In the NXT documentation it says that the Peer protocol uses TCP. But looking through the code all I see is HTTP. Does NXT use HTTP or TCP for the Peer protocol?
I was able to answer my own question through the Nxt dev forum.
Adding it here for others that may have the same question:
Up to version 1.4 Nxt used HTTP for peer communication. Starting with version 1.5 they are moving to WebSocket for peer communication