This read-create integer (1-8) sets which queue number is treated as the Expedited Forwarding priority queue. It matters because it identifies exactly which of the eight hardware queues receives the strict-priority EF scheduling, rather than just toggling EF on or off generically. For example, setting this to 8 designates the highest-numbered queue as the one that gets serviced first, ahead of all WRR queues, for real-time traffic.