This sets the number of bits in the subnet mask applied to cdmipIpRouteDestAddress, defining how broad or narrow this route's destination match is. A mask length of 0 makes this a default or catch-all route matching all destinations, while 32 restricts it to a single host, so getting this wrong, for example accidentally leaving it at 0, could unintentionally make one route absorb traffic meant for other, more specific routes. Setting this to 24 alongside a destination address of 10.5.0.0 scopes the route to exactly the 10.5.0.0/24 subnet, rather than the wider /16 that a mask of 16 would produce.