Does SFU apply to data channels as well?
As I understand it, it doesn't offer any advantage besides moving the broadcasting of messages to the central SFU (and having just one peer connection).
As I understand it now:
Thus, moving the broadcasting of messages from the local peer, to the "remote" SFU. Is this right? And if so, what benefits does this offer?
A SFU has the same advantages for DataChannels as it does for RTP.
Reduce network load on the sender. Instead of uploading your message n times you send it once, and SFU handles replication.
Reduce CPU load on the sender. The sender only has to one run SCTP Association. It doesn't have to spin up all the threads for each individual congestion controller etc..
Reduced distance to peers. Most SFUs are actually made up of a fleet of servers. Each peer connects to the closest SFU geographically to give better round trip times. Senders and Receivers can more quickly respond to loss and other issues.
Privacy. Users may not want to establish a direction connection/expose their IP address.
Insight. When running a SFU you get more insight into your users sessions. I can isolate if the issue was the sender or receiver. A P2P mesh is harder to debug/reproduce issues.