Re: [Idr] RFC 4684 pedantry - routes with no Route Target

[Jeffrey Haas <[e-mail]>]

On Wed, May 21, 2014 at 06:46:03PM +0200, Robert Raszuk wrote:
> Assume I do have a valid SR application to filter tiny subset of
> Internet table. For this I can mark such tiny subset of routes with
> RTs, enable RTC and activate RT filtering on IPv4 session.

After letting this thought get some of my background thinking time during a
very nice vacation, I think you've identified a key argument.  When the
expectation is you want to apply RT-C to an AF that isn't normally VPN-like
(and we've identified we may want to generally do this), the routes may not
be normally tagged with RTs.

This suggests the behavior we want may be:
- Permit a per-peer, per-AFI/SAFI knob to enable/disable RT-C processing.
  JUNOS, e.g., filters VPN families by default.
- Provide for exceptions to the rule and document them.

That second point covers the MDT scenario.  It also suggests that IDR should
probably make sure the other WGs using BGP as a transport for their VPNs or
otherwise using RTs should be reminded that RT-C exists and their extensions
had best document their interaction with it if they inconsistently RT tag
their routes.

-- Jeff