D-Link DES-3550 User manual

D-Link ™ DES-3550
Managed 48-port 10/100Mbps and 2GE ports Layer 2
Ethernet Switch
Manual

DES-3550 Layer 2 Fast Ethernet Switch User’s Guide
ii
____________________
Information in this document is subject to change without notice.
© 2005 D-Link Computer Corporation. All rights reserved.
Reproduction in any manner whatsoever without the written permission of D-Link Computer Corporation is strictly forbidden.
Trademarks used in this text: D-Link and the D-LINK logo are trademarks of D-Link Computer Corporation; Microsoft and Windows are
registered trademarks of Microsoft Corporation.
Other trademarks and trade names may be used in this document to refer to either the entities claiming the marks and names or their products.
D-Link Computer Corporation disclaims any proprietary interest in trademarks and trade names other than its own.
February 2005 P/N 651ES3526015
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
manual, 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.
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.
VCCI Warning
BSMI Warning

CONTENTS
PREFACE.............................................................................................................................................................VIII
INTENDED READERS.............................................................................................................................................VIII
TYPOGRAPHICAL CONVENTIONS ............................................................................................................VIII
NOTES, NOTICES, AND CAUTIONS ...............................................................................................................IX
SAFETY INSTRUCTIONS...................................................................................................................................IX
Safety Cautions....................................................................................................................................................x
General Precautions for Rack-Mountable Products.........................................................................................xi
Protecting Against Electrostatic Discharge .....................................................................................................xii
INTRODUCTION ...................................................................................................................................................13
ETHERNET TECHNOLOGY.......................................................................................................................................13
Fast Ethernet Technology .................................................................................................................................13
Gigabit Ethernet Technology ............................................................................................................................13
SWITCHING TECHNOLOGY......................................................................................................................................14
SWITCH DESCRIPTION ............................................................................................................................................14
Features .............................................................................................................................................................15
Ports...................................................................................................................................................................16
FRONT-PANEL COMPONENTS.................................................................................................................................17
LED Indicators ..................................................................................................................................................17
REAR PANEL DESCRIPTION ....................................................................................................................................18
SIDE PANEL DESCRIPTION......................................................................................................................................18
GIGABIT COMBO PORTS .........................................................................................................................................18
INSTALLATION.....................................................................................................................................................20
Package Contents ..............................................................................................................................................20
BEFORE YOU CONNECT TO THE NETWORK............................................................................................................20
INSTALLING THE SWITCH WITHOUT THE RACK.....................................................................................................21
INSTALLING THE SWITCH IN A RACK .....................................................................................................................21
Mounting the Switch in a standard 19” rack....................................................................................................22
POWER ON..............................................................................................................................................................22
Power Failure....................................................................................................................................................22
CONNECTING THE SWITCH ............................................................................................................................23
SWITCH TO END NODE...........................................................................................................................................23
SWITCH TO HUB OR SWITCH ..................................................................................................................................23
CONNECTING TO NETWORK BACKBONE OR SERVER ............................................................................................24
INTRODUCTION TO SWITCH MANAGEMENT...........................................................................................25
MANAGEMENT OPTIONS ........................................................................................................................................25
Web-based Management Interface....................................................................................................................25
SNMP-Based Management................................................................................................................................25

Command Line Console Interface Through The Serial Port............................................................................25
Connecting the Console Port (RS-232 DCE)....................................................................................................25
First Time Connecting to The Switch................................................................................................................27
PASSWORD PROTECTION........................................................................................................................................29
SNMP Settings...................................................................................................................................................29
IP ADDRESS ASSIGNMENT .....................................................................................................................................31
CONNECTING DEVICES TO THE SWITCH.................................................................................................................32
INTRODUCTION TO WEB-BASED SWITCH CONFIGURATION.............................................................34
Web-based User Interface.................................................................................................................................35
CONFIGURING THE SWITCH...........................................................................................................................37
IP ADDRESS............................................................................................................................................................37
SWITCH INFORMATION...........................................................................................................................................40
Switch Information ............................................................................................................................................40
Advanced Settings..............................................................................................................................................41
PORT CONFIGURATIONS .........................................................................................................................................43
PORT MIRRORING...................................................................................................................................................45
PORT DESCRIPTION ................................................................................................................................................46
IGMP......................................................................................................................................................................48
IGMP Snooping.................................................................................................................................................48
Static Router Ports.............................................................................................................................................49
SPANNING TREE .....................................................................................................................................................51
802.1w Rapid Spanning Tree............................................................................................................................51
STP Switch Settings...........................................................................................................................................52
STP Port Settings...............................................................................................................................................54
FORWARDING FILTERING .......................................................................................................................................57
Unicast Forwarding ..........................................................................................................................................57
Static Multicast Forwarding .............................................................................................................................57
Multicast Port Filtering.....................................................................................................................................58
VLANS...................................................................................................................................................................60
Understanding IEEE 802.1p Priority ...............................................................................................................60
VLANs................................................................................................................................................................61
IEEE 802.1Q VLANs.........................................................................................................................................61
Port-based VLANs.............................................................................................................................................67
Static VLAN Entry .............................................................................................................................................67
Port VLAN ID(PVID) ........................................................................................................................................70
PORT BANDWIDTH..................................................................................................................................................71
SNTP SETTINGS.....................................................................................................................................................73
Current Time Settings........................................................................................................................................73
Time Zone and DST...........................................................................................................................................74

PORT SECURITY......................................................................................................................................................76
QOS........................................................................................................................................................................78
Understanding QoS ...........................................................................................................................................78
Traffic Control...................................................................................................................................................79
802.1p Default Priority .....................................................................................................................................79
802.1p User Priority..........................................................................................................................................81
Scheduling..........................................................................................................................................................81
TRAFFIC SEGMENTATION .......................................................................................................................................82
MAC NOTIFICATION..............................................................................................................................................84
Global Settings...................................................................................................................................................84
Port Settings.......................................................................................................................................................84
LACP .....................................................................................................................................................................86
Understanding Port Trunk Groups...................................................................................................................86
LACP Port..........................................................................................................................................................89
ACCESS PROFILE TABLE.........................................................................................................................................91
CONFIGURING THE ACCESS PROFILE TABLE..........................................................................................................91
SYSTEM LOG SERVER...........................................................................................................................................103
PAE ACCESS ENTITY (802.1X)............................................................................................................................104
Understanding 802.1x Port-based Network Access Control..........................................................................104
Configure Authenticator..................................................................................................................................106
Port Capability Settings ..................................................................................................................................109
Initializing Ports..............................................................................................................................................111
Reauthenticate Port(s).....................................................................................................................................112
RADIUS Server................................................................................................................................................113
MANAGEMENT...................................................................................................................................................115
SECURITY IP.........................................................................................................................................................115
User Accounts..................................................................................................................................................115
ACCESS AUTHENTICATION CONTROL..................................................................................................................117
Policy & Parameters.......................................................................................................................................118
Application’s Authentication Settings.............................................................................................................119
Authentication Server Group Settings.............................................................................................................119
Authentication Server Hosts............................................................................................................................120
Login Method Lists..........................................................................................................................................122
Enable Method Lists........................................................................................................................................124
Local Enable Password...................................................................................................................................126
Enable Admin...................................................................................................................................................126
SNMP...................................................................................................................................................................127
SNMP SETTINGS..................................................................................................................................................127
SNMP USER TABLE.............................................................................................................................................129

SNMP VIEW TABLE.............................................................................................................................................131
SNMP GROUP TABLE ..........................................................................................................................................132
SNMP COMMUNITY TABLE CONFIGURATION.....................................................................................................134
SNMP HOST TABLE.............................................................................................................................................135
SNMP ENGINE ID................................................................................................................................................136
MONITORING......................................................................................................................................................137
PORT UTILIZATION ...............................................................................................................................................137
CPU UTILIZATION................................................................................................................................................138
PACKETS...............................................................................................................................................................139
Received(RX) ...................................................................................................................................................139
UMB_cast(RX).................................................................................................................................................141
Transmitted (TX)..............................................................................................................................................143
ERRORS.................................................................................................................................................................145
Received (RX) ..................................................................................................................................................145
Transmitted (TX)..............................................................................................................................................147
SIZE ......................................................................................................................................................................149
MAC ADDRESS ....................................................................................................................................................150
IGMP SNOOPING GROUP .....................................................................................................................................152
IGMP SNOOPING FORWARDING ..........................................................................................................................153
VLAN STATUS.....................................................................................................................................................153
BROWSE ROUTER PORT........................................................................................................................................154
PORT ACCESS CONTROL.......................................................................................................................................155
Authenticator State..........................................................................................................................................155
MAINTENANCE...................................................................................................................................................156
TFTP SERVICES ...................................................................................................................................................156
Download Firmware From TFTP Server .......................................................................................................156
Download Settings from TFTP Server............................................................................................................157
Upload Settings to TFTP Server .....................................................................................................................157
Upload Log to TFTP Server............................................................................................................................158
Switch History..................................................................................................................................................158
PING TEST.............................................................................................................................................................159
SAVING CHANGES ................................................................................................................................................160
REBOOT SERVICES................................................................................................................................................161
Reboot Device..................................................................................................................................................161
RESET ...................................................................................................................................................................161
LOGOUT................................................................................................................................................................162
SINGLE IP MANAGEMENT..............................................................................................................................163
SINGLE IP MANAGEMENT (SIM) OVERVIEW ......................................................................................................163
SIM USING THE WEB INTERFACE........................................................................................................................164

Topology ..........................................................................................................................................................166
Tool Tips..........................................................................................................................................................168
Right Click .......................................................................................................................................................170
Menu Bar .........................................................................................................................................................174
FIRMWARE UPGRADE ...........................................................................................................................................175
CONFIGURATION FILE BACKUP/RESTORE............................................................................................................176
CABLES AND CONNECTORS..........................................................................................................................179
CABLE LENGTHS...............................................................................................................................................180
GLOSSARY ...........................................................................................................................................................180

DES-3550 Layer 2 Fast Ethernet Switch User’s Guide
viii
Preface
The DES-3550 Manual is divided into sections that describe the system installation and
operating instructions with examples.
Section 1, Introduction - Describes the Switch and its features.
Section 2, Installation– Helps you get started with the basic installation of the Switch
and also describes the front panel, rear panel, side panels, and LED indicators of the
Switch.
Section 3, Connecting the Switch – Tells how you can connect the Switch to your
Ethernet/Fast Ethernet network.
Section 4, Introduction to Switch Management – Introduces basic Switch management
features, including password protection, SNMP settings, IP address assignment, and
connecting devices to the Switch.
Section 5, Introduction to Web-based Switch Management – Talks about connecting
to and using the Web-based switch management feature on the Switch.
Section 6, Configuring the Switch – A detailed discussion about configuring some of the
basic functions of the Switch, including accessing the Switch information, using the
Switch’s utilities, and setting up network configurations, such as Quality of Service, The
Access Profile Table, port mirroring, and configuring the Spanning Tree.
Section 7, Management – A discussion of the security features of the Switch, including
Security IP, User Accounts, Access Authentication Control, and SNMP.
Section 8, Monitoring – Features graphs and screens used in monitoring features and
packets on the Switch.
Section 9, Maintenance – Features information on Switch utility functions, including
TFTP Services, Switch History, Ping Test Save Changes, and Rebooting Services.
Section 10, Single IP Management – Discussion on the Single IP Management function
of the Switch, including functions and features of the Java based user interface and the
utilities of the SIM function.
Appendix A, Technical Specifications – The technical specifications of the DES-3550.
Appendix B, Cables and Connectors – Describes the RJ-45 receptacle/connector,
straight-through and crossover cables and standard pin assignments.
Appendix C, Cable Lengths – Information on cable types and maximum distances.
Glossary – Lists definitions for terms and acronyms used in this document.
Intended Readers
The DES-3550 Manual contains information for setup and management of the Switch. This
manual is intended for network managers familiar with network management concepts and
terminology.
Typographical Conventions
Convention Description

DES-3550 Layer 2 Fast Ethernet Switch User’s Guide
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[ ] In a command line, square brackets indicate an optional entry. For
example: [copy filename] means that optionally you can type copy
followed by the name of the file. Do not type the brackets.
Bold font
Indicates a button, a toolbar icon, menu, or menu item. For example:
Open the File menu and choose Cancel. Used for emphasis. May
also indicate system messages or prompts appearing on your
screen. For example: You have mail. Bold font is also used to
represent filenames, program names and commands. For example:
use the copy command.
Boldface Typewriter
Font
Indicates commands and responses to prompts that must be typed
exactly as printed in the manual.
Initial capital letter Indicates a window name. Names of keys on the keyboard have
initial capitals. For example: Click Enter.
Italics
Indicates a window name or a field. Also can indicate a variable or
parameter that is replaced with an appropriate word or string. For
example: type filename means that you should type the actual
filename instead of the word shown in italic.
Menu Name > Menu Option
Menu Name > Menu Option Indicates the menu structure.
Device > Port > Port Properties means the Port Properties menu
option under the Port menu option that is located under the Device
menu.
Notes, Notices, and Cautions
Safety Instructions
Use the following safety guidelines to ensure your own personal safety and to help protect
your system from potential damage. Throughout this safety section, the caution icon ( ) is
used to indicate cautions and precautions that you need to review and follow.
NOTE: A NOTE indicates important information that helps you make
better use of your device.
NOTICE: A NOTICE indicates either potential damage to hardware or loss
of data and tells you how to avoid the problem.
CAUTION: A CAUTION indicates a potential for property damage,
personal injury, or death.

DES-3550 Layer 2 Fast Ethernet Switch User’s Guide
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Safety Cautions
To reduce the risk of bodily injury, electrical shock, fire, and damage to the equipment,
observe the following precautions.
Observe and follow service markings. Do not service any product except as explained in your
system documentation. Opening or removing covers that are marked with the triangular
symbol with a lightning bolt may expose you to an electrical shock. Only a trained service
technician should service components inside these compartments.
If any of the following conditions occur, unplug the product from the electrical outlet and
replace the part or contact your trained service provider:
– The power cable, extension cable, or plug is damaged.
– An object has fallen into the product.
– The product has been exposed to water.
– The product has been dropped or damaged.
– The product does not operate correctly, when you follow the operating instructions.
• Keep your system away from radiators and heat sources. Also, do not block cooling
vents.
• Do not spill food or liquids on your system components, and never operate the product
in a wet environment. If the system gets wet, see the appropriate section in your
troubleshooting guide or contact your trained service provider.
• Do not push any objects into the openings of your system. Doing so can cause a fire or
an electric shock by shorting out interior components.
• Use the product only with approved equipment.
• Allow the product to cool before removing covers or touching internal components.
• Operate the product only from the type of external power source indicated on the
electrical ratings label. If you are not sure of the type of power source required, consult
your service provider or local power company.
• To help avoid damaging your system, be sure the voltage selection switch (if
provided) on the power supply is set to match the power available at your location:
– 115 volts (V)/60 hertz (Hz) in most of North and South America and some Far
Eastern countries such as South Korea and Taiwan
– 100 V/50 Hz in eastern Japan and 100 V/60 Hz in western Japan
– 230 V/50 Hz in most of Europe, the Middle East, and the Far East
• Also, be sure that attached devices are electrically rated to operate with the power
available in your location.
• Use only approved power cable(s). If you have not been provided with a power cable
for your system or for any AC-powered option intended for your system, purchase a
power cable that is approved for use in your country. The power cable must be rated
for the product and for the voltage and current marked on the product's electrical
ratings label. The voltage and current rating of the cable should be greater than the
ratings marked on the product.
• To help prevent an electric shock, plug the system and peripheral power cables into
properly grounded electrical outlets. These cables are equipped with three-prong plugs

DES-3550 Layer 2 Fast Ethernet Switch User’s Guide
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to help ensure proper grounding. Do not use adapter plugs or remove the grounding
prong from a cable. If you must use an extension cable, use a 3-wire cable with
properly grounded plugs.
• Observe extension cable and power strip ratings. Make sure that the total ampere
rating of all products plugged into the extension cable or power strip does not exceed
80 percent of the ampere ratings limit for the extension cable or power strip.
• To help protect your system from sudden, transient increases and decreases in
electrical power, use a surge suppressor, line conditioner, or uninterruptible power
supply (UPS).
• Position system cables and power cables carefully; route cables so that they cannot be
stepped on or tripped over. Be sure that nothing rests on any cables.
• Do not modify power cables or plugs. Consult a licensed electrician or your power
company for site modifications. Always follow your local/national wiring rules.
• When connecting or disconnecting power to hot-pluggable power supplies, if offered
with your system, observe the following guidelines:
– Install the power supply before connecting the power cable to the power supply.
– Unplug the power cable before removing the power supply.
– If the system has multiple sources of power, disconnect power from the system by
unplugging all power cables from the power supplies.
• Move products with care; ensure that all casters and/or stabilizers are firmly connected
to the system. Avoid sudden stops and uneven surfaces.
General Precautions for Rack-Mountable Products
Observe the following precautions for rack stability and safety. Also, refer to the rack
installation documentation accompanying the system and the rack for specific caution
statements and procedures.
Systems are considered to be components in a rack. Thus, "component" refers to any system
as well as to various peripherals or supporting hardware.
CAUTION: Installing systems in a rack without the front and side
stabilizers installed could cause the rack to tip over, potentially resulting in
bodily injury under certain circumstances. Therefore, always install the
stabilizers before installing components in the rack.
After installing system/components in a rack, never pull more than one
component out of the rack on its slide assemblies at one time. The weight
of more than one extended component could cause the rack to tip over
and may result in serious injury.
• Before working on the rack, make sure that the stabilizers are secured to the rack,
extended to the floor, and that the full weight of the rack rests on the floor. Install front
and side stabilizers on a single rack or front stabilizers for joined multiple racks before
working on the rack.
• Always load the rack from the bottom up, and load the heaviest item in the rack first.
• Make sure that the rack is level and stable before extending a component from the
rack.
• Use caution when pressing the component rail release latches and sliding a component
into or out of a rack; the slide rails can pinch your fingers.

DES-3550 Layer 2 Fast Ethernet Switch User’s Guide
xii
• After a component is inserted into the rack, carefully extend the rail into a locking
position, and then slide the component into the rack.
• Do not overload the AC supply branch circuit that provides power to the rack. The
total rack load should not exceed 80 percent of the branch circuit rating.
• Ensure that proper airflow is provided to components in the rack.
• Do not step on or stand on any component when servicing other components in a rack.
Protecting Against Electrostatic Discharge
Static electricity can harm delicate components inside your system. To prevent static damage,
discharge static electricity from your body before you touch any of the electronic components,
such as the microprocessor. You can do so by periodically touching an unpainted metal
surface on the chassis.
You can also take the following steps to prevent damage from electrostatic discharge (ESD):
1. When unpacking a static-sensitive component from its shipping carton, do not remove
the component from the antistatic packing material until you are ready to install the
component in your system. Just before unwrapping the antistatic packaging, be sure to
discharge static electricity from your body.
2. When transporting a sensitive component, first place it in an antistatic container or
packaging.
3. Handle all sensitive components in a static-safe area. If possible, use antistatic floor
pads, workbench pads, and an antistatic grounding strap.
NOTE: A qualified electrician must perform all connections to DC power
and to safety grounds. All electrical wiring must comply with applicable
local or national codes and practices.
CAUTION: Never defeat the ground conductor or operate the equipment
in the absence of a suitably installed ground conductor. Contact the
appropriate electrical inspection authority or an electrician if you are
uncertain that suitable grounding is available.
CAUTION: The system chassis must be positively grounded to the rack
cabinet frame. Do not attempt to connect power to the system until
grounding cables are connected. Completed power and safety ground
wiring must be inspected by a qualified electrical inspector. An energy
hazard will exist if the safety ground cable is omitted or disconnected.

DES-3550 Layer 2 Fast Ethernet Switch User’s Guide
13
SECTION 1
Introduction
Ethernet Technology
Switch Description
Features
Ports
Front-Panel Components
Side Panel Description
Rear Panel Description
Gigabit Combo Ports
Ethernet Technology
Fast Ethernet Technology
The growing importance of LANs and the increasing complexity of desktop computing
applications are fueling the need for high performance networks. A number of high-speed
LAN technologies are proposed to provide greater bandwidth and improve client/server
response times. Among them, Fast Ethernet, or 100BASE-T, provides a non-disruptive,
smooth evolution from 10BASE-T technology.
100Mbps Fast Ethernet is a standard specified by the IEEE 802.3 LAN committee. It is an
extension of the 10Mbps Ethernet standard with the ability to transmit and receive data at
100Mbps, while maintaining the Carrier Sense Multiple Access with Collision Detection
(CSMA/CD) Ethernet protocol.
Gigabit Ethernet Technology
Gigabit Ethernet is an extension of IEEE 802.3 Ethernet utilizing the same packet structure,
format, and support for CSMA/CD protocol, full-duplex, flow control, and management
objects, but with a tenfold increase in theoretical throughput over 100Mbps Fast Ethernet and
a one hundred-fold increase over 10Mbps Ethernet. Since it is compatible with all 10Mbps
and 100Mbps Ethernet environments, Gigabit Ethernet provides a straightforward upgrade
without wasting a company’s existing investment in hardware, software, and trained
personnel.
The increased speed and extra bandwidth offered by Gigabit Ethernet are essential to coping
with the network bottlenecks that frequently develop as computers and their busses get faster
and more users use applications that generate more traffic. Upgrading key components, such
as your backbone and servers to Gigabit Ethernet can greatly improve network response times
as well as significantly speed up the traffic between your subnetworks.
Gigabit Ethernet enables fast optical fiber connections to support video conferencing,
complex imaging, and similar data-intensive applications. Likewise, since data transfers occur
10 times faster than Fast Ethernet, servers outfitted with Gigabit Ethernet NIC’s are able to
perform 10 times the number of operations in the same amount of time.

DES-3550 Layer 2 Fast Ethernet Switch User’s Guide
14
In addition, the phenomenal bandwidth delivered by Gigabit Ethernet is the most cost-
effective method to take advantage of today and tomorrow’s rapidly improving switching and
routing internetworking technologies.
Switching Technology
Another key development pushing the limits of Ethernet technology is in the field of
switching technology. A switch bridges Ethernet packets at the MAC address level of the
Ethernet protocol transmitting among connected Ethernet or Fast Ethernet LAN segments.
Switching is a cost-effective way of increasing the total network capacity available to users on
a local area network. A switch increases capacity and decreases network loading by making it
possible for a local area network to be divided into different segments, which are not
competing with each other for network transmission capacity, and therefore decrease the load
on each segment.
The Switch acts as a high-speed selective bridge between the individual segments. Traffic that
needs to go from one segment to another (from one port to another) is automatically
forwarded by the Switch, without interfering with any other segments (ports). This allows the
total network capacity to be multiplied, while still maintaining the same network cabling and
adapter cards.
For Fast Ethernet or Gigabit Ethernet networks, a switch is an effective way of eliminating
problems of chaining hubs beyond the “two-repeater limit.” A switch can be used to split parts
of the network into different collision domains, for example, making it possible to expand
your Fast Ethernet network beyond the 205-meter network diameter limit for 100BASE-TX
networks. Switches supporting both traditional 10Mbps Ethernet and 100Mbps Fast Ethernet
are also ideal for bridging between existing 10Mbps networks and new 100Mbps networks.
Switching LAN technology is a marked improvement over the previous generation of network
bridges, which were characterized by higher latencies. Routers have also been used to
segment local area networks, but the cost of a router and the setup and maintenance required
make routers relatively impractical. Today’s switches are an ideal solution to most kinds of
local area network congestion problems.
Switch Description
The DES-3550 is equipped with unshielded twisted-pair (UTP) cable ports providing
dedicated 10 or 100 Mbps bandwidth. The Switch has 24 UTP ports and Auto MDI-X/MDI-II
convertible ports that can be used for uplinking to another switch. These ports can be used for
connecting PCs, printers, servers, hubs, routers, switches, and other networking devices. The
dual speed ports use standard twisted-pair cabling and are ideal for segmenting networks into
small, connected subnetworks for superior performance. Each 10/100 port can support up to
200 Mbps of throughput in full-duplex mode.
In addition, the Switch has two Mini-GBIC combo ports. These two, gigabit combo ports are
ideal for connecting to a server or network backbone.

DES-3550 Layer 2 Fast Ethernet Switch User’s Guide
15
This stand-alone Switch enables the network to use some of the most demanding multimedia
and imaging applications concurrently with other user applications without creating
bottlenecks. The built-in console interface can be used to configure the Switch’s settings for
priority queuing, VLANs, and port trunk groups, port monitoring, and port speed.
Features
• IEEE 802.3 10BASE-T compliant
• IEEE 802.3u 100BASE-TX compliant
• IEEE 802.1p Priority Queues
• IEEE 802.3x flow control in full-duplex mode
• IEEE 802.3ad Link Aggregation Control Protocol support.
• IEEE 802.1x Port-based and MAC-based Access Control
• IEEE 802.1Q VLAN
• IEEE 802.1D Spanning Tree and IEEE 802.1W Rapid Spanning Tree support
• Access Control List (ACL) support
• Single IP Management support
• Access Authentication Control utilizing TACACS, XTACACS, and TACACS+
• Dual Image Firmware
• Simple Network Time Protocol support
• MAC Notification support
• Asymmetric VLAN support
• System and Port Utilization support
• System Log Support
• High performance switching engine performs forwarding and filtering at full wire speed,
maximum 14, 881 packets/sec on each 10Mbps Ethernet port, and maximum 148,810
packet/sec on 100Mbps Fast Ethernet port.
• Full- and half-duplex for both 10Mbps and 100Mbps connections. Full-duplex allows the
switch port to simultaneously transmit and receive data. It only works with connections to
full-duplex-capable end stations and switches. Connections to a hub must take place at half-
duplex.
• Supports broadcast storm filtering
• Non-blocking store and forward switching scheme capability to support rate adaptation
and protocol conversion
• Supports by-port Egress/Ingress rate control.
• Efficient self-learning and address recognition mechanism enables forwarding rate at wire
speed
• Supports port-based enable and disable

DES-3550 Layer 2 Fast Ethernet Switch User’s Guide
16
• Address table: Supports up to 8K MAC addresses per device
• Supports a packet buffer of up to 64 Megabytes
• Supports Port-based VLAN Groups
• Port Trunking with flexible load distribution and fail-over function
• Supports IGMP Snooping
• Supports SNMP
• Supports Port Mirroring
• MIB support for:
• RFC1213 MIB II
• RFC1493 Bridge
• RFC1757 RMON
• RFC1643 Ether-like MIB
• RFC2233 Interface MIB
• Private MIB
• RFC2674 for 802.1p
• IEEE 802.1x MIB
• RS-232 DCE console port for Switch management
• Provides parallel LED display for port status such as link/act, speed, etc.
Ports
• Forty-eight (48) high-performance (MDI-X/MDI-II) ports for connecting to end
stations, servers, hubs, and other networking devices.
• All UTP ports can auto-negotiate between 10Mbps and 100Mbps, half-duplex and
full-duplex, and feature flow control.
• Two 1000BASE-T Mini-GBIC combo ports for connecting 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.
Important Note:
For customers interested in D-View, D-Link Corporation’s proprietary SNMP management
software, go to the D-Link Website (www.dlink.com.cn) and download the software and
manual.

DES-3550 Layer 2 Fast Ethernet Switch User’s Guide
17
Front-Panel Components
The front panel of the Switch consists of LED indicators for power and for each 10/100 Mbps
twisted-pair ports, and two 1000BASE-T Mini-GBIC ports.
DES-3550
Figure 1- 1. Front Panel View of the DES-3550 as shipped
Comprehensive LED indicators display the status of the Swtch and the network.
LED Indicators
The LED indicators of the Switch include Power,Console,Link/Act,Speed, and FDX. This
Switch also includes a LED Mode button, which has the default setting set to Link/Act. The
user may scroll through to show the LED status for Link/Act, Speed, and FDX of each port.
The following shows the LED indicators for the Switch along with an explanation of each
indicator.
Figure 1- 2. LED Indicators
Power This LED will light green after the Switch is powered on to indicate the ready state of
the device. The indicator is dark when the Switch is powered off.
Console
This LED should blink during the Power-On Self Test (POST). When the POST is
finished, the LED goes dark. This indicator is lit solid green when the Switch is being
logged into via out-of-band/local console management through the RS-232 console
port in the back of the Switch using a straight-through serial cable.
RPS This LED will be lit when the redundant power supply is present and in use.
Otherwise, it will remain dark.
Port LEDs
One row of LEDs for each port is located above the ports on the front panel. The first
LED is for the top port and the second one is for the bottom ports. The LED will light
green when there is a secure connection to a device from the corresponding port.
This LED will blink when there is activity on the port.
Gigabit
Ports
The Switch’s two Mini GBIC ports have their own corresponding LEDs. The LED will
light green when there is a secure connection to a device from the corresponding
port. This LED will blink when there is activity on the port.

DES-3550 Layer 2 Fast Ethernet Switch User’s Guide
18
Rear Panel Description
The rear panel of the Switch contains an AC power connector.
Figure 1- 3. Rear panel view of the Switch
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. The Switch automatically adjusts its power setting to any supply
voltage in the range from 100 ~ 240 VAC at 50 ~ 60 Hz.
The rear panel also includes an outlet for an optional external power supply. When power
fails, the optional external RPS will take over all the power immediately and automatically.
The rear panel contains two system fans. The system fans are used to dissipate heat. 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.
Side Panel Description
The right-hand side panel of the Switch contains heat vents to dissipate heat. Keep these
openings clear of obstructions of up to six inches of space. Failure to comply with this may
result in the system overheating and eventually to a system failure.
Figure 1-4. Side Panels
Gigabit Combo Ports
In addition to the 48 10/100 Mbps ports, the Switch features two Gigabit Ethernet Combo
ports. These two ports are 1000BASE-T copper ports (provided) and Mini-GBIC ports
(optional). See the diagram below to view the two Mini-GBIC port modules being plugged
into the Switch. Please note that although these two front panel modules can be used
simultaneously, the ports must be different. The GBIC port will always have the highest
priority.

DES-3550 Layer 2 Fast Ethernet Switch User’s Guide
19
Figure 1- 5. Mini-GBIC modules plug-in to the Switch
Figure 1- 6. Installing the Mini-GBIC Module

DES-3550 Layer 2 Fast Ethernet Switch User’s Guide
20
SECTION 2
Installation
Package Contents
Before You Connect to the Network
Installing the Switch Without the Rack
Rack Installation
Power On
Package Contents
Open the shipping carton of the Switch and carefully unpack its contents. The carton should
contain the following items:
• One DES-3550 Stand-alone Switch
• One AC power cord
• This Manual
• Registration card
• Mounting kit (two brackets and screws)
• Four rubber feet with adhesive backing
• RS-232 console cable
If any item is found missing or damaged, please contact your local D-Link Reseller for
replacement.
Before You Connect to the Network
The site where you install the Switch may greatly affect its performance. Please follow these
guidelines for setting up the Switch.
• Install the Switch on a sturdy, level surface that can support at least 3 kg (6.6 lb) of
weight. Do not place heavy objects on the Switch.
• The power outlet should be within 1.82 meters (6 feet) of the Switch.
• Visually inspect the power cord and see that it is fully secured to the AC power port.
• Make sure that there is proper heat dissipation from and adequate ventilation around
the Switch. Leave at least 15 cm (6 inches) of space at the front and rear of the Switch
for ventilation.
• Install the Switch in a fairly cool and dry place for the acceptable temperature and
humidity operating ranges.
• Install the Switch in a site free from strong electromagnetic field generators (such as
motors), vibration, dust, and direct exposure to sunlight.