[j-nsp] Question on "auto-export" Layer 3 VPN

[Keegan Holley]

2011/8/25 Daniel Roesen <dr at cluenet.de>

> On Thu, Aug 18, 2011 at 11:04:03AM +0530, MSusiva wrote:
> > Can someone please help me understand the following,
> >
> > * Why do I need to configure "auto-export" on Hub router?
> >
> > If I remove the "auto-export" on the Hub router, I'm not receiving the
> > local, direct & static routes from the Spokes.
>
> Hope that helps:
>
> http://kb.juniper.net/library/CUSTOMERSERVICE/GLOBAL_JTAC/auto-export-understanding.pdf


I have to say I found this confusing and I already know what auto-export
does.  So by default juniper will not export routes learned locally by a PE
to vrf's on that same PE even if they match the export policies.  The pdf
says it's split horizon type behavior, but I always thought it was because
the routes were never exported into BGP so the extended communities never
get applied.  Whatever the reason, auto-export makes those
routes eligible to be copied between VRF's local to a PE.