Our friend shrek give public ip address to users so, from his core router have bgp session with two upstream provider.
The problem is that this upstreams have different bandwith capacity so, if I understand, he would like to use "priority" the upstream with more bandwith and secondary as automatic recovery.
I think that there isn't a simple solution to the problem for the nature of bgp protocol becouse it use for its decision many paramiter but not bandwtih limit of upstreams. Where goes traffic depend olso of peering agreements that have your upstreams. If the upstream with less bandwith is more interconnected with other AS I suppose that have more chanche to became preferred way for many of your packet
I have a similar scenario in a production enviorment and my first upstream with upper bandwith is interconnected only to one bigger AS, my second upstream have many peers interconnected.
To "solve" the problem I have used the BGP prepend paramiter in the tab BGP action of Route filter tab (the filter applays to second upstrem).
I'm not a BGP expert and this workaround, in my scenario, was operated by a collegue with more experience.
I would like to know opinions from other expert on this forum.