1. A network planning tool for configuring at least one Ethernet Multi-Link Trunk over a wavelength-division-multiplexed WDM optical network, the network planning tool comprising: at least one processor; and at least one storage medium, the storage medium being operable to store instructions executable by the processor, the instructions comprising: instructions executable to access configuration information for a WDM optical network, the configuration information comprising: geographic location information for photonic layer elements of the WDM optical network; and lightpaths available between specified terminal devices connected to the WDM optical network; and instructions executable to display available lightpaths between specified terminal devices connected to the WDM optical network together with geographic location information associated with each displayed available lightpath; and instructions executable to enable selection of a displayed lightpath for aggregation as a link of an Ethernet Multi-Link Trunk between specified terminal devices connected to the WDM optical network.