Saying BGP runs on top of IP is true but doesn't tell you what BGP does or how Global scale IP doesn't work without BGP. BGP is the protocol Internet Routers (

Saying BGP runs on top of IP is true but doesn't tell you what BGP does or how Global scale IP doesn't work without BGP. BGP is the protocol Internet Routers (i.e. not your home router) use to figure out how to route IP addresses to particular routers. So your home router connects to an internet router at comcast (or your ISP). The Comcast router announces to the rest of the world "Dear world, if you want to connect to any of the IP addresses at X.X.X.X sent those packets to me and I'll deal with them."