[rbak-nsp] bgp bestpath igp-metric ignore

[Yuri Shefer]

Hi Jim,

When separate BGP speakers are configured to announce the best path and
diverse path, and IGP cost is used to select the best path, if costs differ
between the BGP speakers, one speaker's best path might be the other's
diverse path. In such cases, both speakers announce the same path, failing
to achieve the desired path diversity. The "bestpath igp-metric ignore"
command causes the router to discard the IGP cost and restores path
diversity.

Example:

context bgp
!
 router bgp 123
  address-family ipv4 unicast
   bestpath igp-metric ignore



On Wed, Nov 6, 2013 at 6:17 AM, Jim Tyrrell <jim at scusting.com> wrote:

> Below was the 'show bgp route 0.0.0.0/0'.  Here is the show ip route:
>
> #sh ip route 0.0.0.0/0
>     Best match Routing entry for 0.0.0.0/0 is 0.0.0.0/0 , version 30320
>     Route Uptime 01:37:15
>     Paths: total 1, best path count 1
>
>     Route has been downloaded to following slots
>       iPPA: 01 04
>
>     Path information :
>
>       Active path :
>       Known via bgp 6510, type-Internal BGP, distance 200, metric 0,
>       Tag 0, Next-hop 192.168.9.123, NH-ID 0x31200008, Advertising
> router 192.168.9.11
>
> Jim.
>
> On 06/11/2013 13:18, Olivier Benghozi wrote:
> > Hi Jim,
> > I suppose you already checked this, but who knows...
> > What does say a show ip route for these ones ? :)
> >
> >
> > Le 6 nov. 2013 à 13:46, Jim Tyrrell <jim at scusting.com> a écrit :
> >
> >> Is it possible to configure BGP to ignore the IGP metric for bestpath
> >> selection?  I have configured BGP with 'multi-paths internal 2' but BGP
> >> is only using a single path as the IGP metrics to the 2 route reflectors
> >> are different:
> >>
> >> Local
> >>  Nexthop 192.168.9.123 (11), peer 192.168.9.11 (192.168.9.123), AS 6510
> >>  Origin IGP, localpref 10000, med 0, weight 100, internal, best
> >>  Originator: 192.168.9.123, Cluster list: 192.168.9.11
> >>  Community: 6510:0
> >>
> >>
> >> Local
> >>  Nexthop 192.168.9.121 (12), peer 192.168.9.13 (192.168.9.121), AS 6510
> >>  Origin IGP, localpref 10000, med 0, weight 100, internal
> >>  Originator: 192.168.9.121, Cluster list: 192.168.9.13
> >>  Community: 6510:0
> >>
> >> In Cisco you can configure 'bgp bestpath igp-metric ignore', but I cant
> >> see this or an equivalent on the SmartEdge? (SEOS v11).  Does this
> >> option exist or an alternative that will achieve this?
> >
>
>
-- 
Kind regards,
Yuri
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