D-Link xStack DGS-3120 Series Reference Guide

xStack® DGS-3120 Series Layer 3 Managed Gigabit Ethernet Switch Web UI Reference Guide
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Click the Apply button to accept the changes made.
Click the Find button to locate a specific entry based on the information entered.
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.
This window is used to enable or disable HOL Blocking Prevention.
To view the following window, click QoS > HOL Blocking Prevention, as shown below:
Figure 6-10 HOL blocking Prevention window
The fields that can be configured are described below:
Parameter Description
HOL Blocking
Prevention State
Click the radio buttons to enable of disable the HOL blocking prevention global
settings.
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:

D-Link xStack DGS-3120 Series Specifications

General

MAC Address Table	16K entries
Ports	10/100/1000BASE-T ports
VLANs	4094
Jumbo Frame	Up to 9KB
Power Supply	Internal power supply (depending on model)
Power over Ethernet (PoE)	No
Layer 3 Features	RIP
Quality of Service (QoS)	8 queues per port, DiffServ
Security Features	ACLs
Management	Web-based, CLI, SNMP
Operating Temperature	0°C to 40°C
Storage Temperature	-40°C to 70°C
SFP Ports	Combo 10/100/1000BASE-T/SFP ports and/or dedicated SFP/SFP+ ports (depending on model)