88NOTE:• The S5800 Switch Series supports only one parent forwarding group on a port. A parent group can nestup to 16 child forwarding groups.• You can schedule HQoS forwarding groups together with QoS queues. In this example, you can alsoassign packets from VLANs 11 through 20 to QoS queues through their 802.1p priority or localprecedence. For more information, see “Instantiating a forwarding group.”Figure 27 shows a simplified tree-shaped diagram for this HQoS scheduling example.Figure 27 How HQoS worksSchedulerpolicyFG A FG IFP AVLAN1lp=0FP I_10FG Hlp=7FG I_1……FP I_1FG I_10VLAN10FP HFP ILayer 1Layer 2……SchedulerAs shown in Figure 27, HQoS first performs layer-2 scheduling, and then performs layer-1 scheduling forthe scheduled packets together with other packets.HQoS enables you to achieve hierarchical traffic management by configuring match criteria for eachforwarding group at each layer to classify traffic by user or traffic type.You can configure a set of forwarding and scheduling actions (including the scheduling algorithm,scheduling weight, and traffic shaping parameters) for each forwarding group at layer 2 of thescheduling hierarchy. For their parent forwarding group at the layer 1 of the scheduling hierarchy, youcan configure different traffic control parameters.HQoS conceptsThe section describes key terms and concepts of the HQoS configuration procedure.Forwarding groupA forwarding group represents a class of traffic with certain traffic characteristics (VLAN ID or localprecedence value). All traffic assigned to a forwarding group shares a common set of scheduling andforwarding parameters.
