Summarization help

Just do it in binary.

common bits are 10.0.128+0. Therefor the answer is 10.0.128.0/18

Doan

Which naturally does not correspond to any of the answers he said were in the flash book. How do you get the 18?

Write down the third octet in binairy for each IP-address and but them in a list:

They all differ, accept the last two numbers. The last two numbers are always 00. Put a line in this:

Now you can see that you're summerisation is 10.0.152.0/22.. I don't see how you get 10.0.152/21 and 10.0.160.0/19...

"Michael" schreef in bericht news:ku_hg.15803$ snipped-for-privacy@tornado.southeast.rr.com...

And this thread just gets more confusing, doesn't it? Now we have four right answers.

This confermes my opinion:

I believe the book is wrong. It is better to understand the concept than blindly believe in the book. The /18 comes from 8+8+2 (8 in the first octet, 8 in the second octet and 2 in the third octet).

Doan

Aren't you suppose to look at the common bits from left to right?

Doan

"For summarization to work properly, addresses must be carefully assigned in a hierarchical fashion so that summarized addresses share the same high-order bits."

High-order bits are on the left, not right.

Doan

Michael napisa=B3(a):

It's simple ;)

First - let's write down network ranges:

2,3,4,5 and 6 can be summarized to 10.0.160.0/19 range: 10.0.160.0 -=20

all these networks can be summarized to 10.0.128.0/18 range:=20

So the aswer in the flash cards is OK

------------------------ Ern

How do you guys do this quickly ?

Ern wrote:

Thanks, Ern. That is the best explanation!

Doan

I have found the best way is also to write in binary but some of our colleagues have made this somewhat harder than it has to be.

First, convert the 3rd octects into binary:

Then draw a line (starting from the left not the right!) of all matching bits:

The 2nd summariztion is:

Now you can see how the first 3 bits match which gives you

Hope this helps!

I don't know whether to LOL or . We now have at least three different answers in this one thread.

laugh at yourself. 'cos the answer written in the first post by the original poster has been explained many times now. It's the same answer. so I don't see what you're complaining about.

I'm not compla "Just do it in binary.

comm "Write down the third octet in binairy for each IP-address and but them in a list:

They all differ, accept the last two numbers. The last two numbers are always 00. Put a line in this:

Now you can see that you're summerisati "It's simple ;)

First - let's write down network ranges:

2,3,4,5 and 6 can be summarized to 10.0.160.0/19 range: 10.0.160.0 -

all these networks can be summarized to 10.0.128.0/18 range:

So the aswer in the flash cards is OK"

So what I am suggesting is that this appears to be a tricky question, as noted by Ern, and the answer from the uninitiated reading this thread may not be completely clear.

and as noted, it's better to see all ways of answering a question, and it also gave confirmation as to what the correct answers are.

• how one could slip up.

You understand it. Yet you say it's too complicated.

Don't try to dumb things down. Let ppl gain a higher level of understanding.

Sorry, I haven't followed this thread and, as I use outlook express, cannot read the original post. What was the question again?

new guy :)

new guy napisa=B3(a):

use google :)

it took me less than 1 minute to find it

--=20

------------------------ Ern

The question was:

Can someone explain to me exactly how you get to these answers from this question? Its a question from my Cisco Press CCNP flash cards.

What is the best summarization for:

I know the answers are 10.0.152.0/21 and 10.0.160.0/19, but I am a bit confused as to how you work out the problem to find these solutions, especially for the 10.0.160.0/19. Any help is appreciated.

"new guy" schreef in bericht news:4czjg.19488$IK3.8477@pd7tw1no...