How to find supernet address?

[alahlyaly]

Can someone solve this 

What is the supernet address of 192.168.1.0/24, 192.168.2.0/24 and 192.168.3.0/24?

How to calculate supernet address?

[Georg Pauwen]

Hello,

supernet is 192.168.0.0/22.

There are numerous tools and sites available on the Internet, here is one of them:

http://asecuritysite.com/ip/routesum

[alahlyaly]

I'm not asking for a tool how did you get that?

[Georg Pauwen]

Hello,

11000000.10101000.00000001.00000000 (192.168.1.0)
11000000.10101000.00000010.00000000 (192.168.2.0)
11000000.10101000.00000011.00000000 (192.168.3.0)

11000000.10101000.000000 --> this are the common bits (192.168.0.0)

11000000.10101000.00000011.00000000 --> these are the wildcard bits (0.0.3.255)

[Alvi]

Hi
Can some one solve this
What is the supernet Address of
192.168.40.0
192.168.50.0
And
192/168.60.0
?

[Julio E. Moisa · Accepted solution]

Hi

As Georg mentioned the supernet is 192.168.0.0/22. 

The supertnet includes the following prefixes:

-192.168.0.0/24
-192.168.1.0/24
-192.168.2.0/24
-192.168.3.0/24

You can use this formula, using the subnet mask

Supernet = /22 converting: 255.255.252.0

So 256 - 252 = 4  as result the subnet will include 4 subnets starting with the first subnet, in this case --> 192.168.0.0/24 (a even number or multiple of 2 or zero)

This subnets will be changing on the 3rd octect, because you have modified the 3rd octect only of the subnet mask. Please verify this article, is important to know how summarization works. 

http://searchnetworking.techtarget.com/tip/Network-summarization-Supernetting-and-wildcard-masks

Regards. 

[Alvi]

Can some one solve this
What is the supernet Address of
192.168.40.0
192.168.50.0
And
192/168.60.0
?

[Georg Pauwen]

Hello,

according to my calculation it is:

192.168.32.0/19

[Alvi]

Thank you so much...
But do u send me the full calculation?

[Georg Pauwen]

11000000.10101000.00101000.00000000 (192.168.40.0)
11000000.10101000.00110010.00000000 (192.168.50.0)
11000000.10101000.00111100.00000000 (192.168.60.0)

These are the common bits in all three networks. The value equals subnet mask 255.255.224.0, or inverted wildcard 0.0.31.255...

[Alvi]

Thank you so so much.

[liaqat.perwaiz]

your IP range does not meet the conditions for supernetting.

• all IP addresses should be contiguous
• size of all the small networks should be equal and must be in form of 2^n
• first IP address should be exactly divisible by whole size of supernet.

[Joseph W. Doherty]

BTW, one might argue that 192.168.0.0/22 is not the supernet for those 3 prefixes because it also includes 192.168.0.0/24.  To supernet just those 3 prefixes, 192.168.1.0/24 would be left alone, and 192.168.2.0/24 and 192.168.3.0/24 combined into 192.168.2.0/23.