Can i summarize these networks?

[pacquaviva]

Hi,

Is anyone able to tell me if it's possible summarize these networks by aggregate-address command?

The addresses are:

*d 10.25.224.0/24

*d 10.25.225.0/24

*d 10.25.226.0/24

*d 10.25.227.0/24

*d 10.25.228.0/24

*d 10.25.229.0/24

Are there other action that can I do?

Thank you

regards.

Paolo

[rick]

you should be able to summarize as follows

10.25.224.0/22

10.25.228.0/23

[rick]

1

[gpulos]

this can be summarized as:

10.25.224.0/21

ie:

.224 = 11100000

.225 = 11100001

.226 = 11100010

.227 = 11100011

.228 = 11100100

.229 = 11100101

as you can see, the boundry where the bits are always the same is the 5th bit from the left. add these number of bits to the first two octets of 16 bits and you get 21 bits total.

this creates the 10.25.224.0/21 summarization

aka: 10.25.224.0 255.255.224.0

[vladrac-ccna · Accepted solution]

Hey Paolo,

want a fast way to check this, check boson's free utility or any web online tool for SUBNET CALCULATOR.

You'll have answers like this solved in a second.

Vlad

[tdrais · Accepted solution]

Yes you can confugre the command to summerize it to

10.25.224.0/21 if you wish. The problem is that you are also including 10.25.230.0 and 10.25.231.0.

If those are unused there will be no issues. If they are use as long as another router is advertising them into the network then those routes will override this one.

The problems occur when the more specific route is lost and the traffic comes to this router. You may need to gererate a null0 route for the summary. I don't think bgp does that by default when you aggregte routes.