# Route Summarization

Member Posts: 11 ■□□□□□□□□□
Hi, can anyone explain to me how to solve the following question? I encounter this question in the ciscopress self study book but am stuck. Your help would be much appreciated, thanks!

Your company is assigned four Class C networks:

200.39.32.0/24
200.39.33.0/24
200.39.34.0/24
200.39.35.0/24

• Member Posts: 1,745
Hi, can anyone explain to me how to solve the following question? I encounter this question in the ciscopress self study book but am stuck. Your help would be much appreciated, thanks!

Your company is assigned four Class C networks:

200.39.32.0/24
200.39.33.0/24
200.39.34.0/24
200.39.35.0/24

Edit: I'm sorry.

Well, you need to summarize 4 contiguous networks. So, you need a mask that gives you a block size of 4.0 (or, at least, that's my initial hypothesis)
First, you check if that first number is a multiple of 4.0 or not. if not, then you'd have to go up to 8.0.
Since it is a multiple of 4, then you know you can use the mask of 255.255.252.0.
the network is 200.39.32.0
first valid host is 200.39.32.1
last valid host is 200.39.35.254
Currently Working: CCIE R&S
• Member Posts: 1,745
On another thought, to expand upon the initial answer I gave, and to look at the problem again, what if it gave you this?

200.39.33.0/24
200.39.34.0/24
200.39.35.0/24
200.39.36.0/24

And asked you to summarize it to the best of your ability, what would you do?

Well, you could take two approaches

Approach 1: give them exactly what they asked for, summarized as much as possible:
200.39.33.0/24
200.39.34.0/23
200.39.36.0/24

Approach2: If they say to use the smallest possible mask that covers all of the networks given in a single line, then you use this:
200.39.32.0/21

Problems like this illustrate why you should give out network assignments according to binary boundaries
Currently Working: CCIE R&S
• Member Posts: 1,745
Kelvin:

If you could show how you are attempting to solve the problem, we could then assist you. I thought route summarization was a CCNA topic?
Currently Working: CCIE R&S
• Member Posts: 104
instant000 wrote: »
Kelvin:

If you could show how you are attempting to solve the problem, we could then assist you. I thought route summarization was a CCNA topic?

Route summarization is a CCNP topic, not CCNA. It is helpful to know, and is something that you should know moving forward in the networking field. Don't worry about knowing it 100% for the CCNA.
• Member Posts: 104
wrwarwick wrote: »
Route summarization is a CCNP topic, not CCNA. It is helpful to know, and is something that you should know moving forward in the networking field. Don't worry about knowing it 100% for the CCNA.

Well, just saw this on the CCNA topics:
Determine the appropriate classless addressing scheme using VLSM and summarization to satisfy addressing requirements in a LAN/WAN environment

• Member Posts: 11 ■□□□□□□□□□
instant000 wrote: »

Edit: I'm sorry.

Well, you need to summarize 4 contiguous networks. So, you need a mask that gives you a block size of 4.0 (or, at least, that's my initial hypothesis)
First, you check if that first number is a multiple of 4.0 or not. if not, then you'd have to go up to 8.0.
Since it is a multiple of 4, then you know you can use the mask of 255.255.252.0.
the network is [URL="tel:200.39.32.0"]200.39.32.0[/URL]