Sorry for the html but I thought color would allow you to
visualize.
22 would be the answer. A 0 is still a bit so they would
be common. ( red is the same - black is not) if you used a /12 that would be a
major aggregate and you would loose a lot of address space.
a /22 would be a good answer for advertising out of an area a
/12 would be better suited for an Autonomous system
all this red is common all the black is different looks like a
/22 to me.
> 172.16.1.0 in bin -- 10110110.00010000.00000001.00000000
> 172.16.2.0 in bin-->10110110.00010000.00000010.00000000
> 172.16.3.0 in bin-->10110110.00010000.00000011.00000000
> 172.16.2.0 in bin-->10110110.00010000.00000010.00000000
> 172.16.3.0 in bin-->10110110.00010000.00000011.00000000
if you used a /12 you would lose all this address space
(marked in green) that you could use elsewhere.
all the red is common all the green and black combined is
different but you could lengthen the mask to make better use of vlsm.
> 172.16.1.0 in bin --
10110110.00010000.00000001.00000000
> 172.16.2.0 in bin-->10110110.00010000.00000010.00000000
> 172.16.3.0 in bin-->10110110.00010000.00000011.00000000
> 172.16.2.0 in bin-->10110110.00010000.00000010.00000000
> 172.16.3.0 in bin-->10110110.00010000.00000011.00000000
So the real answer is they will both work but what do you want
to advertise to and will you need the address space
Duck
----- Original Message -----
From: <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Cc: <[EMAIL PROTECTED]>
Sent: Thursday, October 19, 2000 3:11 AM
Subject: Re: Summarization
> [EMAIL PROTECTED] writes:
>
>
> > I feel the summarized supernet route should be 172.16.1.0/22
> >
> > from the below fig ..its clear that the no of common bits in the MSB part is
> > 22
> >
>
> It can't be 172.16.1.0/22 because the address of 172.16.2.0 does not share a
> 1 bit with the rest. I thought it was supposed to be the leftmost common
> "bit" for the mask. If so, wouldn't it then be 172.16.0.0/12. If you say it's
> 22 then it's not the leftmost common bit, it's the leftmost
> common...umm...space. ;) Can somebody give a positive answer? Thanks...
>
> 172.16.1.0 in bin -->10110110.00010000.00000001.00000000
> 172.16.2.0 in bin-->10110110.00010000.00000010.00000000
> 172.16.3.0 in bin-->10110110.00010000.00000011.00000000
>
>
> Mark Zabludovsky ~ CCNA, CCDA, 1/4-NP
> <A HREF="mailto: [EMAIL PROTECTED]">[EMAIL PROTECTED]</A>
>
> "If you need luck, apparently you're not prepared...Go study!"
>
> ~Mark Zabludovsky~
>
> _________________________________
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