Re: Stopping a default propagation

From: Eric Leung (eric.lwc@gmail.com)
Date: Wed Sep 12 2007 - 08:37:34 ART


Hi Champika,

1. Any reason for case (2) that the path has to go through R2. Can the path
be like this: R3->L2SW1->L2SW2->R4->R1? If the path can be like this, I
would think of just enabling HSRP on R2 and R4 interfaces connecting to the
switches.

2. Are the costs from R4 to R1 and R2 to R1 equal ?

Eric.

2007/9/12, Champika G <693455@gmail.com>:
>
> The return path for (2) should be R1->R2->R4->L2SW2->L2SW1->R3 &
> The return path for (3) should be R1->R4->R2>L2SW1->R3.
>
> Under normal circumstances R3 should route via R2-R1 link. So
> essentially R2 is the primary router.
>
> On 9/12/07, Champika G <693455@gmail.com> wrote:
> > THe drawing was not very clear.
> > THe connections are;
> >
> > R1-R2 : p2p link
> > R1-R4 : p2p link
> > R2-R4 : p2p link
> > R4-L2SW2 : L2 on SW
> > R2-L2SW1 : L2 on SW
> > L2SW2-R5 : L2 on SW
> > L2SW1-L2SW2 : Trunk
> > L2SW1-R3 : L2 on SW
> > R3-R5 : p2p link
> >
> >
> >
> > On 9/12/07, Champika G <693455@gmail.com> wrote:
> > > Hi Guys
> > > Yes it works that way. I was trying a distribute list out in R2. Silly
> > > me. Should have known better!!!!
> > > Actually my original scenario is as below. I was trying to achieve
> > > fault tolerent routing in R3 & R5.
> > > Two new routers R4 & R5 are there seperated by a L2 switch. Switch to
> > > switch is a trunk.
> > > Area 1 is still a Totally stub area.
> > > Conditions are;
> > > (1) R3 is the HSRP active for ethernet segment vlans
> > > (2) Incase of a link failure bet. R2-L2SW the traffic should be routed
> > > R3->L2SW1->L2SW2->R4->R2->R1. The return path should be the reverse.
> > > No asymetrical routing is allowed.
> > > (3) If R1-R2 link is down traffic should be rerouted via
> > > R3->L2SW1->R2->R4->R1. Return path should be the reverse. Again no
> > > asymetric routing.
> > > (4) R1 is the ABR.
> > >
> > > The question is if (2) or (3) happens the return path does not follow
> > > the same outgoing path. How do i achieve that? Any thoughts
> > >
> > > ========(area 1)R4(area 1)==L2SW2==(area 1)R5-Vlans
> > > || || ||
> > > ||
> > > ==(Area 0)R1(area 1)==(area 1)R2(area 1)==L2SW1==(area 1)R3-vlans
> > >
> > >
> > > On 9/12/07, Champika G <693455@gmail.com> wrote:
> > > > Dear All
> > > >
> > > > I have a situation where i want to stop the default route from
> > > > propagating down to R3.
> > > > R1 is the ABR and area 1 is a totally stub. R1 (ABR) injects a
> default
> > > > to Area 1 and this default i can see in R3 as well.
> > > > I want to stop R3 recieveing this default. ANy ideas how this can be
> > > > done. I tried several methods but they did not work.
> > > >
> > > > OSPF
> > > >
> > > > ==(Area 0)R1(area 1)==(area 1)R2(area 1)==(area 1)R3
> > > >
> > > > Regards
> > > > Champ
>
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