From: kym blair (kymblair@xxxxxxxxxxx)
Date: Tue Apr 16 2002 - 18:25:21 GMT-3
Dan,
Awesome step-by-step explanation. Thanks. Now, how about if you have a /23
coming from OSPF that you want to get into RIP/IGRP? How do you do that?
Thanks,
Kym
>From: "DAN DORTON" <DHSTS68@dhs.state.il.us>
>Reply-To: "DAN DORTON" <DHSTS68@dhs.state.il.us>
>To: <tsabry@houston.sns.slb.com>, <dan_schaw@yahoo.com>
>CC: <ccielab@groupstudy.com>
>Subject: RE: OSPF - IGRP
>Date: Tue, 16 Apr 2002 11:01:40 -0500
>
>Let say you have a range of 172.168.1.0/28 in ospf that you need to get
>into a 172.168.2.0/24 IGRP, or RIP domain.
>
>Summary-address only works INTO ospf right?
>
>You need to make this 172.168.1.0/28 network into a 172.168.1.0/24 network
>to overcome the rip/igrp domains classful boundry problems right?
>
>Create a loopback with address 172.168.1.17/28 at your ASBR.
>Do not advertise this network into OSPF.
>Instead create a route-map to permit it.
>
>access-list 1 permit 172.168.1.16 0.0.0.15
>
>route-map con2ospf permit 10
>match ip address 1
>
>Then create a summary address under ospf.
>
>router ospf 1
>summary-address 172.168.1.0 255.255.255.0
>
>Then redistribute connected INTO ospf with the route-map.
>
>router ospf 1
>redistribute connected subnets route-map con2ospf
>
>Since 172.168.1.16/28 network fits into the summary-address range of
>172.168.1.0/24 ospf will create a route to null 0 for the 172.168.1.0/24
>network.
>
>Because connecteds being redistributed INTO ospf are external networks the
>summary-address works.
>
>Because 172.168.1.0/28 & 172.168.1.16/28 both fit into the major network
>172.168.1.0/24 the summary-address will work to reach both networks.
>
>Because 172.168.1.0/24 route matches the 172.168.2.0/24 network on the
>igrp/rip domain at the classfull 172.168.0.0/16 & the mask of /24 which is
>on the igrp/rip domain the igrp/rip domain will accept the summary route.
>
>Hope this helps everyone.
>
>Dan
>
> >>> Tarek Sabry <tsabry@houston.sns.slb.com> 04/16/02 10:10AM >>>
>Muhammad
>
>Thanks for your reply.
>
>I fully agree that summary-address is for injecting a summary INTO OSPF and
>not to redistribute into another protocol. But I've seen people using it
>otherwise :( Is this IOS-related?
>
>How can I create area-range when the router I'm trying to redistribute at
>is
>not an ABR? I only have area-1 and IGRP on this router.
>
>Creating statics is also prohibited in the lab. Right?
>
>Thanks again
>Tarek
>
>-----Original Message-----
>From: Muhamamd Durrani [mailto:dan_schaw@yahoo.com]
>Sent: Tuesday, April 16, 2002 8:56 AM
>To: Tarek Sabry
>Cc: ccielab@groupstudy.com
>Subject: Re: OSPF - IGRP
>
>
>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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