[c-nsp] how can i use all 3 of these routes for load sharring?

[Andrew Koch]

On Wed, Jul 25, 2012 at 10:34 AM, Aaron <aaron1 at gvtc.com> wrote:
> Any idea why I see 3 default routes in bgp but only 2 get put into rib?  How
> would I get all 3 of these into rib?

Aaron, you will want to review this BGP best-path selection algorithm
http://www.cisco.com/en/US/tech/tk365/technologies_tech_note09186a0080094431.shtml

Take particular note at which point the algorithm no longer applies
when multi-path is used (step 8 and beyond).

I snipped the relevant bits from each route here -
Notice that you have different Metric (MED) and different Origin on
the first two compared to the third. As these are used by the
algorithm before step 8, they do affect your multi-path selection, and
thus the third route is not used as part of your multi-path.

>
> RP/0/RSP0/CPU0:9k#sh bgp vrf one 0.0.0.0
>     10.101.0.1 (metric 3) from 10.101.0.1 (10.101.0.1)
>       Origin incomplete, metric 1, localpref 100, valid, internal,
> multipath, import-candidate, imported
>
>     10.101.0.2 (metric 2) from 10.101.0.2 (10.101.0.2)
>       Origin incomplete, metric 1, localpref 100, valid, internal, best,
> group-best, multipath, import-candidate, imported
>
>     2.4.6.45 from 2.4.6.45 (1.3.9.173)
>       Origin IGP, localpref 100, valid, external, group-best

HTH,
Andy