D-link DGS-3224TG User Manual

DGS-3224TG

Managed 24-Port Gigabit Ethernet Switch

User’s Guide

First Edition (October 2004)

651TG3224015

Printed In Taiwan

RECYCLABLE

Wichtige Sicherheitshinweise

1. Bitte lesen Sie sich diese Hinweise sorgfältig durch.

2. Heben Sie diese Anleitung für den spätern Gebrauch auf.

3. Vor jedem Reinigen ist das Gerät vom Stromnetz zu trennen. Vervenden Sie keine Flüssig- oder Aerosolreiniger. Am besten dient ein
angefeuchtetes Tuch zur Reinigung.

4. Um eine Beschädigung des Gerätes zu vermeiden sollten Sie nur Zubehörteile verwenden, die vom Hersteller zugelassen sind.

5. Das Gerät is vor Feuchtigkeit zu schützen.

6. Bei der Aufstellung des Gerätes ist auf sichern Stand zu achten. Ein Kippen oder Fallen könnte Verletzungen hervorrufen. Verwenden Sie nur
sichere Standorte und beachten Sie die Aufstellhinweise des Herstellers.

7. Die Belüftungsöffnungen dienen zur Luftzirkulation die das Gerät vor Überhitzung schützt. Sorgen Sie dafür, daß diese Öffnungen nicht
abgedeckt werden.

8. Beachten Sie beim Anschluß an das Stromnetz die Anschlußwerte.

9. Die Netzanschlußsteckdose muß aus Gründen der elektrischen Sicherheit einen Schutzleiterkontakt haben.

10. Verlegen Sie die Netzanschlußleitung so, daß niemand darüber fallen kann. Es sollete auch nichts auf der Leitung abgestellt werden.

11. Alle Hinweise und Warnungen die sich am Geräten befinden sind zu beachten.

12. Wird das Gerät über einen längeren Zeitraum nicht benutzt, sollten Sie es vom Stromnetz trennen. Somit wird im Falle einer Überspannung
eine Beschädigung vermieden.

13. Durch die Lüftungsöffnungen dürfen niemals Gegenstände oder Flüssigkeiten in das Gerät gelangen. Dies könnte einen Brand bzw.
Elektrischen Schlag auslösen.

14. Öffnen Sie niemals das Gerät. Das Gerät darf aus Gründen der elektrischen Sicherheit nur von authorisiertem Servicepersonal geöffnet
werden.

15. Wenn folgende Situationen auftreten ist das Gerät vom Stromnetz zu trennen und von einer qualifizierten Servicestelle zu überprüfen:
a – Netzkabel oder Netzstecker sint beschädigt.
b – Flüssigkeit ist in das Gerät eingedrungen.
c – Das Gerät war Feuchtigkeit ausgesetzt.
d – Wenn das Gerät nicht der Bedienungsanleitung ensprechend funktioniert oder Sie mit Hilfe dieser Anleitung keine Verbesserung erzielen.
e – Das Gerät ist gefallen und/oder das Gehäuse ist beschädigt.
f – Wenn das Gerät deutliche Anzeichen eines Defektes aufweist.

16. Bei Reparaturen dürfen nur Orginalersatzteile bzw. den Orginalteilen entsprechende Teile verwendet werden. Der Einsatz von ungeeigneten
Ersatzteilen kann eine weitere Beschädigung hervorrufen.

17. Wenden Sie sich mit allen Fragen die Service und Repartur betreffen an Ihren Servicepartner. Somit stellen Sie die Betriebssicherheit des
Gerätes sicher.

18. Zum Netzanschluß dieses Gerätes ist eine geprüfte Leitung zu verwenden, Für einen Nennstrom bis 6A und einem Gerätegewicht grőßer 3kg ist
eine Leitung nicht leichter als H05VV-F, 3G, 0.75mm2 einzusetzen.

Trademarks

Copyright D-Link Corporation 2002. Contents subject to change without prior notice. D-Link is a registered
trademark of D-Link Corporation/D-Link Systems, Inc. All other trademarks belong to their respective proprietors.

Copyright Statement

No part of this publication may be reproduced in any form or by any means or used to make any derivative such as
translation, transformation, or adaptation without permission from D-Link Corporation/D-Link Systems Inc., as
stipulated by the United States Copyright Act of 1976.

Limited Warranty

Hardware:

D-Link warrants its hardware products to be free from defects in workmanship and materials, under normal use and service, for
the following periods measured from date of purchase from D-Link or its Authorized Reseller:

Product Type
Complete products One year
Spare parts and spare kits 90 days

Warranty Period

If the product proves defective within the applicable warranty period, D-Link will provide repair or replacement of the product.
D-Link shall have the sole discretion whether to repair or replace, and replacement product may be new or reconditioned.
Replacement product shall be of equivalent or better specifications, relative to the defective product, but need not be identical.
Any product or part repaired by D-Link pursuant to this warranty shall have a warranty period of not less than 90 days, from
date of such repair, irrespective of any earlier expiration of original warranty period. When D-Link provides replacement, then
the defective product becomes the property of D-Link.

Warranty service may be obtained by contacting a D-Link office within the applicable warranty period, and requesting a Return
Material Authorization (RMA) number. If Purchaser's circumstances require special handling of warranty correction, then at

the time of requesting RMA number, Purchaser may also propose special procedure as may be suitable to the case.

After an RMA number is issued, the defective product must be packaged securely in the original or other suitable shipping
package to ensure that it will not be damaged in transit, and the RMA number must be prominently marked on the outside of the
package. The package must be mailed or otherwise shipped to D-Link with all costs of mailing/shipping/insurance prepaid;
D-Link will ordinarily reimburse Purchaser for mailing/shipping/insurance expenses incurred for return of defective product in
accordance with this warranty. D-Link shall never be responsible for any software, firmware, information, or memory data of
Purchaser contained in, stored on, or integrated with any product returned to D-Link pursuant to this warranty.

Any package returned to D-Link without an RMA number will be rejected and shipped back to Purchaser at Purchaser's expense,
and D-Link reserves the right in such a case to levy a reasonable handling charge in addition mailing or shipping costs.

Software:

Warranty service for software products may be obtained by contacting a D-Link office within the applicable warranty period. A
list of D-Link offices is provided at the back of this manual.

D-Link warrants that its software products will perform in substantial conformance with the applicable product documentation
provided by D-Link with such software product, for a period of ninety (90) days from the date of purchase from D-Link or its
Authorized Reseller. D-Link warrants the magnetic media, on which D-Link provides its software product, against failure during
the same warranty period. This warranty applies to purchased software, and to replacement software provided by D-Link
pursuant to this warranty, but shall not apply to any update or replacement which may be provided for download via the Internet,
or to any update which may otherwise be provided free of charge.

D-Link's sole obligation under this software warranty shall be to replace any defective software product with product which
substantially conforms to D-Link's applicable product documentation. Purchaser assumes responsibility for the selection of
appropriate application and system/platform software and associated reference materials. D-Link makes no warranty that its

software products will work in combination with any hardware, or any application or system/platform software product provided
by any third party, excepting only such products as are expressly represented, in D-Link's applicable product documentation as
being compatible. D-Link's obligation under this warranty shall be a reasonable effort to provide compatibility, but D-Link shall
have no obligation to provide compatibility when there is fault in the third-party hardware or software. D-Link makes no
warranty that operation of its software products will be uninterrupted or absolutely error-free, and no warranty that all defects in
the software product, within or without the scope of D-Link's applicable product documentation, will be corrected.

LIMITATION OF WARRANTIES

IF THE D-LINK PRODUCT DOES NOT OPERATE AS WARRANTED ABOVE, THE CUSTOMER'S SOLE REMEDY SHALL BE, AT D­LINK'S OPTION, REPAIR OR REPLACEMENT. THE FOREGOING WARRANTIES AND REMEDIES ARE EXCLUSIVE AND ARE IN
LIEU OF ALL OTHER WARRANTIES, EXPRESSED OR IMPLIED, EITHER IN FACT OR BY OPERATION OF LAW, STATUTORY OR
OTHERWISE, INCLUDING WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. D-LINK
NEITHER ASSUMES NOR AUTHORIZES ANY OTHER PERSON TO ASSUME FOR IT ANY OTHER LIABILITY IN CONNECTION
WITH THE SALE, INSTALLATION MAINTENANCE OR USE OF D-LINK'S PRODUCTS
D-LINK SHALL NOT BE LIABLE UNDER THIS WARRANTY IF ITS TESTING AND EXAMINATION DISCLOSE THAT THE ALLEGED
DEFECT IN THE PRODUCT DOES NOT EXIST OR WAS CAUSED BY THE CUSTOMER'S OR ANY THIRD PERSON'S MISUSE,
NEGLECT, IMPROPER INSTALLATION OR TESTING, UNAUTHORIZED ATTEMPTS TO REPAIR, OR ANY OTHER CAUSE BEYOND
THE RANGE OF THE INTENDED USE, OR BY ACCIDENT, FIRE, LIGHTNING OR OTHER HAZARD.

LIMITATION OF LIABILITY

IN NO EVENT WILL D-LINK BE LIABLE FOR ANY DAMAGES, INCLUDING LOSS OF DATA, LOSS OF PROFITS, COST OF COVER
OR OTHER INCIDENTAL, CONSEQUENTIAL OR INDIRECT DAMAGES ARISING OUT THE INSTALLATION, MAINTENANCE, USE,
PERFORMANCE, FAILURE OR INTERRUPTION OF A D- LINK PRODUCT, HOWEVER CAUSED AND ON ANY THEORY OF
LIABILITY. THIS LIMITATION WILL APPLY EVEN IF D-LINK HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
IF YOU PURCHASED A D-LINK PRODUCT IN THE UNITED STATES, SOME STATES DO NOT ALLOW THE LIMITATION OR
EXCLUSION OF LIABILITY FOR INCIDENTAL OR CONSEQUENTIAL DAMAGES, SO THE ABOVE LIMITATION MAY NOT APPLY
TO YOU.

D-Link Offices for Warranty Service

To obtain an RMA number for warranty service as to a hardware product, or to obtain warranty service as to a software product,
contact the D-Link office nearest you. An addresses/telephone/fax list of D-Link offices is provided in the back of this manual.

FCC Warning

This equipment has been tested and found to comply with the limits for a Class A digital device, pursuant to Part 15 of the FCC
Rules. These limits are designed to provide reasonable protection against harmful interference when the equipment is operated in
a commercial environment. This equipment generates, uses, and can radiate radio frequency energy and, if not installed and used
in accordance with this user’s guide, may cause harmful interference to radio communications. Operation of this equipment in a
residential area is likely to cause harmful interference in which case the user will be required to correct the interference at his
own expense.

This device complies with part 15 of the FCC Rules. Operation is subject to the following two conditions: (1) This device may not
cause harmful interference, and (2) this device must accept any interference received, including interference that may cause
undesired operation.

CE Mark Warning

This is a Class A product. In a domestic environment, this product may cause radio interference in which case the
user may be required to take adequate measures.

Warnung!

Dies ist ein Produkt der Klasse A. Im Wohnbereich kann dieses Produkt Funkstoerungen verursachen.
In diesem Fall kann vom Benutzer verlangt werden, angemessene Massnahmen zu ergreifen.

Precaución!

Este es un producto de Clase A. En un entorno doméstico, puede causar interferencias de radio, en
cuyo case, puede requerirse al usuario para que adopte las medidas adecuadas.

Attention!

Ceci est un produit de classe A. Dans un environnement domestique, ce produit pourrait causer des
interférences radio, auquel cas l`utilisateur devrait prendre les mesures adéquates.

Attenzione!

Il presente prodotto appartiene alla classe A. Se utilizzato in ambiente domestico il prodotto può
causare interferenze radio, nel cui caso è possibile che l`utente debba assumere provvedimenti
adeguati.

BSMI Warning

Table of Contents

About This Guide .................................................................................................................................. 1

Overview of this User’s Guide ............................................................................................................. 1

Introduction .......................................................................................................................................... 2

Features ............................................................................................................................................. 2

Ports ................................................................................................................................................ 2

Performance Features......................................................................................................................... 2

Management .................................................................................................................................... 3

Unpacking and Setup............................................................................................................................ 4

Unpacking .......................................................................................................................................... 4

Installation ......................................................................................................................................... 4

Desktop or Shelf Installation ............................................................................................................ 4

Rack Installation.............................................................................................................................. 5

Power on............................................................................................................................................. 6

Power Failure ................................................................................................................................... 6

Identifying External Components .......................................................................................................... 7

Front Panel......................................................................................................................................... 7

Rear Panel .......................................................................................................................................... 7

Side Panels ......................................................................................................................................... 8

LED Indicators ................................................................................................................................... 8

Connecting The Switch.......................................................................................................................... 9

Switch to End Node ............................................................................................................................ 9

Switch to Hub or Switch ..................................................................................................................... 9

Switch Management and Operating Concepts ..................................................................................... 11

Local Console Management .............................................................................................................. 11

Diagnostic (console) port (RS-232 DCE)..........................................................................................11

IP Addresses and SNMP Community Names ..................................................................................... 12

Traps................................................................................................................................................ 13

MIBs................................................................................................................................................. 14

SNMP ............................................................................................................................................... 14

Authentication ............................................................................................................................... 15

Packet Forwarding ............................................................................................................................ 15

MAC Address Aging Time ............................................................................................................... 15

Filtering............................................................................................................................................ 15

Spanning Tree Protocol ..................................................................................................................... 16

STP Operation Levels ..................................................................................................................... 16

Bridge Protocol Data Units ............................................................................................................. 17

Creating a Stable STP Topology ...................................................................................................... 18

STP Port States .............................................................................................................................. 18

User-Changeable STP Parameters ..................................................................................................20

Illustration of STP .......................................................................................................................... 20

VLANs .............................................................................................................................................. 22

Notes About VLANs on the DGS-3224TG........................................................................................ 22

IEEE 802.1Q VLANs....................................................................................................................... 22

802.1Q VLAN Packet Forwarding ...................................................................................................23

802.1Q VLAN Tags ......................................................................................................................... 24

Port VLAN ID.................................................................................................................................. 25

Tagging and Untagging................................................................................................................... 26

Ingress Filtering ............................................................................................................................. 26

DHCP ............................................................................................................................................... 27

Configuring the Switch Using the Console Interface ............................................................................ 29

Before You Start ............................................................................................................................... 29

Connecting to the Switch .................................................................................................................. 29

User Accounts Management ............................................................................................................. 32

Save Changes ................................................................................................................................... 34

Factory Reset ................................................................................................................................. 35

Configuration ................................................................................................................................... 38

Configure IP Address...................................................................................................................... 39

Configure Switch Information and Advanced Settings .................................................................... 41

Configure Ports .............................................................................................................................. 43

Configure Spanning Tree Protocol .................................................................................................. 44

Configure Static (Destination-Address Forwarding) Table ............................................................... 46

Configure VLANs ............................................................................................................................ 49

Configure IGMP Snooping .............................................................................................................. 53

Configure Trunk............................................................................................................................. 55

Configure Port Mirroring ................................................................................................................ 56

Configure Class of Service, Default Priority, and Traffic Class ........................................................ 57

Configure RS232 and SLIP ............................................................................................................. 60

Network Monitoring .......................................................................................................................... 61

Port Utilization ............................................................................................................................... 62

Port Error Packets.......................................................................................................................... 63

Port Packet Analysis....................................................................................................................... 63

Browse MAC Address ..................................................................................................................... 64

Switch History................................................................................................................................ 65

IGMP Snooping .............................................................................................................................. 66

Browse Multicast Status ................................................................................................................ 67

VLAN Status .................................................................................................................................. 68

SNMP Manager Configuration........................................................................................................... 68

System Utilities ................................................................................................................................ 69

Upgrade Firmware from TFTP Server .............................................................................................. 70

Use Configuration File on TFTP Server ...........................................................................................71

Save Settings to TFTP Server .......................................................................................................... 72

Save History Log to TFTP Server..................................................................................................... 73

Ping Test ........................................................................................................................................ 74

Reboot .............................................................................................................................................. 75

Web-Based Network Management ....................................................................................................... 78

Introduction ..................................................................................................................................... 78

Getting Started ................................................................................................................................. 78

Configuration ................................................................................................................................... 82

IP Address...................................................................................................................................... 82

Switch Information......................................................................................................................... 83

Advanced Settings.......................................................................................................................... 84

Port Configuration.......................................................................................................................... 85

Port Mirroring ................................................................................................................................ 86

Port Trunking................................................................................................................................. 87

IGMP Snooping .............................................................................................................................. 87

Spanning Tree................................................................................................................................ 88

Static Forwarding Table ................................................................................................................. 91

VLANs............................................................................................................................................ 92

Port Default Priority ....................................................................................................................... 95

Class of Traffic ............................................................................................................................... 96

Class of Service .............................................................................................................................. 96

RS232 & SLIP ................................................................................................................................ 98

Management..................................................................................................................................... 99

Security IP ..................................................................................................................................... 99

SNMP Manager .............................................................................................................................. 99

Trap Manager............................................................................................................................... 100

User Accounts.............................................................................................................................. 100

Monitoring...................................................................................................................................... 101

Port Utilization ............................................................................................................................. 101

Packets ........................................................................................................................................ 102

Errors .......................................................................................................................................... 108

Size .............................................................................................................................................. 113

MAC Address Table ...................................................................................................................... 115

IGMP Snooping Table ................................................................................................................... 116

VLAN Multicast Table................................................................................................................... 117

IGMP Multicast Table ................................................................................................................... 117

VLAN Status ................................................................................................................................ 117

Maintenance................................................................................................................................... 118

TFTP Services............................................................................................................................... 118

Switch History.............................................................................................................................. 120

Ping Test ...................................................................................................................................... 121

Save Changes............................................................................................................................... 122

Factory Reset ............................................................................................................................... 123

Restart System............................................................................................................................. 123

Connection Timeout ..................................................................................................................... 124

Logout.......................................................................................................................................... 124

Help................................................................................................................................................ 124

Technical Specifications .................................................................................................................... 125

Cable Lengths ................................................................................................................................... 128

Runtime Switching Software Default Settings.................................................................................... 129

Understanding and Troubleshooting the Spanning Tree Protocol....................................................... 130

Blocking State.............................................................................................................................. 130

Listening State ............................................................................................................................. 131

Learning State.............................................................................................................................. 132

Forwarding State.......................................................................................................................... 133

Disabled State.............................................................................................................................. 134

Troubleshooting STP....................................................................................................................... 135

Spanning Tree Protocol Failure .................................................................................................... 135

Full/Half Duplex Mismatch.......................................................................................................... 136

Unidirectional Link ...................................................................................................................... 137

Packet Corruption ........................................................................................................................ 138

Resource Errors ........................................................................................................................... 138

Identifying a Data Loop ................................................................................................................ 138

Avoiding Trouble .......................................................................................................................... 138

Brief Review of Bitwise Logical Operations......................................................................................... 141

Index................................................................................................................................................. 142

DGS-3224TG Gigabit Ethernet Switch User’s Guide

ABOUT THIS GUIDE

This User’s guide tells you how to install your DGS-3224TG, how to connect it to your Gigabit Ethernet
network, and how to set its configuration using the built-in console interface.

Overview of this User’s Guide

• Chapter 1, “Introduction.” Describes the Switch and its features.

• Chapter 2, “Unpacking and Setup.” Helps you get started with the basic installation of the Switch.

• Chapter 3, “Identifying External Components.” Describes the front panel, rear panel, and LED

indicators of the Switch.

• Chapter 4, “Connecting the Switch.” Tells how you can connect the DGS-3224TG to your Gigabit
Ethernet network.

• Chapter 5, “Switch Management and Operating Concepts.” Talks about Local Console
Management via the RS-232 DCE console port and other aspects about how to manage the
Switch.

• Chapter 6, “Using the Console Interface.” Tells how to use the built-in console interface to change,
set, and monitor Switch performance and security.

• Chapter 7, “Web-Based Network Management.” Tells how to manage the Switch through an
Internet browser.

• Appendix A, “Technical Specifications.” Lists the technical specifications of the DGS-3224TG.

• Appendix B, “Cable Lengths.” Contains chart for fiber-optic and copper cable maximum

distances.

• Appendix C, “Factory Default Settings.”

• Appendix D, “Understanding and Troubleshooting the Spanning Tree Protocol.”

• Appendix E, “Brief Review of Bitwise Logical Operations.”

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DGS-3224TG Gigabit Ethernet Switch User’s Guide

1

INTRODUCTION

This section describes the features of the DGS-3224TG.

Features

The DGS-3224TG was designed for departmental and enterprise connections. As an all-gigabit-port
switch, it is ideal for backbone and server connection. Powerful and versatile, the switch eliminates
network bottlenecks while giving users the capability to fine-tune performance

Switch features include:

Ports

• Twenty high performance 1000BASE-T ports for making 10/100/1000 connections to a
backbone, end stations, and servers.

• Four GBIC ports to connect fiber optic media to another switch, server or network backbone.

• RS-232 DCE Diagnostic port (console port) for setting up and managing the Switch via a

connection to a console terminal or PC using a terminal emulation program.

Performance Features

• Store-and-forward switching scheme.

• High-speed data forwarding rate of 1,488,100 pps per port at 100% of wire-speed for 1000 Mbps

speed.

• Optimized 32K entry address database without flooding.

• 802.1D Spanning Tree support. Can be disabled on the entire switch or on a per-port basis.

• 802.1Q Tagged VLAN support, including GVRP (GARP VLAN Registration Protocol).

• Support for 200 VLANs in total, including 64 static VLANs.

• IGMP snooping support per switch.

• Link aggregation support for up to 6 trunk groups and 16 trunk members per group.

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DGS-3224TG Gigabit Ethernet Switch User’s Guide

Management

• RS-232 console port for out-of-band network management via a console terminal.

• Spanning Tree Algorithm Protocol for creation of alternative backup paths and prevention of

network loops.

• SNMP V.1.

• Fully configurable either in-band or out-of-band control via SNMP based software.

• Flash memory for software upgrades. This can be done in-band via TFTP or out-of-band via the

console.

• Built-in SNMP management:

 Bridge MIB (RFC 1493)

 MIB-II (RFC 1213)

 802.1P/Q MIB (RFC 2674)

 Interface MIB (RFC 2233)

 Mini-RMON MIB (RFC 1757) – 4 groups. The RMON specification defines the counters for

the receive functions only. However, the DGS-3224TG provides counters for both receive
and transmit functions.

• Supports Web-based management.

• TFTP support.

• BOOTP support.

• DHCP Client support.

• Password enabled.

• Telnet remote control console.

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DGS-3224TG Gigabit Ethernet Switch User’s Guide

2

UNPACKING AND SETUP

This chapter provides unpacking and setup information for the Switch.

Unpacking

Open the shipping carton of the switch and carefully unpack its contents. The carton should contain
the following items:

• One DGS-3224TG 24-Port Gigabit Ethernet Switch

• Mounting kit: 2 mounting brackets and screws

• Four rubber feet with adhesive backing

• One AC power cord

• This User’s Guide

If any item is found missing or damaged, please contact your local reseller for replacement.

Installation

Use the following guidelines when choosing a place to install the switch:

• The surface must support at least 6.5 kg.

• The power outlet should be within 1.82 meters (6 feet) of the device.

• Visually inspect the power cord and see that it is secured to the AC power connector.

• Make sure that there is proper heat dissipation from and adequate ventilation around the switch.

Do not place heavy objects on the switch.

Desktop or Shelf Installation

When installing the switch on a desktop or shelf, the rubber feet included with the device should first
be attached. Attach these cushioning feet on the bottom at each corner of the device. Allow adequate
space for ventilation between the device and the objects around it.

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DGS-3224TG Gigabit Ethernet Switch User’s Guide

Figure 2-1. Installing rubber feet for desktop installation

Rack Installation

The DGS-3224TG can be mounted in an EIA standard-sized, 19-inch rack, which can be placed in a
wiring closet with other equipment. To install, attach the mounting brackets on the switch’s side panels
(one on each side) and secure them with the screws provided.

Figure 2- 2A. Attaching the mounting brackets

Then, use the screws provided with the equipment rack to mount the witch on the rack.

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DGS-3224TG Gigabit Ethernet Switch User’s Guide

Figure 2-2B. Installing in an equipment rack

Power on

The switch can be used with AC power supply 100-240 VAC, 50 - 60 Hz. The switch’s power supply will
adjust to the local power source automatically and may be powered on without having any or all LAN
segment cables connected.

After the switch is plugged in, the LED indicators should respond as follows:

• All LED indicators will momentarily blink. This blinking of the LED indicators represents a reset
of the system.

• The power LED indicator will blink while the switch loads onboard software and performs a self­test. After approximately 20 seconds, the LED will light again to indicate the switch is in a ready
state.

Power Failure

As a precaution in the event of a power failure, unplug the switch. When power is resumed, plug the
switch back in.

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DGS-3224TG Gigabit Ethernet Switch User’s Guide

3

IDENTIFYING EXTERNAL COMPONENTS

This chapter describes the front panel, rear panel, side panels, and LED indicators of the DGS-3224TG.

Front Panel

The front panel of the switch consists of LED indicators, an RS-232 communication port, 20
1000BASE-T ports, and 4 GBIC ports.

Figure 3-1. Front panel view

• An RS-232 DCE console port for setting up and managing the switch via a connection to a
console terminal or PC using a terminal emulation program.

• Comprehensive LED indicators display the status of the switch and the network (see the LED
Indicators section below).

• Four GBIC ports to connect fiber optic media to another switch, server, or network backbone.

• Twenty 1000BASE-T Ethernet ports for 10/100/1000 connections to a backbone, end stations,

and servers.

Rear Panel

The rear panel of the switch contains an AC power connector.

Figure 3-2. Rear panel view

• The AC power connector is a standard three-pronged connector that supports the power cord.
Plug-in the female connector of the provided power cord into this socket, and the male side of the
cord into a power outlet. Supported input voltages range from 100 ~ 240 VAC at 50 ~ 60 Hz.

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DGS-3224TG Gigabit Ethernet Switch User’s Guide

Side Panels

The right side panel of the switch contains two system fans (see the top part of the diagram below). The
left side panel contains heat vents.

Figure 3-3. Side panel views of the Switch

• The system fans are used to dissipate heat. The sides of the system also provide heat vents to
serve the same purpose. Do not block these openings, and leave at least 6 inches of space at the
rear and sides of the switch for proper ventilation. Be reminded that without proper heat
dissipation and air circulation, system components might overheat, which could lead to system
failure.

LED Indicators

The LED indicators of the switch include Status, Speed, Full Duplex, and Link/Activity. The following
shows the LED indicators for the switch along with an explanation of each indicator.

Figure 3-4. LED indicators

• Status – This indicator on the front panel blinks green when the system is booting up. It is solid
green when the system is operating normally and solid red if the system fails.

• Speed – There are three rows of indicators for the 20 copper ports. The top LED is solid green for
1000 Mbps connections and solid amber for 100 Mbps connections. The indicator is off for 10
Mbps connections.

• Full Duplex – This indicator for the 20 copper ports is located in the middle row. Solid green
indicates a full-duplex connection. The LED is off for half-duplex connections.

• Act/Link – This indicator is located in the bottom row for the 20 copper ports and directly to the
left of the four GBIC ports. In each case, these indicators light solid green when there is a secure
connection (or link) to a device on any of the ports. The LEDs blink green whenever there is
reception or transmission (i.e. Activity--Act) of data occurring on a port.

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DGS-3224TG Gigabit Ethernet Switch User’s Guide

4

CONNECTING THE SWITCH

This chapter describes how to connect the DGS-3224TG to your Gigabit Ethernet network.

Switch to End Node

End nodes include PCs outfitted with a 10, 100 or 10/100 Mbps RJ-45 Ethernet/Fast Ethernet
Network Interface Card (NIC) and most routers.

An end node can be connected to the switch via a two-pair Category 3, 4, 5, or 5e UTP/STP cable—for
optimal performance, Category 5e is recommended. The end node should be connected to any of the
ports of the switch.

Figure 4-1. Switch connected to an End Node

The Link/Act LEDs on the bottom row of the front panel of the device light green when the link is
valid. The LED on the top row indicates port speed. It will light solid green for 1000 Mbps
connections, solid amber for 100 Mbps connections, and will remain off for 10 Mbps connections. A
blinking green LED on the bottom row indicates packet activity on that port.

Switch to Hub or Switch

These connections can be accomplished in a number of ways using a normal cable.

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DGS-3224TG Gigabit Ethernet Switch User’s Guide

• A 10BASE-T hub or switch can be connected to the switch via a two-pair Category 3, 4, 5, or 5e
UTP/STP cable.

• A 100BASE-TX hub or switch can be connected to the switch via a two-pair Category 5 or 5e
UTP/STP cable.

• A 1000BASE-T switch can be connected to the switch via four-pair straight Category 5 or 5e
UTP/STP cable.

Figure 4-2. Switch connected to a normal (non-Uplink) port on a hub or switch using a straight or crossover

cable

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DGS-3224TG Gigabit Ethernet Switch User’s Guide

5

SWITCH MANAGEMENT AND OPERATING

CONCEPTS

This chapter discusses many of the concepts and features used to manage the switch, as well as the
concepts necessary for the user to understand the functioning of the switch. Further, this chapter
explains many important points regarding these features.

Configuring the switch to implement these concepts and make use of its many features is discussed in
detail in the next chapters.

Local Console Management

A local console is a terminal or a workstation running a terminal emulation program that is connected
directly to the switch via the RS-232 console port on the front of the switch. A console connection is
referred to as an ‘Out-of-Band’ connection, meaning that console is connected to the switch using a
different circuit than that used for normal network communications. So, the console can be used to set
up and manage the switch even if the network is down.

Local console management uses the terminal connection to operate the console program built-in to the
switch (see Chapter 6, “Using the Console Interface”). A network administrator can manage, control and
monitor the switch from the console program.

The DGS-3224TG contains a CPU, memory for data storage, flash memory for configuration data,
operational programs, and SNMP agent firmware. These components allow the switch to be actively
managed and monitored from either the console port or the network itself (out-of-band, or in-band).

Diagnostic (console) port (RS-232 DCE)

Out-of-band management requires connecting a terminal, such as a VT-100 or a PC running a terminal
emulation program (such as HyperTerminal, which is automatically installed with Microsoft Windows) a
to the RS-232 DCE console port of the switch. Switch management using the RS-232 DCE console port
is called Local Console Management to differentiate it from management performed via management
platforms, such as D-View, HP OpenView, etc.

The console port is set at the factory for the following configuration:

• Baud rate: 9,600

• Data width: 8 bits

• Parity: none

• Stop bits: 1

• Flow Control None

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DGS-3224TG Gigabit Ethernet Switch User’s Guide

Make sure the terminal or PC you are using to make this connection is configured to match these
settings.

If you are having problems making this connection on a PC, make sure the emulation is set to VT-

100. If you still don’t see anything, try hitting <Ctrl> + r to refresh the screen.

IP Addresses and SNMP Community Names

Each switch must be assigned its own IP Address, which is used for communication with an SNMP
network manager or other TCP/IP application (for example BOOTP, TFTP). The switch’s default IP
address is 10.90.90.90. You can change the default switch IP Address to meet the specification of your
networking address scheme.

The switch is also assigned a unique MAC address by the factory. This MAC address cannot be
changed, and can be found from the initial boot console screen – shown below.

Figure 5-1. Boot Procedure screen

The switch’s MAC address can also be found from the console program under the Switch Information
menu item, as shown below.

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DGS-3224TG Gigabit Ethernet Switch User’s Guide

Figure 5-2. Switch Information menu

In addition, you can also set an IP address for a gateway router. This becomes necessary when the
network management station is located on a different IP network from the switch, making it necessary
for management packets to go through a router to reach the network manager, and vice-versa.

For security, you can set in the switch a list of IP Addresses of the network managers that allow you to
manage the switch. You can also change the default SNMP Community Strings in the switch and set
the access rights of these Community Strings. In addition, a VLAN may be designated as a Management
VLAN.

Traps

Traps are messages that alert you of events that occur on the switch. The events can be as serious as a
reboot (someone accidentally turned OFF the switch), or less serious like a port status change. The
switch generates traps and sends them to the network manager (trap recipient).

Trap recipients are special users of the network who are given certain rights and access in overseeing
the maintenance of the network. Trap recipients will receive traps sent from the switch; they must
immediately take certain actions to avoid future failure or breakdown of the network.

You can also specify which network managers may receive traps from the switch by entering a list of
the IP addresses of authorized network managers. Up to four trap recipient IP addresses, and four
corresponding SNMP community strings can be entered.

SNMP community strings function like passwords in that the community string entered for a given IP
address must be used in the management station software, or a trap will be sent.

The following are trap types the switch can send to a trap recipient:

• Cold Start – This trap signifies that the switch has been powered up and initialized such that
software settings are reconfigured and hardware systems are rebooted. A cold start is different

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DGS-3224TG Gigabit Ethernet Switch User’s Guide

from a factory reset in that configuration settings saved to non-volatile RAM used to
reconfigure the switch.

• Authentication Failure – This trap signifies that someone has tried to logon to the switch
using an invalid SNMP community string. The switch automatically stores the source IP
address of the unauthorized user.

• New Root – This trap indicates that the switch has become the new root of the Spanning Tree,
the trap is sent by the switch soon after its election as the new root. This implies that upon
expiration of the Topology Change Timer the new root trap is sent out immediately after the
switch’s election as the new root.

• Topology Change (STP) – A Topology Change trap is sent by the switch when any of its
configured ports transitions from the Learning state to the Forwarding state, or from the
Forwarding state to the Blocking state. The trap is not sent if a new root trap is sent for the
same transition.

MIBs

Management and counter information are stored in the switch in the Management Information Base
(MIB). The switch uses the standard MIB-II Management Information Base module. Consequently,
values for MIB objects can be retrieved from any SNMP-based network management software. In
addition to the standard MIB-II, the switch also supports its own proprietary enterprise MIB as an
extended Management Information Base. These MIBs may also be retrieved by specifying the MIB’s
Object-Identity (OID) at the network manager. MIB values can be either read-only or read-write.

Read-only MIBs variables can be either constants that are programmed into the switch, or variables
that change while the switch is in operation. Examples of read-only constants are the number of port
and type of ports. Examples of read-only variables are the statistics counters such as the number of
errors that have occurred, or how many kilobytes of data have been received and forwarded through a
port.

Read-write MIBs are variables usually related to user-customized configurations. Examples of these are
the switch’s IP Address, Spanning Tree Algorithm parameters, and port status.

If you use a third-party vendors’ SNMP software to manage the switch, a diskette listing the switch’s
propriety enterprise MIBs can be obtained by request. If your software provides functions to browse or
modify MIBs, you can also get the MIB values and change them (if the MIBs’ attributes permit the write
operation). This process however can be quite involved, since you must know the MIB OIDs and retrieve
them one by one.

SNMP

The Simple Network Management Protocol (SNMP) is an OSI layer 7 (the application layer) protocol for
remotely monitoring and configuring network devices. SNMP enables network management stations to
read and modify the settings of gateways, routers, switches, and other network devices. SNMP can be
used to perform many of the same functions as a directly connected console, or can be used within an
integrated network management software package such as HP OpenView or DView.

SNMP performs the following functions:

• Sending and receiving SNMP packets through the IP protocol.

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DGS-3224TG Gigabit Ethernet Switch User’s Guide

• Collecting information about the status and current configuration of network devices.

• Modifying the configuration of network devices.

The DGS-3224TG has a software program called an ‘agent’ that processes SNMP requests, but the user
program that makes the requests and collects the responses runs on a management station (a
designated computer on the network). The SNMP agent and the user program both use the UDP/IP
protocol to exchange packets.

Authentication

The authentication protocol ensures that both the router SNMP agent and the remote user SNMP
application program discard packets from unauthorized users. Authentication is accomplished using
‘community strings’, which function like passwords. The remote user SNMP application and the router
SNMP must use the same community string. SNMP community strings of up to 20 characters may be
entered under the Remote Management Setup menu of the console program.

Packet Forwarding

The switch enters the relationship between destination MAC or IP addresses and the Ethernet port or
gateway router the destination resides on into its forwarding table. This information is then used to
forward packets. This reduces the traffic congestion on the network, because packets, instead of being
transmitted to all ports, are transmitted to the destination port only. Example: if Port 1 receives a
packet destined for a station on Port 2, the switch transmits that packet through Port 2 only, and
transmits nothing through the other ports. This process is referred to as ‘learning’ the network
topology.

MAC Address Aging Time

The Aging Time affects the learning process of the Switch. Dynamic forwarding table entries, which are
made up of the source and destination MAC addresses and their associated port numbers, are deleted
from the table if they are not accessed within the aging time.

The aging time can be from 17.2 to 2,200 seconds with a default value of 300 seconds. A very long
aging time can result in dynamic forwarding table entries that are out-of-date or no longer exist. This
may cause incorrect packet forwarding decisions by the Switch.

If the Aging Time is too short however, many entries may be aged out too soon. This will result in a high
percentage of received packets whose source addresses cannot be found in the forwarding table, in
which case the switch will broadcast the packet to all ports, negating many of the benefits of having a
switch.

Static forwarding entries are not affected by the aging time.

Filtering

The switch uses a filtering database to segment the network and control communication between
segments. It can also filter packets off the network for intrusion control. Static filtering entries can
be made by MAC Address filtering.

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DGS-3224TG Gigabit Ethernet Switch User’s Guide

Each port on the switch is a unique collision domain and the switch filters (discards) packets whose
destination lies on the same port as where it originated. This keeps local packets from disrupting
communications on other parts of the network.

For intrusion control, whenever a switch encounters a packet originating from or destined to a MAC
address entered into the filter table, the switch will discard the packet.

Some filtering is done automatically by the switch:

• Dynamic filtering – automatic learning and aging of MAC addresses and their location on the
network. Filtering occurs to keep local traffic confined to its segment.

• Filtering done by the Spanning Tree Protocol that can filter packets based on topology,
making sure that signal loops don’t occur.

• Filtering done for VLAN integrity. Packets from a member of a VLAN (VLAN 2, for example)
destined for a device on another VLAN (VLAN 3) will be filtered.

Spanning Tree Protocol

The IEEE 802.1D Spanning Tree Protocol allows for the blocking of links between switches that form
loops within the network. When multiple links between switches are detected, a primary link is
established. Duplicated links are blocked from use and become standby links. The protocol allows for
the duplicate links to be used in the event of a failure of the primary link. Once the Spanning Tree
Protocol is configured and enabled, primary links are established and duplicated links are blocked
automatically. The reactivation of the blocked links (at the time of a primary link failure) is also
accomplished automatically – without operator intervention.

This automatic network reconfiguration provides maximum uptime to network users. However, the
concepts of the Spanning Tree Algorithm and protocol are a complicated and complex subject and must
be fully researched and understood. It is possible to cause serious degradation of the performance of
the network if the Spanning Tree is incorrectly configured. Please read the following before making any
changes from the default values.

The switch STP performs the following functions:

• Creates a single spanning tree from any combination of switching or bridging elements.

• Automatically reconfigures the spanning tree to compensate for the failure, addition, or removal

of any element in the tree.

• Reconfigures the spanning tree without operator intervention.

STP Operation Levels

STP calculates the Bridge Identifier for each switch and then sets the Root Bridge and the Designated
Bridges.

The following are the user-configurable STP parameters for the switch level:

Parameter Description Default

Value

Bridge Identifier A combination of the User-set

priority and the switch’s MAC

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DGS-3224TG Gigabit Ethernet Switch User’s Guide

(Not user­configurable except
by setting priority
below)

Priority A relative priority for each switch –

Hello Time The length of time between

Maximum Age Timer Measures the age of a received

Forward Delay Timer The amount time spent by a port

address. The Bridge Identifier
consists of two parts: a 16-bit
priority and a 48-bit Ethernet MAC
address

lower numbers give a higher
priority and a greater chance of a
given switch being elected as the
root bridge

broadcasts of the hello message by
the switch

BPDU for a port and ensures that
the BPDU is discarded when its
age exceeds the value of the
maximum age timer.

in the learning and listening states
waiting for a BPDU that may
return the port to the blocking
state.

Table 5-1. STP Parameters – Switch Level

32768

2 seconds

20 seconds

15 seconds

The following are the user-configurable STP parameters for the port or port group level:

Variable Description Default

Value

Port Priority A relative priority for each port –

lower numbers give a higher
priority and a greater chance of a
given port being elected as the root
port

Port Cost A value used by STP to evaluate

paths.

32768

19

Table 5-2. STP Parameters – Port Group Level

Bridge Protocol Data Units

For STP to arrive at a stable network topology, the following information is used:

• The unique switch identifier

• The path cost to the root associated with each switch port

• The port identifier

STP communicates between switches on the network using Bridge Protocol Data Units (BPDUs). Each
BPDU contains the following information:

• The unique identifier of the switch that the transmitting switch currently believes is the root
switch

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DGS-3224TG Gigabit Ethernet Switch User’s Guide

• The path cost to the root from the transmitting port

• The port identifier of the transmitting port

The switch sends BPDUs to communicate and construct the spanning-tree topology. All switches
connected to the LAN on which the packet is transmitted will receive the BPDU. BPDUs are not directly
forwarded by the switch, but the receiving switch uses the information in the frame to calculate a
BPDU, and, if the topology changes, initiates a BPDU transmission.

The communication between switches via BPDUs results in the following:

• One switch is elected as the root switch

• The shortest distance to the root switch is calculated for each switch

• A designated switch is selected. This is the switch closest to the root switch through which

packets will be forwarded to the root.

• A port for each switch is selected. This is the port providing the best path from the switch to the
root switch.

• Ports included in the STP are selected.

Creating a Stable STP Topology

If all switches have STP enabled with default settings, the switch with the lowest MAC address in the
network will become the root switch. By increasing the priority (lowering the priority number) of the
best switch, STP can be forced to select the best switch as the root switch.

When STP is enabled using the default parameters, the path between source and destination stations
in a switched network might not be ideal. For instance, connecting higher-speed links to a port that has
a higher number than the current root port can cause a root-port change. The goal is to make the
fastest link the root port.

STP Port States

The BPDUs take some time to pass through a network. This propagation delay can result in topology
changes where a port that transitioned directly from a Blocking state to a Forwarding state could create
temporary data loops. Ports must wait for new network topology information to propagate throughout
the network before starting to forward packets. They must also wait for the packet lifetime to expire for
BPDU packets that were forwarded based on the old topology. The forward delay timer is used to allow
the network topology to stabilize after a topology change. In addition, STP specifies a series of states a
port must transition through to further ensure that a stable network topology is created after a topology
change.

Each port on a switch using STP exists is in one of the following five states:

• Blocking – the port is blocked from forwarding or receiving packets

• Listening – the port is waiting to receive BPDU packets that may tell the port to go back to the

blocking state

• Learning – the port is adding addresses to its forwarding database, but not yet forwarding
packets

• Forwarding – the port is forwarding packets

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DGS-3224TG Gigabit Ethernet Switch User’s Guide

• Disabled – the port only responds to network management messages and must return to the
blocking state first

A port transitions from one state to another as follows:

• From initialization (switch boot) to blocking

• From blocking to listening or to disabled

• From listening to learning or to disabled

• From learning to forwarding or to disabled

• From forwarding to disabled

• From disabled to blocking

Figure 5-3. STP Port State Transitions

When you enable STP, every port on every switch in the network goes through the blocking state and
then transitions through the states of listening and learning at power up. If properly configured, each
port stabilizes to the forwarding or blocking state.

No packets (except BPDUs) are forwarded from, or received by, STP enabled ports until the forwarding
state is enabled for that port.

Default Spanning-Tree Configuration

Feature Default Value

Enable state STP enabled for all ports

Port priority 128

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DGS-3224TG Gigabit Ethernet Switch User’s Guide

Port cost 19

Bridge Priority 32,768

Table 5-3. Default STP Parameters

User-Changeable STP Parameters

The factory default setting should cover the majority of installations. However, it is advisable to keep
the default settings as set at the factory, unless it is absolutely necessary. The user changeable
parameters in the Switch are as follows:

• Priority – A Priority for the switch can be set from 0 to 65535. 0 is equal to the highest
Priority.

• Hello Time – The Hello Time can be from 1 to 10 seconds. This is the interval between two
transmissions of BPDU packets sent by the Root Bridge to tell all other switches that it is
indeed the Root Bridge. If you set a Hello Time for your switch, and it is not the Root Bridge,
the set Hello Time will be used if and when your switch becomes the Root Bridge.

Note: The Hello Time cannot be longer than the Max. Age. Otherwise, a configuration error will

occur.

• Max. Age – The Max. Age can be from 6 to 40 seconds. At the end of the Max. Age, if a BPDU
has still not been received from the Root Bridge, your switch will start sending its own BPDU
to all other switches for permission to become the Root Bridge. If it turns out that your
Switch has the lowest Bridge Identifier, it will become the Root Bridge.

• Forward Delay Timer – The Forward Delay can be from 4 to 30 seconds. This is the time any
port on the switch spends in the listening state while moving from the blocking state to the
forwarding state.

Note: Observe the following formulas when setting the above parameters:

Max. Age ≤ 2 x (Forward Delay - 1 second)

Max. Age ≥ 2 x (Hello Time + 1 second)

• Port Priority – A Port Priority can be from 0 to 255. The lower the number, the greater the
probability the port will be chosen as the Root Port.

• Port Cost – A Port Cost can be set from 1 to 65535. The lower the number, the greater the
probability the port will be chosen to forward packets.

Illustration of STP

A simple illustration of three Bridges (or three switches) connected in a loop is depicted in Figure 5-3.
In this example, you can anticipate some major network problems if the STP assistance is not applied.
If Bridge A broadcasts a packet to Bridge B, Bridge B will broadcast it to Bridge C, and Bridge C will
broadcast it to back to Bridge A, and so on. The broadcast packet will be passed indefinitely in a loop,
potentially causing a network failure.

STP can be applied as shown in Figure 5-4. In this example, STP breaks the loop by blocking the
connection between Bridge B and C. The decision to block a particular connection is based on the STP
calculation of the most current Bridge and Port settings. Now, if Bridge A broadcasts a packet to Bridge
C, then Bridge C will drop the packet at port 2 and the broadcast will end there.

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DGS-3224TG Gigabit Ethernet Switch User’s Guide

Setting-up STP using values other than the defaults can be complex. Therefore, you are advised to keep
the default factory settings and STP will automatically assign root bridges/ports and block loop
connections. Influencing STP to choose a particular switch as the root bridge using the Priority setting,
or influencing STP to choose a particular port to block using the Port Priority and Port Cost settings
is, however, relatively straight forward.

Figure 5-4. Before Applying the STA Rules

In this example, only the default STP values are used.

Figure 5-5. After Applying the STA Rules

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DGS-3224TG Gigabit Ethernet Switch User’s Guide

The switch with the lowest Bridge ID (switch C) was elected the root bridge, and the ports were selected
to give a high port cost between switches B and C.

Note also that the example network topology is intended to provide redundancy to protect the network
against a link or port failure – not a switch failure or removal. For example, a failure of switch A would
isolate LAN 1 from connecting to LAN 2 or LAN 3.

VLANs

A Virtual Local Area Network (VLAN) is a network topology configured according to a logical scheme
rather than the physical layout. VLANs can be used to combine any collection of LAN segments into an
autonomous user group that appears as a single LAN. VLANs also logically segment the network into
different broadcast domains so that packets are forwarded only between ports within the VLAN.
Typically, a VLAN corresponds to a particular subnet, although not necessarily.

VLANs can enhance performance by conserving bandwidth, and improve security by limiting traffic to
specific domains.

A VLAN is a collection of end nodes grouped by logic instead of physical location. End nodes that
frequently communicate with each other are assigned to the same VLAN, regardless of where they are
physically on the network. Logically, a VLAN can be equated to a broadcast domain, because broadcast
packets are forwarded to only members of the VLAN on which the broadcast was initiated.

Notes About VLANs on the DGS-3224TG

1. No matter what basis is used to uniquely identify end nodes and assign these nodes VLAN
membership, packets cannot cross VLANs without a network device performing a routing
function between the VLANs.

2. The DGS-3224TG supports only IEEE 802.1Q VLANs. The port untagging function can be
used to remove the 802.1Q tag from packet headers to maintain compatibility with devices
that are tag-unaware.

3. The switch’s default is to assign all ports to a single 802.1Q VLAN named
DEFAULT_VLAN.

4. The DEFAULT_VLAN has a VID = 1.

IEEE 802.1Q VLANs

Some relevant terms:

• Tagging – The act of putting 802.1Q VLAN information into the header of a packet.

• Untagging – The act of stripping 802.1Q VLAN information out of the packet header.

• Ingress port – A port on a switch where packets are flowing into the switch and VLAN

decisions must be made.

• Egress port – A port on a switch where packets are flowing out of the switch, either to
another switch or to an end station, and tagging decisions must be made.

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DGS-3224TG Gigabit Ethernet Switch User’s Guide

IEEE 802.1Q (tagged) VLANs are implemented on the DGS-3224TG. 802.1Q VLANs require tagging,
which enables them to span the entire network (assuming all switches on the network are IEEE

802.1Q-compliant).

VLANs allow a network to be segmented in order to reduce the size of broadcast domains. All packets
entering a VLAN will only be forwarded to the stations (over IEEE 802.1Q enabled switches) that are
members of that VLAN, and this includes broadcast, multicast and unicast packets from unknown
sources.

VLANs can also provide a level of security to your network. IEEE 802.1Q VLANs will only deliver
packets between stations that are members of the VLAN.

Any port can be configured as either tagging or untagging. The untagging feature of IEEE 802.1Q VLANs
allows VLANs to work with legacy switches that don’t recognize VLAN tags in packet headers. The
tagging feature allows VLANs to span multiple 802.1Q-compliant switches through a single physical
connection and allows Spanning Tree to be enabled on all ports and work normally.

The IEEE 802.1Q standard restricts the forwarding of untagged packets to the VLAN the receiving port
is a member of.

The main characteristics of IEEE 802.1Q are as follows:

• Assigns packets to VLANs by filtering.

• Assumes the presence of a single global spanning tree.

• Uses an explicit tagging scheme with one-level tagging.

802.1Q VLAN Packet Forwarding

Packet forwarding decisions are made based upon the following three types of rules:

• Ingress rules – rules relevant to the classification of received frames belonging to a VLAN.

• Forwarding rules between ports – decides filter or forward the packet

• Egress rules – determines if the packet must be sent tagged or untagged.

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DGS-3224TG Gigabit Ethernet Switch User’s Guide

Figure 5-6. IEEE 802.1Q Packet Forwarding

802.1Q VLAN Tags

The figure below shows the 802.1Q VLAN tag. There are four additional octets inserted after the source
MAC address. Their presence is indicated by a value of 0x8100 in the EtherType field. When a packet’s
EtherType field is equal to 0x8100, the packet carries the IEEE 802.1Q/802.1p tag. The tag is
contained in the following two octets and consists of 3 bits or user priority, 1 bit of Canonical Format
Identifier (CFI – used for encapsulating Token Ring packets so they can be carried across Ethernet
backbones) and 12 bits of VLAN ID (VID). The 3 bits of user priority are used by 802.1p. The VID is the
VLAN identifier and is used by the 802.1Q standard. Because the VID is 12 bits long, 4094 unique
VLANs can be identified.

The tag is inserted into the packet header making the entire packet longer by 4 octets. All of the
information contained in the packet originally is retained.

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DGS-3224TG Gigabit Ethernet Switch User’s Guide

Figure 5-7. IEEE 802.1Q Tag

The EtherType and VLAN ID are inserted after the MAC source address, but before the original
EtherType/Length or Logical Link Control. Because the packet is now a bit longer than it was originally,
the Cyclic Redundancy Check (CRC) must be recalculated.

Figure 5-8. Adding an IEEE 802.1Q Tag

Port VLAN ID

Packets that are tagged (are carrying the 802.1Q VID information) can be transmitted from one 802.1Q
compliant network device to another with the VLAN information intact. This allows 802.1Q VLANs to
span network devices (and indeed, the entire network – if all network devices are 802.1Q compliant).

Unfortunately, not all network devices are 802.1Q compliant. These devices are referred to as tag-
unaware. 802.1Q devices are referred to as tag-aware.

Prior to the adoption 802.1Q VLANs, port-based and MAC-based VLANs were in common use. These
VLANs relied upon a Port VLAN ID (PVID) to forward packets. A packet received on a given port would
be assigned that port’s PVID and then be forwarded to the port that corresponded to the packet’s

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DGS-3224TG Gigabit Ethernet Switch User’s Guide

destination address (found in the switch’s forwarding table). If the PVID of the port that received the
packet is different from the PVID of the port that is to transmit the packet, the switch will drop the
packet.

Within the switch, different PVIDs mean different VLANs (remember that two VLANs cannot
communicate without an external router). So, VLAN identification based upon the PVIDs cannot create
VLANs that extend outside a given switch (or switch stack).

Every physical port on a switch has a PVID. 802.1Q ports are also assigned a PVID, for use within the
switch. If no VLANs are defined on the switch, all ports are then assigned to a default VLAN with a PVID
equal to 1. Untagged packets are assigned the PVID of the port on which they were received.
Forwarding decisions are based upon this PVID, in so far as VLANs are concerned. Tagged packets are
forwarded according to the VID contained within the tag. Tagged packets are also assigned a PVID, but
the PVID is not used to make packet forwarding decisions, the VID is.

Tag-aware switches must keep a table to relate PVIDs within the switch to VIDs on the network. The
switch will compare the VID of a packet to be transmitted to the VID of the port that is to transmit the
packet. If the two VIDs are different, the switch will drop the packet. Because of the existence of the
PVID for untagged packets and the VID for tagged packets, tag-aware and tag-unaware network devices
can coexist on the same network.

A switch port can have only one PVID, but can have as many VIDs as the switch has memory in its
VLAN table to store them.

Because some devices on a network may be tag-unaware, a decision must be made at each port on a
tag-aware device before packets are transmitted – should the packet to be transmitted have a tag or
not? If the transmitting port is connected to a tag-unaware device, the packet should be untagged. If
the transmitting port is connected to a tag-aware device, the packet should be tagged.

Tagging and Untagging

Every port on an 802.1Q compliant switch can be configured as tagging or untagging.

Ports with tagging enabled will put the VID number, priority and other VLAN information into the
header of all packets that flow into and out of it. If a packet has previously been tagged, the port will
not alter the packet, thus keeping the VLAN information intact. The VLAN information in the tag can
then be used by other 802.1Q-compliant devices on the network to make packet forwarding decisions.

Ports with untagging enabled will strip the 802.1Q tag from all packets that flow into and out of those
ports. If the packet doesn’t have an 802.1Q VLAN tag, the port will not alter the packet. Thus, all
packets received by and forwarded by an untagging port will have no 802.1Q VLAN information
(Remember that the PVID is only used internally within the switch). Untagging is used to send packets
from an 802.1Q-compliant network device to a non-compliant network device.

Ingress Filtering

A port on a switch where packets are flowing into the switch and VLAN decisions must be made is
referred to as an ingress port. If ingress filtering is enabled for a port, the switch will examine the VLAN
information in the packet header (if present) and decide whether or not to forward the packet.

If the packet is tagged with VLAN information, the ingress port will first determine if the ingress port
itself is a member of the tagged VLAN. If it is not, the packet will be dropped. If the ingress port is a
member of the 802.1Q VLAN, the switch then determines if the destination port is a member of the

802.1Q VLAN. If it is not, the packet is dropped. If the destination port is a member of the 802.1Q
VLAN, the packet is forwarded and the destination port transmits it to its attached network segment.

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DGS-3224TG Gigabit Ethernet Switch User’s Guide

If the packet is not tagged with VLAN information, the ingress port will tag the packet with its own PVID
as a VID. The switch then determines if the destination port is a member of the same VLAN (has the
same VID) as the ingress port. If it does not, the packet is dropped. If it has the same VID, the packet is
forwarded and the destination port transmits it on its attached network segment.

This process is referred to as ingress filtering and is used to conserve bandwidth within the switch by
dropping packets that are not on the same VLAN as the ingress port at the point of reception. This
eliminates the subsequent processing of packets that will just be dropped by the destination port.

DHCP

The Dynamic Host Configuration Protocol (DHCP) can reduce the administrative burden of assigning
and maintaining IP address information. DHCP provides reliable and simple TCP/IP network
configuration, ensures that address conflicts do not occur, and helps to conserve the use of IP
addresses through the centralized management of address allocation.

Dynamic address allocation enables a client to be assigned an IP address from a pool of free addresses.
Each address is assigned with a lease and a lease expiration period. The client must renew the lease to
continue using the assigned address. Dynamically assigned addresses can be returned to the free
address pool if the computer is not being used, if it is moved to another subnet, of if its lease expires.
Usually, network policy ensures that the same IP address is assigned to a client each time and that
addresses returned to the free address pool are reassigned.

When the address lease expires, the DHCP client enters the renewing state. The client sends a request
message to the DHCP server that provided the address. The DHCP server sends an acknowledgement
that contains the new lease and configuration parameters. The client then updates its configuration
values and returns to the bound state.

When the DHCP client is in the renewing state, it must release its address immediately in the rare event
that the DHCP server sends a negative acknowledgment. The DHCP server sends this message to
inform a client that it has incorrect configuration information, forcing it to release its current address
and acquire new information.

If the DHCP client cannot successfully renew its lease, the client enters a rebinding state. The client
then sends a request message to all DHCP servers in its range, attempting to renew its lease. Any
DHCP server that can extend the lease sends an acknowledgement containing the extended lease and
updated configuration information. If the lease expires or if a DHCP server responds with a negative
acknowledgement, the client must release its current configuration, and then return to the initializing
state.

If the DHCP client uses more than one network adapter to connect to multiple networks, this protocol is
followed for each adapter that the user wants to configure for TCP/IP. Multi-homed systems are
selectively configured for any combination of the system’s interfaces.

When a DHCP-enabled computer is restarted, it sends a message to the DHCP server with its current
configuration information. The DHCP server either confirms this configuration or sends a negative reply
so that the client must begin the initializing state again. System startup might, therefore, result in a
new IP address for a client computer, but neither the user nor the network administrator has to take
any action in the configuration process.

Before loading TCP/IP with an address acquired from the DHCP server, DHCP clients check for an IP
address conflict by sending an Address Resolution Protocol (ARP) request containing the address. If a
conflict is found, TCP/IP does not start, and the user receives an error message. The conflicting address
should be removed for the list of active leases or it should be excluded until the conflict is identified
and resolved.

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DGS-3224TG Gigabit Ethernet Switch User’s Guide

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DGS-3224TG Gigabit Ethernet Switch User’s Guide

6

CONFIGURING THE SWITCH USING THE

CONSOLE INTERFACE

Your 24-port Gigabit Ethernet switch supports a console management interface that allows you to set
up and control your switch, either with an ordinary terminal (or terminal emulator), or over the network
using the TCP/IP Telnet protocol. You can use this facility to perform many basic network management
functions. In addition, the console program will allow you to configure the switch for management using
an SNMP-based network management system. This chapter describes how to use the console interface
to access the switch, change its settings, and monitor its operation.

Notes are added where clarification is necessary.

Before You Start

The DGS-3224TG supports a wide array of functions and gives great flexibility and increased network
performance by eliminating the routing bottleneck between the WAN or Internet and the Intranet. Its
function in a network can be thought of as a new generation of router that performs routing functions
in hardware, rather than software.

This flexibility and rich feature set requires a bit of thought to arrive at a deployment strategy that will
maximize the potential of the switch.

Connecting to the Switch

You can use the console interface by connecting the switch to a VT100-compatible terminal or a
computer running an ordinary terminal emulator program (e.g., the terminal program included with the
Windows operating system) using an RS-232C serial cable. Your terminal parameters will need to be set
to:

• VT-100/ANSI compatible

• 9,600 baud

• 8 data bits

• No parity

• One stop bit

• No flow control

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DGS-3224TG Gigabit Ethernet Switch User’s Guide

You can also access the same functions over a Telnet interface. Once you have set an IP address for your
switch, you can use a Telnet program (in VT-100 compatible terminal mode) to access and control the
switch. All of the screens are identical, whether accessed from the console port or from a Telnet
interface.

Console Usage Conventions

The console interface makes use of the following conventions:

1. Items in <angle brackets> can be toggled between several choices using the space bar.

2. Items in [square brackets]can be changed by typing in a new value. You can use the backspace

and delete keys to erase characters behind and in front of the cursor.

3. The up and down arrow keys, the left and right arrow keys, the tab key and the backspace key,
can be used to move between selected items.

4. Items in UPPERCASE are commands. Moving the selection to a command and pressing Enter will
execute that command, e.g. APPLY, etc.

Please note that the command APPLY only applies for the current session. Use Save Changes from the
main menu for permanent changes. Save Changes enters the current switch configuration into non­volatile RAM, and then reboots the switch.

First Time Connecting to The Switch

The switch supports user-based security that can allow you to prevent unauthorized users from
accessing the switch or changing its settings. This section tells how to log onto the switch.

Note: The passwords used to access the switch are case-sensitive; therefore, “S” is not the same

as “s.”

When you first connect to the switch, you will be presented with the first login screen (shown below).

Note: Press Ctrl+R to refresh the screen. This command can be used at any time to force the

console program in the switch to refresh the console screen.

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DGS-3224TG Gigabit Ethernet Switch User’s Guide

Figure 6-1. Initial screen, first time connecting to the switch

Note: There is no initial username or password. Leave the Username and Password fields blank.

Press Enter in both the Username and Password fields. You will be given access to the main menu
shown below:

Figure 6-2. Main menu

Note: The first user automatically gets Root privileges (See Table 6-1). It is recommended to create

at least one Root-level user for the switch.

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DGS-3224TG Gigabit Ethernet Switch User’s Guide

User Accounts Management

To create a new user account, highlight User Accounts Management from the main menu and press
Enter:

Figure 6-3. Main menu

Figure 6-4. Setup User Accounts screen

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DGS-3224TG Gigabit Ethernet Switch User’s Guide

From the main menu, highlight User Accounts Management and press Enter, then the Setup User
Accounts screen appears.

1. Toggle the Action field to <Add> using the space bar. This will allow the addition of a new user. The

other options are <Delete> - this allows the deletion of a user entry, and <Update> - this allows for
changes to be made to an existing user entry.

2. Enter the new user name, assign an initial password, and then confirm the new password.
Determine whether the new user should have <Root>, <User+>, or <User> privileges. The space bar
toggles between the three options.

3. Highlight APPLY and press Enter to make the user addition effective.

4. Press Esc. to return to the previous screen or Ctrl+T to go to the root screen.

5. A listing of all user accounts and access levels is shown below the user setup menu. This list is

updated when APPLY is executed.

6. Please remember that APPLY makes changes to the switch configuration for the current session
only. All changes (including User additions or updates) must be entered into non-volatile ram using

the Save Changes command on the main menu - if you want these changes to be permanent.

Root, User+ and Normal User Privileges

There are three levels of user privileges: Root and User+, and User. Some menu selections available to
users with Root privileges may not be available to those with User+ and User privileges.

The following table summarizes the Root, User+ and User privileges:

Switch Configuration Privilege
Management Root User+ User

Configuration Yes Read Only Read Only

Network Monitoring Yes Read Only Read Only

Community Strings and Trap
Stations

Update Firmware and Configuration
Files

System Utilities Yes Ping Only Ping Only

Factory Reset Yes No No

Reboot Switch Yes Yes No

User Accounts Management

Add/Update/Delete User Accounts Yes No No

View User Accounts Yes No No

Yes Read Only Read Only

Yes No No

Table 6-1. Root, User+, and User Privileges

After establishing a User Account with Root-level privileges, press Esc. Then highlight Save Changes
and press Enter (see below). The Switch will save any changes to its non-volatile ram and reboot. You
can logon again and are now ready to continue configuring the Switch.

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DGS-3224TG Gigabit Ethernet Switch User’s Guide

Save Changes

The DGS-3224TG has two levels of memory; normal RAM and non-volatile or NV-RAM. Configuration
changes are made effective by highlighting APPLY and pressing Enter. When this is done, the settings
will be immediately applied to the switching software in RAM, and will immediately take effect.

Some settings, though, require you to restart the switch before they will take effect. Restarting the
switch erases all settings in RAM and reloads the stored settings from the NV-RAM. Thus, it is
necessary to save all setting changes to NV-RAM before rebooting the switch.

To retain any configuration changes permanently, highlight Save Changes from the main menu.

Figure 6-5. Main menu

The following screen will appear to verify that your new settings have been saved to NV-RAM:

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DGS-3224TG Gigabit Ethernet Switch User’s Guide

Figure 6-6. Save changes screen

Once the switch configuration settings have been saved to NV-RAM, they become the default settings
for the switch. These settings will be used every time the Switch is rebooted.

Factory Reset

The only way to change the configuration stored in NV-RAM is to save a new configuration using Save
Changes, or to execute a Load Factory Default Configuration from the System Reboot menu (under
Reboot on the main menu). This will clear all settings and restore them to their initial values listed in

the appendix. These are the configuration settings entered at the factory and are the same settings
present when the switch was purchased.

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DGS-3224TG Gigabit Ethernet Switch User’s Guide

Figure 6-7. Main menu

Highlight Reboot from the main menu and press Enter.

Figure 6-8. System Reboot menu

Highlight the appropriate choice and press Enter to reset the switch’s NV-RAM to the factory default settings
(or just reboot the switch). Loading the Factory Default Configuration will erase any User Accounts (and all
other configuration settings) you may have entered and return the switch to the state it was in when it was

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DGS-3224TG Gigabit Ethernet Switch User’s Guide

purchased. The Load Factory Default Configuration Except IP Address option is used when the switch
will be managed by the Telnet manager, which requires knowledge of the switch’s IP address to function.

Logging Onto The Switch Console

To log in once you have created a registered user, from the login screen:

1. Type in your Username and press Enter.

2. Type in your Password and press Enter.

3. The main menu screen will be displayed based on your access level or privilege.

Updating or Deleting User Accounts

To update or delete a user password:

Choose User Accounts Management from the main menu. The following Setup User Accounts
screen appears:

Figure 6-9. Setup User Accounts screen

1. Toggle the Action field using the space bar to choose Add, Update, or Delete.

2. Type in the Username for the user account you wish to change.

3. You can now modify the password or the privilege level for this user account.

4. If the password is to be changed, type in the New Password you have chosen, and press
Enter. Type in the same new password in the following field to verify that you have not
mistyped it.

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DGS-3224TG Gigabit Ethernet Switch User’s Guide

5. If the privilege level is to be changed, toggle the Access Level field until the appropriate level
is displayed – Root, User+ or User.

6. Highlight APPLY and press Enter to make the change effective.

7. You must enter the configuration changes into the non-volatile ram (NV-RAM) using Save
Changes from the main menu if you want the configuration to be used after a switch reboot.

Only a user with Root privileges can make changes to user accounts.

Viewing Current User Accounts

Access to the console, whether using the console port or via Telnet, is controlled using a user name and
password. Up to eight user accounts can be created. The console interface will not let you delete the
current logged-in user, to prevent accidentally deleting all of the users with Root privilege.

Only users with the Root privilege can delete users.

To view the current user accounts, highlight User Accounts Management from the main menu. The
current user accounts can be read from the Setup User Accounts screen.

Deleting a User Account

1. Toggle the Action field to Delete.

2. Enter the Username for the account you want to delete. You must enter the password for the
account to be able to delete it.

3. Highlight APPLY and press Enter to make the deletion of the selected user take effect.

4. You must enter the configuration changes into the non-volatile ram (NV-RAM) using Save
Changes from the main menu if you want the configuration to be used after a switch reboot.

Only users with root privileges can delete user accounts.

Configuration

This section will help prepare the switch user by describing the Remote Management Setup, Switch
Information, Configure Advanced Switch Features, Configure Ports, Configure Spanning Tree,
Port Spanning Tree Settings, Setup Unicast Forwarding Table, Setup Static Multicast Forwarding
Table, IEEE 802.1Q VLANs Configuration, 802.1Q Static VLAN Settings, Port VLAN assignment,
Ingress Filter Settings, Port GVRP Settings, IGMP Snooping Settings, Link Aggregation, Setup
Port Mirroring, Class of Service Configuration, Port Default Priority assignment, Traffic Class
Configuration, and Serial Port and SLIP Settings screens, all of which can be found under the
Configuration menu, along with various submenus.

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DGS-3224TG Gigabit Ethernet Switch User’s Guide

Figure 6-10. Configuration menu

Configure IP Address

Some settings must be entered to allow the switch to be managed from an SNMP-based Network
Management System such as SNMP v1 or to be able to access the switch using the Telnet protocol.

The Remote Management Setup screen lets you specify how the switch will be assigned an IP address
to allow the switch to be identified on the network.

To setup the switch for remote management, highlight Configure IP Address from the Configuration
menu. The following screen appears:

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DGS-3224TG Gigabit Ethernet Switch User’s Guide

Figure 6-11. Remote Management Setup screen

The switch needs to have an IP address assigned to it so that an in-band network management system
(e.g. Telnet) client can find it on the network. The Remote Management Setup screen allows you to
change the settings for the two different management interfaces used on the switch: the Ethernet
interface used for in-band communication, and the SLIP interface used over the console port for out-of­band communication. Please see the Configure RS232 and SLIP section later in this manual for further
information.

The fields listed under the Current Switch IP Settings heading are those currently being used by the
switch. Those fields listed under the New Switch IP Settings heading are those that will be used after
the switch has been rebooted.

Toggle the Get IP From field using the space bar to choose from Manual, BOOTP, or DHCP. This selects
how the switch will be assigned an IP address on the next reboot (or startup).

The Get IP From options are:

• BOOTP – The switch will send out a BOOTP broadcast request when it is powered up. The
BOOTP protocol allows IP addresses, network masks, and default gateways to be assigned by
a central BOOTP server. If this option is set, the switch will first look for a BOOTP server to
provide it with this information before using the default or previously entered settings.

• DHCP – The switch will send out a DHCP broadcast request when it is powered up. The
DHCP protocol allows IP addresses, network masks, and default gateways to be assigned by a
DHCP server. If this option is set, the switch will first look for a DHCP server to provide it
with this information before using the default or previously entered settings.

• Manual – Allows the entry of an IP address, Subnet Mask, and a Default Gateway for the
switch. These fields should be of the form xxx.xxx.xxx.xxx, where each xxx is a number
(represented in decimal form) between 0 and 255. This address should be a unique address
on the network assigned for use by the network administrator. The fields which require
entries under this option are as follows:

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DGS-3224TG Gigabit Ethernet Switch User’s Guide

 IP Address – Determines the IP address used by the switch for receiving SNMP and Telnet

communications. These fields should be of the form xxx.xxx.xxx.xxx, where each xxx is a
number (represented in decimal) between 0 and 255. This address should be a unique
address on a network assigned to you by the central Internet authorities. The same IP
address is shared by both the SLIP and Ethernet network interfaces

 Subnet Mask – A bitmask that determines the extent of the subnet that the switch is on.

Should be of the form xxx.xxx.xxx.xxx, where each xxx is a number (represented in
decimal) between 0 and 255. The value should be 255.0.0.0 for a Class A network,

255.255.0.0 for a Class B network, and 255.255.255.0 for a Class C network, but custom
subnet masks are allowed.

 Default Gateway – IP address that determines where packets with a destination address

outside the current subnet should be sent. This is usually the address of a router or a
host acting as an IP gateway. If your network is not part of an intranet, or you do not
want the switch to be accessible outside your local network, you can leave this field
unchanged.

• Management VID:[ ] – Allows the entry of the VLAN ID (VID) of a VLAN that will have access
to the Telnet manager. This will be the VID of the VLAN that a management station is located
on.

Configure Switch Information and Advanced Settings

Highlight Configure Switch Information and Advanced Settings on the Configuration menu and
press Enter:

Figure 6-12. Switch Information menu

The Switch Information shows the type of switch and it’s MAC Address (assigned by the factory and
unchangeable). In addition, the Boot PROM Version, Firmware Version, and hardware version
numbers are shown. This information 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.

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DGS-3224TG Gigabit Ethernet Switch User’s Guide

You can also enter the name of the System, its location, and the name and telephone number of the
system administrator. It is recommended that the person responsible for the maintenance of the
network system that this switch is installed on be listed here.

Configure Advanced Switch Features

Select ADVANCED SETTINGS at the bottom of the Switch Information menu and press Enter to
access the following Configure Advanced Switch Features menu:

Figure 6-13. Configure Advanced Switch Features menu

This screen allows you to set the following features:

• Auto-Logout:<Never> – This sets the time the interface can be idle before the switch automatically
logs-out the user. The options are 2 mins, 5 mins, 10 mins, 15 mins, or Never.

• MAC Address Aging Time (sec):[300 ] – This field specifies the length of time a learned MAC
Address will remain in the forwarding table without being accessed (that is, how long a learned MAC
Address is allowed to remain idle). The Aging Time can be set to any value between 17 and 2200
seconds.

Note: A very long Aging Time can result with the out-of-date Dynamic Entries that may cause

incorrect packet filtering/forwarding decisions. A very short aging time may cause entries to
be aged out to soon, resulting in a high percentage of received packets whose source
addresses cannot be found in the address table, in which case the switch will broadcast the
packet to all ports, negating many of the benefits of having a Switch.

• IGMP Snooping:<Disabled> – This setting enables Internet Group Management Protocol (IGMP)
Snooping, which enables the switch to read IGMP packets being forwarded through the switch in
order to obtain forwarding information from them (learn which ports contain Multicast members.

• Switch GVRP:<Disabled> – Group VLAN Registration Protocol is a protocol that allows members to
dynamically join VLANs. This is used to enable or disable GVRP on the switch.

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DGS-3224TG Gigabit Ethernet Switch User’s Guide

• Scheduling Mechanism for CoS Queues:<Strict> – There are two Class of Service queue options,
RoundRobin and Strict. If Strict is selected, when the highest priority queue is full, those packets will

be the first to be forwarded. If RoundRobin is selected, the forwarding is based on the settings made
on the Class of Service Configuration screen.

• Trunk Load Sharing Algorithm:<Src Address> – The trunk load sharing options are Dst Address,
Src&Dst Address, and Src Address.

In addition, clicking REALCLOCK SETTINGS at the bottom of the Configure Advanced Switch
Features menu will allow you to configure the Real-time Clock for network monitoring and

troubleshooting purposes.

Figure 6-14. Setup Realtime Clock screen

Configure Ports

Highlight Configure Ports from the Configuration menu and press Enter:

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DGS-3224TG Gigabit Ethernet Switch User’s Guide

Figure 6-15. Configure Ports screen

Toggle the View Ports field, using the space bar, to view the configuration of either ports 1 through 12,
13 through 20, or 21 through 24. To configure a specific port, toggle the Configure Port from [ ] to [ ]
field until the appropriate port number or port range appears.

Toggle the State field to either enable or disable a given port.

Toggle the Speed/Duplex field to select the speed and duplex/half-duplex state of the ports1x to 20x.
Auto means auto-negotiation between 10, 100, and 1000 Mbps devices, in full- or half-duplex mode.
The Auto setting allows the twenty copper ports 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
100M/Full, 100M/Half, 10M/Full, 10M/Half. There is no automatic adjustment of port settings with
any option other than Auto. Flow Control can be enabled or disabled manually when any setting other
than Auto is selected. Please note that the switch’s four GBIC ports only support 1000M/Full.

Configure Spanning Tree Protocol

To globally configure STP on the Switch, highlight Configure Spanning Tree Protocol on the
Configuration menu and press Enter:

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DGS-3224TG Gigabit Ethernet Switch User’s Guide

Figure 6-16. Configure Spanning Tree menu

The Spanning Tree Protocol (STP) operates on two levels: on the switch level, the settings are globally
implemented. On the port level, the settings are implemented on a per user-defined group basis.

Note: The factory default settings should cover the majority of installations. Therefore, it is

advisable to keep the default settings as set at the factory unless it is absolutely necessary
to change them.

The user-changeable parameters in the Switch are as follows:

• Status:<Disabled> – Toggle to Enabled to implement the Spanning Tree Protocol on the

switch.

• Max Age: [20] – The Maximum Age can be set from 6 to 40 seconds. At the end of the Max

Age, if a BPDU has still not been received from the Root Bridge, your switch will start sending
its own BPDU to all other switches for permission to become the Root Bridge. If it turns out
that your switch has the lowest Bridge Identifier, it will become the Root Bridge.

• Hello Time: [2 ] – The Hello Time can be set from 1 to 10 seconds. This is the interval

between two transmissions of BPDU packets sent by the Root Bridge to tell all other switches
that it is indeed the Root Bridge. If you set a Hello Time for your switch, and it is not the Root
Bridge, the set Hello Time will be used if and when your switch becomes the Root Bridge.

Note: The Hello Time cannot be longer than the Max. Age. Otherwise, a configuration error will

occur.

• Forward Delay: [15] – The Forward Delay can be from 4 to 30 seconds. This is the time any

port on the switch spends in the listening state while moving from the blocking state to the
forwarding state.

• Priority: [32768] – A Priority for the switch can be set from 0 to 65535. 0 is equal to the

highest Priority. This number is used in the voting process between switches on the network
to determine which switch will be the root switch. A low number indicates a high priority, and
a high probability that this switch will be elected as the root switch.

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DGS-3224TG Gigabit Ethernet Switch User’s Guide

Note: Observe the following formulas when setting the above parameters:

Max. Age ≤ 2 x (Forward Delay - 1 second)

Max. Age ≥ 2 x (Hello Time + 1 second)

Port Spanning Tree Settings

In addition to setting Spanning Tree parameters for use on the switch level, the DGS-3224TG allows for
the configuration of Spanning Tree Protocol on individual ports.

To define individual ports, highlight Port Settings on the Configure Spanning Tree menu above and
press Enter.

Figure 6-17. Port Spanning Tree Settings screen

Toggle the View Ports field to the range of ports to be configured. Enter the port number or port range
in the Configure Port from [ ] to [ ] field. After enabling or disabling STP Status, you can set the
spanning tree port cost and priority.

Configure Static (Destination-Address Forwarding) Table

The Configure Static (Destination-Address Forwarding) Table menu allows you to access screens to
create, modify, and delete both Static Unicast Forwarding Table and Static Multicast Forwarding Table
entries, respectively.

Highlight Configure Static (Destination-Address Forwarding) Table on the Configuration menu and
press Enter:

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DGS-3224TG Gigabit Ethernet Switch User’s Guide

Figure 6-18. Configure Static (Destination-Address Forwarding) Table menu

Setup Unicast Forwarding Table

Highlight Configure Static Forwarding Table on the menu above to access the following screen:

Figure 6-19. Setup Unicast Forwarding Table screen

The Action field can be toggled between Add/Modify and Delete using the space bar. Enter the VID in
the VLAN ID field and the MAC address to be statically entered in the forwarding table in the MAC

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DGS-3224TG Gigabit Ethernet Switch User’s Guide

Address field. There are two static unicast forwarding types to select from, Permanent and
DeleteOnReset. Enter the port number in the Port field.

Highlight APPLY and press Enter to make the changes current. Use Save Changes from the main
menu to enter the changes into NV-RAM.

Setup Static Multicast Forwarding Table

To edit the IEEE 802.1q Multicast Filtering settings, highlight Configure Static Multicast Forwarding
Table on the Configure Static (Destination-Address Forwarding) Table menu above to access the

following screen:

Figure 6-20. Setup Static Multicast Forwarding Table screen

The Action field can be toggled between Add/Modify and Delete using the space bar. To add a new
entry to the static multicast forwarding table, select Add/Modify and enter the VLAN ID number of the
VLAN that will be receiving the multicast packets. Enter the MAC address of the multicast source, and
then enter the member ports. Each port can be either Egress or a non-member of the multicast group,
on a per-VLAN basis. There are two static multicast forwarding types to select from, Permanent and
DeleteOnReset.

To set a port’s multicast group membership status, highlight the first field of (E/-). Each port’s
multicast group membership can be set individually by highlighting the port’s entry using the arrow
keys, and then toggling between E and – using the space bar.

• E (Egress Member) – Specifies the port as being a static member of the multicast group.
Egress Member Ports are ports that will be transmitting traffic for the multicast group.

• – (Non-Member) – Specifies the port as not being a member of the multicast group, but the
port can become a member of the multicast group dynamically.

Highlight APPLY and press Enter to make the changes current. Use Save Changes from the main
menu to enter the changes into NV-RAM.

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DGS-3224TG Gigabit Ethernet Switch User’s Guide

Note: The DGS-3224TG supports a maximum of 16K multicast MAC address entities.

Configure VLANs

The switch reserves one VLAN, VID = 1, called the DEFAULT_VLAN for internal use. The factory default
setting assigns all ports on the switch to the DEFAULT_VLAN. As new VLANs are configured, their
respective member ports are removed from the DEFAULT_VLAN. If the DEFAULT_VLAN is reconfigured,
all ports are again assigned to it. Ports that are not wanted as part of the DEFAULT_VLAN are removed
during the configuration.

Packets cannot cross VLANs. If a member of one VLAN wants to connect to another VLAN, it must be
through a router.

Note: The switch’s default is to assign all ports to a single 802.1Q VLAN named

DEFAULT_VLAN. As new VLANs are created, the member ports assigned to the new
VLAN will be removed from the default VLAN port member list.

Note: The DEFAULT_VLAN has a VID = 1. An IP interface called System in the IP interface entry

menu also has a VID = 1, and therefore corresponds to the DEFAULT_VLAN.

To create a new 802.1Q VLAN:

The VLAN menu adds an entry to edit the VLAN definitions and to configure the port settings for IEEE

802.1Q VLAN support. Highlight Configure VLANs from the Configuration menu and press Enter.

Figure 6-21. IEEE 802.1Q VLANs Configuration menu

802.1Q Static VLAN Settings

To create an 802.1Q VLAN, highlight Configure Static VLAN Entry and press Enter:

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DGS-3224TG Gigabit Ethernet Switch User’s Guide

Figure 6-22. 802.1Q Static VLAN Settings screen

To create an 802.1Q VLAN, enter a VLAN ID number in the VID field and a name for the new VLAN in
the VLAN Name field.

To set the 802.1Q VLAN membership status of a port:

To enter the 802.1Q VLAN status for a port, highlight the first field of Egress/Forbidden. Each port’s

802.1Q VLAN membership can be set individually by highlighting the port’s entry using the arrow keys,
and then toggling among E, F, and – using the space bar.

• E (Egress Member) – Specifies the port as being a static member of the VLAN. Egress
Member Ports are ports that will be transmitting traffic for the VLAN. These ports can be
either tagged or untagged.

• F (Forbidden Non-Member) – Defines the port as a non-member and also forbids the port
from joining a VLAN dynamically.

• – (Non-Member) – Specifies the port as not being a member of the VLAN, but the port can
become a member of the VLAN dynamically.

Next, determine which of the ports that are members of the new VLAN will be Tagged or Untagged
ports.

To set a port as either a Tagged or an Untagged port:

Highlight the first field of Tag/Untag field. Each port’s state can be set by highlighting the port’s entry
using the arrow keys and then toggling between U or T using the space bar.

• U - specifies the port as an Untagged member of the VLAN. When an untagged packet is

transmitted by the port, the packet header remains unchanged. When a tagged packet exits
the port, the tag is stripped and the packet is changed to an untagged packet.

• T - specifies the port as a Tagged member of the VLAN. When an untagged packet is

transmitted by the port, the packet header is changed to include the 32-bit tag associated

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with the PVID (Port VLAN Identifier – see below). When a tagged packet exits the port, the
packet header is unchanged.

If the port is attached to a device that is not IEEE 802.1Q VLAN compliant (VLAN-tag unaware), then
the port should be set to U – Untagged.

If the port is attached to a device that is IEEE 802.1Q VLAN compliant, (VLAN-tag aware), then the port
should be set to T – Tagged.

Once you have toggled between Active and Inactive under State, press APPLY to make the additions or
deletions effective for the current session. To enter the changes into Non-volatile RAM, highlight Save
Changes from the main menu and press Enter.

Port VLAN assignment

To assign a port a PVID, highlight Configure Port VLAN ID on the IEEE 802.1Q VLANs Configuration
menu and press Enter:

Figure 6-23. Port VLAN assignment screen

Highlight the Configure Port from [1 ] to [1 ] field and enter the range of port numbers you want to
configure. Next, highlight the PVID field and enter the PVID for the VLAN’s member ports you want to
configure.

Port VLAN Identifier (PVID) is a classification mechanism that associates a port with a specific VLAN
and is used to make forwarding decisions for untagged packets received by the port. For example, if
port #2 is assigned a PVID of 3, then all untagged packets received on port #2 will be assigned to VLAN

3. This number is generally the same as the VID# number assigned to the port in the 802.1Q Static
VLAN Settings screen above.

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Ingress Filter Settings

To set ingress filtering on a port, highlight Configure Port Ingress Filter on the IEEE 802.1Q VLANs
Configuration menu and press Enter:

Figure 6-24. Ingress Filter Settings screen

Highlight the Configure Port from [1 ] to [1 ] field and enter the range of port numbers you want to
configure. Then use the space bar to toggle between On and Off in the Ingress Filter field.

An Ingress Filter enables the port to compare the VID tag of an incoming packet with the both the VIDs
and PVIDs of VLANs assigned to the port. If the VID tag of an incoming port is different from either the
VID or PVID assigned to the port, the port filters (drops) the packet.

Port GVRP Settings

GARP VLAN Registration Protocol (GVRP) is a Generic Attribute Registration Protocol (GARP) application
that provides 802.1Q-compliant VLAN pruning and dynamic VLAN creation. With GVRP, the switch can
exchange VLAN configuration information with other GVRP switches, prune unnecessary broadcast and
unknown unicast traffic, and dynamically create and manage VLANs on switches connected through

802.1Q ports.

To enable a port to dynamically become a member of a VLAN, highlight Configure Port GVRP Settings
on the IEEE 802.1Q VLANs Configuration menu and press Enter:

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DGS-3224TG Gigabit Ethernet Switch User’s Guide

Figure 6-25. Port GVRP Settings screen

This screen allows you to enable or disable GARP VLAN Registration Protocol (GVRP), where GARP is
the Generic Attribute Registration Protocol, on individual ports. Enter the range of ports to be
configured in the first two fields and then toggle the GVRP State to On. Press APPLY to let your changes
take effect.

GVRP updates dynamic VLAN registration entries and communicates the new VLAN information across
the network. This allows, among other things, for stations to physically move to other switch ports and
keep their same VLAN settings, without having to reconfigure VLAN settings on the switch.

Configure IGMP Snooping

IGMP Snooping can be globally enabled or disabled from the IGMP Snooping Settings screen.

To configure IGMP Snooping, highlight Configure IGMP Snooping on the Configuration menu and
press Enter.

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Figure 6-26. IGMP Snooping Settings screen

To configure IGMP Snooping:

Toggle the Switch IGMP Snooping field to Enabled. Toggle the Querier State field to the appropriate
choice between Non-Querier, V1-Querier, and V2-Querier to determine the version of IGMP that is used
in your network. A value between 1 and 255 can be entered for the Robustness Variable (default is 2).
The Query Interval can be set between 1 and 65500 seconds (default is 125 seconds). This sets the
time between IGMP queries. The Max Response allows a setting between 1 and 25 seconds (default is

10) and specifies the maximum amount of time allowed before sending a response report.

Highlight APPLY and press Enter to make the settings effective.

The user-changeable parameters in the switch are as follows:

• Switch IGMP Snooping:<Disabled> – This field can be toggled using the space bar between
Disabled and Enabled. This is used to enable or disable IGMP Snooping, globally, on the switch.

• Action:<Add/Modify> – Toggle to the desired option, Add/Modify or Delete.

• VLAN ID:[1] – Enter the appropriate VLAN ID in this field.

• State:<Enabled> – Toggle this field to Enabled to activate this entry.

• Querier State:<Non-Querier> – This field can be toggled between Non-Querier, V1-Querier, and V2-

Querier. This is used to specify the IGMP version (1 or 2) that will be used by the IGMP interface
when making queries.

• Robustness Variable:[2 ] – A tuning variable to allow for sub-networks that are expected to lose a
large number of packets. A value between 1 and 255 can be entered, with larger values being
specified for sub-networks that are expected to lose larger numbers of packets.

• Query Interval:[125 ] – Allows the entry of a value between 1 and 65500 seconds, with a default of
125 seconds. This specifies the length of time between sending IGMP queries.

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DGS-3224TG Gigabit Ethernet Switch User’s Guide

• Max Response:[10] – Sets the maximum amount of time allowed before sending an IGMP response
report. A value between 1 and 25 seconds can be entered, with a default of 10 seconds.

Configure Trunk

To configure a port trunking group, highlight Configure TRUNK on the Configuration menu and press
Enter.

Figure 6-27. Link Aggregation screen

Link aggregation, or port trunking, allows several ports to be grouped together and to act as a single
link. This gives a bandwidth that is a multiple of a single link’s bandwidth.

Port trunking is most commonly used to link a bandwidth intensive network device or devices – such as
a server – to the backbone of a network.

The switch allows the creation of up to 6 port trunking groups, each group consisting of up to 16 links
(ports). The trunked ports can be non-continuous (that is, have non-sequential port numbers). All of
the ports in the group must be members of the same VLAN. Further, the trunked ports must all be of
the same speed and should be configured as full duplex.

The configuration of the lowest numbered port in the group becomes the configuration for all of the
ports in the port trunking group. This port is called the Master Port of the group, and all configuration
options – including the VLAN configuration – that can be applied to the Master Port are applied to the
entire port trunking group.

Load balancing is automatically applied to the ports in the trunked group, and a link failure within the
group causes the network traffic to be directed to the remaining links in the group.

The Spanning Tree Protocol will treat a port trunking group as a single link, on the switch level. On the
port level, the STP will use the port parameters of the Master Port in the calculation of port cost and in
determining the state of the port trunking group. If two redundant port trunking groups are configured

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on the Switch, STP will block one entire group – in the same way STP will block a single port that has a
redundant link.

The user-changeable parameters in the switch are as follows:

• Group ID:[1] – This field is for a group ID number for the port trunking group.

• Group Name:[ ] – Enter a name for the port trunking group.

• Member ports – Toggle between M to indicate membership of the port trunking group, or a dash (–)

to indicate non-membership.

• State:<Disabled> – This field can be toggled between Enabled and Disabled. This is used to turn a
port trunking group on or off. This is useful for diagnostics, to quickly isolate a bandwidth
intensive network device or to have an absolute backup aggregation group that is not under
automatic control.

Configure Port Mirroring

The switch allows you to copy frames transmitted and received on a port and redirect the copies to
another port. You can attach a monitoring device to the mirrored port, such as a sniffer or an RMON
probe, to view details about the packets passing through the first port. This is useful for network
monitoring and troubleshooting purposes.

Choose Configure Port Mirroring on the Configuration menu to access the following screen:

Figure 6-28. Setup Port Mirroring screen

To configure a mirror port, enter the port from where you want to copy frames in the Source Port field,
select the desired source direction in the next field, and then enter the port that receives the copies
from the source port in the Target Port field. The target port is where you will connect a

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monitoring/troubleshooting device such as a sniffer or an RMON probe. Finally, toggle the Mirror
Status field to Enabled, highlight APPLY, and press Enter.

Note: You cannot mirror a fast port onto a slower port. For example, if you try to mirror the traffic

from a 100 Mbps port onto a 10 Mbps port, this can cause throughput problems. The port you
are copying frames from should always support an equal or lower speed than the port to which
you are sending the copies. Also, the target port cannot be a member of a trunk group.

Note: Port mirroring is not possible if you use the same egress and ingress port.

Note: Port mirroring is only possible for ports 1–12 or ports 13–24. This means the source port and

the target port must be between ports 1–12 or 13–24.

Configure Class of Service, Default Priority, and Traffic Class

The DGS-3224TG allows you to customize class of service, port default priority, and traffic class
settings on the following menu.

Select Configure Class of Service, Default Priority and Traffic Class on the Configuration menu
and press Enter.

Figure 6-29. Configure Class of Service, Default Priority and Traffic Class menu

Class of Service Configuration

Select Configure Class of Service and press Enter to access the following menu:

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Figure 6-30. Class of Service Configuration menu

This menu allows you to set the following features:

• Max. Packets – Use the space bar in this column to select the maximum number of packets the
Class of Service priority queue can hold. The range of values is from 0 to 512 packets.

• Max. Latency – The maximum allowable time a packet will stay in the CoS queue, in microseconds
and seconds. The packets in this queue are not delayed more than the maximum allowable latency
entered in this field. Maximum latency takes precedence over the CoS scheduling algorithm.

In addition, clicking ADVANCED SETTINGS at the bottom of the Class of Service Configuration menu
will enable you to select the desired port queue priority:

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DGS-3224TG Gigabit Ethernet Switch User’s Guide

Figure 6-31. Port Maxlimit Drop Settings screen

The Switch divides the buffer into four parts: Queue0, Queue1, Queue2, and Queue3. Queue0 is the
highest priority and Queue3 is the lowest. Press APPLY to let the change take effect.

Port Default Priority assignment

Select Configure Default Priority and press Enter to access the following screen:

Figure 6-32. Port Default Priority assignment screen

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DGS-3224TG Gigabit Ethernet Switch User’s Guide

This screen allows you to set a default priority for packets that have not already been assigned a
priority value. After filling out the two fields offered, press APPLY to let your changes take effect.

Traffic Class Configuration

Select Configure Traffic of Class and press Enter to access the following screen:

Figure 6-33. Traffic Class Configuration screen

This screen allows you to configure traffic class priority by specifying the class value, from 0 to 3, of the
switch’s eight levels of priority. Press APPLY to let your changes take effect.

Configure RS232 and SLIP

Select Configure RS232 and SLIP and press Enter to access the following screen:

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Figure 6-34. Serial Port and SLIP Settings screen

The following fields can then be set:

• Baud Rate:<9600> – Sets the serial bit rate that will be used to communicate the next time
the switch is restarted. Available speeds are 9600, 19200, 38400 and 115200 bits per
second. The default setting is 9600.

• Data Bits:<8> – Select 7 or 8. The default is 7.

• Parity:<None> – Choose from None, Even or Odd. The default is None.

• Stop Bits:<1> – Select 1 or 2. The default is 1.

• Auto-Logout:<Never> – This sets the time the interface can be idle before the switch

automatically logs-out the user. The options are 2 mins, 5 mins, 10 mins, 15 mins, or Never.

• Serial Port For:<Console> – Change this field to SLIP and enter the appropriate information
in the Interface Name, Local IP Address, Remote IP Address, and MTU fields which
become active once SLIP is selected.

Network Monitoring

The DGS-3224TG provides extensive network monitoring capabilities.

To display the network data compiled by the switch, highlight Network Monitoring on the main menu
and press Enter.

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Figure 6-35. Network Monitoring Menu

Port Utilization

To view the port utilization of all the ports on the switch, highlight Port Utilization on the Network
Monitoring Menu and press Enter:

Figure 6-36. Port Utilization screen

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DGS-3224TG Gigabit Ethernet Switch User’s Guide

The Port Utilization screen shows the number of packets transmitted and received per second and
calculates the percentage of the total available bandwidth being used on the port (displayed under
%Util.). Highlight CLEAR COUNTER and press Enter to reset the counters.

Port Error Packets

To view the error statistics for a port, highlight Port Error Packets on the Network Monitoring Menu
and press Enter:

Figure 6-37. Packet Error Statistic screen

Enter the port number of the port to be viewed. The Interval field can be toggled from 2 seconds to 1
minute, or suspend. This sets the interval at which the error statistics are updated. Highlight CLEAR
COUNTER and press Enter to reset the counters.

Port Packet Analysis

To view an analysis of the size of packets received or transmitted by a port, highlight Port Packet
Analysis on the Network Monitoring Menu and press Enter:

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Figure 6-38. Packet Analysis screen

In addition to the size of packets received or transmitted by the selected port, statistics on the number
of unicast, multicast, and broadcast packets are displayed. Highlight CLEAR COUNTER and press
Enter to reset the counters.

Browse MAC Address

To view the MAC address forwarding table, highlight Browse MAC Address on the Network Monitoring
Menu and press Enter:

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DGS-3224TG Gigabit Ethernet Switch User’s Guide

Figure 6-39. Browse Address Table screen

The Browse By field can be toggled between ALL, MAC Address, Port, and VLAN. This sets a filter to
determine which MAC addresses from the forwarding table are displayed. ALL specifies no filter.

To search for a particular MAC address:

Toggle the Browse By field to MAC Address. A MAC Address field will appear. Enter the MAC address
in the field and press Enter. Highlight BROWSE and press Enter to initiate the browsing action.
Highlight CLEAR ALL and press Enter to reset the table counters.

Switch History

To view the switch history log, highlight Switch History from the Network Monitoring Menu and
press Enter:

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DGS-3224TG Gigabit Ethernet Switch User’s Guide

Figure 6-40. Switch History screen

IGMP Snooping

This allows the switch’s IGMP Snooping table to be viewed. IGMP Snooping allows the switch to read
the Multicast Group IP address and the corresponding MAC address from IGMP packets that pass
through the switch. The ports where the IGMP packets were snooped are displayed, signified with an M.
The number of IGMP reports that were snooped is also displayed in the Reports field.

To view the IGMP Snooping table, highlight IGMP Snooping on the Network Monitoring Menu and
press Enter.

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Figure 6-41. IGMP Snooping Status screen

Enter a VLAN ID number in the first field and press GO to display the desired IGMP Snooping Status
screen.

Browse Multicast Status

Figure 6-42. Multicast Address Status screen

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DGS-3224TG Gigabit Ethernet Switch User’s Guide

This read-only screen displays the VLAN ID, group address, and static/IGMP snooping port list for
multicast addresses.

VLAN Status

This allows the status for each of the switch’s VLANs to be viewed.

To view the VLAN Status table, highlight VLAN Status on the Network Monitoring Menu and press
Enter.

Figure 6-43. VLAN Status screen

This read-only screen displays VLAN information. Press CTRL + N to see the VLAN on the next page or
CTRL + P to see an entry from a previous page.

SNMP Manager Configuration

The switch sends out SNMP traps to network management stations whenever certain exceptional events
occur, such as when the switch is turned on or when a system reset occurs. The switch allows traps to
be routed to up to four different network management hosts.

For a detailed list of Trap Types used for this switch, see the Traps section of Chapter 5, “Switch
Management and Operating Concepts.”

SNMP (V1) implements a rudimentary form of security by requiring that each request include a
community name. A community name is an arbitrary string of characters used as a “password” to
control access to the switch. If the switch receives a request with a community name it does not
recognize, it will trigger an authentication trap.

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The SNMP allows up to four different community names to be defined. The community name public is
defined by default; you can change this name in addition to adding others. You will need to coordinate
these names with the community name settings you use in your network management system.

Choose SNMP Manager Configuration to access the third item on the main menu. The following screen
appears:

Figure 6-44. SNMP Manager Configuration screen

The following SNMP Manager and Trap Manager Configuration parameters can be set:

• SNMP Community String – The community string that will be included on SNMP packets sent
to and from the switch. Any station not privy to this community will not receive the packet.

• Access Right – Allows each community to be separately set to either Read Only, meaning that
the community member can only view switch settings or Read/Write, which allows the member
to change settings in the switch.

• Status – Determines whether this community name entry is Valid or Invalid. An entry can be
disabled by changing its status to Invalid.

• IP Address – The IP address of the network management station to receive traps.

The Security IP section allows you to create a list of IP addresses that are allowed to access the switch
via SNMP or Telnet.

Highlight APPLY and press Enter to allow your changes to take effect.

System Utilities

To access the Switch Utilities menu, highlight System Utilities on the main menu and press Enter.

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DGS-3224TG Gigabit Ethernet Switch User’s Guide

Figure 6-45. Switch Utilities menu

Note: Trivial File Transfer Protocol (TFTP) services allow the switch firmware to be upgraded by

transferring a new firmware file from a TFTP server to the Switch. A configuration file can
also be loaded into the Switch from a TFTP server, switch settings can be saved to the TFTP
server, and a history log can be uploaded from the Switch to the TFTP server.

Upgrade Firmware from TFTP Server

To update the switch’s firmware, highlight Upgrade Firmware from TFTP Server and press Enter.

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DGS-3224TG Gigabit Ethernet Switch User’s Guide

Figure 6-46. Upgrade Firmware screen

Enter the IP address of the TFTP server in the Server IP Address field.

Note: The TFTP server must be on the same IP subnet as the switch.

Enter the path and the filename to the firmware file on the TFTP server.

Note: The TFTP server must be running TFTP server software to perform the file transfer. TFTP

server software is a part of many network management software packages, or can be
obtained as a separate program.

Highlight APPLY and press Enter to record the IP address of the TFTP server. Use Save Changes from
the main menu to enter the address into NV-RAM

Highlight START and press Enter to initiate the file transfer.

Use Configuration File on TFTP Server

To download a switch configuration file from a TFTP server, highlight Use a Configuration File on
TFTP Server and press Enter.

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Figure 6-47. Use Configuration File on TFTP Server screen

Enter the IP address of the TFTP server and specify the location of the switch configuration file on the
TFTP server.

Highlight APPLY and press Enter to record the IP address of the TFTP server. Use Save Changes from
the main menu to enter the address into NV-RAM

Highlight START and press Enter to initiate the file transfer.

Save Settings to TFTP Server

To upload a settings file to the TFTP server, highlight Save Settings to TFTP Server and press Enter.

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Figure 6-48. Save Settings to TFTP Server screen

Enter the IP address of the TFTP server and the path and filename of the settings file on the TFTP
server and press APPLY. Highlight START and press Enter to initiate the file transfer.

Save History Log to TFTP Server

To save a History Log on a TFTP server, highlight Save History Log to TFTP Server and press Enter.

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DGS-3224TG Gigabit Ethernet Switch User’s Guide

Figure 6-49. Save Log to TFTP Server screen

Enter the IP address of the TFTP server and the path and filename for the history log on the TFTP
server. Highlight APPLY and press Enter to make the changes current. Highlight START and press
Enter to initiate the file transfer.

Ping Test

To test the connection with another network device using Ping, highlight Ping Test and press Enter.

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DGS-3224TG Gigabit Ethernet Switch User’s Guide

Figure 6-50. Ping screen

Enter the IP address of the network device to be Pinged and the number of test packets to be sent (3 is
usually enough). Highlight START and press Enter to initiate the Ping program.

Reboot

The DGS-3224TG has several reboot options.

To reboot the switch from the console, highlight Reboot from the main menu and press Enter.

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Figure 6-51. System Reboot menu

The reboot options are as follows:

• Reboot – Simply restarts the switch. Any configuration settings not saved using Save Changes
from the main menu will be lost. The switch’s configuration will be restored to the last configuration
saved in NV-RAM.

• Save Configuration & Reboot – Saves the configuration to NV-RAM (identical to using Save
Changes) and then restarts the switch.

• Reboot & Load Factory Default Configuration – Restarts the switch using the default factory
configuration. All configuration data will be lost. This is identical to using Factory Reset and then
Reboot.

• Reboot & Load Factory Default Configuration Except IP Address – Restarts the switch using the
default factory configuration, except the user configured IP address will be retained. All other
configuration data will be lost.

A confirmation screen will appear:

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DGS-3224TG Gigabit Ethernet Switch User’s Guide

Figure 6-52. System Reboot confirmation screen

To reboot the switch, in the mode entered above, highlight Yes and press Enter.

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7

WEB-BASED NETWORK MANAGEMENT

Introduction

The DGS-3224TG offers an embedded Web-based (HTML) interface allowing users to manage the switch
from anywhere on the network through a standard browser, such as Opera, Netscape
Navigator/Communicator, or Microsoft Internet Explorer. The Web browser acts as a universal access
tool and can communicate directly with the switch using the HTTP protocol. Your browser window may
vary with the screen shots (pictures) in this guide.

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.

Note: This Web-based Management Module does not accept Chinese language input (or other

languages requiring 2 bytes per character).

Getting Started

The first step in getting started in using Web-based management for your switch is to secure a browser.
A Web browser is a program that allows a person to read hypertext, for example, Opera, Netscape
Navigator, or Microsoft Internet Explorer. Follow the installation instructions for the browser.

The second and last step is to configure the IP interface of the switch. This should be done manually
through a console (see the Configure IP Address section in the “Using The Console Interface” chapter).

You are now ready to begin managing your switch by simply running the browser installed on your
computer and pointing 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. Please note that the proxy for session connection should be turned off.

Depending on which browser you are using, a dialog box similar to the following will open:

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DGS-3224TG Gigabit Ethernet Switch User’s Guide

Click OK as there is no preset user name or password on the switch. This opens the main page in the
management module.

The top panel shows a real-time front panel display of the DGS-3224TG. Clicking on an individual port
on this display will connect you to the Rx Packets Analysis window (see Monitoring→Packets→
Received(RX)) for a detailed description)

The panel on the left-hand side contains the main menu. The featured items include: Configuration,
Management, Monitoring, Maintenance, and Help. The whole menu looks like this:

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DGS-3224TG Gigabit Ethernet Switch User’s Guide

These are the major categories for switch management. If the sub-menus for each main category do not
appear, click on the small square hyperlink to the left of the folder icon.

The switch management features available in the Web-based are explained below.

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Configuration

The first category includes: IP Address, Switch Information, Advanced Settings, Port Configuration,
Port Mirroring, Port Trunking, IGMP Snooping, Spanning Tree, Static Forwarding Table, VLANs,
Port Default Priority, Class of Traffic, Class of Service, and RS232&SLIP, as well secondary

screens.

IP Address

Figure 7-1. TCP/IP Parameters Setup window

This window is used to determine whether the switch should get its IP Address settings from the user
(Manual), a BOOTP server, or a DHCP server. If you are not using either BOOTP or DHCP, enter the IP
Address, Subnet Mask, and Default Gateway of the switch. If you enable BOOTP, you do not need to
configure any IP parameters because a BOOTP server automatically assigns IP configuration
parameters to the switch. If you enable DHCP, a Dynamic Host Configuration Protocol request will be
sent when the switch is powered up. Once you have selected a setting under Get IP From, click Apply
to activate the new settings.

The information is described as follows:

• MAC Address – The Ethernet address for the device. Also known as the physical address

• Get IP From – There are three choices for how the switch receives its IP Address settings:

Manual, BOOTP, and DHCP.

• IP Address – The host address for the device on the TCP/IP network.

• Subnet Mask – The address mask that controls subnetting on your TCP/IP network.

• Default Gateway – The IP address of the device, usually a router, that handles connections to

other subnets and/or other TCP/IP networks.

• VID – The VLAN ID number.

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Switch Information

Figure 7-2. Switch Information (Basic Settings) window

To set basic switch settings, enter a System Name in the first field, the physical location of the switch
in the System Location field, and the name of the contact person responsible for the switch in the
System Contact field. Then click Apply.

The information is described as follows:

• Device Type – A description of the switch type.

• MAC Address – The Ethernet address for the device.

• Boot PROM Version – Version number for the firmware chip. This information is needed for

new runtime software downloads.

• Firmware Version – Version number of the firmware installed on the switch. This can be
updated by using the Update Firmware window in the Reset and Update section.

• H/W Version – Version of the switch hardware.

• System Name – A user-assigned name for the switch.

• System Location – A user-assigned description for the physical location of the switch.

• System Contact – Name of the person to contact should there be any problems or questions

with the system. You may also want to include a phone number or extension.

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Advanced Settings

Figure 7-3. Switch Information (Advanced Settings) window

DGS-3224TG Gigabit Ethernet Switch User’s Guide

After making the desired advanced setting Layer 2 changes, click Apply to let them take effect.

The information in the window is described as follows:

• Auto-Logout [Never] – This sets the time the interface can be idle before the switch automatically
logs-out the user. The options are 2 minutes, 5 minutes, 10 minutes, 15 minutes, or Never.

• MAC Address Aging Time [10-2100(sec)] [300 ] – This field specifies the length of time a learned
MAC Address will remain in the forwarding table without being accessed (that is, how long a learned
MAC Address is allowed to remain idle). The Aging Time can be set to any value between 10 and
2100 seconds.

Note: A very long Aging Time can result with the out-of-date Dynamic Entries that may cause

incorrect packet filtering/forwarding decisions. A very short aging time may cause entries to
be aged out to soon, resulting in a high percentage of received packets whose source
addresses cannot be found in the address table, in which case the switch will broadcast the
packet to all ports, negating many of the benefits of having a switch.

• IGMP Snooping [Disabled] – This setting enables Internet Group Management Protocol (IGMP)
Snooping, which enables the switch to read IGMP packets being forwarded through the switch in
order to obtain forwarding information from them (learn which ports contain Multicast members).

• GVRP Status [Enabled] – Group VLAN Registration Protocol is a protocol that allows members to
dynamically join VLANs. This is used to enable or disable GVRP on the switch

• Scheduling Mechanism for CoS Queues [Strict] – There are two Class of Service queue options,
RoundRobin and Strict. If Strict is selected, when the highest priority queue is full, those packets will

be the first to be forwarded. If RoundRobin is selected, the forwarding is based on the settings made
on the Class of Service Configuration screen.

• Trunk Load Sharing Algorithm [Source Addr] – The trunk load sharing options are Destination
Addr, Src & Dest Addr, and Source Addr.

• Year/Month/Date – This allows you to set the year, month, and date.

• Hour/Minute/Second – This allows you to set the hour, minute, and second.

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Port Configuration

Figure 7-4. Port Configuration window

Select the port you want to configure by using the drop-down menus in the From and To fields. Follow
these steps:

1. Enable or disable the port. If you choose Disabled in the State field, devices connected to that

port cannot use the switch, and the switch purges their addresses from its address table after
the MAC address aging time elapses.

2. Configure the Speed/Duplex setting for the twenty 10/100/1000 ports. Select Auto to allow the

port to select the best transmission speed, duplex mode, and flow control settings based on the

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DGS-3224TG Gigabit Ethernet Switch User’s Guide

capabilities of the device at the other end. The other selections allow you to force the port to
operate in the specified manner. Select 1000M/Full for port operation at 1000 Mbps and full
duplex. Select 100M/Half for port operation at 100 Mbps and half duplex Select 100M/Full for
port operation at 100 Mbps and full duplex. Select 100M/Half for port operation at 100 Mbps
and half duplex. Select 10M/Full for port operation at 10 Mbps and full duplex. Select
10M/Half for port operation at 10 Mbps and half duplex. The four GBIC ports are 1000M/Full
only.

3. Configure the Flow Control setting for the port. Selecting Enabled in full-duplex mode will

implement IEEE 802.3x flow control. Select Disabled for no flow control. Also, if the port is set
for Auto (NWay) in the speed/duplex field above and flow control is enabled, flow control
(whether full- or half-duplex) will only be implemented if the other device can auto-negotiate
flow control.

4. Click Apply to let your changes take effect.

Port Mirroring

Figure 7-5. Port Mirroring window

The switch allows you to copy frames transmitted and received on a port and redirect the copies to
another port. You can attach a monitoring device to the mirrored port, such as a sniffer or an RMON
probe, to view details about the packets passing through the first port.

To configure a mirror port, first select the Source Port—from where you want to copy frames—and the
Ingress Target Port or Egress Target Port—which receives the copies from the source port. This is the
port where you will connect a monitoring/troubleshooting device such as a sniffer or an RMON probe.
Next, select the Source Direction, Ingress, Egress, or Ingress & Egress , and None from the Status pull-
down menu. Finally, click Apply to let the changes take effect.

Note: You cannot mirror a fast port onto a slower port. For example, if you try to mirror the traffic

from a 100 Mbps port onto a 10 Mbps port, this can cause throughput problems. The port
you are copying frames from should always support an equal or lower speed than the port
to which you are sending the copies. Also, the target port for the mirroring cannot be a
member of a trunk group. Please note a target port and a source port cannot be the same
port.

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Port Trunking

Figure 7-6. Port Trunking Settings window

The Switch supports up to 6 trunk groups. Trunks are groups of ports that are banded together to form
a single, logical, high-bandwidth data pipe. The maximum number of member ports for a trunk group is

16.

To create or modify a trunk group, enter a name in the first field, check the ports that will compose the
port trunk, and change the Status field to Enabled. Click Apply to activate your settings.

Items in the above window are defined as follows:

• Name – The user-assigned name of the trunk group.

• Member Ports – Check the number of ports that will be members of the trunk group.

• State – Enables or disables the trunk group.

IGMP Snooping

Figure 7-7. IGMP Snooping Settings window

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DGS-3224TG Gigabit Ethernet Switch User’s Guide

Internet Group Management Protocol (IGMP) snooping allows the switch to recognize IGMP queries and
reports sent between network stations or devices and an IGMP host. When enabled for IGMP snooping,
the switch can open or close a port to a specific device based on IGMP messages passing through the
switch.

To set up IGMP snooping, enter a VLAN ID number in the first field and change the State field to
Enabled. Next, select the desired setting in the Querier State field—this determines the version of
IGMP that is used in your network—and enter values in the following three fields. A value between 1
and 255 can be entered for the Robustness Variable (default is 2). The Query Interval can be set
between 1 and 65500 seconds. This sets the time between IGMP queries. The Max Response allows a
setting between 1 and 25 seconds and specifies the maximum amount of time allowed before sending a
response report. Click APPLY to make the settings effective.

The user-changeable parameters in the switch are as follows:

• VLAN ID/VID – Enter a VLAN ID number in this field.

• State – Use the drop-down menu to enable or disable IGMP settings.

• Querier State – Select from Non-Querier, V1-Querier, and V2-Querier. This is used to specify the

IGMP version (1 or 2) that will be used by the IGMP interface when making queries.

• Robustness Variable – A tuning variable to allow for sub-networks that are expected to lose a large
number of packets. A value between 1 and 255 can be entered, with larger values being specified for
sub-networks that are expected to lose larger numbers of packets.

• Query Interval – Allows the entry of a value between 1 and 65500 seconds, with a default of 125
seconds. This specifies the length of time between sending IGMP queries.

• Max Response – Sets the maximum amount of time allowed before sending an IGMP response
report. A value between 1 and 25 seconds can be entered.

• Add/Modify – Click this hyperlink to add or modify an IGMP entry on this window.

• VLAN Name – The name you have assigned to a specified VLAN.

• Age-Out – The time-out for entries on this table.

• Delete – Click this hyperlink to delete an IGMP entry on this window.

Spanning Tree

This section includes two windows, STP Switch Settings and STP Port Settings.

STP Switch Settings

The switch supports 801.2d Spanning Tree Protocol, which allows you to create alternative paths (with
multiple switches or other types of bridges) in your network. See the Spanning Tree Algorithm section of
the “Switch Management and Operating Concepts” chapter for a detailed explanation.

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DGS-3224TG Gigabit Ethernet Switch User’s Guide

Figure 7-8. Switch Spanning Tree Settings window

Click Apply after making changes to the window above.

Parameters that you can change are:

• Spanning Tree Protocol – This drop-down menu allows you to enable the Spanning Tree Protocol
setting.

• Bridge Max Age (6-40 Sec) <20> – The Maximum Age can be from 6 to 40 seconds. At the end
of the Maximum Age, if a BPDU has still not been received from the Root ridge, your switch will
start sending its own BPDU to all other switches for permission to become the Root Bridge. If it
turns out that your switch has the lowest Bridge Identifier, it will become the Root Bridge.

• Bridge Hello Time (1-10 Sec) <2> – The Hello Time can be from 1 to 10 seconds. This is the
interval between two transmissions of BPDU packets sent by the Root Bridge to tell all other
switches that it is indeed the Root Bridge. If you set a Hello Time for your switch, and it is not
the Root Bridge, the set Hello Time will be used if and when your switch becomes the Root
Bridge.

• Bridge Forward Delay (4-30 Sec) <15> – The Forward Delay can be from 4 to 30 seconds. This
is the time any port on the switch spends in the listening state while moving from the blocking
state to the forwarding state.

• Bridge Priority (0-65535 Sec) <32768> – A Bridge Priority can be from 0 to 65535. Zero is
equal to the highest Bridge Priority.

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STP Port Settings

DGS-3224TG Gigabit Ethernet Switch User’s Guide

Figure 7-9. STP Port Settings window

To configure Spanning Tree Protocol functions for individual ports, enter the desired information in the
fields on this window (see the descriptions below for assistance) and then click Apply.

The information on the window is described as follows:

• From – Enter the first port to be configured.

• To – Enter the last port to be configured.

• State – The Spanning Tree Protocol state for a selected port can either be Enabled or Disabled.

• Cost (1~65535) – A port cost can be set between 1 and 65535. The lower the cost, the greater

the probability the port will be chosen as the designated port (chosen to forward packets).

• Priority (0~255) – A port priority can be set from 0 to 255. The lower the priority, the greater
the probability the port will be chosen as the root port.

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