I am hoping you can clarify something for me in regards to the priority queue and the two ingress queues. I watched Kevin’s video and it explained a lot however it is still unclear to me even after reading several Cisco docs and other training material how the ingress queues are serviced. The way I understand it is that there are two ingress queues (1 and 2). By default, queue 2 is the priority queue and is guaranteed 10% of the internal ring bandwidth. This leaves 90% of the internal ring bandwidth to be divided by the two ingress queues 45% each by default. So does that mean that queue 2 really gets 55% (10% priority and 45% normal) or does queue 2 get serviced two times (once for priority traffic and once for normal traffic) for every time queue 1 gets serviced? If queue 2 is truly just a single file line handling both normal and priority traffic how do the priority packets get moved to the front of the line to be expedited by SRR? It seems like there would have to be two sub queues within queue 2, one for normal traffic and one for priority traffic.
Also, if the priority queue of each port is given 10% of the internal ring bandwidth and I have a 24 port GigE switch with a 32Gig backplane this would give each port 1.3 Gbps reserved bandwidth on the internal ring. However, each port is only a 1G port so it seems like in this scenario that the priority traffic could starve out normal traffic even though it is limited to 10% of internal ring bandwidth due to the fact that the faction of internal ring bandwidth allocated to the priority queue of each port exceeds the physical port bandwidth capacities. Do I have my logic and math correct here?