Hub patching
A jacktrip hub server can be launched with the option -p (aka --hubpatch), followed by a number specifying one of these “hub patching modes”:

0 “server-to-clients” (default)
All clients get mixed to server’s output; server’s input feeds to all clients. (How would this be useful? Imagine a central site with a large mixing board with remote clients piped in: something outside of jacktrip makes “the mix” including the remote clients’ sound plus local sound, and feeds that mix back to the remote clients through the jacktrip server machine. Could also use for music broadcast.)
1 “client loopback”
Each client hears only herself
2 “client fan out/in but not loopback”
Everybody hears everybody else, but not themselves. Recommended for attempting to play together when latency is high (to avoid the annoying delayed-echo-of-yourself)
3 “reserved for TUB”
??? (XXX what does this do?)
4 “full mix”
Each client hears the full mix including herself. (Like a combination of 1 and 2.) Recommended for initial connection testing and in cases where all players need to hear exactly the same mix.
5 “no connections”
In this mode, the jacktrip hub server does not create any jack connections at all; it’s for situations where some other mechanism will handle jacktrip’s jack connections.