Indicate the mask to be logical-ANDed with the destination address before being compared to the value in the aniDevRouteDest field. For those systems that do not support arbitrary subnet masks, an agent constructs the value of the aniDevRouteMask by determining whether the value of the correspondent aniDevRouteDest field belong to a class-A, B, or C network, and then using one of: mask network 255.0.0.0 class-A 255.255.0.0 class-B 255.255.255.0 class-C If the value of the aniDevRouteDest is 0.0.0.0 (a default route), then the mask value is also 0.0.0.0. It should be noted that all IP routing subsystems implicitly use this mechanism. In case of any other aniDevRouteDest (other than the default route), 0.0.0.0 subnet mask is considered an invalid mask. Subnet mask 255.255.255.255 indicates that the route is a Host route. A Network route cannot have subnet mask as 255.255.255.255.