D-Link xStack User manual

August 2010
Web UI Reference Guide
Product Model:
xStack® DGS-3120 Series
Layer 2 Managed Stackable Gigabit Switch
Release 1.0

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i
Information in this document is subject to change without notice.
© 2010 D-Link Corporation. All rights reserved.
Reproduction of this document in any manner whatsoever without the written permission of D-Link Corporation is strictly forbidden.
Trademarks used in this text: D-Link and the D-LINK logo are trademarks of D-Link Corporation; Microsoft and Windows are registered trademarks of
Microsoft Corporation.
Other trademarks and trade names may be used in this document to refer to either the entities claiming the marks and names or their products. D-
Link Corporation disclaims any proprietary interest in trademarks and trade names other than its own.
August 2010 P/N 651GS3120005G

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Table of Contents
Intended Readers............................................................................................................................1
Typographical Conventions.............................................................................................................................................1
Notes, Notices and Cautions...........................................................................................................................................1
Chapter 1 Web-based Switch Configuration...........................................................................2
Introduction......................................................................................................................................................................2
Login to the Web Manager..............................................................................................................................................2
Web-based User Interface ..............................................................................................................................................3
Areas of the User Interface..........................................................................................................................................3
Web Pages......................................................................................................................................................................4
Chapter 2 System Configuration..............................................................................................5
Device Information ..........................................................................................................................................................5
System Information Settings...........................................................................................................................................6
Port Configuration ...........................................................................................................................................................7
Port Settings................................................................................................................................................................7
Port Description Settings.............................................................................................................................................9
Port Error Disabled......................................................................................................................................................9
Jumbo Frame Settings ..............................................................................................................................................10
PoE................................................................................................................................................................................10
PoE System Settings.................................................................................................................................................11
PoE Port Settings ......................................................................................................................................................12
Serial Port Settings .......................................................................................................................................................13
Warning Temperature Settings.....................................................................................................................................14
System Log configuration..............................................................................................................................................15
System Log Settings..................................................................................................................................................15
System Log Server Settings......................................................................................................................................15
System Log................................................................................................................................................................16
System Log & Trap Settings......................................................................................................................................17
System Severity Settings...........................................................................................................................................18
Time Range Settings.....................................................................................................................................................19
Port Group Settings (EI Mode Only) .............................................................................................................................20
Time Settings ................................................................................................................................................................20
User Accounts Settings.................................................................................................................................................21
Command Logging Settings..........................................................................................................................................22
Stacking.........................................................................................................................................................................22
Stacking Device Table...............................................................................................................................................24
Stacking Mode Settings.............................................................................................................................................25
Chapter 3 Management...........................................................................................................26
ARP...............................................................................................................................................................................26
Static ARP Settings ...................................................................................................................................................26
Proxy ARP Settings (EI Mode Only)..........................................................................................................................27
ARP Table .................................................................................................................................................................27
Gratuitous ARP .............................................................................................................................................................28
Gratuitous ARP Global Settings................................................................................................................................28

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Gratuitous ARP Settings............................................................................................................................................29
IPv6 Neighbor Settings (EI Mode Only)........................................................................................................................29
IP Interface....................................................................................................................................................................30
System IP Address Settings......................................................................................................................................30
Interface Settings.......................................................................................................................................................32
Management Settings ...................................................................................................................................................35
Session Table................................................................................................................................................................36
Single IP Management..................................................................................................................................................36
Single IP Settings ......................................................................................................................................................38
Topology....................................................................................................................................................................39
Firmware Upgrade.....................................................................................................................................................46
Configuration File Backup/Restore............................................................................................................................46
Upload Log File .........................................................................................................................................................47
SNMP Settings..............................................................................................................................................................47
SNMP Global Settings...............................................................................................................................................48
SNMP Traps Settings................................................................................................................................................49
SNMP Linkchange Traps Settings ............................................................................................................................49
SNMP View Table Settings .......................................................................................................................................50
SNMP Community Table Settings.............................................................................................................................51
SNMP Group Table Settings.....................................................................................................................................52
SNMP Engine ID Settings .........................................................................................................................................54
SNMP User Table Settings........................................................................................................................................54
SNMP Host Table Settings........................................................................................................................................55
SNMPv6 Host Table Settings (EI Mode Only)...........................................................................................................56
RMON Settings..........................................................................................................................................................56
Telnet Settings ..............................................................................................................................................................57
Web Settings.................................................................................................................................................................57
Chapter 4 L2 Features.............................................................................................................59
VLAN.............................................................................................................................................................................59
802.1Q VLAN Settings ..............................................................................................................................................64
802.1v Protocol VLAN ...............................................................................................................................................67
802.1v Protocol Group Settings............................................................................................................................67
802.1v Protocol VLAN Settings .............................................................................................................................68
Asymmetric VLAN Settings .......................................................................................................................................69
GVRP.........................................................................................................................................................................69
GVRP Global Settings ............................................................................................................................................69
GVRP Port Settings................................................................................................................................................70
MAC-based VLAN Settings.......................................................................................................................................72
Private VLAN Settings...............................................................................................................................................72
PVID Auto Assign Settings........................................................................................................................................74
Voice VLAN ...............................................................................................................................................................74
Voice VLAN Global Settings ..................................................................................................................................74
Voice VLAN Port Settings......................................................................................................................................75
Voice VLAN OUI Settings.......................................................................................................................................76
Voice VLAN Device................................................................................................................................................76

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VLAN Trunk Settings.................................................................................................................................................77
Browse VLAN ............................................................................................................................................................77
Show VLAN Ports......................................................................................................................................................78
Spanning Tree...............................................................................................................................................................79
STP Bridge Global Settings.......................................................................................................................................81
STP Port Settings......................................................................................................................................................82
MST Configuration Identification ...............................................................................................................................83
STP Instance Settings...............................................................................................................................................84
MSTP Port Information..............................................................................................................................................85
Link Aggregation ...........................................................................................................................................................86
Port Trunking Settings...............................................................................................................................................87
LACP Port Settings....................................................................................................................................................88
FDB...............................................................................................................................................................................90
Static FDB Settings ...................................................................................................................................................90
Unicast Static FDB Settings ...................................................................................................................................90
Multicast Static FDB Settings................................................................................................................................90
MAC Notification Settings..........................................................................................................................................91
MAC Address Aging Time Settings...........................................................................................................................92
MAC Address Table ..................................................................................................................................................93
ARP & FDB Table......................................................................................................................................................94
L2 Multicast Control ......................................................................................................................................................95
IGMP Snooping .........................................................................................................................................................95
IGMP Snooping Settings .......................................................................................................................................95
IGMP Snooping Rate Limit Settings ......................................................................................................................98
IGMP Snooping Static Group Settings ..................................................................................................................98
IGMP Router Port ...............................................................................................................................................100
IGMP Snooping Group ........................................................................................................................................100
IGMP Snooping Forwarding Table ......................................................................................................................101
IGMP Snooping Counter .....................................................................................................................................101
MLD Snooping.........................................................................................................................................................103
MLD Snooping Settings.......................................................................................................................................104
MLD Snooping Rate Limit Settings......................................................................................................................106
MLD Snooping Static Group Settings..................................................................................................................107
MLD Router Port.................................................................................................................................................108
MLD Snooping Group..........................................................................................................................................109
MLD Snooping Forwarding Table........................................................................................................................109
MLD Snooping Counter.......................................................................................................................................110
Multicast VLAN........................................................................................................................................................111
IGMP Multicast Group Profile Settings...............................................................................................................112
IGMP Snooping Multicast VLAN Settings............................................................................................................113
MLD Multicast Group Profile Settings ................................................................................................................115
MLD Snooping Multicast VLAN Settings .............................................................................................................116

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Multicast Filtering ........................................................................................................................................................118
IPv4 Multicast Filtering ............................................................................................................................................118
IPv4 Multicast Profile Settings............................................................................................................................119
IPv4 Limited Multicast Range Settings ...............................................................................................................120
IPv4 Max Multicast Group Settings ....................................................................................................................120
IPv6 Multicast Filtering ............................................................................................................................................121
IPv6 Multicast Profile Settings............................................................................................................................121
IPv6 Limited Multicast Range Settings ...............................................................................................................122
IPv6 Max Multicast Group Settings ....................................................................................................................123
Multicast Filtering Mode...........................................................................................................................................124
LLDP ...........................................................................................................................................................................125
LLDP Global Settings..............................................................................................................................................125
LLDP Port Settings..................................................................................................................................................126
LLDP Management Address List.............................................................................................................................127
LLDP Basic TLVs Settings ......................................................................................................................................127
LLDP Dot1 TLVs Settings........................................................................................................................................128
LLDP Dot3 TLVs Settings........................................................................................................................................130
LLDP Statistic System.............................................................................................................................................131
LLDP Local Port Information ...................................................................................................................................131
LLDP Remote Port Information ...............................................................................................................................133
NLB FDB Settings.......................................................................................................................................................133
Chapter 5 L3 Features...........................................................................................................135
IPv4 Default Route Settings (SI Mode Only)...............................................................................................................135
IPv4 Static/Default Route Settings (EI Mode Only).....................................................................................................135
IPv4 Route Table ........................................................................................................................................................136
IPv6 Static/Default Route Settings (EI Mode Only).....................................................................................................137
IP Forwarding Table....................................................................................................................................................137
Chapter 6 QoS........................................................................................................................139
802.1p Settings ...........................................................................................................................................................140
802.1p Default Priority Settings...............................................................................................................................141
802.1p User Priority Settings...................................................................................................................................141
Bandwidth Control.......................................................................................................................................................142
Bandwidth Control Settings.....................................................................................................................................142
Queue Bandwidth Control Settings .........................................................................................................................144
Traffic Control Settings................................................................................................................................................145
DSCP ..........................................................................................................................................................................148
DSCP Trust Settings ...............................................................................................................................................148
DSCP Map Settings.................................................................................................................................................148
HOL Blocking Prevention............................................................................................................................................150
Scheduling Settings ....................................................................................................................................................150
QoS Scheduling.......................................................................................................................................................150
QoS Scheduling Mechanism...................................................................................................................................151
Chapter 7 ACL........................................................................................................................153
ACL Configuration Wizard...........................................................................................................................................153
Access Profile List.......................................................................................................................................................154

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CPU Access Profile List ..............................................................................................................................................171
ACL Finder..................................................................................................................................................................186
ACL Flow Meter...........................................................................................................................................................186
Egress Access Profile List (EI Mode Only).................................................................................................................190
Egress ACL Flow Meter (EI Mode Only).....................................................................................................................201
Chapter 8 Security.................................................................................................................205
802.1X.........................................................................................................................................................................205
802.1X Global Settings............................................................................................................................................208
802.1X Port Settings................................................................................................................................................209
802.1X User Settings...............................................................................................................................................210
Guest VLAN Settings...............................................................................................................................................211
Authenticator State..................................................................................................................................................212
Authenticator Statistics............................................................................................................................................213
Authenticator Session Statistics..............................................................................................................................214
Authenticator Diagnostics........................................................................................................................................215
Initialize Port(s)........................................................................................................................................................216
Reauthenticate Port(s).............................................................................................................................................217
RADIUS.......................................................................................................................................................................218
Authentication RADIUS Server Settings .................................................................................................................218
RADIUS Accounting Settings..................................................................................................................................219
RADIUS Authentication...........................................................................................................................................219
RADIUS Account Client...........................................................................................................................................221
IP-MAC-Port Binding (IMPB) (EI Mode Only).............................................................................................................222
IMPB Global Settings ..............................................................................................................................................222
IMPB Port Settings ..................................................................................................................................................223
IMPB Entry Settings ................................................................................................................................................224
MAC Block List ........................................................................................................................................................225
DHCP Snooping ......................................................................................................................................................225
DHCP Snooping Maximum Entry Settings ..........................................................................................................225
DHCP Snooping Entry..........................................................................................................................................226
MAC-based Access Control (MAC).............................................................................................................................227
MAC-based Access Control Settings ......................................................................................................................227
MAC-based Access Control Local Settings.............................................................................................................229
MAC-based Access Control Authentication State...................................................................................................230
Web-based Access Control (WAC).............................................................................................................................230
WAC Global Settings...............................................................................................................................................233
WAC User Settings..................................................................................................................................................234
WAC Port Settings...................................................................................................................................................234
WAC Authentication State.......................................................................................................................................236
Compound Authentication...........................................................................................................................................236
Compound Authentication Settings.........................................................................................................................236
Compound Authentication Guest VLAN Settings (EI Mode Only)...........................................................................238
Port Security................................................................................................................................................................239
Port Security Settings..............................................................................................................................................239
Port Security VLAN Settings ...................................................................................................................................241
Port Security Entries................................................................................................................................................241

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ARP Spoofing Prevention Settings .............................................................................................................................242
BPDU Attack Protection..............................................................................................................................................243
Loopback Detection Settings ......................................................................................................................................245
Traffic Segmentation Settings.....................................................................................................................................246
NetBIOS Filtering Settings ..........................................................................................................................................247
DHCP Server Screening.............................................................................................................................................248
DHCP Server Screening Port Settings....................................................................................................................248
DHCP Offer Permit Entry Settings ..........................................................................................................................249
Access Authentication Control....................................................................................................................................249
Enable Admin ..........................................................................................................................................................250
Authentication Policy Settings.................................................................................................................................251
Application Authentication Settings.........................................................................................................................252
Authentication Server Group Settings.....................................................................................................................253
Authentication Server Settings................................................................................................................................254
Login Method Lists Settings ....................................................................................................................................255
Enable Method Lists Settings..................................................................................................................................256
Local Enable Password Settings.............................................................................................................................258
SSL Settings................................................................................................................................................................258
SSH.............................................................................................................................................................................261
SSH Settings ...........................................................................................................................................................261
SSH Authentication Method and Algorithm Settings...............................................................................................262
SSH User Authentication List..................................................................................................................................264
Trusted Host Settings..................................................................................................................................................265
Safeguard Engine Settings .........................................................................................................................................266
Chapter 9 Network Application ............................................................................................269
DHCP..........................................................................................................................................................................269
DHCP Relay ............................................................................................................................................................269
DHCP Relay Global Settings ................................................................................................................................269
DHCP Relay Interface Settings ............................................................................................................................272
DHCP Relay Option 60 Server Settings ...............................................................................................................272
DHCP Relay Option 60 Settings...........................................................................................................................273
DHCP Relay Option 61 Settings...........................................................................................................................274
DHCP Local Relay Settings.....................................................................................................................................274
SNTP...........................................................................................................................................................................275
SNTP Settings.........................................................................................................................................................275
Time Zone Settings .................................................................................................................................................276
Flash File System Settings..........................................................................................................................................277
Chapter 10 OAM.......................................................................................................................280
Cable Diagnostics .......................................................................................................................................................280
Chapter 11 Monitoring ............................................................................................................281
Utilization.....................................................................................................................................................................281
CPU Utilization ........................................................................................................................................................281
DRAM & Flash Utilization ........................................................................................................................................282
Port Utilization .........................................................................................................................................................282
Statistics......................................................................................................................................................................283

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Port Statistics...........................................................................................................................................................283
Packets................................................................................................................................................................283
Errors ..................................................................................................................................................................288
Packet Size..............................................................................................................................................................292
Mirror...........................................................................................................................................................................294
Port Mirror Settings..................................................................................................................................................294
RSPAN Settings ......................................................................................................................................................295
sFlow (EI Mode Only)..................................................................................................................................................296
sFlow Global Settings..............................................................................................................................................296
sFlow Analyzer Server Settings ..............................................................................................................................297
sFlow Flow Sampler Settings..................................................................................................................................298
sFlow Counter Poller Settings.................................................................................................................................299
Ping Test.....................................................................................................................................................................299
Trace Route.................................................................................................................................................................301
Peripheral....................................................................................................................................................................303
Device Environment ................................................................................................................................................303
Chapter 12 Save and Tools.....................................................................................................304
Save Configuration / Log.............................................................................................................................................304
Stacking Information ...................................................................................................................................................304
Download firmware .....................................................................................................................................................306
Upload Firmware.........................................................................................................................................................307
Download Configuration..............................................................................................................................................308
Upload Configuration ..................................................................................................................................................309
Upload Log File...........................................................................................................................................................311
Reset...........................................................................................................................................................................312
Reboot System............................................................................................................................................................313
Appendix A Mitigating ARP Spoofing Attacks Using Packet Content ACL.........................315
Appendix B Password Recovery Procedure ..........................................................................321
Appendix C Trap Logs..............................................................................................................322
Appendix D Glossary................................................................................................................325

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Intended Readers
Typographical Conventions
Notes, Notices and Cautions
Safety Instructions
General Precautions for Rack-Mountable Products
Protecting Against Electrostatic Discharge
The DGS-3120 Series Web UI Reference Guide contains information for setup and management of the Switch. This
manual is intended for network managers familiar with network management concepts and terminology.
Typographical Conventions
Convention Description
[ ] In a command line, square brackets indicate an optional entry. For example: [copy
filename] means that optionally you can type copy followed by the name of the file. Do
not type the brackets.
Bold font Indicates a button, a toolbar icon, menu, or menu item. For example: Open the File
menu and choose Cancel. Used for emphasis. May also indicate system messages or
prompts appearing on screen. For example: You have mail. Bold font is also used to
represent filenames, program names and commands. For example: use the copy
command.
Boldface Typewriter
Font
Indicates commands and responses to prompts that must be typed exactly as printed in
the manual.
Initial capital letter Indicates a window name. Names of keys on the keyboard have initial capitals. For
example: Click Enter.
Menu Name > Menu
Option Menu Name > Menu Option Indicates the menu structure. Device > Port > Port Properties means the Port Properties menu option under the Port menu option that is
located under the Device menu.
Notes, Notices and Cautions
A NOTE indicates important information that helps make better use of the device.
A NOTICE indicates either potential damage to hardware or loss of data and tells how to avoid the
problem.
A CAUTION indicates a potential for property damage, personal injury, or death.

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Chapter 1 Web-based Switch Configuration
Introduction
Login to the Web Manager
Web-based User Interface
Web Pages
Introduction
All software functions of the DGS-3120 Series switches can be managed, configured and monitored via the embedded
web-based (HTML) interface. Manage the Switch from remote stations anywhere on the network through a standard
browser. The browser acts as a universal access tool and can communicate directly with the Switch using the HTTP
protocol.
The Web-based management module and the Console program (and Telnet) are different ways to access the same
internal switching software and configure it. Thus, all settings encountered in web-based management are the same as
those found in the console program.
Login to the Web Manager
To begin managing the Switch, simply run the browser installed on your computer and point it to the IP address you
have defined for the device. The URL in the address bar should read something like: http://123.123.123.123, where the
numbers 123 represent the IP address of the Switch.
NOTE: The factory default IP address is 10.90.90.90.
This opens the management module's user authentication window, as seen below.
Figure 1-1 Enter Network Password window
Leave both the User Name field and the Password field blank and click OK. This will open the Web-based user
interface. The Switch management features available in the web-based manager are explained below.

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Web-based User Interface
The user interface provides access to various Switch configuration and management windows, allows you to view
performance statistics, and permits you to graphically monitor the system status.
Areas of the User Interface
The figure below shows the user interface. Three distinct areas divide the user interface, as described in the table.
Figure 1-2 Main Web-Manager page
Area
Number Function
Area 1 Select the menu or window to display. Open folders and click the hyperlinked menu buttons
and subfolders contained within them to display menus. Click the D-Link logo to go to the D-
Link website.
Area 2
Presents a graphical near real-time image of the front panel of the Switch. This area displays
the Switch's ports, console and management port, showing port activity.
Some management functions, including save, reboot, download and upload are accessible
here.
Area 3 Presents switch information based on user selection and the entry of configuration data.
AREA 2
AREA 1
AREA 3

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Web Pages
When connecting to the management mode of the Switch with a web browser, a login screen is displayed. Enter a user
name and password to access the Switch's management mode.
Below is a list of the main folders available in the Web interface:
System Configuration - In this section the user will be able to configure features regarding the Switch’s configuration.
Management - In this section the user will be able to configure features regarding the Switch’s management.
L2 Features - In this section the user will be able to configure features regarding the Layer 2 functionality of the Switch.
L3 Features - In this section the user will be able to configure features regarding the Layer 3 functionality of the Switch.
QoS - In this section the user will be able to configure features regarding the Quality of Service functionality of the
Switch.
ACL - In this section the user will be able to configure features regarding the Access Control List functionality of the
Switch.
Security - In this section the user will be able to configure features regarding the Switch’s security.
Network Application - In this section the user will be able to configure features regarding network applications
handled by the Switch.
OAM - In this section the user will be able to configure features regarding the Switch’s operations, administration and
maintenance (OAM).
Monitoring - In this section the user will be able to monitor the Switch’s configuration and statistics.
NOTE: Be sure to configure the user name and password in the User Accounts menu before
connecting the Switch to the greater network.

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Chapter 2 System Configuration
Device Information
System Information Settings
Port Configuration
PoE
Serial Port Settings
Warning Temperature Settings
System Log configuration
Time Range Settings
Port Group Settings (EI Mode Only)
Time Settings
User Accounts Settings
Command Logging Settings
Stacking
Device Information
This window contains the main settings for all the major functions for the Switch. It appears automatically when you log
on to the Switch. To return to the Device Information window after viewing other windows, click the DGS-3120 Series
link.
The Device Information window shows the Switch’s MAC Address (assigned by the factory and unchangeable), the
Boot PROM Version, Firmware Version, Hardware Version, and many other important types of information. This is
helpful to keep track of PROM and firmware updates and to obtain the Switch’s MAC address for entry into another
network device’s address table, if necessary. In addition, this window displays the status of functions on the Switch to
quickly assess their current global status.
Many functions are hyper-linked for easy access to enable quick configuration from this window.

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Figure 2-1 Device Information window
Click the Settings link to navigate to the appropriate feature page for configuration.
System Information Settings
The user can enter a System Name, System Location, and System Contact to aid in defining the Switch.
To view the following window, click System Configuration > System Information Settings, as show below:
Figure 2-2 System Information Settings window
The fields that can be configured are described below:

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Parameter Description
System Name Enter a system name for the Switch, if so desired. This name will identify it in the Switch
network.
System Location
Enter the location of the Switch, if so desired.
System Contact
Enter a contact name for the Switch, if so desired.
Click the Apply button to implement changes made.
Port Configuration
Port Settings
This page used to configure the details of the switch ports.
To view the following window, click System Configuration > Port Configuration > Port Settings, as show below:
Figure 2-3 Port Settings window
To configure switch ports:
1. Choose the port or sequential range of ports using the From Port and To Port pull-down menus.
2. Use the remaining pull-down menus to configure the parameters described below:
The fields that can be configured are described below:

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Parameter Description
Unit
Select the unit you wish to configure.
From Port / To Port
Select the appropriate port range used for the configuration here.
State
Toggle the State field to either enable or disable a given port or group of ports.
Speed/Duplex Toggle the Speed/Duplex field to select the speed and full-duplex/half-duplex state of the
port. Auto denotes auto-negotiation among 10, 100 and 1000 Mbps devices, in full- or half-
duplex (except 1000 Mbps which is always full duplex). The Auto setting allows the port to
automatically determine the fastest settings the device the port is connected to can handle,
and then to use those settings. The other options are 10M Half, 10M Full, 100M Half, 100M
Full, 1000M Full_Master, 1000M Full_Slave, and 1000M Full. There is no automatic
adjustment of port settings with any option other than Auto.
The Switch allows the user to configure three types of gigabit connections; 1000M
Full_Master, 1000M Full_Slave, and 1000M Full. Gigabit connections only support full
duplex connections and take on certain characteristics that are different from the other
choices listed.
The 1000M Full_Master and 1000M Full_Slave parameters refer to connections running a
1000BASE-T cable for connection between the Switch port and other device capable of a
gigabit connection. The master setting (1000M Full_Master) will allow the port to advertise
capabilities related to duplex, speed and physical layer type. The master setting will also
determine the master and slave relationship between the two connected physical layers.
This relationship is necessary for establishing the timing control between the two physical
layers. The timing control is set on a master physical layer by a local source. The slave
setting (1000M Full_Slave) uses loop timing, where the timing comes from a data stream
received from the master. If one connection is set for 1000M Full_Master, the other side of
the connection must be set for 1000M Full_Slave. Any other configuration will result in a link
down status for both ports.
Flow Control Displays the flow control scheme used for the various port configurations. Ports configured
for full-duplex use 802.3x flow control, half-duplex ports use backpressure flow control, and
Auto ports use an automatic selection of the two. The default is Disabled.
Connection
Here the current connection speed will be displayed.
MDIX Auto - Select auto for auto sensing of the optimal type of cabling.
Normal - Select normal for normal cabling. If set to normal state, the port is in MDI mode
and can be connected to a PC NIC using a straight-through cable or a port (in MDI mode)
on another switch through a cross-over cable.
Cross - Select cross for cross cabling. If set to cross state, the port is in MDIX mode, and
can be connected to a port (in MDI mode) on another switch through a straight cable.
Address Learning Enable or disable MAC address learning for the selected ports. When Enabled, destination
and source MAC addresses are automatically listed in the forwarding table. When address
learning is Disabled, MAC addresses must be manually entered into the forwarding table.
This is sometimes done for reasons of security or efficiency. See the section on
Forwarding/Filtering for information on entering MAC addresses into the forwarding table.
The default setting is Enabled.
Medium Type
If configuring the Combo ports, this defines the type of transport medium to be used.
Click the Apply button to implement changes made.
Click the Refresh button to refresh the display section of this page.

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Port Description Settings
The Switch supports a port description feature where the user may name various ports.
To view the following window, click System Configuration > Port Configuration > Port Description Settings, as
show below:
Figure 2-4 Port Description Settings window
The fields that can be configured are described below:
Parameter Description
Unit
Select the unit you wish to configure.
From Port / To Port
Select the appropriate port range used for the configuration here.
Medium Type Specify the medium type for the selected ports. If configuring the Combo ports, the Medium
Type defines the type of transport medium to be used, whether Copper or Fiber.
Description
Users may then enter a description for the chosen port(s).
Click the Apply button to implement changes made.
Port Error Disabled
The following window displays the information about ports that have been disconnected by the Switch when a packet
storm occurs or a loop was detected.
To view the following window, click System Configuration > Port Configuration > Port Error Disabled, as show
below:

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Figure 2-5 Port Error Disabled
The fields that can be displayed are described below:
Parameter Description
Port
Display the port that has been error disabled.
Port State
Describe the current running state of the port, whether enabled or disabled.
Connection Status
Display the uplink status of the individual ports, whether enabled or disabled.
Reason Describe the reason why the port has been error-disabled, such as it has become a
shutdown port for storm control.
Jumbo Frame Settings
The Switch supports jumbo frames. Jumbo frames are Ethernet frames with more than 1,518 bytes of payload. The
Switch supports jumbo frames with a maximum frame size of up to 13312 bytes.
To view the following window, click System Configuration > Port Configuration > Jumbo Frame Settings, as show
below:
Figure 2-6 Jumbo Frame Settings window
The fields that can be configured are described below:
Parameter Description
Jumbo Frame Use the radio buttons to enable or disable the Jumbo Frame function on the Switch. The
default is Disabled. When disabled, the maximum frame size is 1536 bytes. When enabled,
the maximum frame size is 13312 bytes.
Click the Apply button to implement changes made.
PoE
The DGS-3120-24PC and DGS-3120-48PC switches support Power over Ethernet (PoE) as defined by the IEEE
802.3af and 802.3at. All ports can support PoE up to 30W. Ports 1-24 can supply about 48 VDC power to Powered
Devices (PDs) over Category 5 or Category 3 UTP Ethernet cables. The Switch follows the standard PSE (Power
Sourcing Equipment) pinout Alternative A, whereby power is sent out over pins 1, 2, 3 and 6. The Switches work with
all D-Link 802.3af capable devices.
The Switch includes the following PoE features:

xStack® DGS-3120 Series Layer 2 Stackable Managed Switch Web UI Reference Guide
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•Auto-discovery recognizes the connection of a PD (Powered Device) and automatically sends power to
it.
•The Auto-disable feature occurs under two conditions: firstly, if the total power consumption exceeds
the system power limit; and secondly, if the per port power consumption exceeds the per port power
limit.
•Active circuit protection automatically disables the port if there is a short. Other ports will remain active.
Based on 802.3af/at PDs receive power according to the following classification:
Class Maximum power available to PD
0 15.4W
1 4.0W
2 7.0W
3 15.4W
4 15.4W
To configure the PoE features on the Switch, click System Configuration >PoE. The PoE System Settings window
is used to assign a power limit and power disconnect method for the whole PoE system. To configure the Power Limit
for the PoE system, enter a value between 1W and 370W for the Switch in the Power Limit field. When the total
consumed power exceeds the power limit, the PoE controller (located in the PSE) disconnects the power to prevent
overloading the power supply.
PoE System Settings
To view the following window, click System Configuration > PoE > PoE System Settings, as show below:
PSE provides power according to the following classification:
Class Max power used by PSE
0 16.2W
1 4.2W
2 7.4W
3 16.2W
User define 31.2W