The typical network topology is a star configuration. This means that every BBB board has its own connection to the switch, and the switch itself is connected to the local area network (LAN). On most Beowulf clusters, there is one special board called the master node. This master node is used to provide the bridge between the cluster and the rest of the LAN. All users (if there are more persons that use the cluster) log in to the master node, and it is only responsible for user management and starting the correct programs on specified nodes. It usually doesn't contribute to any calculation tasks.

However, as BBB only has one network connector, it is not possible to use it as a bridge, because a bridge requires two network ports:

Because of this, we only define one node as the master node, providing some special software features but also contributing to the calculations of the cluster. This way...