From: Mike Kraus \(mikraus\) (mikraus@cisco.com)
Date: Thu Jun 28 2007 - 11:39:44 ART
Note, the internetwork expert guide would be for a wildcard mask. You
would need to calculate the subnet mask for a summary address.
As Sean said, "The best you can do is 10.1.0.0/18, which covers 0-63 in
the third octet."
To see this:
convert them to binary (use calc if you need):
00010110 - 22
00100010 - 34
00100101 - 37
00101111 - 47
Determine which bits are the same for all subnets:
00010110 - 22
00100010 - 34
00100101 - 37
00101111 - 47
^^
In this case, the first two match. Converting 11000000 (matched bits)
back into decimal you get 192. So, the best summarized space would be
10.1.0.0 255.255.192.0. This would cover all networks from 10.1.0.0 all
the way up to 10.1.63.0 (and includes a lot of networks you don't really
own).
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Douglas M Todd, Jr
Sent: Thursday, June 28, 2007 9:23 AM
To: Eric Dobyns
Cc: ccielab@groupstudy.com
Subject: Re: Is there a trick to this?
Yip, there is a way to do this.
Best to read up on access-lists and "and" "or" operations.
You will need to find with the "and" operation the network.
You will need to find with the "or" operation the ""mask""
This will create a one line access-list which will cover the whole
range.
This may help you out.
http://www.internetworkexpert.com/resources/01700370.htm
Eric Dobyns wrote:
> Take the following 4 loopback interfaces:
>
>
>
>
>
> 10.1.22.1 255.255.255.0
>
> 10.1.34.1 255.255.255.0
>
> 10.1.37.1 255.255.255.0
>
> 10.1.47.1 255.255.255.0
>
>
>
> Redistribute them into IGP as a single advertisement while wasting the
> least amount of address space.
>
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