Round Robin style multiple channel queue
rbqueue is a queue that enlists items according to their group name, and serve them back with round robin scheduling. It also has a priority system which multiples quantum number according to the priority a group has. For example :
group A / priority : 1 group B / priority : 1
Both group A and B is served equal times at every cycle.
group A / priority : 1 group B / priority : 2
If group A is served 1 time, B is served 2 times.
So it is basically a proportionally linear priority.