8.2.6.5.3 Fixed Priority

Any of the active queues can be selected as fixed priority and this is the default mode of operation for all queues. The queue index is used as the priority, where a higher index will have a higher priority than a lower index. The scheduler will always attempt to transmit from fixed priority queues with the highest priority (i.e. a fixed priority queue with a high queue index will always take precedence over a priority queue with a lower index).