summarization

[jonk34567]

172.16.128.0/18

172.16.32.0/24

172.16.64.0/18 

if those 3 routes are summarized. can 172.168.128.0/17 be the summarized route ?

[Joseph W. Doherty]

No.

[burleyman]

First Joseph is correct.

Now there may be a typo in your answer. You have 172.168.128.0/17...check second octet.

Now figure out the ranges for you 3 choices and figure out the range for your answer, does your answer include all the addresses for your 3 ranges?

Post your work and we will check it out.

Mike

[jonk34567]

there is a typo error . actual summarized route is 172.16.128.0/17 . is it correct ? 

[burleyman]

No.

[burleyman]

No

The summarized route must include all the addresses you listed and you answer does not.

It helps to write out the ranges for the the subnets you listed and it will help you see.

Mike

[burleyman]

It looks like based on your posts you are studying for something, CCNA?

If so it would be very helpful for you in your studies to write it out and you will see where your answer won't fit.

Write it out and post it here and we can help.

Mike

[jonk34567]

consider the third octate

172.16.128.0/18 1000 0000

172.16.64.0/18   0100 0000

172.16.32.0/24   0010 0000

if we make all 3 bit positions 0 then sammurized route will be 172.16.0.0/16

if we make 2 bit positions 0 then sammurized route will be 172.16.128.0/17

Are they correct ? if they are wrong can you pls explain me ?

[burleyman]

Ok lets list out the subnets

172.16.32.0/24  - 172.16.32.0 to 172.16.32.255 (Note third octet is just 32)

172.16.64.0/18 - 172.16.64.0 to 172.16.127.255 (Note the third octet goes from 64 to 127)

172.16.128.0/18 - 172.16.128.0 to 172.16.191.255 (Note the third octet goes from 128 to 191)

So you need something that includes 172.16.32.0 to 172.16.191.255

Now lets look at you answers.

172.16.0.0/16 - 172.16.0.0 to 172.16.255.255 (Note third octet goes from 0 to 255)

So this one would be correct for your networks.

172.16.128.0/17 - 172.16.128.0 to 172.16.255.255 (Note third octet goes from 128 to 255)

This one does not cover any of the subnets under 172.16.128.0 so this would not work.