[j-nsp] track-igp-metric in LDP

[Dave Bell]

If you are running next hop self on your BGP routes at the edge, the best
path will be via a loopback in an  LSP.

If you have two identical routes, one of the tie breakers is IGP
preference. If that knob isn’t set the IGP cost will be 1 for everything,
and you will progress down to less helpful tue breakers like router id.

Regards,
Dave

On Sun, 2 Aug 2020 at 11:58, Chen Jiang <ilovebgp4 at gmail.com> wrote:

> Hi! Michael
>
> Thanks for your clarification.
>
> Sure, it will let LDP use IGP metric, but is there any benefit?
>
> Cause per my understanding LDP only works for label distributing, not path
> selection, and LDP always follows the IGP path, so what is the difference
> or benefit to add additional configuration knob to let LDP use IGP metric?
>
> BR!
>
> Chen Jiang
>
> On Sun, Aug 2, 2020 at 6:32 PM Michael Hallgren <mh at xalto.net> wrote:
>
> > Hi James,
> >
> > From memory, Junos assigns metric 1 by default to "LDP routes", not IGP
> > metric, unless you push this button.
> >
> > Cheers,
> > mh
> > ------------------------------
> > *De :* Chen Jiang <ilovebgp4 at gmail.com>
> > *Envoyé :* dimanche 2 août 2020 12:10
> > *À :* Juniper List
> > *Objet :* [j-nsp] track-igp-metric in LDP
> >
> > Hi! Experts
> >
> > Sorry for disturbing, I am curious about track-igp-metric knob under LDP,
> > is there any scenarios it will be useful? I think ldp is just a label
> > distribution protocol, the forwarding path always follows the IGP
> shortest
> > path, is there any benefit for using track-igp-metric?
> >
> > Thanks for your help!
> >
> > --
> > BR!
> >
> >
> >
> >            James Chen
> > _______________________________________________
> > juniper-nsp mailing list juniper-nsp at puck.nether.net
> > https://puck.nether.net/mailman/listinfo/juniper-nsp
> >
>
>
> --
> BR!
>
>
>
>            James Chen
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