This read-write TruthValue indicates whether Available Bit Rate traffic can be routed over the trunk; if True it can be rerouted, otherwise it cannot. An administrator relies on this together with the ABR flow-control setting (parSwFuncAbrVsvd) to decide whether flow-controlled best-effort connections are allowed onto the trunk. For example, enabling Abr on a trunk with variable spare capacity lets ABR connections opportunistically use whatever bandwidth other classes leave unused.