From: Kevin Baumgartner (kbaumgar@xxxxxxxxx)
Date: Mon Jan 22 2001 - 01:44:53 GMT-3
>
> 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.
So look at the above and see what matches.
Bits 128 thru 4 are matches for 29,30 and 31.
And bits 2 and 1 are not.
So just write down the matching bits and
put zero for the non-matching (bits 1 and 2 ).
0 0 0 1 1 1 0 0 = 28
and for
the mask 1 1 1 1 1 1 0 0 = 252
Kevin
>
> Please help.
>
>
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