[cranekam]

> On the backbone nothing uses TCP, not even IP. It's all BGP or other proprietary formats.

Do what? "The backbone" usually refers to the core networks internet service providers and so on use. They carry whatever higher-layer protocols (including TCP and UDP) that their users want to use. It's like saying "on the highway nobody uses cars". The two are different parts of the stack.

Also, BGP is a routing protocol (to share IP reachability information) which runs over TCP. It's not a replacement for TCP. I can't download cat pictures over BGP. Are you referring to things like MPLS? Even that isn't a TCP-level thing. It's a halfway between layer 2 (Ethernet and friends) and layer 3 (mostly IP). TCP is still on top of all of this.