Dell PowerConnect 8100 User's Configuration Guide - Page 843

ETS Theory of Operation First Level of Scheduling To understand the first level of scheduling, consider Table 29-1. Assume that we have eight ingress ports, each one receiving line rate traffic with one dot1p priority each. The table shows the mapping of dot1p priorities to the cosqueues, the min-bandwidth settings, and scheduler modes. Table 29-3. First Level of Scheduling Dot1p Priority 0 1 2 3 4 5 6 7 CoS Queue 0 1 2 3 4 5 6 6 CoS Minbandwidth 10 10 10 10 15 15 30 - Scheduler TCG WRR 0 WRR 1 Strict 1 WRR 1 WRR 2 WRR 2 WRR 2 - - Input to TCG 100% of pri0 10% each of pri1, pri3 and 80% of pri2 25% each of pri4, pri5 and 50% of pri6/pri7 In this scenario, the input to the TCGs is as follows: • All of the pri0 traffic reaches the TCG0. This is because there is no other priority contending for the same TCG. The minimum bandwidth setting on the CoS queue does not have any effect. • TCG1 would receive 10% each of pri1 and pri3 and 80% of pri2. Even though strict mode is enabled for pri2, the minimum bandwidth of pri1 and pri3 is first honored before applying strict mode on pri2. • TCG2 receives 25% each of pri4 and pri5 traffic and the other 50% can be of pri6 or pri7. This is based on the minimum bandwidth ratio, which is 15:15:30, converted to 1:1:2. Configuring Data Center Bridging Features 843