Open problem
Browsers can't dial any native transport
open
Execution nodes speak RLPx over TCP, with discovery over UDP. Consensus nodes speak libp2p over TCP and, increasingly, QUIC.
The web platform offers no raw sockets. A browser can open HTTPS, WebSocket, WebRTC, and WebTransport connections, and nothing else. Every native transport the network runs today falls outside that list.
Serving browsers therefore means serving a web transport. See connectivity for the candidate transports and their constraints.