Is optical mostly a waste of time versus Ethernet?

Thank you, although still unclear how are you have cured bidirectional Ethernet connection with a server.  Unfortunately isn't two way communication integral to the process?

A router without Wi-Fi means you should be using a switch if needed.  Not really practical though.

Well, certainly there is bidirectionality on ethernet between router and server, router needs to know server there. The difference is information from music player (Roon in my case) doesn't follow that path, it goes out second ethernet port directly to FMC (in my case) could be streamer or renderer for someone else. Without the second ethernet port information from music player has to go back through the ethernet cable connecting to router or switch.

Isn't a router without wifi a switch, never heard of a router without wifi.

@yyzsantabarbara yeah, no. Read up on what you are typing before you type is my suggestion. If you program this “stuff”, you really should know more than what your post implies, which is 0.

look at the cable itself. 

@sns you have never heard of it because it is not your area of expertise, or even foundational knowledge… largest manufacturer of networking equipment in the world and its landing page for routers :

@fredrik222 

Did you forget to answer to my question of how streaming is done? Here is your statement.

If an error is detected the frame, or packet, or datagram is discarded, or in the case of error correction, discarded and the retransmit requested.

@yyzsantabarbara  I certainly did not, here was my answer:

"@yyzsantabarbara yeah, no. Read up on what you are typing before you type is my suggestion. If you program this “stuff”, you really should know more than what your post implies, which is 0."

You don't know what you are talking about. There is no broadcast protocols in streaming.