Route summarization

Which summary route can  summarize the following network

Can I summarize it as / 19 ?
Who is Participating?
Predrag JovicConnect With a Mentor Network EngineerCommented:
Not correct. is summary. That one is covering IP address range -

I am trying to give you wider picture in explanation above. :)
Predrag JovicNetwork EngineerCommented:
Network address for summary is in this case, subnet mask is good. <-- address range -
So all networks are included, however, there are many unused network ranges included.

Consider this for example:
 If you want summarize and summarization will be done in this fashion:
will be summarized with
will be summarized with

Whole range will be covered with ( - You don't start with smallest network address that is included in summarization, but with network address of whole range.

Networks and are summarized in - networks that are not present will not be advertised. That's why planning of network address space is important. You need to start to think about it when you start to design your network to be able to have good summarizations.
Second part of this would be: divide network space per region from the start so you can have good summary address for each region.
Also when preparing network addresses for summary - you do not to start network addresses with power of 10 like you did,,, but choose network addresses as power of 2 (0, 1, 2, 4, 8, 16, 32, 64 etc...).
AXISHKAuthor Commented:
But giving that, and 172.16.30/024 need to be summarized in the question. Should the only best solution is / 19 which covers IP range from -, correct ?

Thx again.
AXISHKAuthor Commented:
Here is my calculation, please comment.

1. Convert the 3rd octet in the networks,,  to binary format.
       10 : 00001010
       20 : 00010100
       30 : 00011110
2. The common pattern of digits in 3rd octet ends is "000". Hence, the first 19 bits of the IP address from to are the same. The best summary route is /19 which will cover, and 172.16.30/024 although it will also include network that are not presented.
Predrag JovicNetwork EngineerCommented:
That's it.
All Courses

From novice to tech pro — start learning today.