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DGS-3130 Series Layer 3 Stackable Managed Switch Web UI Reference Guide
Parameter
Unit
From Port - To Port
Direction
Policy Map Name
Click the Apply button to accept the changes made.
WRED
Weighted Random Early Detection (WRED) is another implementation for QoS that will help the overall throughput for
your QoS queues. Based on the egress queue of the QoS function set on the Switch, this method will analyze these
packets and their QoS queue to determine if there will be an overflow of packets entering the QoS queues and
consequentially, minimize the packet flow into these queues by dropping random packets. WRED employs two
methods of avoiding congestion within the QoS queue.
1. Every QoS queue has a minimum and a maximum level for acceptance of packets. Once the maximum
threshold has been reached for this queue, the Switch will begin discarding all ingress packets, this minimizing
the allotted bandwidth for QoS. When below the minimum threshold, the Switch will accept all ingress packets.
2. When the ingress packets are somewhere between the maximum and minimum queue, the Switch will use a
slope probability function to determine a random method of dropping packets based on the maximum drop rate
which specifies the drop probability when the queues reach maximum threshold. If queues are closer to the
maximum threshold, the Switch will increase the discarding of random packets to even out the flow to the
queues and avoid overflows to higher priority queues.
WRED Profile
This window is used to display and configure the Weighted Random Early Detection (WRED) profile settings.
To view the following window, click QoS > WRED > WRED Profile, as shown below:
The fields that can be configured are described below:
Description
Select the Switch unit that will be used for this configuration here.
Select the range of ports that will be used for this configuration here.
Select the direction option here. Options to choose from are Input and Output.
Input specified ingress traffic and output specifies egress traffic.
Enter the policy map name here. This name can be up to 32 characters long.
Select the None option to not tie a policy map to this entry.
Figure 7-20 WRED Profile Window
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