Re: MPLS Route Targets

Carlos,

I did not miss your point. YOU MISSED YOUR POINT.
You need to pay attention Sir. You did not complete your lab testing before
making yet another incorrect assumption. That's 4 times in this thread.

Did I not tell you that I modified the path using LOCAL PREFERENCE to choose
the very same prefix using 2 unique RD's? How can you say that " If you use
different RDs then BGP does not compare those routes *while they are vpnv4
routes*."

You are making absolutely NO SENSE. Your lab output does not reflect the
complete story. Also, the fact that you continue to try and prove yourself
correct in spite of the evidence you provided, incomplete if I might add,
proves you have more issues than just observing MPLS behaviors.

Here, let me show you how to test something.

A) This is the topology

C PE P PE C
R1 -> R2 -> R3 - > R4 -> R5
                | ^
                | |
                |
                |----> R6 -> R7
                       PE C

B) Here is the VPNv4 Table on R2 prior to routing changes.

R2#sh ip bgp vpnv4 all
BGP table version is 1, local router ID is 200.200.200.2
Status codes: s suppressed, d damped, h history, * valid, > best, i -
internal,
              r RIB-failure, S Stale
Origin codes: i - IGP, e - EGP, ? - incomplete

   Network Next Hop Metric LocPrf Weight Path
Route Distinguisher: 65000:1001
* i5.0.0.0 200.200.200.4 0 100 0 65015 i
* i7.0.0.0 200.200.200.4 0 100 0 65015 i
* i55.0.0.0 200.200.200.4 0 100 0 65015 i
* i77.0.0.0 200.200.200.4 0 100 0 65015 i
Route Distinguisher: 65000:1002
* i5.0.0.0 200.200.200.6 0 100 0 65015 i
* i7.0.0.0 200.200.200.6 0 100 0 65015 i
* i55.0.0.0 200.200.200.6 0 100 0 65015 i
* i77.0.0.0 200.200.200.6 0 100 0 65015 I

2 different sets of routes from 2 different PE's with 2 different RD's. They
are the same prefixes, but not to MP-BGP.

C) Here is the output of R6 prior to changing the policy.

R6#sh ip bgp vpnv4 all
BGP table version is 53, local router ID is 200.200.200.6
Status codes: s suppressed, d damped, h history, * valid, > best, i -
internal,
              r RIB-failure, S Stale
Origin codes: i - IGP, e - EGP, ? - incomplete

   Network Next Hop Metric LocPrf Weight Path
Route Distinguisher: 65000:1001
*>i5.0.0.0 200.200.200.4 0 100 0 65015 i
*>i7.0.0.0 200.200.200.4 0 100 0 65015 i
*>i55.0.0.0 200.200.200.4 0 100 0 65015 i
*>i77.0.0.0 200.200.200.4 0 100 0 65015 i
Route Distinguisher: 65000:1002 (default for vrf VPNB)
* i5.0.0.0 200.200.200.4 0 100 0 65015 i
*> 131.1.67.7 0 65015 i
* i7.0.0.0 200.200.200.4 0 100 0 65015 i
*> 131.1.67.7 0 0 65015 i
* i55.0.0.0 200.200.200.4 0 100 0 65015 i
*> 131.1.67.7 0 65015 i
* i77.0.0.0 200.200.200.4 0 100 0 65015 i
*> 131.1.67.7 0 0 65015 I

R6 has options from PE4 and itself due to the matching Route-Targets. 2
different RD's.

D) here we apply and verify the policy:

R6(config)#router bgp 65000
R6(config-router)#address ipv4 vrf VPNB
R6(config-router-af)#neighbor 131.1.67.7 route-map LOCALPREF in

R6#sh ip bgp vpnv4 all
BGP table version is 61, local router ID is 200.200.200.6
Status codes: s suppressed, d damped, h history, * valid, > best, i -
internal,
              r RIB-failure, S Stale
Origin codes: i - IGP, e - EGP, ? - incomplete

   Network Next Hop Metric LocPrf Weight Path
Route Distinguisher: 65000:1000
*>i1.0.0.0 200.200.200.2 0 100 0 65015 i
*>i11.0.0.0 200.200.200.2 0 100 0 65015 i
Route Distinguisher: 65000:1001
*>i5.0.0.0 200.200.200.4 0 100 0 65015 i
*>i7.0.0.0 200.200.200.4 0 100 0 65015 i
*>i55.0.0.0 200.200.200.4 0 100 0 65015 i
*>i77.0.0.0 200.200.200.4 0 100 0 65015 i
Route Distinguisher: 65000:1002 (default for vrf VPNB)
*>i1.0.0.0 200.200.200.2 0 100 0 65015 i
* i5.0.0.0 200.200.200.4 0 100 0 65015 i
*> 131.1.67.7 200 0 65015 i
* i7.0.0.0 200.200.200.4 0 100 0 65015 i
*> 131.1.67.7 0 200 0 65015 i
*>i11.0.0.0 200.200.200.2 0 100 0 65015 i
* i55.0.0.0 200.200.200.4 0 100 0 65015 i
*> 131.1.67.7 200 0 65015 i
   Network Next Hop Metric LocPrf Weight Path
* i77.0.0.0 200.200.200.4 0 100 0 65015 i

Notice how the PE not only sets the routes in MP-BGP VPNV4 context but it
also makes a routing decision and passes on the BEST routes. Just as you
thought.

E) The PE2 VPNv4 peer not only sees the LocalPreference but obeys it's
wishes. From 2 different PE's that have 2 different RD's concerning the same
prefixes.

R2#sh ip bgp vpnv4 all
BGP table version is 33, local router ID is 200.200.200.2
Status codes: s suppressed, d damped, h history, * valid, > best, i -
internal,
              r RIB-failure, S Stale
Origin codes: i - IGP, e - EGP, ? - incomplete

   Network Next Hop Metric LocPrf Weight Path
Route Distinguisher: 65000:1000 (default for vrf VPNA)
*> 1.0.0.0 131.1.12.1 0 0 65015 i
*>i5.0.0.0 200.200.200.6 0 200 0 65015 i
*>i7.0.0.0 200.200.200.6 0 200 0 65015 i
*> 11.0.0.0 131.1.12.1 0 0 65015 i
*>i55.0.0.0 200.200.200.6 0 200 0 65015 i
*>i77.0.0.0 200.200.200.6 0 200 0 65015 i
Route Distinguisher: 65000:1002
*>i5.0.0.0 200.200.200.6 0 200 0 65015 i
*>i7.0.0.0 200.200.200.6 0 200 0 65015 i
*>i55.0.0.0 200.200.200.6 0 200 0 65015 i
*>i77.0.0.0 200.200.200.6 0 200 0 65015 i

What? It sets the routes in a different RD? I'm sure you are still puzzled.
I am so happy for the rest of the forum that I am not.

Like I said, I will protect the Integrity of the Forum by eliminating Facts
that are materialized through presumption and invalid or incomplete testing.
You should have stuck with your original posture...here it is:
You admitted that you "have never labbed nor have experience in
inter-AS mpls vpn." That statement is why you were and still are confused
about how RD's work.

 The reason why I mentioned NAT, which you also missed, is to make the point
that although the routes are kept separate, that does not excuse the C
routers from making mistakes. By NOT making the RD's match, the customer
cannot blame the cloud for the Route not making it to the other side. It is
also very useful for troubleshooting in a NOC environment.

I did not mean to come off irritated but this was getting out of hand. You
should have unicasted me to get your facts straight before we presented it
to the forum for the benefit of all. If you are an instructor, I hope you
don't do this to your students or I might have to change your name to the
Minister of Misinformation.

Paul

-- 
Paul Negron
CCIE# 14856 CCSI# 22752
Senior Technical Instructor
www.micronicstraining.com
> From: Carlos G Mendioroz <tron_at_huapi.ba.ar>
> Date: Tue, 24 Aug 2010 14:01:51 -0300
> To: Paul Negron <negron.paul_at_gmail.com>
> Cc: Narbik Kocharians <narbikk_at_gmail.com>, Adam Booth <adam.booth_at_gmail.com>,
> Brad Edgeworth <edgie512_at_gmail.com>, Cisco certification
> <ccielab_at_groupstudy.com>
> Subject: Re: MPLS Route Targets
> 
> Paul,
> you are missing my point. I said that same RD was needed if the routes
> referred to the same network.
> 
> NAT makes no sense if this is the case!
> 
> My test was to have a direct comparison of the outcome of doing it
> one way or the other (common RD or different RD). So the idea is that
> there is one VPN that has two PEs with access to the same network.
> 
> If you use same RD, you'll get BGP to do its thing and elect the best
> route on intermediate nodes. If you use different RDs then BGP
> does not compare those routes *while they are vpnv4 routes*.
> 
> -Carlos
> 
> Paul Negron @ 24/8/2010 13:44 -0300 dixit:
>> Cool.
>> 
>> As you saw. The fact they come into 1 BGP RIB is why you are still able to
>> retain route policy between them. It just keeps them from looking the same
>> if both clients used the same IP Addressing scheme. Your 10.0.0.0 in this
>> case. They are technically 3 different routes that terminate to the same
>> place.
>> 
>> The clients may have to run NAT or the provider can do it but only if the
>> customer still uses the same addressing scheme on both sides of the cloud.
>> 
>> Paul
> 
> -- 
> Carlos G Mendioroz  <tron_at_huapi.ba.ar>  LW7 EQI  Argentina
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