From: Mike McSpedon (mike@xxxxxxxxxxxxxx)
Date: Mon Jan 22 2001 - 02:05:51 GMT-3
The mask is /22 (.252 in the 3rd octet). 28 is divisible by 4.
28 = 0 0 0 1 1 1 0 0
Therefore 172.16.28.0 /22 matches 28, 29, 30, and 31 in the 3rd octet.
HTH,
Mike
At 04:29 AM 1/22/01 +0000, peter brown wrote:
>I have always been confused about summarization. The part that confuses me
>is not how you get the mask but how you change the bits in the octet
>
>For example Caslow in page 306
>
>Summarize 172.16.29.0, 172.16.30.0, 172.16.31,0
>
> 128 64 32 16 8 4 2 1
>29 0 0 0 1 1 1 0 1
>30 0 0 0 1 1 1 1 0
>31 0 0 0 1 1 1 1 1
>
>he then said the summary is 172.16.28.0 255.255.252.0
>My question is how did he get 28 in the third octet.
>
>Please help.
>
>
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