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Re: Conditional injection of default route with rip: IE lab 13, task 5.12 posted 12/29/2004
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Basically, this feature is only designed to work for a prefix-list or
standard acl. Correct me it I am wrong but I always assumed the route-map
can't determine the up/down state of the interface so the interface exists
regardless of the state, therefore it would always advertise the default. It
can however check for the prefix. Hence, the reason why this feature and I
have seen this with a couple other features has to match on a prefixIf you
think about the logic that takes place here, I think it would be fairly
difficult to match on the interface.

<begin thinking out loud>
What we need is this:
route-map CONDITIONAL-DEFAULT permit 10
match interface Serial0/0 state up
</end thinking out loud>




----- Original Message -----
From: "ccie2be" <ccie2be@xxxxxxxxxx>
To: "Roberto Adjakou" <radjakou@xxxxxxx>; "Group Study"
<ccielab@xxxxxxxxxxxxxx>
Sent: Wednesday, December 29, 2004 3:35 PM
Subject: Re: Conditional injection of default route with rip: IE lab 13,
task 5.12


> Hi Roberto,
>
> Based on what you said, I tried this:
>
> route-map CONDITIONAL-DEFAULT permit 10
>  match interface Serial0/0.501 Serial0/0.502
>
> I figured that since both sub-interfaces were up/up and had ip addresses
> assigned to them, this would work.
>
> It didn't.
>
> Apparently, this conditional default only works if an acl or prefix list
is
> referenced in the match statement
>
> of the route-map.
>
> Any ideas why that is?
>
> TIA, Tim
>
> ----- Original Message -----
> From: "Roberto Adjakou" <radjakou@xxxxxxx>
> To: "ccie2be" <ccie2be@xxxxxxxxxx>; "Group Study" <ccielab@xxxxxxxxxxxxxx>
> Sent: Tuesday, December 28, 2004 7:32 AM
> Subject: RE: Conditional injection of default route with rip: IE lab 13,
> task 5.12
>
>
> > Since there is no ip address configured on s0/0, no routing protocol
> relies on it.
> > In fact, ISIS is enabled on s0/0.501 and s0/0502 not on s0/0!!
> >
> > sh ip route | i Serial0/0 should  edify on this point.
> >
> > -----Message d'origine-----
> > De : ccie2be [mailto:ccie2be@xxxxxxxxxx]
> > Envoyi : lundi 27 dicembre 2004 19:30
> > @ : Group Study
> > Objet : Conditional injection of default route with rip: IE lab 13, task
> 5.12
> >
> > Hi guys,
> >
> > Depending on what is being matched in the route-map, I discovered that
> > sometimes the
> >
> > conditional default injection works and sometimes it doesn't even though
> it
> > seems to me that it
> >
> > should work either way.
> >
> > The objective is to advertise a default route to R1 if either of R2's
s0's
> > sub-interfaces is up.
> >
> > Here's the scenario:
> >
> > R1  --- rip --- r2 s0
> >
> >
> > s0 is using frame encap and has 2 sub-interfaces s0.501 and s0.502
> >
> > And, R2's rip config is like this:
> >
> > router rip
> > ver 2
> > default-info originate route-map CONDITIONAL
> >
> > r1 sees the default route if the route-map on R2 matches against the ip
> > address
> >
> > configured on s0.501 and s0.502 when a prefix list is used
> >
> > route-map CONDITIONAL
> > mat ip address prefix FRAME   <- the prefix list specifies the ip
> addresses
> > configured on s0.501 and s0.502
> >
> > If the route-map matches on interface s0/0, it doesn't work.
> >
> > route-map CONDITIONAL
> > match int s0                     <- Configured this way, R1 doesn't see
> the
> > default route.
> >
> >
> >
> > The way I see it, if either of the s0 sub-interfaces is up, then s0
itself
> > will be up and therefore, R2
> >
> > should advertise the default route.
> >
> > Can anyone explain why I need to match against an ip prefix list for
this
> to
> > work and why matching against
> >
> > the interface doesn't work?
> >
> > TIA, Tim
> >
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