I don't know that you need an explanation so simple/abstract but I couldn't help taking a crack at it too. Imagine you had to deliver a package to a university

I don't know that you need an explanation so simple/abstract but I couldn't help taking a crack at it too. Imagine you had to deliver a package to a university but only through your direct friends. You'd have to hand it off to somebody who goes to that university or somebody who knows somebody(or knows somebody, etc) that goes to that university. BGP helps routers maintain the list of their friends(other directly connected routers) that can get packages(packets) to remote locations(networks).