Re: ospf distance

As Marc said, distance is a parameter we can use to set a preference INSIDE
the same routing protocol
Distance is a differentiation between different protocols

Another example would to configure the following :

distance ospf inter-area 110 intra-area 180
This would allow eigrp external routes to be preferred over OSPF intra-area
routes
BUT inside OSPF intra-area routes would still be prefered over inter-area
since distance is not taken into account inside OSPF

To prefer inside OSPF, I see 2 solutions :
B - play with metric-type : intra-area is better than inter-area which is
better than external 1 with is better than external 2 (or N1/N2 for NSSA
area)
B - play with metric (lower cost)

Route filtering is another option

Hope that is clear.

> Message du 25/07/12 C 15h49
> De : "shekhar sharma"
> A : "Aaron"
> Copie C : "Gilles FABRE" , "Cisco certification"
> Objet : Re: ospf distance
>
> Aaron,
>
> i know numerous ways to disable load-balance.....
>
> But i want to check the particularly its beaviour with distance .......thts
> nt wrking in my case......
>
>
>
>
> On Wed, Jul 25, 2012 at 5:38 PM, Aaron wrote:
>
> > isn't that to be expected since you altered learned routes from 150.1.4.4
> > to
> > all be same AD.....and then if they have same metric LB will occur. If
you
> > don't won't load balancing, perhaps alter ip ospf cost on one of your
> > interfaces towards 142.1.0.4 or 142.1.0.3. I see them on s0/0.....is that
> > over a frame relay cloud? If so can you alter metric or cost in a frame
> > relay map and make one look less attractive than the other? Or perhaps
put
> > them on subinterfaces as p-to-p and do the aforementioned ip ospf cost on
> > R5's subint towards the less desireable next hop
> >
> > -----Original Message-----
> > From: nobody_at_groupstudy.com [mailto:nobody_at_groupstudy.com] On Behalf Of
> > shekhar sharma
> > Sent: Wednesday, July 25, 2012 7:40 AM
> > To: Gilles FABRE
> > Cc: Cisco certification
> > Subject: Re: ospf distance
> >
> > Try that already ,
> >
> > Distance changed but still it load-balance
> >
> > R5(config)#router ospf 1
> > R5(config-router)#distance 109 150.1.4.4 0.0.0.0
> >
> > R5#sh ip route 142.1.34.3
> > Routing entry for 142.1.34.0/24
> > Known via "ospf 1", distance 109, metric 65, type intra area
> > Last update from 142.1.0.4 on Serial0/0, 00:01:16 ago
> > Routing Descriptor Blocks:
> > 142.1.0.4, from 150.1.4.4, 00:01:16 ago, via Serial0/0
> > Route metric is 65, traffic share count is 1
> > * 142.1.0.3, from 150.1.4.4, 00:01:16 ago, via Serial0/0
> > Route metric is 65, traffic share count is 1
> >
> >
> >
> >
> > On Wed, Jul 25, 2012 at 4:12 PM, Gilles FABRE
> > wrote:
> >
> > > For OSPF, you should refer not to neighbor adress but router-id
> > >
> > > please try instead :
> > >
> > > distance 109 150.1.4.4 0.0.0.0
> > >
> > > Best regards.
> > >
> > > > Message du 25/07/12 ` 12h02
> > > > De : "shekhar sharma"
> > > > A : "Cisco certification"
> > > > Copie ` :
> > > > Objet : ospf distance
> > >
> > > >
> > > > Hi All,
> > > >
> > > >
> > > > I was working with manipulating OSPF distance.
> > > >
> > > > Not able to change ospf distance per neigbour...Not sure if this is
> > > config
> > > > issue or OSPF doesn't support it like EIGRP
> > > >
> > > > R5(config-router)#router ospf 1
> > > > R5(config-router)#distance 109 142.1.0.4 0.0.0.0
> > > >
> > > > R5#sh ip route 142.1.34.4
> > > > Routing entry for 142.1.34.0/24
> > > > Known via "ospf 1", distance 110, metric 65, type intra area Last
> > > > update from 142.1.0.4 on Serial0/0, 00:00:36 ago Routing Descriptor
> > > > Blocks:
> > > > 142.1.0.4, from 150.1.4.4, 00:00:36 ago, via Serial0/0 Route metric
> > > > is 65, traffic share count is 1
> > > > * 142.1.0.3, from 150.1.4.4, 00:00:36 ago, via Serial0/0 Route
> > > > metric is 65, traffic share count is 1 Regards, Shekhar
> > > >
> > > >
> > > > Blogs and organic groups at http://www.ccie.net
> > > >
> > > >
Received on Wed Jul 25 2012 - 16:22:39 ART