This read-write value caps the maximum path cost PXM's cost-based routing algorithm is allowed to use when selecting a route for this connection. It lets an admin constrain how expensive, in whatever cost metric the network uses, often related to trunk cost or distance, a path can be before the switch would rather fail to route than use it. An admin who wants a connection to only ever use low-cost, short paths would set bbChanMaxCost to a low value, preventing PXM from routing it over an expensive long-haul backup path.