From: nenad pudar (nenad.pudar@gmail.com)
Date: Sun Mar 20 2005 - 13:23:39 GMT-3
Kim
This does not work ,because it is CDP related and applys only on the
direct phisycal next-hops.
In e-mail from Alex you can see a new features which add the
additional tracking capabilities to this.
The source of problem here is that new next-hop router is not directly
connected.
Additionaly here in this case there is 3-level of BGP refelection what
make the problem even more complex.
In any case thanks everybody for help I decided for the time being to
play withe traffic with one big customer connected to this router .
Two BGP sessions one over direct link ,the other one multihop to new
next-hop-router with higher LP
(For those who try this there is a litlle trick here; if you use
next-hop-self on the backbone routers----- you will need to put in
forwarding path for the loopback interface of customer router
additional configuration to prefer the routes from directly connected
BGP session -ex. localy using the weight ,otherwise you will end up
having loop)
nenad
On Sat, 19 Mar 2005 14:00:04 -0500, Jongsoo.Kim@intelsat.com
<Jongsoo.Kim@intelsat.com> wrote:
> Nenad
>
> If you enable cdp,and you the following under your route-map config below.
> set ip next-hop ADDRESS1 ADDRESS2
> set ip next-hop verify-availability
>
> Your original intended config may work for you.
> I found this from another policy-routing but it may work for BGP next-hop.
> I am intersted in finding out as well because if this works, this may be
> some cool command in BGP world.
>
> Thanks
>
>
> Jongsoo
>
> -----Original Message-----
> From: nenad pudar [mailto:nenad.pudar@gmail.com]
> Sent: Saturday, March 19, 2005 11:03 AM
> To: asadovnikov
> Cc: ccielab@groupstudy.com
> Subject: Re: Complex real-life BGP problem
>
> Thanks for this
> However in IOS version We have not natch of this is supported .Even if
> it was this is mainly PBR based and I do not know will it be possible
> to implement this in BGP
>
> nenad
> On Fri, 18 Mar 2005 17:20:47 -0500, asadovnikov <asadovnikov@comcast.net>
> wrote:
> > Nenad,
> >
> >
> http://www.cisco.com/en/US/about/ac123/ac114/ac173/Q2-04/department_techtips
> > .html
> > You going to have to play with the feature to make sure it does what you
> > want.
> >
> > I have to say that from design perspective I do not necessarily like what
> > you are trying to do.
> >
> > Best Regards,
> > Alexei
> >
> >
> > -----Original Message-----
> > From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
> > nenad pudar
> > Sent: Thursday, March 17, 2005 11:16 AM
> > To: ccielab@groupstudy.com
> > Subject: Complex real-life BGP problem
> >
> > Hi
> > I want to change the bgp next-hop from being the router receiving some
> > routes through EBGP (policy will apply to selcted routes) to be the
> > other router in network (many hops away)
> > This is for purpose of traffic balancing.
> > The problem with this that if the new next-hop-router goes down I will
> > be blackholing the selected routes from the router in question.
> > So am looking for for some kind of policy that will change next-hop
> > only if the new-next-hop router is up.
> > Simplified config looks like this
> >
> > route-map NEXT-HOP PERMIT 10
> > match as-path 33------ selected routes
> > set ip next-hope NEW ROUTER
> >
> > route-map NEXT-HOP PERMIT 20
> >
> > neighbor backbone route-map NEXT-HOP out
> >
> > The only option I see so far is to use something like this
> > set ip next-hop ADDRESS1 ADDRESS2
> > Now according to some Cisco documents if ADDRESS1 is unreachible it
> > will use ADDRESS2
> > BUT IT DOES NOT SEEM TO BE WORKING
> > EVEN IF ADDRESS1 GETS UNREACHEBLE all routers continue to have this
> > address as next-hop marked with unaccessible.
> >
> > If anybody already tried to do this or know for some option I will
> > appreciate help
> > thanks
> > nenad
> >
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