Hol Blocking Prevention; Scheduling Settings; Qos Scheduling - D-Link xStack DGS-3420 Series Reference Manual

xStack® DGS-3420 Series Layer 2 Managed Stackable Gigabit Switch Web UI Reference Guide

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:
The fields that can be configured are described below:
Parameter
HOL Blocking Prevention
State
Click the Apply button to accept the changes made.

Scheduling Settings

QoS Scheduling

This window allows the user to configure the way the Switch will map an incoming packet per port based on its
802.1p user priority, to one of the eight available hardware priority queues available on the Switch.
To view this window, click QoS > Scheduling Settings > QoS Scheduling as shown below:
The following parameters can be configured:
Figure 6-7 HOL blocking Prevention window
Description
Click the radio buttons to enable of disable the HOL blocking prevention global
settings.
Figure 6-8 QoS Scheduling window
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