From: Logan, Harold (loganh@xxxxxxxxxxxx)
Date: Tue Apr 16 2002 - 15:26:23 GMT-3
After I sent that I decided to double-check it. (Wrong order, I know, oh well)
I mistook "shouldn't" for "can't". Since normally Area 0 will be at the top of
your IP addressing hierarchy within the OSPF domain, I've never had a need to
summarize it. It loks like the primary reason it's not recommended has to do
with an OSPF area that has more than one connection to the backbone area. If
you summarize area 0 on one of those ABR's, then traffic exiting the area will
take the router with the summary addy on it, regardless of which is the best
path out of the area. And in most situations, if you have only one point where
an area is connected to area 0, then that area will be configured as a stub or
totally stub.
Thanks for checking that Chris.
Hal
-----Original Message-----
From: Larson, Chris (Contractor) [mailto:Chris.Larson@ed.gov]
Sent: Tuesday, April 16, 2002 2:04 PM
To: Logan, Harold
Cc: ccielab@groupstudy.com
Subject: RE: OSPF - IGRP
I just tried this on the Ipexpert ospf base config. I did the area 0 range at
R2 for the 150.50.100.0 network to a /24. On R4 is shows up as a /24 on R5 and
R6 it does not. R4 is in area 1 with R2 the ABR.
R2---------------R4
/\
/ \
/ \
R5 R6
-----Original Message-----
From: Logan, Harold [ mailto:loganh@mcc.cc.fl.us]
Sent: Tuesday, April 16, 2002 1:18 PM
Cc: ccielab@groupstudy.com
Subject: RE: OSPF - IGRP
Minor correction: As I understand things, you can't summarize area 0. The area
range command is used on an ABR to summarize routes getting advertized into
area 0, and summary-address is used on an ASBR.
-----Original Message-----
From: kenairs [ mailto:kenairs@hotmail.com]
Sent: Tuesday, April 16, 2002 12:41 PM
To: Annu Roopa; Muhamamd Durrani; Tarek Sabry
Cc: ccielab@groupstudy.com
Subject: Re: OSPF - IGRP
i think the area range to summarise area 0 is to do it on another ABR that
connects area 0 and area 1 example.
Cannot do it on the ASBR.
corrections ?
----- Original Message -----
From: Annu Roopa <annu_roopa@yahoo.com>
To: Muhamamd Durrani <dan_schaw@yahoo.com>; Tarek Sabry
<tsabry@houston.sns.slb.com>
Cc: <ccielab@groupstudy.com>
Sent: Wednesday, April 17, 2002 12:03 AM
Subject: Re: OSPF - IGRP
> Hi,
>
> Just a doubt ? I thought the area range command is
> only for inter OSPF areas on the ABR. So does the area
> range command work on ASBR too ?? in which case it
> wont summarize the routes to IGRP.
>
> Let me know.Thanks
> Annu
>
> --- Muhamamd Durrani <dan_schaw@yahoo.com> wrote:
> > Hi Tarek ,
> >
> > With Summary-Address you cannot re-distribute to
> > other
> > routing protocol . Its for the Summary Address for
> > Ecternal Routes .
> >
> > I would rather say create a Summary Address with
> > "Area
> > range " commad on the router you want to summarized
> > the addresses on, with the mask configured on the
> > interfaces running IGRP. If the mask is now same as
> > configured on IGRP interfaces than you wil not see
> > the
> > route on IGRP router .
> >
> > Another way that I could see is to create a static
> > route on ASBR to NULL 0 and redistribute static into
> > IGRP process ..but again the mask SHOULD match with
> > interaces configured with IGRP .
> >
> >
> > Let me know id I am wrong .
> >
> > Regards,
> > Muhammad
> >
> >
> > --- Tarek Sabry <tsabry@houston.sns.slb.com> wrote:
> > > Hi
> > >
> > > I understand that there may be more than one way
> > to
> > > redistribute VLSM into
> > > FLSM. However the only way that seems to work for
> > me
> > > when redistributing
> > > OSPF into IGRP is the brilliant method suggested
> > by
> > > someone a little while
> > > back, whereby I need to create an intermediate
> > OSPF
> > > process. I don't feel
> > > comfortable with just this way though, because the
> > > proctors may object to
> > > it.
> > >
> > > So let's say we have a /26 network connected to
> > the
> > > OSPF side of the
> > > redistributing router. Someone had suggested
> > before
> > > that a good way of
> > > achieveing what I want would be to redistribute
> > > connected into OSPF and
> > > create a "summary-address" of a /24, and this
> > route
> > > would be redistributed
> > > into IGRP with the rest of the OSPF routes.
> > >
> > > Is that supposed to work??? Well doesn't the
> > > "summary-address" inject a
> > > route INTO OSPF and not OUT OF it?? Also how come
> > I
> > > do not see any routes to
> > > "Null 0" after I create my OSPF summary address?
> > >
> > > What are common gotchas for OSPF summaries??
> > >
> > > Thanks a lot
> > > Tarek
> > >
> >
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