US Patent 9479437 Efficient updates of weighted cost multipath (WCMP) groups

Exemplary embodiments provide changes to routing schemes, i.e. WCMP groups or WCMP sets, installed in a network traffic distribution table, e.g. multipath table. WCMP groups of a multipath table are updated to accommodate a new WCMP group. This can be achieved by reducing the size of the existing WCMP groups on the multipath table. The goal is to reduce the existing WCMP groups just enough to make room for the new WCMP group. An objective is to minimize the number of existing WCMP groups to be reduced before a new WCMP group can be installed in the multipath table.