From: Arne Holick-Kuhlmann (ccie-lab@xxxxxxx)
Date: Thu Oct 19 2000 - 04:36:16 GMT-3
There is a difference between summarization and filtering.
Yes, the wildcard mask Mike provided would match all the routes that need to be
summarized but it is not valid for summarization. So with this wildcard mask yo
u
could create a route-map to filter those routes, but when you try to do a
ip route 160.10.10.0 240.255.255.0 null0
your router will tell you that this ain't gonna work: "%Inconsistent address an
d
mask"
As others have pointed out, the 240.0.0.0 mask would be correct. (Giving you a
route of 160.0.0.0/4).
To get really familar with subnets masks and subnetting I would suggest getting
a subnet calculator (like the one from boson.com). It greatly helped me to
understand this subject.
Arne
Mike Hess wrote:
>
> The the masks here are all wildcard masks not subnet masks. I believe to
> summarize 160.10.10.0/24, 161.10.10.0/24, and 170.10.10.0/24 into 1 route
> would be a subnet mask of 240.255.255.0. This would summarize all
> X.10.10.0/24 routes where X is from 160-175. Oh yeah the wildcard for this
> is 15.0.0.255.
>
> Mike
>
> Mike
> ----- Original Message -----
> From: "Konstantin Kostenko" <konstantin.kostenko@worldnet.att.net>
> To: "Justin Menga" <Justin.Menga@computerland.co.nz>
> Cc: <ccielab@groupstudy.com>
> Sent: Wednesday, October 18, 2000 13:03
> Subject: Re: Summarization
>
> >
> >
> > Justin Menga wrote:
> > >
> > > This would cover from 160.0.0.0 thru to 175.255.255.255
> > >
> > > You could also use 160.0.0.0 11.255.255.255 - this would summarize
> 160.x.x.x
> >
> > This mask is invalid, if I not mistaken. You can not use it.
> > 7.255.255.255 is ok, but not appropriate here.
> > 15.255.255.255 is more suitable.
> >
> > > -> 163.x.x.x and 170.x.x.x -> 173.x.x.x.........
> > >
> > > -----Original Message-----
> > > From: Derek Buelna [mailto:dameon@aracnet.com]
> > > Sent: Wednesday, October 18, 2000 7:13 PM
> > > To: 'Marc Russell'; ccielab@groupstudy.com
> > > Subject: Summarization
> > >
> > > Hi,
> > >
> > > I was trying to figure out how to summarize 160.10.10.1/24,
> 161.10.10.1/24
> > > and 170.10.10.1/24 into one route.
> > >
> > > If I use the prefix 160.0.0.0 and mask it with 15.255.255.255, I was
> > > thinking that it would care about the first 4 bits and not care about
> the
> > > rest. Would that cover 160.0.0.0 through 175.254.254.254?
> > >
> > > Thanks,
> > >
> > > -Derek
> > >
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