D-Link DGS-3120-24TC - HOL Blocking Prevention

xStack® DGS-3120 Series Managed Switch Web UI Reference Guide
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Figure 6–9 DSCP Map Settings - DSCP DSCP window
The fields that can be configured are described below:
Parameter Description
Unit
Select the unit you want to configure.
From Port / To Port
Use the drop-down menu to select a range of port to configure.
DSCP Map
Use the drop-down menu to select one of two options:
DSCP Priority – Specifies a list of DSCP values to be mapped to a specific priority.
DSCP DSCP – Specifies a list of DSCP value to be mapped to a specific DSCP.
DSCP List
Enter a DSCP List value.
Priority
Use the drop-down menu to select a Priority value. This appears when selecting
DSCP Priority in the DSCP Map drop-down menu.
DSCP Enter a DSCP value. This appears when selecting DSCP Priority in the DSCP
DSCP drop-down menu.
Click the Apply button to accept the changes made.
HOL Blocking Prevention
HOL (Head of Line) Blocking happens when one of the destination ports of a broadcast or multicast packet are
busy. The switch will hold this packet in the buffer while the other destination port will not transmit the packet even
they are not busy.
The HOL Blocking Prevention will ignore the busy port and forward the packet directly to have lower latency and
better performance.
On this page the user can enable or disable HOL Blocking Prevention.
To view the following window, click QoS > HOL Blocking Prevention, as show below:
Figure 6–10 HOL blocking Prevention window
The fields that can be configured are described below:
Parameter Description