From: sabrina pittarel (sabri_esame@yahoo.com)
Date: Fri Aug 11 2006 - 20:07:56 ART
Hi Michael,
I know the theory behind the use of the distance
command, and I know that the reason why the ping to R6
and/or R5 loopbacks fails because R1 sends the echo
request to R2 and even if it'll make it all the why to
R4, R4 it'll send it back to R3.
What puzzles me is why the router doesn't do what is
supposed to in my topology.
I'm explicitly telling him to set the distance to 109
for routes coming from a particular route-source. Why
the hell is not doing it!!
Sorry. It is driving me crazy.
Sabrina
--- Michael Stout <michaelgstout@hotmail.com> wrote:
> I don't think you network is a good candidate for
> studying distannce.
>
> try this
> r1-----------r2---------r3------r4
> r1----------r6---------r5-------r4
> OSPF on top RIP on bottom>
> redistriburte mutually using default rip metric of
> 1>
> from r1 trace to R5 rip>
> You trace will go r2--r3--r4--r5
> that is because ospf has a better DISTANCE and r1
> thinks the path to r5
> is one hop away if it uses the ospf path but it
> thinks the path to R5 is
> 2 hops away if it takes the path through r6.
> You need distance so you use the native protocol
>
> Next ad loopbacks to R6 and R5.
> You will not be able to trace to the loopbacks from
> the ospf network
> You need to use distance to kill the loop
>
>
>
--------------------------------------------------------------------
>
> From: sabri_esame@yahoo.com
> Reply-To: sabri_esame@yahoo.com
> To: ccielab@groupstudy.com
> Subject: OSPF and the distance command
> Date: Fri, 11 Aug 2006 17:50:07 -0400
> Hi all,
> I'm trying to understand how ospf behaves in
> relation with the
> following command:
>
> distance <#> <route-source> <wildcard> <acl>
>
> I have the following topology:
>
> R1 --------
> |
> R3
> |
> R2 --------
>
> R1, R2 and R3 are all in area 0. All routers have
> their loopbacks
> advertised in area0.
>
> R1 and R2 are also ASBRs and can reach the same
> set of external
> networks.
>
> I want to configure R3 in such a way it will
> forward all traffic for
> external networks to R2.
> I know I can accomplish that modifying the
> redistribution metrics in
> R1
> and R2, but as I said I'm trying to understand how
> the *distance*
> command behaves.
>
> I thought I could solve the problem doing the
> following:
>
> R3
> ---
>
> router ospf #
> distance 109 <R2 RID> 0.0.0.0 1
>
> access-list 1 deny <R1's loopback>
> access-list 1 permit any
>
> but it doesn't work.
>
> All external routes are still load balanced
> between R1 and R2 and
> show
> up in the routing table with AD 110.
> The only route with AD = 109 is R2's loopback. If
> I remove the acl
> from
> the distance command, i.e.
>
> distance 109 <R2 RID> 0.0.0.0
>
> also R1's loopback will be shown with distance 109
> and R2 will be
> preferred (!!!). All other routes will still be
> load balanced and
> will have
> AD 110
>
> Only if I shut the link between R1 and R3 I
> finally see these routes
> with an AD of 109.
>
> I really don't understand what is going on, any
> ideas?
>
> Thanks
> Sabrina
>
>
>
This archive was generated by hypermail 2.1.4 : Fri Sep 01 2006 - 15:41:56 ART