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Route Summarization

rai_praveen
Level 1
Level 1

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

1 Accepted Solution

Accepted Solutions

cadet alain
VIP Alumni
VIP Alumni

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.

Don't forget to rate helpful posts.

View solution in original post

2 Replies 2

cadet alain
VIP Alumni
VIP Alumni

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.

Don't forget to rate helpful posts.

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