[c-nsp] Large scale "central services" VRF, best practice?

[Peter Rathlev]

On Fri, 2011-03-18 at 09:31 -0400, schilling wrote:
> I don't think any of them will work.  The router import and export has
> to be symmetric if you want bidirectional communication.
[...]

But how was that not acheived in all the three scenarios I described?
Your suggestion:

>      ip vrf A
>       rd 1:1
>       route-target both 1:1
>       route-target import 1:3
>      !
>      ip vrf B
>       rd 1:2
>       route-target both 1:2
>       route-target import 1:3
>      !
>      ip vrf Central_Services
>       rd 1:3
>       route-target both 1:3
>       route-target import 1:1
>       route-target import 1:2

... just does it in a fourth way, using only import statements.

I fail to see how "route-target import <VRF Y>" in VRF X is any
different from "route-target export <VRF X>" in VRF Y. Am I missing
something?

-- 
Peter