On 21/Jun/20 12:45, Baldur Norddahl
wrote:
Yes I once made a plan to have one VRF per transit
provider plus a peering VRF. That way our BGP customers
could have a session with each of those VRFs to allow them
full control of the route mix. I would of course also need a
Internet VRF for our own needs.
But the reality of that would be too many copies of the
DFZ in the routing tables. Although not necessary in the FIB
as each of the transit VRFs could just have a default route
installed.
We just opted for BGP communities :-).
Not really the same. Lets say the best path is through transit 1 but the customer thinks transit 1 sucks balls and wants his egress traffic to go through your transit 2. Only the VRF approach lets every BGP customer, even single homed ones, make his own choices about upstream traffic.
You would be more like a transit broker than a traditional ISP with a routing mix. Your service is to buy one place, but get the exact same product as you would have if you bought from top X transits in your area. Delivered as X distinct BGP sessions to give you total freedom to send traffic via any of the transit providers.
This is also the reason you do not actually need any routes in the FIB for each of those transit VRFs. Just a default route because all traffic will unconditionally go to said transit provider. The customer routes would still be there of course.
Regards,
Baldur