One of the nodes, called a hub, is used to manage wavelengths. A hub may assign a set of wavelengths to a particular light path. Wavelengths may be added or dropped at a node while the remaining wavelength passes transparently through it. In some cases, the hub may receive a wavelength from a node and convert it another wavelength. Such a network is called Broadcast and Select Network.

In a Star topology , signal to and from every node passes through a central node, which is either an active or a passive optical coupler.

In a Mesh topology , the interconnections are from any node to any other node in the network. The topology uses optical cross connects which have the ability to connect any input port with any output port. Fault tolerance is inherently built into this topology as there are several paths between a pair of nodes. For instance, in the adjoining figure, the nodes 1 and 9 are connected by the paths or or etc.