From: Ravi (s_ravichandran@xxxxxxxxxxx)
Date: Sat Aug 18 2001 - 22:33:00 GMT-3
Hi,
Could you tell more about the reverse summary address with examples please,
Regards,
Ravi
----- Original Message -----
From: "Daniel C. Young" <danyoung99@mediaone.net>
To: <ccielab@groupstudy.com>
Sent: Sunday, August 05, 2001 8:47 PM
Subject: ospf: reverse summary-address usage (answers)
> I have answered my own questions.
>
> For reverse summary-address to work, all that you need is to mutually
> redistribute. You do not need to disable split-horizon, and you do not
need
> to redistribute connected. Just make sure that the routes you want to
> summarize get mutually redistributed. It works with both rip and igrp, but
> only for shorter-mask networks.
>
> For longer-mask networks, there still maybe a workaround. If the
longer-mask
> networks are over frame-relay, then you can change the ospf network type
to
> p2m, which will treat the network as a collection of p2p links.
>
> Daniel
>
> -----Original Message-----
> From: Daniel C. Young [mailto:danyoung99@mediaone.net]
> Sent: Sunday, August 05, 2001 4:51 PM
> To: 'Padhu (LFG)'; 'ccielab@groupstudy.com'
> Subject: ospf: reverse summary-address usage
>
>
> Group,
>
> Backgound: Some of you have advocated the use of reverse summary-address
to
> solve the VLSM/FLSM issue. That is, instead of using summary-address to
> summarize external routes going into OSPF, you can use it to summarize
ospf
> routes into external routing domains.
>
> Testbed: Fatkid labs 502 and 501.
>
> 501 has a /28 ospf subnet that a rip domain needs to see. I configured the
> summary-address statement to convert it to a /24 mask on r3, who is the
ASBR
> for the rip domain. Works great!
>
> 502 has a /22 ospf subnet that an igrp domain needs to see.
Summary-address
> did not anywhere, except on a separate ospf process on r2, who is the ASBR
> for the other ospf process. This created another problem where the longest
> matching rule preffered the "summary" route to the null0. Nonetheless, the
> summary-address itself worked.
>
> Conclusion: Normal summary-address can summarize for longer-mask networks.
> Reverse summary-address can summarize for shorter-mask networks in rip.
> Reverse summary-address does not work for longer-mask networks in igrp.
>
> Question: Does reverse summary-address work for shorter-mask network igrp
as
> well? Can you perform a reverse summary-address for longer-mask networks
in
> rip?
>
> Regards,
> Daniel
> **Please read:http://www.groupstudy.com/list/posting.html
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