Quality of Service | 871You can create a custom WRED profile or use on of the five pre-defined profiles listed in Table 41-7.Create WRED ProfilesTo create a WRED profile:1. Create a WRED profile using the command wred from CONFIGURATION mode.2. The command wred places you in WRED mode. From this mode, specify minimum and maximumthreshold values using the command threshold.Apply a WRED profile to trafficOnce you create a WRED profile you must specify to which traffic FTOS should apply the profile.FTOS assigns a color (also called drop precedence)—red, yellow, or green—to each packet based on itDSCP value before queuing it. DSCP is a 6 bit field. Dell Force10 uses the first three bits of this field (DP)to determine the drop precedence. DP values of 110 and 100 map to yellow, and all other values map togreen. If you do not configure FTOS to honor DSCP values on ingress (Honor DSCP values on ingresspackets on page 865) see all traffic defaults to green drop precedence.Assign a WRED profile to either yellow or green traffic from QOS-POLICY-OUT mode using thecommand wred.Configure WRED for Storm ControlConfigure WRED for Storm Control is supported only on platform eStorm control limits the percentage of the total bandwidth that broadcast traffic can consume on aninterface (if configured locally) or on all interfaces (if configured globally). For storm-control broadcast 50out, the total bandwidth that broadcast traffic can consume on egress on a 1Gbs interface is 512Mbs. Themethod by which packets are selected to be dropped is the "tail-drop" method, where packets exceedingthe specified rate are dropped.Table 41-7. Pre-defined WRED ProfilesDefault ProfileNameMinimumThresholdMaximumThresholdwred_drop 0 0wred_ge_y 1024 2048wred_ge_g 2048 4096wred_teng_y 4096 8192wred_teng_g 8192 16384
