Route Summarization Help, PLEASE!!!

[Muziq]

I’m currently using the 6th Edition CCNA Study Guide (Deluxe Edition) by Sybex and Todd Lammle. I’ve just completed Chapter 5 and need help with the Written Lab 5 questions.

Route Summarization was only covered for 2.5 pages (pg 186-189). I didn’t find the examples given in those pages helpful when referencing them to solve the 10 Written Lab 5 questions.

The Written Lab 5 Scenario states:
For each of the following sets of networks, determine the summary address and the mask to be used that will summarize the subnets.

I don’t know where to begin with solving these problems. I know how to subnet and understand VLSM subnetting but am still lost. Todd states that once you’ve determined the block size then you can find the network address and mask to summarize these advertisements into one advertisement. I’ve tried this but am obviously missing something???

Here are a few examples from each class and the answers. I’m hoping someone would be kind enough to help me understand how to arrive at the answer so I can go back and work the rest of the problems.

Thanks in advance,

Muziq

Example 1
Problem:192.168.1.0/24 through 192.168.12.0/24
Answer:192.168.0.0/20

Example 2
Problem:172.148.0.0/13 through 172.156.0.0/13
Answer: 172.144.0.0/16

Example 3
Problem:66.66.0.0 through 66.66.15.0
Answer: 66.66.0.0/16

[ciscodaze]

see this thread
http://www.lammle.com/discussion/showthread.php?t=5258&highlight=route+summarization (http://www.lammle.com/discussion/showthread.php?t=5258&highlight=route+summarization)

or just search the forum for that topic, lots of posts.

[Muziq]

Thanks Ciscodaze! I appreciate your post; this really helps.

[yuronald]

If you understand the concept of subnetting, just write out the subnets that need to be summarized on top of each other, and start from left to right and see where they all match. Draw a vertical line, and what you have on the left (all matches) is your summarization.