For BGP AS relationship, I have the following explanations:
Prefer routes in which the next-hop AS is a customer over routes in which the next-hop is a peer. Prefer routes in which the nexthop AS is a peer over routes in which the next-hop is a provider.
AS prefers to use customer path, then peer, then provider.
And I know that peer-to-peer means two entities agree to provide free routing service to each other.
But I still cannot understand above explanations well. Please give me an example to explain it.