Owners Manual

Allocating Bandwidth to Queue
Schedule packets for egress based on Deficit Round Robin (DRR). These strategies both offer a
guaranteed data rate.
The following table lists the default bandwidth weights for each queue, and their equivalent percentage
which is derived by dividing the bandwidth weight by the sum of all queue weights.
Table 57. Default Bandwidth Weights
Queue Default Weight Equivalent Percentage
0 1 6.67%
1 2 13.33%
2 4 26.67%
3 8 53.33%
• Allocate bandwidth to queues.
bandwidth-percentage
Specifying WRED Drop Precedence
Specifying WRED drop precedence is supported on the S4820T platform.
• Specify a WRED profile to yellow and/or green traffic.
QOS-POLICY-OUT mode
wred
For more information, refer to Applying a WRED Profile to Traffic.
Create Policy Maps
There are two types of policy maps: input and output.
Creating Input Policy Maps
There are two types of input policy-maps: Layer 3 and Layer 2.
1. Create a Layer 3 input policy map.
CONFIGURATION mode
policy-map-input
Create a Layer 2 input policy map by specifying the keyword layer2 with the policy-map-input
command.
2. After you create an input policy map, do one or more of the following:
Applying a Class-Map or Input QoS Policy to a Queue
Applying an Input QoS Policy to an Input Policy Map
Honoring DSCP Values on Ingress Packets
Honoring dot1p Values on Ingress Packets
3. Apply the input policy map to an interface.
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Quality of Service (QoS)