[c-nsp] PFR Question

[David Prall]

Is MPLS Domain a single carrier, or two carriers. If two carriers then the
CE3/CE4 site will see that they can't reach via CE3/CE1 path and switch over
to CE4/CE2 path. If a single carrier, then the CE4/CE2 path needs to be via
a second RD so that the paths within the carrier are preferred and the same
will happen. PfR is providing end-to-end reachability information in this
case, and based on that changing the local routing table. 

David

--
http://dcp.dcptech.com


> -----Original Message-----
> From: jack daniels [mailto:jckdaniels12 at gmail.com]
> Sent: Thursday, March 25, 2010 1:07 PM
> To: David Prall
> Cc: cisco-nsp at puck.nether.net
> Subject: Re: [c-nsp] PFR Question
> 
> But if you have --
> 
> 
>                       |CE1--------PE1
> PE3--------CE3
>  X.X.X.X---------|                 --------------------MPLS DOMAIN-----
> --------------
>                      |  CE2--------PE2
> PE4--------CE4
> 
> 
> Now my primary link is CE1-PE1 and secondary is CE2-PE2
> If my CE1-PE1 goes down i route traffic via CE2-PE2<<<<<<I understand
> this ok...
> 
> when traffic from CE3 for X.X.X.X reaches PE3 , next hop is still PE1 (
> as MPBGP has not converged so fast in MPLS domain of SP) ...so how will
> traffic be forwareded , as PFR claims 3 sec.
> 
> 
> On Thu, Mar 25, 2010 at 10:16 PM, David Prall <dcp at dcptech.com> wrote:
> 
> 
> 	PfR is a unidirectional feature. The router on the other end
> needs to be
> 	configured with PfR as well in order to have bidirectional
> visibility.
> 	Typically the master controller will be local to the site.
> 
> 	--
> 	http://dcp.dcptech.com <http://dcp.dcptech.com/>
> 
> 
> 
> 	> -----Original Message-----
> 	> From: cisco-nsp-bounces at puck.nether.net [mailto:cisco-nsp-
> 	> bounces at puck.nether.net] On Behalf Of jack daniels
> 	> Sent: Thursday, March 25, 2010 12:35 PM
> 	> To: cisco-nsp at puck.nether.net
> 	> Subject: Re: [c-nsp] PFR Question
> 	>
> 	> dear guys,
> 	>
> 	> is my mail being delivered to group as no one replied.
> 	>
> 	> On Wed, Mar 24, 2010 at 11:42 PM, jack daniels
> 	> <jckdaniels12 at gmail.com>wrote:
> 	>
> 	> > Hi Network champs,
> 	> >
> 	> > I'm stuck in understanding of PFR . Docs say it converges in
> 3 sec (
> 	> for
> 	> > realtime traffic VOICE )...
> 	> >
> 	> > I understand you can send traffic out secondry link but what
> about
> 	> traffic
> 	> > which has to come back from remote end ( for which SP has not
> 	> converged).
> 	> >
> 	> > But if you have --
> 	> >
> 	> >
> 	> >
> 	> > |CE1--------PE1
> 	> > PE3--------CE3
> 	> >  X.X.X.X---------|                 --------------------MPLS
> 	> > DOMAIN-------------------
> 	> >                      |  CE2--------PE2
> 	> > PE4--------CE4
> 	> >
> 	> >
> 	> > Now my primary link is CE1-PE1 and secondary is CE2-PE2
> 	> > If my CE1-PE1 goes down i route traffic via CE2-PE2<<<<<<I
> understand
> 	> this
> 	> > ok...
> 	> >
> 	> >
> 	> > BUT MY QUESTION IS -
> 	> >
> 	> > PE3 and PE4 ( for this VRF) still has NOW converged the BGP
> and still
> 	> for
> 	> > it next hop for X.X.X.X is PE1. So how fwd can happen in 3
> sec untill
> 	> > Service providers all routers dont converge and understand
> that CE1-
> 	> PE1 link
> 	> > is down.
> 	> >
> 	> >
> 	> > Regards
> 	> >
> 	> >
> 
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