Route Summarization

[rai_praveen]

what would be the best Route Summarization for this network which cover all 4 network

192.168.1.100/30
192.168.1.104/30
192.168.1.108/30
192.168.1.112/30

pls mention the method and one more request could any body tell me the summarization method so i learn do to summarization

if i break last octat number in binary

100 - 1100100

104 - 1101000

108 - 1101100

112 - 1110000

only first two bit from left side match so as per my calculation it summary route would be 192.168.1.100/26 but i don't know i did right or wrong so pls also tell me how to know my summarization is right or not

as per my knowledge summary address 192.168.1.100/26 has block size of 64 so it starts from

192.168.1.0

192.168.1.64

192.168.1.128 so my 4 networks comes in between 64-128

pls pls teach me summarization

[cadet alain · Accepted solution]

Hi,

192.168.1.100/30
192.168.1.104/30
192.168.1.108/30
192.168.1.112/30

you select the interesting octet which is last octet here and convert to binary like you did

100 - 01100100

104 - 01101000

108 - 01101100

112 - 01110000

beginning from left how many bits have you in common? The first 3 so the mask is indeed /27 ( /24 + 3 common bits) and the summary octet is

01100000 which is equal to decimal 96

So summary is 192.168.1.96/27 which gives a range from 192.168.1.97 to 192.168.1.126 so it is indeed a valid summary but it encompasses a lot more subnets than the ones given.

So if we look at the 3 first numbers we have 4 bits in common so summary is 192.168.1.96/28 which gives a range of  192.168.1.97 to 192.168.1.110

and we're left with the last subnet not summarized.

Regards.

Alain.

[rai_praveen]

hi  Cadetalain

   would you pls tell me some more summarization method to find out easily and corrent summary address and how do i check that my summary address is valid

what you above told i got it.just pls pls tell me little bit more handone on summarization