A method in a management node (250; 350) for deciding ports suitable to be communicatively connected to each other in a communications network (210; 310), said communications network (210; 310) comprising one or more available ports (230A-C; 233A, 233C; 330A), wherein an available port (230A; 330A) of the one or more available ports (230A-C, 233A, 233C; 330A) is comprised in a first network node (220A; 320A) and communicatively connected to the communications network (210; 310), and a discovered port (233B; 330B) comprised in a second network node (232B; 330B), which discovered port (233B; 330B) is a port discovered as being communicatively connected to the communications network (210; 310), wherein the communications network (210; 310) is a wavelength division multiplexed, WDM, optical network, the method comprising: - obtaining information associating at least the available port (230A; 330A) and the discovered port (233B; 330B) with respective one or more attributes and with a respective attribute identifier identifying the respective one or more attributes; - receiving, from a port discovering network node (225; 320B), a message comprising the attribute identifier associated with the discovered port (233B; 330B); - obtaining rules for finding that the available port (230A; 330A) is suitable to be connected with the discovered port (233B; 330B); and - deciding that the available port (230A; 330A) is suitable to be communicatively connected with the discovered port (233B; 330B) in the event that the respective one or more attributes are considered to be matched based on the obtained rules, wherein one or more matched attributes associated with the available port (230A; 330A) and one or more matched attributes associated with the discovered port (233B; 330B), respectively, comprise at least one attribute identifying a desired number of connections between the first network node (220A; 320A) and the second network node (232B; 330B), and wherein the available port (230A; 330A) and the discovered port (233B; 330B) each comprises an additional attribute which adds a priority to each desired connection between the first network node (220A; 320A) and the second network node (232B; 330B). - obtaining information associating at least the available port (230A; 330A) and the discovered port (233B; 330B) with respective one or more attributes and with a respective attribute identifier identifying the respective one or more attributes; - receiving, from a port discovering network node (225; 320B), a message comprising the attribute identifier associated with the discovered port (233B; 330B); - obtaining rules for finding that the available port (230A; 330A) is suitable to be connected with the discovered port (233B; 330B); and - deciding that the available port (230A; 330A) is suitable to be communicatively connected with the discovered port (233B; 330B) in the event that the respective one or more attributes are considered to be matched based on the obtained rules, wherein one or more matched attributes associated with the available port (230A; 330A) and one or more matched attributes associated with the discovered port (233B; 330B), respectively, comprise at least one attribute identifying a desired number of connections between the first network node (220A; 320A) and the second network node (232B; 330B), and wherein the available port (230A; 330A) and the discovered port (233B; 330B) each comprises an additional attribute which adds a priority to each desired connection between the first network node (220A; 320A) and the second network node (232B; 330B).