Service Manual

Allocating Bandwidth to Queue
The switch schedules packets for egress based on Deficit Round Robin (DRR). This strategy offers a
guaranteed data rate.
Allocate bandwidth to queues only in terms of percentage in 4-queue and 8-queue systems. The
following table shows the default bandwidth percentage for each queue.
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 71. Default Bandwidth Weights
Queue Default Bandwidth Percentage
for 4–Queue System
Default Bandwidth Percentage
for 8–Queue System
0 6.67% 1%
1 13.33% 2%
2 26.67% 3%
3 53.33% 4%
4 - 5%
5 - 10%
6 - 25%
7 - 50%
NOTE: In Dell Networking OS we support 8 data queues in S4048, S6000, Z9500 and 4 data queues
in S3048, S4810. S4820T and, S5000.
When you assign a percentage to one queue, note that this change also affects the amount of bandwidth
that is allocated to other queues. Therefore, whenever you are allocating bandwidth to one queue, Dell
Networking recommends evaluating your bandwidth requirements for all other queues as well.
• Assign each queue a bandwidth percentage ranging from 1 to 100%, in increments of 1%.
bandwidth-percentage
Specifying WRED Drop Precedence
You can configure the WRED drop precedence in an output QoS policy.
• 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.
Quality of Service (QoS)
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