Method and System for Link Aggregation

A method in a primary system for providing Link Aggregation Control between a plurality of systems adapted for Link Aggregation and including the primary system having a primary system identifier, a first secondary system having a first system identifier, and a second secondary system having a second system identifier, the primary system comprising a first set of primary ports being linked to a first set of ports of the first secondary system by first links, the primary system further comprising a second set of primary ports being linked to a second set of ports of the second secondary system by second links, wherein the method comprises the steps of:

• forming in said primary system a link aggregation group, wherein the link aggregation group includes at least one first link between the primary system and the first secondary system and at least one second link between the primary system and the second secondary system;
• selecting in said primary system a preferred system among the secondary systems having links within the link aggregation group;
• setting in said primary system the status of the primary ports according to the selection of the preferred system;
• evaluating in said primary system the at least one link between the primary system and the preferred system according to a minimum active links requirement;
• and
• in case the minimum active links requirement is not fulfilled, selecting an alternative preferred system among the other secondary systems having links within the link aggregation group, and setting the status of the primary ports according to the selection of the preferred system.