A community hub is similar to the peer-to-peer network, with the only difference being that it accepts connections from multiple Moodle servers. While this could be set up manually using a number of peer-to-peer connections, the hub mode automatically accepts any hosts that try to connect to it.
A learning portal that contains resources to be shared across a number of sites is typically implemented using the hub mode.
Once networking has been turned on, choose the Moodle site that will act as a hub and go to Networking | Peers to turn on Register all hosts (Hub mode).
All the other settings are identical to the peer-to-peer parameters. You might decide that traffic (that is, authentication and enrolment) should only go one-way, that is from the different Moodle sites to the hub. You can control this by the Publish and Subscribe options, as seen before under the Peers Services section.