Re: Question about overlapping IP space and L3VPN central

You can use import/export maps for more granular control over which routes get imported.

Obviously you're going to have problems if you import all routes from customers with overlapping address space.

 - Lindsay
On 30/07/2012, at 11:12 AM, John Neiberger <jneiberger_at_gmail.com> wrote:

> I'm just now getting around to really studying L3VPN. I'm playing around
> with GNS3 while watching some training videos and my latest little lab
> setup involves configuring basic central services. For the sake of
> discussion, imagine three VRFs: A, B and C, as well as a new VRF called
> SERVICES. I have customers in these VRFs spread out across the network, and
> they do use overlapping IP space. When I configured this in my lab with one
> customer, I found (remember, I'm new to this!) that I had to import the
> customer routes into the new SERVICES VRF, which makes sense. Without those
> routes in the VRF, the router can't forward packets to those destinations
> even if the correct routes exist in other VRFs on that router.
>
> But what happens when I import another customer into that table? Let's say
> the VPN associated with VRF A is using 10/8 space, and so it the VPN
> associated with VRF B. If I have already imported the routes for Customer A
> into my Services VRF, how is this going to behave if I then import the
> routes for Customer B using the same space? I realize that VPNv4 routes are
> kept unique with the use of an RD. Does a PE router do something similar
> when importing multiple sets of routes into a VRF? Does it retain the RD to
> keep them unique somehow? If not, how do I handle having to import
> overlapping prefixes to make central services work?
>
> Thanks!
> John
>
>
> Blogs and organic groups at http://www.ccie.net
>
> _______________________________________________________________________
> Subscription information may be found at:
> http://www.groupstudy.com/list/CCIELab.html

Blogs and organic groups at http://www.ccie.net
Received on Mon Jul 30 2012 - 14:31:07 ART