[j-nsp] MPLS VPN BGP Local Convergence

[Adam Vitkovsky]

Right the documentation is concerning the BGP PIC Edge just for MPLS L3VPNs and in a context that it is a remedy for only PE failure not the CE-PE link failure (I'll assume the draft has been followed though). 
But now I'm thinking since it's configured under the routing options -wouldn't it work for all AFs i.e. non VPN traffic as well? 
Has anyone tested that please? 
Or has anyone tested the Junos BGP PIC Edge for CE-PE link failure for that matter? 

 
adam
> -----Original Message-----
> From: juniper-nsp [mailto:juniper-nsp-bounces at puck.nether.net] On Behalf
> Of Adam Vitkovsky
> Sent: 20 January 2015 23:08
> To: Saku Ytti; juniper-nsp at puck.nether.net
> Subject: Re: [j-nsp] MPLS VPN BGP Local Convergence
> 
> Hi Saku,
> 
> Yeah the "BGP local convergence" is an old one indeed from days where we
> had to run iBGP multipath load sharing to get two paths programed into the
> HW.
> However this feature is essential for fast convergence.
> 
> This feature prevents from blackholing during BGP convergence in cases
> where you have primary and backup egress PEs and  a PE-CE link fails on the
> primary PE.
> While the BGP infrastructure is converging the ingress PEs keep on sending
> data towards the primary PE with the failed PE-CE link that would otherwise
> drop the packets.
> Primary PE running "MPLS VPN BGP Local Convergence" feature will keep the
> VPN(e.g. per in-vrf-NH) label for the failed link for some time (which would
> be otherwise released).
> But the label no longer points to the egress PE-CE in-vrf-NH but now it points
> to a NH label on the path towards the backup PE.
> So that's how the Primary PE does kind of local repair till the BGP converges
> and ingres PEs start using backup PE as the NH for the VPN prefixes.
> 
> Right solving a PE router failure is easy as IGP will notify all PEs in no time and
> they can then start using the preinstalled backup path(PIC)  or just reprogram
> the chained NHs to point to an alternate forwarding NH which should be
> fairly quick as well.
> 
> But with failed CE-PE link all you've got to let everybody know is the slow BGP
> process (unless you put your CE-PE links into IGP which is the way it was
> done back in the old old days - pure ipv4 BGP core).
> This is where the BGP local convergence feature becomes handy.
> 
> adam
> > -----Original Message-----
> > From: juniper-nsp [mailto:juniper-nsp-bounces at puck.nether.net] On
> Behalf
> > Of Saku Ytti
> > Sent: 20 January 2015 18:49
> > To: juniper-nsp at puck.nether.net
> > Subject: Re: [j-nsp] MPLS VPN BGP Local Convergence
> >
> > On (2015-01-20 16:57 +0000), Adam Vitkovsky wrote:
> >
> > > Hi Folks,
> > >
> > > Is there an equivalent to the "MPLS VPN BGP Local Convergence" feature
> > on Junos please?
> > > Possibly for non VPN prefixes as well.
> >
> >
> http://www.juniper.net/documentation/en_US/junos14.2/topics/task/confi
> > guration/layer3-vpn-bgp-pic-edge-configuring.html
> >
> > I don't really recall difference in 'local convergence' and BGP PIC, but I
> > seem to recall, 'local convergence' didn't install backup path, but
> > recalculated it when fault occurred.
> > I don't know if this inferior version is available in JunOS or if you'd even
> > want to run it, if it were.
> >
> > <rant>
> > Unfortunately only for VPN. Why oh why do we have concept of global
> table
> > and
> > VRF, INET should in same code path as VRF, with no special treatment.
> > Juniper
> > still introduced in 14.2 features that work only in global table. This feature
> > disparity between global and vrf is highly annoying. And I'm sure it adds
> > development costs to consider these different things. Rather than pay one
> > time
> > cost to redesign the legacy code, vendors opt to pay for decades to support
> > the old architecture which things they are different things.
> > </rant>
> >
> >
> > --
> >   ++ytti
> > _______________________________________________
> > juniper-nsp mailing list juniper-nsp at puck.nether.net
> > https://puck.nether.net/mailman/listinfo/juniper-nsp
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