[c-nsp] PFR Question
David Prall
dcp at dcptech.com
Thu Mar 25 14:59:29 EDT 2010
1)
On PE1
vrf description customer
rd 1:1
route-target both 1:1
route-target import 1:2
On PE2
vrf description customer
rd 1:2
route-target both 1:2
route-target import 1:1
In a multipath instance PE1 will install the Equal Cost route with rd 1:1
first, using 1:2 as a secondary path only. Opposite on PE2.
2)
Could use different VRF's. Just like dual carriers. A key concern is a dual
failure, site 1 on network 1 and site 2 on network 2. The customer will need
to provide a path between the two networks via one of their sites.
David
--
http://dcp.dcptech.com
> -----Original Message-----
> From: jack daniels [mailto:jckdaniels12 at gmail.com]
> Sent: Thursday, March 25, 2010 2:41 PM
> To: David Prall
> Cc: cisco-nsp at puck.nether.net
> Subject: Re: [c-nsp] PFR Question
>
> Hi David ,
>
> thanks man I got the basic idea :)
>
> 1) but please explain in more detail this
>
> Single VRF, 2 distinct RD's. The VRF imports both, exports one. The
> RD's are
> different so that multipath can be used within the core typically. But
> in
> this case they wouldn't use multipath and the local RD would be used as
> the
> determining factor on import of which route is installed first.??????
>
>
> 2) Also if I use diffrent VRF for CE4---CE2 path that will also work -
> ??
>
>
> On Thu, Mar 25, 2010 at 11:57 PM, David Prall <dcp at dcptech.com> wrote:
>
>
> If the link goes away, then the update should be pretty quick.
>
> Single VRF, 2 distinct RD's. The VRF imports both, exports one.
> The RD's are
> different so that multipath can be used within the core
> typically. But in
> this case they wouldn't use multipath and the local RD would be
> used as the
> determining factor on import of which route is installed first.
>
> The local CE (CE3) is probing for the subnet at CE1. When it is
> no longer
> reachable by CE3 it will move the route to CE4. As long as CE4 is
> using CE2
> as the path via the cloud then no issue.
>
>
> David
>
> --
> http://dcp.dcptech.com <http://dcp.dcptech.com/>
>
>
> > -----Original Message-----
> > From: jack daniels [mailto:jckdaniels12 at gmail.com]
>
> > Sent: Thursday, March 25, 2010 2:19 PM
> > To: David Prall
> > Cc: cisco-nsp at puck.nether.net
> > Subject: Re: [c-nsp] PFR Question
> >
>
> > 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.????
> > DO YOU mean we need to have diifrent vrf on secondry end to end
> path.
> >
> > I didnt get this if single carrier as link PE1 and CE1 link
> fails
> > ....CE3 send traffic for X.X.X.X to PE3.PE3 still has next hop
> in its
> > vrf table as PE1....
> >
> >
> >
> >
> > Please help me as still confused if two carriers , how will
> this
> > hhappen
> >
> >
> > On Thu, Mar 25, 2010 at 11:29 PM, David Prall <dcp at dcptech.com>
> wrote:
> >
> >
> > 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 <http://dcp.dcptech.com/>
> <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/>
> <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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> nsp at puck.nether.net
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> nsp
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> > >
> > >
> > >
> >
> >
> >
> >
>
>
>
>
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