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 configured to store instructions executable by the processor, the instructions comprising: instructions executable to access configuration information for the WDM optical network, the configuration information comprising: geographic location information for photonic layer elements of the WDM optical network; and available lightpaths between specified terminal devices connected to the WDM optical network; and instructions executable to display the available lightpaths between the specified terminal devices connected to the WDM optical network together with geographic location information associated with each of the available lightpaths; and instructions executable to enable selection of one of the available lightpaths for aggregation as a link of an Ethernet Multi-Link Trunk between the specified terminal devices connected to the WDM optical network.