This read-only value reports outgoing bandwidth currently allocated to active QoS Class 4 connections on this port, the in-use complement to lportOutVAvailbwQoS4. An admin checks this mainly to understand how much of the best-effort reservation is being actively used, useful context when overall port utilization seems high but it is unclear which QoS class is driving it. For example, a port showing high overall lportTrkUtil but low lportOutAllocbwQoS4 relative to the other classes indicates the load is coming from the higher-priority QoS classes rather than best-effort traffic.