[j-nsp] load balancing in Route reflector scenario

[Ivan Ivanov]

Hello,

On this link http://goo.gl/6FgnZ from Cisco site you can find the
below quote:

"Route Reflector Limitation

When multiple iBGP paths installed in a routing table, a route reflector
will advertise only one paths (next hop). If a router is behind a route
reflector, all routers that are connected to multihomed sites will not be
advertised unless a different route distinguisher is configured for each
VRF."

To be honest I don't why is like this, but I think that with 'multipath' it
won't work.

HTH

On Wed, Aug 10, 2011 at 23:32, Humair Ali <humair.s.ali at gmail.com> wrote:

> just to clarify ,
>
> you have :
>
> PE2 with 2 link , 1 to RR1 (let's call it link 1)  and 1 to RR2 (link 2)
> PE3 with 2 link , 1 to RR1 (let's call it Link 3) and 1 to RR2  (link4)
>
> you could set local pref to link to PE2 to 150 (RR1 to PE2 will be
> preferred), and link 2 (PE2 to RR2) as standard 100
> then set link 3 standard 100 (PE3 to RR1)  but set link 4 with 150  (RR2 to
> PE3 will be preferred)
>
> then RR1 has prefered path via PE2 (via link 1 high local pref), RR2 have
> prefered path via PE3( via link 4 high local pref) , Each RR may advertise
> both route to PE1
>
> then on PE1 , u need load balancing configured , I can't guarantee either ,
> but need to be tested.
>
> On 10 August 2011 21:06, Stefan Fouant <sfouant at shortestpathfirst.net
> >wrote:
>
> > Have you tried the advertise-inactive knob on the RR? I can't guarantee
> > that this will work but it just might also advertise the route towards
> PE3
> > as well.
> >
> > Of course, if this works, then you would need to enable multipathing on
> PE1
> > accordingly.
> >
> > Stefan Fouant
> > JNCIE-M, JNCIE-ER, JNCIE-SEC, JNCI
> > Technical Trainer, Juniper Networks
> > http://www.shortestpathfirst.net
> > http://www.twitter.com/sfouant
> >
> > Sent from my iPad
> >
> > On Aug 10, 2011, at 2:44 PM, biwa net <biwa2go at gmail.com> wrote:
> >
> > > Dear All
> > >
> > > I have a setup where I need to load balancing routes received from 2 RR
> > in
> > > IPV4 environment (not VPN-IPV4)
> > >
> > > I have my  PE (let's called PE1) connected to 2 RR (cluster), my
> > destination
> > > subnet eg: 10.1.1.1/24 is behind 2 PE (PE-2 and PE3) which are also
> > client
> > > of the same 2RR
> > >
> > > PE-2 and PE3 are sending the same route 10.1.1.1/24 to the RR ,  which
> > as
> > > per normal behavior is selecting the best route to PE1  ,
> > >
> > > My issue is that RR is always advertising the route 10.1.1.1/24through
> > PE2
> > > (due to lower router id) as best path and I would like to load balanced
> > it
> > > through PE2 and PE3
> > >
> > > Anyone can recommend a way to load balance ?
> > >
> > > Unfortunately I dont have a lab to test any solution and there are live
> > > traffic on this ,so all I can do is guessing is whether the below 2
> > option
> > > would work or not.
> > >
> > > 2 option I have
> > >
> > > 1.So here I am trying to thinking about testing the multipath command
> > under
> > > the RR configuration  to see if I am receiving routes from both PE or
> not
> > ,
> > >
> > > 2.  try to put all devices them in routing instance VRF , with the BGP
> > > configuration under it (both RR and client) , and RD configured in the
> > VRF
> > > (but not putting any vpn family under bgp) so that it stays IPV4 routes
> ,
> > > maybe I could cheat the RR to believe these are 2 differentes routes
> due
> > to
> > > the RD, but dont know if this works or not .
> > >
> > > anyone has had similar issue and found a workaround ?
> > >
> > > does the 2 option above actually work or not ?
> > >
> > > thanks for any input
> > > _______________________________________________
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> >
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> >
>
>
>
> --
> Humair
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>



-- 
Best Regards!

Ivan Ivanov