We have two separate/disparate networks (separate upstream providers, different IP networks, supernets, etc...). Both networks have BGP peers to different upstream providers. This has been in place for awhile now. Each network acts on it's own individually, completely disparate.
Because of these two networks we want to provide dual connections to our customers, acting as two separate ISP's for redundancy using BGP directly with them. This is something we haven't done yet, and what I'm looking for guidance on.
I've assigned them a /24 to use on both networks. I understand how to peer and advertise with our upstream's, and I understand how to peer to our customer just fine. And I understand how to to do this with on both networks.
The issue I'm trying to wrap my head around is, and it pertains to only one of my networks, if my connection to my customer goes down the BGP peer/session will drop between my router and the customers router and this will bring down BGP between us...and I will stop getting advertisements from them...
but, my peer with my upstream will still be active/advertising their /24 to the Internet!
So from the Internet's point of view I could still get traffic sent to my network that has a down BGP peer. In the event of my connection going down I want the advertisement of their IP's to stop being advertised to my upstream.
Is there a way for the peering between myself and my customer to control their IP block being advertised to my upstream?
I'm sure I'm missing something simple here, I hoping someone out there has done this before or is doing it.
Thanks in advance.