Re: MPLS L3 VPN Questions

Elliot,
this has been beaten a number of times. It might be worth looking at the
archives so you get to speed.

Couple of things:
-RDs are NOT locally significant. They are part of the vpnv4 prefix!
-RDs and RTs need not match. Simple VPNs use the same value for
simplicity sake.
-It will have litle or no impact if you have one RD per PE per VPN.
RTs do the route selection magic, not RDs.

-Carlos

Elliott Reyes @ 03/06/2011 14:01 -0300 dixit:
> Hey Guys,
>
> I'm just trying to get a better understanding of how to build these
> MPLS VPN's properly and I guess the documentation and INE workbook just
> confuses me a little bit. So if anyone can assist me that would be great.
>
>
> Like Denzel in the movie Philadelphia. Explain it to me like I'm a 6 year
> old.
>
> 1. When defining the VRF's between two PE routers.
>
>
> Example
>
> R1
>
> Step 1 - Create VRF locally on R1
>
> ip vrf VPN_A
>
> rd 100:1 <---- ROUTE DISTINGUISHER (This is locally significant to R1 and
> add's a 8 byte value to IPV4 prefix to create a VPNIPV4 prefix. )
>
>
> Step 2 - Assign Route-Target command
> route-target both 100:1 <----- allows routing information from to traverse
> from R1 VPN_A to R2 VPN_A thru their connected interfaces and import/export
> routing information.
>
> R1 <----------> R2
>
> int fa0/1 (R1)
> ip vrf forwarding VPN_A
> ip add 10.1.1.1 255.255.255.0
>
>
> R2
>
> Step 1 - Create VRF locally on R2
>
> ip vrf VPN_A
>
> rd 100:1 <---- ROUTE DISTINGUISHER (This is locally significant to R2 and
> add's a 8 byte value to IPV4 prefix to create a VPNIPV4 prefix. )
>
>
> Step 2 - Assign Route-Target command
> route-target both 100:1 <----- allows routing information from to traverse
> from R2 VPN_A to R1 VPN_A thru their connected interfaces and import/export
> routing information.
>
> Question - Does the route-target have to match the route distinguisher on
> both ends. if the route-target is say 100:2 and the route distinguisher is
> 100:1 on VPN_A this technically shouldn't work
> across the VPN correct.
>
> R2 <----------> R1
>
> int fa0/1 (R2)
> ip vrf forwarding VPN_A
> ip add 10.1.1.2 255.255.255.0
>
>
> thanks
>
>
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-- 
Carlos G Mendioroz  <tron_at_huapi.ba.ar>  LW7 EQI  Argentina
Blogs and organic groups at http://www.ccie.net