From: Johnny Dedon (johnny.dedon@xxxxxxxxxx)
Date: Fri May 11 2001 - 17:54:16 GMT-3
Correction on summary route.
I spoke too soon on the summary route.
The summary route can be created within OSFP for redistribution into an
external routing protocol. If you want a summary to appear in ospf then it
must be created from routes external to the OSPF process or it must be
created using the area range command where it can only be seen by routers
belonging to areas other than the area it is advertised from.
HTH
Johnny Dedon
Senior Staff Consultant
Exodus Professional Services
johnny.dedon@exodus.net
www.exodus.net
----- Original Message -----
From: "Johnny Dedon" <johnny.dedon@exodus.net>
To: "Mohamed Heeba" <MAHeeba@itqan.co.ae>
Cc: <ccielab@groupstudy.com>
Sent: Friday, May 11, 2001 3:37 PM
Subject: Re: Fatkid lab 502 ,expert redistribution
> Mohamed,
> Responses inline
> Johnny Dedon
> Senior Staff Consultant
> Exodus Professional Services
> johnny.dedon@exodus.net
> www.exodus.net
> ----- Original Message -----
> From: "Mohamed Heeba" <MAHeeba@itqan.co.ae>
> To: "'Johnny Dedon'" <johnny.dedon@exodus.net>; "Mohamed Heeba"
> <MAHeeba@itqan.co.ae>
> Cc: <ccielab@groupstudy.com>
> Sent: Friday, May 11, 2001 3:12 PM
> Subject: RE: Fatkid lab 502 ,expert redistribution
>
>
> > well;
> > i think things are more difficult than this ..let me share my ideas here
> > i agree that the OSPF summary command is used to summarize the external
> > routes INTO the OSPF domain ,however in some solutions out there ,it is
> used
> > to summarize the OSPF itself to other protocols like IGRP ,but this will
> > work only if the subnets of the OSPF domain can be summarized at the
IGRP
> > subnet boundary ,also the summary route will be propagated into the OSPF
> YOU HAVE TO HAVE A ROUTE TO CREATE THAT SUMMARY WITH AND IT MUST BE
EXTERNAL
> TO OSPF
> > domain as E2 route which i wasnt able to filter it at all(or it will
aslo
> > disapear from the IGRP !!)
> > wat u explained about the route feedback is another problem called black
> > holes ( i hope im right in this ) ]
> WHAT I TRIED TO EXPLAIN IS THE OSPF ROUTE WITH AN ADMINISTRATIVE DISTANCE
OF
> 110 GETS DISTRIBUTED INTO IGRP WHERE IT GETS AND ADMINISTRATIVE DISTANCE
OF
> 100. IF MUTUAL REDISTRIBUTION IS TAKING PLACE THEN THIS ROUTE WILL BE
> REDISTRIBUTED BACK TO OSPF WHERE THE ROUTER WILL SEE THAT THIS ROUTE
COMING
> FROM IGRP HAS A LOWER ADMIN DISTANCE THAN THAT OF THE OSPF ROUTES AND
> THEREFORE USE THIS ROUTE IN IT'S TABLE. IF YOU DO A SHOW IP ROUTE, THEN
ALL
> OF THE OSPF ROUTES THAT WERE DISTRIBUTED INTO IGRP AND THEN BACK WILL BE
> LISTED AS E2. ANOTHER NOTE HERE IS THAT IN SOME CASES SPLIT HORIZON WILL
> NOT ALLOW THE ROUTES BACK OUT OF IGRP SO THIS FEEDBACK DOES NOT OCCUR.
> > where the routes of less admin distance will replace those of higher
ones
> > and the routes will stuck in one domain ...this problem will only happen
> if
> > u have TWO points of redistribution .
> > AS per doyle , route feedback will happen when u have one point of
> > redistribution and u do mutual redistribution from two domain one to the
> > other ...doyle required to put filter in each domain to prevent this
> > ....while without the filter things work fine with me ...that is why im
> > confused ???
> >
> > DO I HAVE TO PUT FILTERS IF ONLY 1 REDISTRIBUTION ROUTER AND MUTUAL
REDIST
> > IS THERE ?? OR I NEED ONLY THIS WHEN I HAVE TWO POINTS OF REDIST.
>
> IT IS GOOD PRACTICE TO FILTER ROUTES ANY TIME MUTUAL REDISTRIBUTION
OCCURS.
> IT IS ONLY NECESSARY WHEN REDISTRIBUTING FROM A HIGHER ADMIN COST TO A
LOWER
> ADMIN COST .
> > secondly ,i didnt find anyway to summarize the OSPF 22 masks into the
IGRP
> > 24 domain without using either static routes or the summary address and
> let
> > the summary route propagate back to the OSPF domain ...
> >
> > any more ideas guys
> > > -----Original Message-----
> > > From: Johnny Dedon [SMTP:johnny.dedon@exodus.net]
> > > Sent: Friday, May 11, 2001 1:01 PM
> > > To: Mohamed Heeba
> > > Subject: Re: Fatkid lab 502 ,expert redistribution
> > >
> > > Mohamed,
> > > The summary route is used to summarize routes external to the ospf
> process
> > > for reditribution into the OSPF process. Have you looked at changing
> the
> > > mask on the link between igrp and ospf to a 22 bit mask ? Or have you
> > > looked at sending a default route into igrp. Route feedback occurs
when
> > > you
> > > redistribute ospf routes into igrp and since igrp has a lower admin
and
> > > the
> > > routes are now igrp routes they get advertised back to the
> redistributing
> > > router where they get put in the route table as ospf external routes.
> Get
> > > it, they WERE ospf internal routes until you redistributed them to
igrp
> > > and
> > > they got redistributed back. You should not allow this to happen. Use
> > > route-maps or distribute list to stop this.
> > > Johnny Dedon
> > > Senior Staff Consultant
> > > Exodus Professional Services
> > > johnny.dedon@exodus.net
> > > www.exodus.net
> > > ----- Original Message -----
> > > From: "Mohamed Heeba" <MAHeeba@itqan.co.ae>
> > > To: <ccielab@groupstudy.com>
> > > Sent: Friday, May 11, 2001 1:45 PM
> > > Subject: Fatkid lab 502 ,expert redistribution
> > >
> > >
> > > > guys ;
> > > > i have a problem here which is similar to some post was here very
> > > soon...
> > > > it is regarding the redist of the OSPF into the IGRP ,here is my
notes
> > > and
> > > > questions
> > > > the case is :
> > > > the ospf is having different masks of the network 135.1.x.x ,the
masks
> > > are
> > > > /22
> > > > ,/24,28 while the IGRP is only 24
> > > > now i didnt get a clear answer about this question
> > > > 1-does the summary address of the OSPF used to summarize the OSPF
> domain
> > > to
> > > > other protocols or it is ONLY used to summarize the other protocols
> > > domains
> > > > into the OSPF ??
> > > > i noticed that the summary address will NOT work until u redist IGRP
> > > into
> > > > the ospf process even before u redist the OSPF into the IGRP
> > > >
> > > > 2- how to redist the mask 22 in the IGRP ? it is not normal to
> summarize
> > > > this mask at the 24 boundary (i know this can be done to solve the
> lab )
> > > but
> > > > the problem is that the OSPF will create a static route to the null0
> in
> > > the
> > > > redist router and this will take all the traffic to null0 (since 24
is
> > > more
> > > > specific than the 22 in teh routing table
> > > >
> > > > 3- is the solution for this problem by using the area range command
> > > > somewhere in teh OSPF domain
> > > >
> > > > 4-can someone define how the route feedback can heppen ?? becaue
when
> i
> > > > tried to filter in the ospf domain the routes (to accept those only
> > > coming
> > > > from OSPF and not IGRP ,)teh summary disappeared from the route
table
> as
> > > if
> > > > it is coming from the IGRP
> > > > i want to understand this point "is the route feedback means that
the
> > > > routes goes inside the domain to downstream routers and then come
back
> > > ,or
> > > > it is only comes back on the redistribution router "
> > > >
> > > >
> > > > i hope someone is patient to answer all this :)
> > > > thx
> > > > **Please read:http://www.groupstudy.com/list/posting.html
> **Please read:http://www.groupstudy.com/list/posting.html
**Please read:http://www.groupstudy.com/list/posting.html
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