is there a way for BGP to switch and prefer IGP, after the routing table uses BGP as prefered route?
here is a scenario:
- 2 different sites connect to an ISP, so both CE has different AS numbers.
- both CEs are advertises each site's prefixes with network statement.
- both sites reach each other via ISP cloud as normal.
- issue arise when both sites connected to each other via backdoor link, and run IGP - ospf or eigrp. So both routers are doing IGP and BGP.
- routing table of both CE still use BGP as preferred routes, until do clear bgp neighbor.