This read-create integer configures the affinity mask value for this MPLS traffic-engineering tunnel, specifying which bits of csMplsPathAffinity are actually significant when matching against a candidate link's administrative-group attributes. It works together with csMplsPathAffinity to let an administrator selectively enforce only certain link-color constraints while ignoring others. An operator who only cares about one specific attribute bit among several defined colors would set csMplsPathAffinityMask so only that bit is evaluated during path computation.