From: Sam.MicroGate@xxxxxxxxxxxxxx
Date: Wed Apr 24 2002 - 16:31:03 GMT-3
I think you switched R5 with R4 because R5 is attached to area 0 and always
an ABR.
Or there is something I do not understand. Here is the diagram again.
172.10.7.0/28 172.10.128.0/26
LB0:172.10.5.4/24
R2------------------R5------------------------------R4---------
area 0 area 2 area 3
Frame Relay Ethernet LB
of R4
-----Original Message-----
From: Peter van Oene [mailto:pvo@usermail.com]
Sent: Wednesday, April 24, 2002 3:10 PM
To: Sam.MicroGate@usa.telekom.de
Subject: RE: How does OSPF enter routes into the routing table?
as soon as R5 becomes an ABR (Virtual link comes up) it is no longer
allowed to consider non area 0 resident summary LSA's and hence can no
longer use the type 3 from R4. Prior to the V-Link being up, R5 has no
connection to area 0, and thus is not an abr, and is allowed to use the
type 3 from R4.
Pete
At 02:52 PM 4/24/2002 -0400, you wrote:
>Yes. First R4 receive the /24 O and place it in the routing table. Then
when
>the virtual link gets established, it receives the /28 O and install it in
>the routing table and moves the /24 from the routing table. Can you analyze
>this?
>
>-----Original Message-----
>From: Peter van Oene [mailto:pvo@usermail.com]
>Sent: Wednesday, April 24, 2002 2:43 PM
>To: Sam.MicroGate@usa.telekom.de
>Subject: RE: How does OSPF enter routes into the routing table?
>
>
>ahh.. i didn't scan the entire thread. if each are individually the best
>route the router has to each unique prefix, they should both enter the
>routing table. Is this not the case in your findings?
>
>
>At 02:39 PM 4/24/2002 -0400, you wrote:
> >My original question was why they do not?
> >
> >-----Original Message-----
> >From: Peter van Oene [mailto:pvo@usermail.com]
> >Sent: Wednesday, April 24, 2002 2:36 PM
> >To: Sam.MicroGate@usa.telekom.de; jambern@MerchantWired.com
> >Cc: ccielab@groupstudy.com
> >Subject: RE: How does OSPF enter routes into the routing table?
> >
> >
> >In this case, both should go into the table.
> >
> >At 12:19 PM 4/24/2002 -0400, Sam.MicroGate@usa.telekom.de wrote:
> > >I think you are correct. The same prefixes with two different subnet
>masks.
> > >R4 receives 172.10.7.0/24 O IA and 172.10.7.0/28 O and then installs
the
> >/28
> > >in the routing table. That is because, of cource, it is O.
> > >
> > >Sam
> > >
> > >-----Original Message-----
> > >From: Ambern, Jeff [mailto:jambern@MerchantWired.com]
> > >Sent: Wednesday, April 24, 2002 11:25 AM
> > >To: 'Sam.MicroGate@usa.telekom.de'
> > >Cc: 'ccielab@groupstudy.com'
> > >Subject: RE: How does OSPF enter routes into the routing table?
> > >
> > >
> > >I still believe that it has to do with the prefix being the same length
> > >and the first route is an intra-area route. Try making the /28
something
> > >other than subnet-zero and see the /24 shows up in the routing table.
> > >
> > >Jeff
> > >
> > >-----Original Message-----
> > >From: Sam.MicroGate@usa.telekom.de
[mailto:Sam.MicroGate@usa.telekom.de]
> > >Sent: Wednesday, April 24, 2002 10:18 AM
> > >To: jambern@MerchantWired.com
> > >Subject: RE: How does OSPF enter routes into the routing table?
> > >
> > >
> > >What about the scenario below? did you take a look at it?
> > >
> > >Sam
> > >
> > >-----Original Message-----
> > >From: Ambern, Jeff [mailto:jambern@MerchantWired.com]
> > >Sent: Wednesday, April 24, 2002 11:14 AM
> > >To: 'Sam.MicroGate@usa.telekom.de'
> > >Subject: How does OSPF enter routes into the routing table?
> > >
> > >
> > >Ospf will insert Intra-Area routes into the routing table befor
>Inter-Area
> > >routes.
> > >The order of preference is:
> > >O
> > >IA
> > >E1
> > >E2
> > >Jeff
> > >
> > >
> >
>
>--------------------------------------------------------------------------
> > >Hello all,
> > >
> > >Last night I worked in a distribution lab from fatkid.com. In this lab
I
> >had
> > >the following problem:
> > >Area 2 is configured a virtual area between routers R5 and R4. I used
>area
> >0
> > >range command to summarize the /28 subnet into area 2. Now the problem
is
> >R4
> > >receive both routes the 172.10.7.0/28 as O and 172.10.7.0/24 as O IA
and
> > >strangely choose the first to install in the routing table. The /24
>subnet
> > >gets suppressed and does not make it to the routing table. Shouldn't I
>see
> > >both routes in R4 because OSPF supports VLSM? Why OSPF choose the route
> >with
> > >the longer mask and ignored the one with shorter mask? If this the
>default
> > >behavior, How can I make the summary address /24 reach R4. Thank you
all
> >for
> > >your help.
> > >
> > >
> > >
> > >172.10.7.0/28 172.10.128.0/26 LB0:172.10.5.4/24
> >
>
>R2------------------------------R5------------------------------R4---------
> >-
> > >-------------------
> > >area 0 area 2 area 3
> > >Frame Relay Ethernet LB of R4
> > >
> > >At R5:
> > >area 0 range 172.10.7.0 255.255.255.0
> > >
> > >
> > >
> > >
> > >Elsayed Mohamed
> > >Sr. Network Consultant
> > >Microgateds, Inc.
> > >732-936-4413
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