Hi,
I'm trying to understand Summarization aka Route Aggregation. I don't understand what is it that I'm mistaking in this exercise:
"Find the summary address and mask of the following set of networks
a) 172. 148. 0. 0/13 through 172. 156. 0. 0/13"
MY ATTEMPT:
Clearly it's the 2nd octet that is changing, so the mask will be 255. ___.0.0
The number of networks are: (156 -148) +1= 9 nets
I need to cover at least 9 nets. Which block size will I use? Not 8 but 16.
16 means 4 bits on (starting from the left, from the most significant bit) i.e. 240.
So the mask should ultimately be:
255. 240. 0.0
and that means (8 +4)=12 bits on therefore it's going to be a /12
As to the summary addr., it's the 1st of the block, right?
Maybe 172. 148. 0. 0 /12 ?
However this answer is wrong.
CORRECT ANSWER
172. 144. 0. 0 /16
Where did I go wrong?
