 10:51

Problem 1: 10.96.0.0/12
Problem 2: 172.16.204.0/22
Problem 3: 192.168.1.64/26

• e=mc2 April 16, 13:45

Correct ^-^

• TECH-NY June 18, 13:29

128 64 32 16 8 4 2 1

10.01100|101.00000000.00000000
10.01100|110.00000000.00000000
10.01100|100.00000000.00000000
10.01100|001.00000000.00000000

10.96.0.0/13
————————————

172.16.110011|11
172.16.110011|01
172.16.110011|10
172.16.110011|00

172.16.204.0/22
———————————–

192.168.1.01|100100
192.168.1.01|010000
192.168.1.01|001000
192.168.1.01|101111

192.168.1.64/26

The actually summarized network is 10.96.0.0/12 instead of 10.96.0.0/13
There is a mistake in conversion of 104 to binary.
0110 0100 -100
0110 0101 -101
0110 0110 -102
0110 1000 -104

• Bharat October 28, 02:21

Problem 1- 10.96.0.0/12
Problem 2- 172.16.200.0/21
Problem 3- 192.168.1.64/26

• Dinar April 11, 02:03

3. cew February 17, 21:06

The first list is much easier because all network addresses are 16-bit addresses; I assume (I hope correctly) that in the remaining lists, where for example in one the network addresses are alternately 26-bit, 25-bit, and 24-bit, I will have to leave the lesser amount of bits for individual addresses, and will have to use the full 26-bits for the network addresses — thus I’ll have only 38 bits left for the individual addresses in this case.

• CCENTSkills February 18, 09:28

Hi Cew,
I agree, the first problem was a little easier than the other two (on purpose!). By the way, no sure what you meant about that last comment, about leaving 38 bits for the individual addresses.
I’ll have the answers posted on Friday.
Wendell

4. Shiloh May 30, 15:56

• CCENTSkills May 30, 16:13

We have a few broken links. I’ve got my part time worker going through the entire blog history looking for broken links. I just fixed this one, though. Thanks for the heads up! Should have the rest fixed in the next few weeks.
Wendell

Good practice

6. Pavel July 26, 03:34

PRB 1:10.96.0.0/12
PRB 2:172.16.204.0/22
PRB 3:192.168.1.64/26

• CCENTSkills August 3, 16:08

Pavel,
Thanks for playing! You can see the longer explanation by following the links at the end of the post (above this comment section).
Wendell

7. Tiger December 28, 12:51

“The ISP Company has IPv4 addresses 193.6.128.0/21, 193.6.132.0/21 and 193.6.145.0/24. Because of the address sparing requirement, the company applies superneting mechanism. Calculate the smallest possible list of Supernets for the company ISP?”

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