D-Link DES-3225G, DES-3225GF User Manual 2

DES-3225G

DES-3225GF

24-Port Fast Ethernet

Switch

User’s Guide

First Edition (October, 1999)

6DES3225G.01

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 si chere 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 z u 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 u ng ee igneten
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 Betriebssiche rheit des Gerätes sicher .

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

WARRANTIES EXCLUSIVE

IF THE D-LINK PRODUCT DOES NOT OPERATE AS WARRANTED ABOVE, THE
CUSTOMER'S SOLE REMEDY SHALL BE, AT D-LINK'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.

Limited Warranty

Hardware:

D-Link warrants each of its hardware products to be free from defects in
workmanship and materials under normal use and service for a period commencing
on the date of purchase from D-Link or its Authorized Reseller and extending for the
length of time stipulated by the Authorized Reseller or D-Link Branch Office nearest
to the place of purchase.

This Warranty applies on the condition that the product Registration Card is filled
out and returned to a D-Link office within ninety (90) days of purchase. A list of
D-Link offices is provided at the back of this manual, together with a copy of the
Registration Card.

If the product proves defective within the applicable warranty period, D-Link will
provide repair or repl acement of the p roduct. 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
defectiv e product, but need not be identical. A ny 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 a
Registration Card for the product in question has not been returned to D-Link, then a
proof of purchase (such as a copy of the dated purchase invoice) must be provided. 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 cas e.

After an RMA n um ber is issued , the defec tive product mus t be pa ckaged 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 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 rea so n abl e h andling charg e in addition m aili ng 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, together with a copy of the Registration Card. If a Registration Card
for the product in question has not been returned to a D-Link office, then a proof of
purchase (such as a copy of the dated purchase invoice) must be provided when
requesting wa rra nty s er v ic e. The term "purchase" in this software warr anty refers to
the purchase transaction and resulting license to use such software.

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
otherwi se be pro v ided 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 softwar e pr oducts 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 warran ty sha l l 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.

D-Link Offices for Registration and Warranty Service

The product's Registration Card, provided at the back of this manual, must be sent to
a D-Link office. 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 address/telephone/fax/e-mail/Web site list of D-Link offices is
provided in the back of this manual.

Trademarks

Copyright 1999 D-Link Corp oration.
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.

Copyrig ht 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.

FCC Warni ng

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.

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.

VCCI Warning

BSMI Warning

  

ABOUT THIS GUIDE ................................ ................................ ............. V

T

................................ ................................ ................................ .....

ERMS

O

VERVIEW OF THIS USER’S GUIDE

INTRODUCTION................................ ................................ .................... 1

................................ .............................

V
V

F

AST ETHERNET TECHNOLOGY

G

IGABIT ETHERNET TECHNOLOGY

S

WITCHING TECHNOLOGY

F

EATURES

................................ ................................ ................................ 4

................................ ................................ . 1

................................ ............................ 2

................................ ................................ ........ 3

Ports ................................ ................................ ................................ .... 4

Performance features ................................ ................................ ........... 5

Management................................ ................................ ......................... 6

UNPACKING AND SETUP................................ ................................ ..... 7

U

NPACKING

I

NSTALLATION

................................ ................................ .............................. 7

................................ ................................ .......................... 8

Desktop or Shelf Installation ................................ ................................ 8

Rack Installation ................................ ................................ .................. 9

P

OWER ON

................................ ................................ ............................... 10

Power Failure................................ ................................ ..................... 11

IDENTIFYING EXTERNA L COMPONENTS................................ ......12

F

RONT PANEL

R

EAR PANEL

S

IDE PANELS

O

PTIONAL PLUG-IN MODULES

................................ ................................ .......................... 12

................................ ................................ ............................ 13

................................ ................................ ........................... 14

................................ ................................ ..15

100BASE-TX Module ................................ ................................ ..........15

100BASE-FX Fiber Module................................ ................................ .16

100BASE-FX Fiber (MTRJ Type) Module................................ ............17

1000BASE-SX Gigabit Module ................................ ............................ 17

LED I

NDICATORS

................................ ................................ .................... 18

CONNECTING THE SWITCH................................ .............................. 20

S

WITCH TO END NODE

S

WITCH TO HUB OR SWITCH

................................ ................................ .............20

................................ ................................ .....21

10BASE-T Device................................ ................................ ................ 23

100BASE-TX Device ................................ ................................ ........... 23

SWITCH MANAGEMENT CONCEPTS................................ ............... 24

L

OCAL CONSOLE MANAGEMENT

................................ .............................. 24

Diagnostic (console) port (RS-232 DCE)................................ ............. 25

IP A

DDRESSES AND

................................ ................................ ................................ .....26

T

RAPS

................................ ................................ ................................ ......28

MIB

S

P

ACKET FORWARDING

SNMP C

OMMUNITY NAMES

................................ ................................ .............30

................................ ......26

Aging Time................................ ................................ .......................... 30

Filtering Database ................................ ................................ ..............31

S

PANNING TREE ALGORITHM

................................ ................................ ...32

STA Operation Levels................................ ................................ ..........32

On the Bridge Level................................ ................................ .................... 33

On the Port Level................................ ................................ ........................ 34

User-Changeable STA Parameters ................................ ...................... 34

Illustration of STA................................ ................................ ...............36

P

ORT TRUNKING

................................ ................................ ...................... 38

VLAN................................ ................................ ................................ ....40

MAC-based VLANs................................ ................................ ..............41

Port-based VLANs................................ ................................ ...............42

VLA N Segmentation................................ ................................ ................... 43

Sharing Resources Across VLANs ................................ .............................. 43

VLANs Spanning Multiple Switches................................ ........................... 45

B

ROADCAST STORMS

................................ ................................ ...............49

Segmenting Broadcast Domains ................................ .......................... 50

Eliminating Broadcast Storms................................ ............................. 50

USING THE CONSOLE INTERFACE................................ .................. 52

C

ONNECTING TO THE SWITCH

C

ONSOLE USAGE CONVENTIONS

F

IRST TIME CONNECTING TO THE SWITCH

................................ ................................ ..52

................................ ............................... 53

................................ ............... 54

User Accounts Management................................ ................................ 56

Saving Changes................................ ................................ ................... 57

L

OGGING ONTO THE SWITCH CONSOLE BY REGISTERED USERS

................ 59

Create/Modify User Accounts................................ ................................ ..... 59

View/Delete User Accounts................................ ................................ ........ 61

S

ETTING UP THE SWITCH

................................ ................................ .........62

Configuration................................ ................................ ...................... 62

Configure IP Address................................ ................................ .................. 63

Configure Console................................ ................................ ...................... 65

Configure Switch................................ ................................ ........................ 66

Configure Ports................................ ................................ ........................... 69

Configure Slot1 Module................................ ................................ .............. 73

Configure Slot2 Module................................ ................................ .............. 76

Configure Port Mirroring................................ ................................ ............ 78

Configure Spanning Tree Protocol................................ ............................... 79

Configure Filtering and Forwarding Table................................ ................... 85

Configure IGMP Filtering................................ ................................ ........... 90

Configure VLAN................................ ................................ ........................ 94

Configure Trunk................................ ................................ ....................... 104

Update Firmware and Configuration Files ................................ ........105

System Utilities ................................ ................................ ................. 107

Ping Test ................................ ................................ ................................ .. 107

Save Settings to TFTP Server................................ ................................ .... 109

Save Switch History to TFTP Server ................................ ......................... 110

SNMP Manager Configuration................................ .......................... 111

S

WITCH MONITORING

................................ ................................ ............113

Network Monitoring................................ ................................ ..........113

Traffic Statistics ................................ ................................ ....................... 114

Browse Address Table................................ ................................ .............. 121

Browse IGMP Status................................ ................................ ................. 122

Switch History................................ ................................ .......................... 124

R

ESETTING THE SWITCH

................................ ................................ ........125

Restart System................................ ................................ ................... 126

Factory Reset................................ ................................ .................... 126

Logout................................ ................................ ............................... 127

WEB-BASED NETWORK MANAGEMENT ................................ .....128

I

NTRODUCTION

G

ETTING STARTED

M

ANAGEMENT

................................ ................................ ...................... 128

................................ ................................ ................ 129

................................ ................................ ...................... 129

Configure Switch................................ ................................ ............... 130

IP Setti ngs................................ ................................ ................................ 131

Port Settings................................ ................................ ............................. 132

Port Mirroring ................................ ................................ .......................... 135

Switch Settings................................ ................................ ......................... 136

Filtering and Forwarding Table ................................ ................................ . 139

Spanning Tree ................................ ................................ .......................... 147

IGMP Filtering................................ ................................ ......................... 152

VLAN................................ ................................ ................................ ....... 155

Trunk ................................ ................................ ................................ ....... 161

Configure Management................................ ................................ .....162

Traps and Community Strings................................ ................................ ... 162

User Accounts................................ ................................ ........................... 164

Console Port Settings................................ ................................ ................ 165

Monitor................................ ................................ ............................. 166

Switch Overview ................................ ................................ ...................... 167

Port Statistics................................ ................................ ............................ 168

Browse Address Table................................ ................................ .............. 175

Browse IGMP Status................................ ................................ ................. 176

Switch History................................ ................................ .......................... 177

Reset and Update ................................ ................................ .............. 178

Reboot Switch ................................ ................................ .......................... 178

Reset to Factory Default................................ ................................ ............ 179

Update Firmware................................ ................................ ...................... 180

Change Configuration File................................ ................................ ........ 181

Save Settings to TFTP Server................................ ................................ .... 182

Upload Log File................................ ................................ ........................ 183

Save Changes................................ ................................ .................... 184

Help................................ ................................ ................................ ..184

TECHNICAL SPECI F I CA TIONS ................................ ........................ 185

RJ-45 PIN SPECIFICATION ................................ ............................... 188

SAMPLE CONFIGURATION F I LE................................ .................... 190

Commands ................................ ................................ ............................... 190

Notes about the Configuration File ................................ ........................... 192

RUNTIME SWITCHING SOFTWARE DEFAULT SETTINGS........193

INDEX ................................ ................................ ................................ ...195

24-port NWay Ethernet Swi t ch User’s Guide

BOUT THIS

A

This User’s guide tells you how to install your DES-3225G,
how to connect it to your Ethernet network, and how to set
its configuration using either the built-in console interface
or Web-based management.

UIDE

G

Terms

For simplicity, this documentation uses the terms “Switch”
(first letter upper case) to refer to the DES-3225G 24-port
NWay Ethernet Switch, and “switch” (first letter lower case)
to refer to all Ethernet switches, including the DES-3225G.

Overview of this User’s Guide

♦

Chapter 1,
features.

♦

Chapter 2,
started with the basic installation of the Switch.

♦

Chapter 3,
Describes the front panel, rear panel, optional plug­in modules, and LED indicators of the Switch.

About This Guide

Introduction

Unpacking and Setup

Identifying External Components

. Describes the Switch and its

. Helps you get

.

v

24-port NWay Ethernet Swi t ch User’s Guide

♦

Chapter 4,

Connecting the Switch

. Tells how you can

connect the DES-3225G to your Ethernet network.

♦

Chapter 5,

Switch Management

. 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

how to manage the Switch through an Internet
browser.

♦

Appendix A,

Technical Specifications

. Lists the

technical specifications of the DES-3225G.

♦

Appendix B,

RJ-45 Pin Specifications

. Shows the
details and pin assignments for the RJ-45
receptacle/connector.

. Tells

♦

Appendix C,

♦

Appendix D,

Settings

vi

Sample Configuration File.

Runtime Switching Software Default

.

About This Guide

24-port NWay Ethernet Swi t ch User’s Guide

1

NTRODUCTION

I

This section describes the features of the Switch, as well as
giving some background information about Ethernet/Fast
Ethernet, Gigabit Ethernet, and switching technology.

Fast Ethernet Technolog

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 pr ovide
greater bandwidth and improve client/server response
times. Among them, Fast Ethernet, or 100BASE-T, provides
a non-disruptive, smooth evolution from the current
10BASE-T technology. The dominating market position
virtually guarantee cost effective and high performance
Fast Ethernet solutions in the years to come.

100Mbps Fast Ethernet is a standard specified by the IEEE

802.3 LAN committee. It is an extensi on of the 10Mbps
Ethernet standard with the ability to transmit and receive
data at 100Mbps, while mainta in ing th e Carrier Sense
Multiple Access with Collision Detection (CSMA/CD)
Ethernet protocol.

Introduction

1

24-port NWay Ethernet Swi t ch User’s Guide

Gigabit Ethernet Technolog

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 is 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 subnets.

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.

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. And
with expected advances in the coming years in silicon

2 Introduction

24-port NWay Ethernet Swi t ch User’s Guide

technology and digital signal processing that will enable
Gigabit Ethernet to eventually operate over unshielded
twisted-pair (UTP) cabling, outfitting your network with a
powerful 1000Mbps-capable backbone/server connection
creates a flexible foundation for the next generation of
network technology products.

Switching Techno l og

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
compete with each other for network transmission
capacity, giving a decreased load on each.

segments

which don’t

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

Introduction

3

24-port NWay Ethernet Swi t ch User’s Guide

to split parts of the network into di fferent 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 traditi onal 10Mbps Ethernet a nd 100Mbps
Fast Ethernet are also id eal for bridg ing be tween 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.

Features

The DES-3225G Switch was designed for easy installation
and high performance in an environment where traffic on
the network and the number of users increase
continuously.

Switch features include:

Ports

♦

24 high performance NWay ports all operating at
10/100 Mbps for connecting to end stations, servers
and hubs (22 MDI-X 10/100 Ethernet UTP ports and 2
MDI-II Uplink ports).

4 Introduction

24-port NWay Ethernet Swi t ch User’s Guide

♦

All ports can aut o-negotiate (NWay ) between 10Mbps/
100Mbps, half-duplex or full duplex and flow control.

♦

One rear panel slide-in module interface for a 1-port
1000BASE-SX Gigabit Ethernet module for
connecting to another switch.

♦

One slide-in module interface in the front panel for 1
or 2 port 10/100M Ethernet connection. Three
modules are ava ilable: 2 ports TX module, 2 ports FX
MT-RJ type module, and 1 port FX SC type module.

♦

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 capability to
support rate adaptation and protocol conversion.

♦

Full and half-duplex for both 10Mbps and 100Mbps
connections. The 1000BASE-SX Gigabit Ethernet
module operates at full-duplex only. Full-duplex
allows the switch port to simultaneously transmit
and receive data, and only works with connections to
full-duplex capable end stations and switches.
Connections to hubs must take place at half-duplex.

♦

Auto-p o larity d e t e c t io n and corr ec tion of incorrect
polarity on the receive twisted-pair at each port.

♦

Data forwarding rate 14,880pps per port at 100% of
wire-speed for 10Mbps speed.

Introduction

5

24-port NWay Ethernet Swi t ch User’s Guide

♦

Data forwarding rate 148,800pps per port at 100% of
wire-speed for 100Mbps speed.

♦

Data filtering rate eliminates all error packets, runts,
etc. at 14,880pps per port at 100% of wire-speed for
10Mbps speed.

♦

Data filtering rate eliminates all error packets, runts,
etc. at 148,800pps per port at 100% of wire-speed for
100Mbps speed.

♦

12K active MAC address en try table per device with
automatic learning and a g i ng (10 to 9999 seconds).

♦

12 MB packet buffer per device.

♦

Broadcast storm filtering.

♦

IGMP Multicast support.

Management

♦

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

♦

Spanning Tree Algorithm Protocol for creation of
alternative backup paths and prevention of network
loops.

♦

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),
RMON MIB (RFC 1757), and MIB-II (RFC 1213).

6 Introduction

24-port NWay Ethernet Swi t ch User’s Guide

2

NPACKING AND SETUP

U

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 DES-3225G 24-port NWay Ethernet Switch

♦

One 2-port 100BASE-TX Fast Ethernet module
preinstalled on front panel (DES-3225GF includes a 1­port 100BASE-FX module preinstalled).

♦

Mounting kit: 2 mounting brackets and screws

♦

Four rubber feet with adhesive backing

♦

One AC power cord

♦

This User’s Guide CD-ROM with a Registration Card

Unpacking and Setup

7

24-port NWay Ethernet Swi t ch User’s Guide

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

Installation

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

♦

The surface must support at least 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.

8 Unpacking and Setup

24-port NWay Ethernet Swi t ch User’s Guide

Figur e 2 - 1 . Ins t a l l i ng r u b be r fe e t f o r de sk top installation

Rack Installation

The DES-3225G can be mounted in an EIA standard-sized,
19-inch rack, which c an be placed in a wiring closet with
other equipment. To install, attach the mount ing 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 to the switch

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

Unpacking and Setup

9

24-port NWay Ethernet Swi t ch User’s Guide

Figure 2-2B. Installing the switch on an equipment rack

Power on

The DES-3225G switch can be used with AC power supply
100-240 VAC, 50 - 60 Hz. The power switch is located at the
rear of the unit adjacent to the AC power connector and
the system fan. The switch ’s power supply will adjust to
the local power source automatically and may be turned
on without having any or all LAN segment cables
connected.

After the power switch is turned on, 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.

10 Unpacking and Setup

24-port NWay Ethernet Swi t ch User’s Guide

♦

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

♦

The console LED indicator will remain ON if there is
a connection at the RS-232 port, otherwise this LED
indicator is OFF.

♦

The 100M LED indicator may remain ON or OFF
depending on the transmission speed.

Power Failure

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

Unpacking and Setup

11

24-port NWay Ethernet Swi t ch User’s Guide

3

DENTIFYING EXTERNAL

I

OMPONENTS

C

This chapter describes the front panel, rear panel, optional
plug-in modules, and LED indicators of the DES-3225G.

Front Panel

The front panel of the Switch consists of LED indicators,
an RS-232 communication port, a slide-in module slot, two
uplink ports, and 22 (10/100 Mbps) Ethernet/Fast Ethernet
ports.

Figu re 3-1. Front panel view of the Switch

♦

Comprehensive LED indicators display the status of
the switch and the network. A description of these
LED indicators follows (see the
section below).

12 Identifying External Components

LED Indicators

24-port NWay Ethernet Swi t ch User’s Guide

♦

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.

♦

A front-panel slide-in module slot for 10/100 Mbps
Ethernet ports can accommodate a 2-port
10/100BASE-TX Fast Ethernet module, a 2-port
100BASE-FX MT-RJ type module, or a 1-port
100BASE-FX SC type module.

♦

Two MDI-II Uplink jacks which can be used to connect
a straight-through cable to a normal (non-Uplink)
port on a switch or hub. Do not use port 1X if the top
Uplink port is occupied or Port 2X if the bottom
Uplink port is occupied.

♦

Twenty-two high-performance, NWay Ethernet ports
all of which operate at 10/100 Mbps for connections to
end stations, servers and hubs. All ports can auto­negotiate between 10Mbps or 100Mbps, full or half
duplex, and flow control.

Rear Panel

The rear panel of the switch consists of a slot for an
optional Gigabit Ethernet fiber port and an AC power
connector. The following displays the rear panel of the
switch.

Figure 3-2. Rear panel view of the Switch

Identifying External Components

13

24-port NWay Ethernet Swi t ch User’s Guide

Figure 3-3. Rear panel view of the Switch fitted with the optional

Gigabit Ethernet slide-in modul

♦

The optional Gigabit Ethernet slide-in module has a
1000BASE-SX fiber port for connecting to another
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. Supported input voltages range from 100 ~ 240
VAC at 50 ~ 60 Hz.

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 3-4. Side panel views of the Switch

14 Identifying External Components

24-port NWay Ethernet Swi t ch User’s Guide

♦

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.

Optional Plug-in Modules

The DES-3225G 24-port NWay Ethernet Switch is able to
accommodate a range of plug-in modules in order to
increase functionality and performance.

100BASE-TX Module

Figure 3-5. 100BASE-TX two-port modul

♦

Front-panel module.

♦

Connects to 100Base-TX devices at full or half duplex.

Identifying External Components

15

24-port NWay Ethernet Swi t ch User’s Guide

♦

Supports Category 5 UTP or STP cable connections of
up to 100 meters.

100BASE-FX Fiber Module

Figure 3-6. 100BASE-FX one-port modul

♦

Front-panel module.

♦

Connects to 100BASE-FX devices at full or half-duplex.

♦

Supports multi-mode fiber-optic cable connections of up
to 412 meters in half-duplex or 2 km in full-duplex mode.

16 Identifying External Components

24-port NWay Ethernet Swi t ch User’s Guide

100BASE-FX Fiber (MTRJ Type) Module

Figure 3-7. 100BASE-FX two-port modul

♦

Front-panel module.

♦

Connects to 100BASE-FX devices at full or half-duplex.

♦

Supports multi-mode fiber-optic cable connections of up
to 412 meters in half-duplex or 2 km in full-duplex mode.

1000BASE-SX Gigabit Module

Figure 3-8. 1000BASE-SX gigabit one-port modul

♦

Rear-panel module.

♦

Connects to 1000BASE-SX devices at full duplex only.

♦

Allows multi-mode fiber optic cable runs of up to 2 km in
full-duplex mode (only).

Identifying External Components

17

24-port NWay Ethernet Swi t ch User’s Guide

LED Indicators

The LED indicators of the Switch include Power, Consol e,
Slot, Giga, Speed, and Link/Act. The following shows the
LED indicators for the Switch along with an explanation of
each in dicator .

Figur e 3 - 9. T h e LE D i nd i c a tors

♦

Power This indicator on the front panel should be
colored amber during the Power-On Self Test (POST).
It will light green approximately 2 seconds after the
switch is powered on to indicate the ready state of
the device. The LED will blink green while
downloading new software for the switch, or if the
system’s configuration has changed and will light
yellow when an error occurs.

♦

Console This indicator is lit green when the switch is
being managed via out-of-band/local console
management through the RS-232 console port using a
straight-through serial cable.

♦

Slot 2 This indicator is lit green when the Gigabit
Ethernet slide-in module is present in the rear panel
of the Sw itch.

18 Identifying External Components

24-port NWay Ethernet Swi t ch User’s Guide

♦

Giga This indicator is lit green when a link is
established. It blinks green when the Gig abit port is
active.

♦

100M These indicators are illuminated green when a
100 Mbps device is connected to any of the 24 ports or
uplink port. If a 10 Mbps device is connected to any of
the 24 ports or uplink port, these LEDs remain dark.

♦

Link/Act. These indicators are lit when there is a
secure conn ection (or link) to a dev ice at any of the
ports. The LEDs blink whenever there is reception or
transmission (i.e. Activity--Act) of data occurring at a
port.

Identifying External Components

19

24-port NWay Ethernet Swi t ch User’s Guide

4

ONNECTING THE

C

WITCH

S

This chapter describes how to connect the DES-3225G to
your Fast 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. The RJ-45 UTP ports on NICs
and most routers are MDI-II. When using a normal
straight-through cable, an MDI-II port must connect to an
MDI-X port.

An end node can be connected to the Switch via a two-pair
Category 3, 4, 5 UTP/STP straight cable (be sure to use
Category 5 UTP or STP cabling for 100 Mbps Fast Ethernet
connections). The end node should be connected to any of
the twenty-two ports (1x - 22x) of the DES-3225G or to
either of the two 100BASE-TX ports on the front-panel
module that came preinstalled on the switch. An end node
should not be connected to an Uplink port (u nless using a
crossover cable), and if the top Uplink po rt is in use, Port

20 Connecting The Switch

24-port NWay Ethernet Swi t ch User’s Guide

1X must remain vacant; if the bottom Uplink port is in use,
Port 2X cannot be used.

Figur e 4 -1. Swi tc h co nne c te d t o a n End Nod

The LED indicators for the port the end node is connected
to are lit according to the capabilities of the NIC. If LED
indicators are not illuminated after making a proper
connection, check the PC’s LAN card, the cable, switch
conditions, and connecti ons.

The following LED indicator states are possible for an end
node to switch connection:

1. The 100M LED indicator comes ON for a 100 Mbps
and stays

2. The Link/Act LED indicator lights up upon hooking
up a PC that is powered on.

OFF

for 10 Mbps.

Switch to Hub or Switch

These connections can be accomplished in a number of
ways. The most important consideration is that when
using a normal, straight-through cable, the connection
should be made between a normal crossed port (Port 1X, 2X,
etc.) and an Uplink (MDI-II) port. If you are using a

Connecting The Switch

21

24-port NWay Ethernet Swi t ch User’s Guide

crossover cable, the connect ion must be made from Uplink
to Uplink, or from a crossed port to another crossed port.

♦

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

♦

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

If the other switch or hub contains an unused Uplink port,
we suggest connecting the other device’s Uplink (MDI-II)
port to any of the switch’s (MDI-X) ports (1x - 22x, or one of
the 100BASE-TX module ports) using a normal straight­through cable, as shown below.

If the other device does not have an unused Uplink port,
make the connection with a normal straight-through cable
from one of the Uplink ports on the switch to any normal
crossed port on the hub. Alternatively, if you have a
crossover cable you can save the Uplink ports for other
connections and make this one from a crossed port to
another crossed port.

Figu re 4-2 . Swi tc h c onn ec te d t o a no rma l (n on -Uplink) port on

hub or switch using a straight or crossover cabl

22 Connecting The Switch

24-port NWay Ethernet Swi t ch User’s Guide

10BASE-T Device

For a 10BASE-T device, the Switch’s LED indicators should
display the following:

♦

100M LED speed indicator is

♦

Link/A ct indica tor is ON.

OFF.

100BASE-TX Device

For a 100BASE-TX device, the Switch’s LED indicators
should display the following:

♦

100M LED speed indicator is

♦

Link/Act is ON.

ON.

Connecting The Switch

23

24-port NWay Ethernet Swi t ch User’s Guide

5

WITCH

S

This chapter discusses many of the features used to
manage the switch, and explains many concepts and
important points regardi ng these features. Configuring the
switch to implement these concepts is discussed in detail
in the next chapters.

ANAGEMENT

M

ONCEPTS

C

Local Console Management

Local console management involves the administration of
the DES-3225G Switch via a direct connection to the RS­232 DCE console port. This is an Out-Of-Band connection,
meaning that it is on a different circuit than normal
network communications, and thus works even when the
network is down.

The local console management connection involves a
terminal or PC running terminal emulation software to
operate the switch’s built-in console program (see Chapter
6 – Using the Console Interface). Using the console
program, a network administrator can manage, control
and monitor the many functions of the Switch.

24 Switch Management Concepts

24-port NWay Ethernet Swi t ch User’s Guide

Hardware components in the Switch allow it to be an
active part of a manageable network. These components
include a CPU, memory for data storage, other related
hardware, and SNMP agent firmware. Activities on the
Switch can be monitored with these components, while the
Switch can be manipulated to carry out specific tasks.

Diagnostic (console) port (RS-232 DCE)

Out-of-band management requires connecting a terminal,
such as a VT-100 or a PC running 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

Management

management platforms, such as D-View, HP OpenView, etc.
The console port is set for the following configuration:

to differentiate it from management done via

Local Console

◊

Baud rate: 9,600

◊

Data width: 8 bits

◊

Parity: none

◊

Stop bits: 1

◊

Flow Control None

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

Switch Management Concepts

25

24-port NWay Ethernet Swi t ch User’s Guide

IP Addresses and SNMP
Community Names

Each Switch has its own IP Address, which is used for
communication with an SNMP network manager or other
TCP/IP application (for example BOOTP, TFTP). You can
change the default Switch IP Address to meet the
specification of your networki ng address scheme.

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 as
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 you allow to
manage the Switch. You can also change the default
Community Name in the Switch and set access rights of
these Community Names.

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
serious like a port status change. The Switch generates
traps and sends them to the network manager (trap
managers). The following lists the types of events that can
take place on the Switch.

26 Switch Management Concepts

OFF

the Switch), or less

24-port NWay Ethernet Swi t ch User’s Guide

◊

System resets

◊

Errors

◊

Status changes

◊

Topology changes

◊

Operation

You can also specify which network managers may receive
traps from the Switch by setting a list of IP Addresses of
the authorized network managers.

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

The following are trap types a trap manager will receive:

♦

Cold Start This trap signifies that the Switch has
been powered up and initialized such that software
settings are reconfigured and h ardware systems are
rebooted. A cold start is different from a factory reset.

♦

Warm Start This trap signifies that the Switch has been
rebooted, however the POST (Power On Self-Test) is
skipped.

♦

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

Switch Management Concepts

27

24-port NWay Ethernet Swi t ch User’s Guide

♦

New Root This trap indicates that the Switch has
become the new root of the Spanning Tree, the trap is
sent by a bridge 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 selection as a new root.

♦

Topology Change A Topo logy C hange 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.

♦

Link Change Event This trap is sent whenever the
link of a port changes from link up to link down or
from link down to link up.

♦

Port Partition This trap is sent whenever the port
state enters the partition mode (or automatic
partitioning, port disable) when more than thirty-two
collisions occur while transmitting at 10Mbps or
more than sixty-four collisions occur while
transmitting at 100Mbps. .

♦

Broadcast Storm This trap is sent whenever the port
reaches the broadcast storm rising or falling
threshold.

MIBs

Management information and counters are stored in the
Switch in the Management Information Base (MIB). The
Switch uses the standard MIB-II Management Information

28 Switch Management Concepts

24-port NWay Ethernet Swi t ch User’s Guide

Base module. Consequently, values for MIB objects can be
retrieved from any SNMP-based network manager
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 ports and types 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 user­customized 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.

Switch Management Concepts

29

24-port NWay Ethernet Swi t ch User’s Guide

Packet Forwarding

The Switch learns the network configuration and uses this
information to forward packets. This reduces the traffic
congestion on the network, because packets, instead of
being transmitted to all segments, are transmitted to the
destination 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 thro ugh
the other ports.

Aging Time

The Aging Time is a parameter that affects the auto-learn
process of the Switch in terms of the network
configuration. Dynamic Entries, which make up the auto­learned-node address, are aged out of the address table
according to the Aging Time that you set.

The Aging Time can be from 10 seconds to 9999 seconds. A
very long Aging Time can result with the out-of-date
Dynamic Entries that may cause incorrect packet
filtering/forwarding decisions.

In the opposite case, if the Aging Time is too short, many
entries may be aged out 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.

30 Switch Management Concepts

24-port NWay Ethernet Swi t ch User’s Guide

Filtering Database

A switch uses a filtering database to segment the
network and control communications between segments.
It also filters packets off the network for intrusion
control (MAC Address filtering).

For port filtering, 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
defined by the user, the switch will discard the packet.

Filtering includes:

1. 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.

2. MAC address filtering – the manual entry of specific
MAC addresses to be filtered from the network.

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

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

Switch Management Concepts

31

24-port NWay Ethernet Swi t ch User’s Guide

Spanning Tree Algorithm

The Spanning Tree Algorithm (STA) in the Switch allows
you to create alternative paths (with multiple switches or
other types of bridges) in your network. These backup
paths are idle until the Switch determines that a pro blem
has developed in the pri mary paths. When a primary path
is lost, the switch providing the alternative path will
automatically go into service with no operator
intervention. This automatic network reconfiguration
provides maximum uptime to network users. The concept
of the Spanning Tree Algorithm is a complicated and
complex subject and must be fully researched and
understood. Please read the following before making any
changes.

♦

Network loop detection and prevention With STA,
there will be only one path between any two LANs. If
there is more than one path, forwarded packets will
loop indefinitely. STA detects any looped path and
selects the path with the lowest path cost as the
active path, while blocking the other path and using
it as the backup path.

♦

Automatic topology re-conf iguration When the path
for which there is a backup path fails, the backup
path will be automatically activated, and STA will
automatically re-configure the network topology.

STA Operation Levels

STA operates on two levels: the bridge level and the port
level. On the bridge level, STA calculates the Bridge
Identifier for each Switch, then sets the Root Bridge and

32 Switch Management Concepts

24-port NWay Ethernet Swi t ch User’s Guide

the Designated Bridges. On the port level, STA sets the
Root Port and Designated Ports. Details are as follows:

On the Bridge Level

♦

Root Bridge The switch with the lowest Bridge
Identifier is the Root Bridge. Naturally, you will want
the Root Bridge to be the best switch among the
switches in the loop to ensure the highest network
performance and reliability.

♦

Bridge Identifier This is the combination of the

Bridge Priority (a parameter that you can set) and
the MAC address of the switch. Example: 4 00 80 C8
00 01 00, where 4 is the Bridge Priority. A lower
Bridge Identifier results in a higher priority for the
switch, and thus increases it probably of being
selected as the Root Bridge.

♦

Designated Bridge From each LAN segment, the

attached Bridge that has the lowest Root Path Cost to
the Root Bridge is the Designated Bridge. It forwards
data packets for that LAN segmen t. In cases where all
Switches have the same Root Path Cost, the switch
with the lowest Bridge Identifier becomes the
Designated Bridge.

♦

Root Path Cost The Root Path Cost of a switch is the
sum of the Path Cost of the Root Port and the Root
Path Costs of all the switches that the packet goes
through. The Root Path Cost of the Root Bridge is
zero.

♦

Bridge Priority This is a parameter that users can
set. The smaller the number you set, the higher the
Bridge Priority is. The higher the Bridge Priority,

Switch Management Concepts

33

24-port NWay Ethernet Swi t ch User’s Guide

the better the chance the Switch will be selected as
the Root Bridge.

On the Port Level

♦

Root Port Each switch has a Root Port. This is the
port that has the lowest Path Cost to the Root Bridge.
In case there are several such ports, then the one
with the lowest Port Identifier is the Root Port.

♦

Designated Port This is the port on each Designated
Bridge that is attached to the LAN segment for
which the switch is the Designated Bridge.

♦

Port Priority The smaller this number, the higher
the Port Priority is. With higher Port Priority, the
higher the probability that the port will be selected
as the Root Port.

♦

Path Cost This is a changeable parameter and may
be modified according to the STA specification. The
100Mbps segment has an assigned Path Cost of 10,
and each 10Mbps segment has an assigned Path Cost
of 100, based on the STA specifications.

User-Changeable STA 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 param eters in the Switch
are as follows:

♦

Bridge Priority A Bridge Priority can be from 0 to

65535. 0 is equal to the highes t Bridg e Priority.

34 Switch Management Concepts

24-port NWay Ethernet Swi t ch User’s Guide

♦

Bridge 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.

♦

Bridge 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.

♦

Bridge Forward Delay The Forward Delay can be

from 4 to 30 seconds. This is the ti me any port on the
Switch spends in the listening state while moving
from the blocking state to the forwarding state.

Observe the following formulas when you set the
above parameters:

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

2. 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.

Switch Management Concepts

35

24-port NWay Ethernet Swi t ch User’s Guide

Illustration of STA

A simple illustration of three Bridges (or the Switch)
connected in a loop is depicted in
example, you can anti cipate some major network problems
if the STA assistance is not applied. For instance, if Bridge
1 broadcasts a packet to Brid ge 2, Bridge 2 will broadcast
it to Bridge 3, and Bridge 3 will broadcast it to Bridge

1...and so on. The broadcast packet will be passed

indefinitely in a loop, causing a serious network failure.
To alleviate network loop problems, STA can be applied as

shown in
by blocking the connection between Bridge 1 and 2. The
decision to block a particular connection is based on the
STA calculation of the most current Bridge and Port
settings. Now, if Bridge 1 broadcasts a packet to Bridge 3,
then Bridge 3 will broadcast it to Bridge 2 and the
broadcast will end there.

Figure

5-2. In this example, STA breaks the loop

Figure 5-1

. In this

STA setup can be somewhat complex. Therefore, you are
advised to keep the default factory settings and STA will
automatically assign root bridges/ports and block loop
connections. However, if you need to customize the STA
parameters, refer to

36 Switch Management Concepts

Table 5-1

.

24-port NWay Ethernet Swi t ch User’s Guide

Figure 5-1. Before Applying the STA Rule

Figure 5-2. After Applying the STA Rule

STA parameters Settings Effects Comment

Bridge Priority

Switch Management Concepts

lower the #,
higher the
priorit

Increases chance of
becoming the Ro ot
Bridg

Avoid, if the switch is
used in workgroup
level of a large network

37

24-port NWay Ethernet Swi t ch User’s Guide

Hello Time

Max. Age Time

Forward Delay

Enable / Disable

Port Priority

1 - 10 sec. No effect, if not

6 - 40 sec. Compete for Root

4 - 30 sec. High # delays the

Port Level STA parameters

Enable /
Disable

lower the #,
higher the
priorit

Table 5-1. User-selective STA parameter

Port Trunking

Root Bridge

Bridge, if BPDU i s
not received

change in state

Enable or disable
this LAN segment

Increases chance of
become Root Port

Never set greater than
Max. Age Time

Avoid low number for
unnecessary reset of
Root Bridge

Max. Age ≤ 2 x
(Forward Delay - 1)
Max. Age ≥ 2 x (Hello
Time + 1)

Disable a port for
security or problem
isolation

Port trunking is used to combine a number of ports
together to make a single high-bandwidth data pipeline.
The participating parts are called members of a trunk
group, with one port designated as the

master

of the group.
Since all members of the trunk group must be configured
to operate in the same manner, all settings changes made
to the master port are applied to all members of the trunk
group. Thus, when configuring the ports in a trunk group,
you only need to configure the master port.

The DES-3225G supports 3 trunk groups, which may
include from 2 to 8 switch ports each, except for the third

38 Switch Management Concepts

24-port NWay Ethernet Swi t ch User’s Guide

trunk group which consists of the 2 ports of the Slot 1,
100BASE-TX or 100BASE-FX front-panel module. The
master port for the first group is preset as port 7, the
master port for the second group is port 15 and the master
port for the third group is the first port (1x) on the 2-port
module.

The switch treats all ports in a trunk group as a single port.
As such, trunk ports will not be blocked by Spanning Tree.

Data transmitted to a specific host (destination address)
will always be transmitted over the same port in a trunk
group. This allows packets in a data stream to arrive in the
same order they were sent. A trunk connection can be
made with any other switch that maintains host-to-host

Switch Management Concepts

39

24-port NWay Ethernet Swi t ch User’s Guide

data streams over a single trunk port. Switches that use a
load-balancing scheme that sends the packets of a host-to­host data stream over multiple trunk ports cannot have a
trunk connection with the DES-3225G switch.

VLAN

VLANs are a collection of users or po rts grouped together
in a secure, autonomous broadcast and multicast domain .
Membership to a VLAN is not restricted by a physical
location and can be defined across multiple LAN switches.

Two types of VLANs are implemented: MAC-based VLANs
and port-based VLANs. MAC-based VLANs are limited to
the switch and the devices connected to it, while port­based VLANs support IEEE 802. 1Q tagging , which enables
them to span the entire network (assuming all switches on
the network are IEEE 802.1Q-compliant).

Both MAC-based and port-based 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 (MAC-based) or ports (port-based)
that are members of that VLAN, and this even includes
Multicast frames and unknown unicast frames.

Another benefit of VLANs is that you can change the
network topology without physically moving stations or
changing cable connections. Stations can be ‘moved’
simply by changing VLAN settings from one VLAN (the
sales VLAN, for example) to another VLAN (the marketing
VLAN). This allows VLANs to accommodate network moves,
changes and additions with the utmost flexibility.

40 Switch Management Concepts

24-port NWay Ethernet Swi t ch User’s Guide

VLANs can also provide a level of security to your network.
MAC-based VLANs will only deliver packets between
stations that are members of the VLAN. Port-based VLANs
allow you to configure ports to not accept packets from
outside of the VLAN.

untagging

The
to work with legacy switches that don ’t recognize VLAN
tags in packet headers. The
to span multiple 802.1Q-compliant switches through a
single physical con nection and a llows Span ning Tre e to be
enabled on all ports and work normally.

feature of IEEE 802.1Q VLANs allow VLANs

tagging

feature allows VLANs

MAC-based VLANs

The DES-3225G supports up to 12 MAC-based VLANs,
which are by their nature, limited to the switch itself and
the devices connected to it. Two key features inherent in
MAC-based VLANs are flexibility and security.

Since MAC addresses are hard-wired into a station’s
network interface card (NIC), MAC-based VLANs enable
network managers to move a station to a different physical
location on the network and have that station
automatically retain its VLAN membership. This provides
the network with a high degree of flexibility since even
notebook PC’s can plug into any available port on a
network and communicate with the same people and use
the same resources that have been allocated to the VLAN
in which it is a member.

MAC-based VLANs include groups of individual devices.
Communications can be rest ricted to only certa in devices
that are members of a common VLAN. This provides a high
degree of security by allowing network managers to decide
access rights on a device-per-devic e basis.

Switch Management Concepts

41

24-port NWay Ethernet Swi t ch User’s Guide

Setting up MAC-based VLANs is a relatively straight­forward process. Simply create the VLAN by assigning it a
name (description) and add MAC addresses for the stations
that will be members.

Port-based VLANs

The DES-3225G supports up to 96 port-based VLANs. Port­based VLANs limit traffic that flows into and o ut of switch
ports. Thus, all devices connected to a port are members of
the VLAN(s) the port belongs to, whether there is a single
computer directly connected to a switch, or an entire
department.

On port-based VLANs, NICs do not need to be able to
identify 802.1Q tags in packet headers. NICs send and
receive normal Ethernet packets. If the packet’s
destination lies on the same segment, communications
take place using normal Ethernet protocols. Even though
this is always the case, when the destin ation for a packet
lies on another switch port, VLAN considerations come
into play to decide if the packet gets dropped by the switch
or delivered.

There are two key components to understanding port­based VLANs; Port VLAN ID numbers (PVID) and VLAN ID
numbers (VID). Both variables are assigned to a switch
port, but there are important differences between them. A
user can only assign one PVID to each switch port. The
PVID defines which VLAN a switch will forward packets
from the connected segment on, when pac kets need to be
forwarded to another switch port or somewhere else on the
network. On the other hand, a user can define a port as a
member of multiple VLANs (VIDs), allowing the segment
connected to it to receive packets from many VLANs on the
network. These two variables control a port’s ability to

42 Switch Management Concepts

24-port NWay Ethernet Swi t ch User’s Guide

transmit and receive VLAN traffic, and the difference
between them provides network segmentation, while still
allowing resources to be shared across more than one
VLAN.

VLAN Segmentation

Take for example a packet that is transmitted by a
machine on Port 1 that is a member of VLAN 2 and has the
Port VLAN ID number 2 (PVID=2). If the destination lies on
another port (found through a normal forwarding table
lookup), the switch then looks to see if the other port (Port

10) is a member of VLAN 2 (and can therefore receive
VLAN 2 packets). If port 10 is not a member of VLAN 2,
then the packet will be dropped by the switch an d will not
reach it’s destination. If Port 10 is a member of VLAN 2, the
packet will go through. This selective forwarding feature
based on VLAN criteria is how VLANs segment networks.
The key point being that Port 1 will only transmit on VLAN
2, because it’s Port VLAN ID number is 2 (PVID=2).

Sharing Resources Across VLANs

Network resources such as printers and servers however,
can be shared across VLANs. This is achieved by setting up
overlapping VLANs as shown in the d iagram below.

Switch Management Concepts

43

24-port NWay Ethernet Swi t ch User’s Guide

VLA

N

3

VLAN 2

5678910

Port
PVID = 3

11 12

Network

Server

Port
VIDs = 2

Graphics

Workstations

Workstations

1234

Port
VIDs = 1

VLAN 1

In the above example, there are three different VLANs and
each port can transmit packets on one of them according
to their Port VLAN ID (PVID) number. However, a port can
receive packets on all VLANs (VID) that it belo ngs to. The
assignments are as follows:

Transmit on VLAN

Member of VLAN #

#

Port PVID VID Ports

Port 1 1 1 1,2,3,7
Port 2 1
Port 3 1

Port 7 3 3 1,2,3,7,11,12

Port 11 2 2 11,12,7
Port 12 2

The server attached to Port 7 is shared by VLAN 1 and
VLAN 2 because Port 7 is a member of both VLANs (it is
listed as a member of VID 1 and 2). Since it can receive
packets from both VLANs, all ports can successfully send

44 Switch Management Concepts

24-port NWay Ethernet Swi t ch User’s Guide

packets to it to be printed. Ports 1, 2 and 3 send these
packets on VLAN 1 (their PVID=1), and Ports 11 and 12
send these packets on VLAN 2 (PVID=2). The third VLAN
(PVID=3) is used by the server to transmit files that had
been requested on VLAN 1 or 2 back to the computers. All
computers that use the server will receive transmissions
from it since they are all located on ports which are
members of VLAN 3 (VID=3).

VLANs Spanning Multiple Switches

VLANs can span multiple switches and indeed, your entire
network. Two considerations to keep in mind while
building VLANs of this sort are whether the switches are
IEEE 802.1Q-compliant, and thus, whether or not tagging
should be performed.

Definitions of relevant terms are as follows:
Tagging - The act of putting 802.1Q VLAN information into

the header of a packet. Ports with tagging enabled will put
the VID number, priority and other VLAN information into
all packets that flow into and out it. If a packet has
previously been tagged , the port will not alter th e packet,
thus keeping the VLAN information intact. Tagging is used
to send packets from one 802.1Q-compliant device to
another.

Untagging - The act of stripping 802.1Q VLAN information
out of the packet header. Ports with untagging enabled
will take all VLAN information out of all packets that flow
into and out of a port. If the packet doesn’t have a VLAN
tag, the port will not alter the packet, thus keeping the
packet free of VLAN information. Untagging is used to
send packets from an 802.1Q-compliant switch to a non­compliant device.

Switch Management Concepts

45

24-port NWay Ethernet Swi t ch User’s Guide

Ingress port - A port on a switch where packets are flowing
into the switch and VLAN decisions must be made.
Basically, the switch examines VLAN information in the
packet header (if present) and decides whether to forwa rd
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 and can thus receive
the packet (if the Ingress Filter is enabled), and then it
decides if the destination port is a member of the VLAN.
Assuming both ports ar e members of the tagged VLAN, the
packet will be forwarded. If the packet doesn’t have VLAN
information in its header (is untagged), the ingress port
first determines if the ingress port itself can receive the
packet (if the Ingress Filter is enabled), will tag it with its
own PVID (if it defined as a tagging port) and check to see
if the destination port is on the same VLAN as its own
PVID and can thus receive the packet. If Ingress filtering
is disabled and the destination port is a member of the
VLAN used by the ingress port, the packet will be
forwarded. If the ingress port is an untagging port, it will
only check the filter condition - if the ingress filter is
enabled - before forwarding the packet.

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. If an egress
port is connected to an 802.1Q-compliant switch, tagging
should be enabled so t he other switch can take VLAN data
into account when making forwarding decisions. If an
egress connection is to a non-compliant switch or end­station, tags should be stripped so the (now normal
Ethernet) packet can be read by the receiving device.

46 Switch Management Concepts

24-port NWay Ethernet Swi t ch User’s Guide

   

When switches maintaining the same VLANs are 802.1Q­compliant, it is possible to use tagging. Tagging puts

802.1Q VLAN information into each packet header,
enabling other 802.1Q-com pliant switches that receive the
packet to know how to treat it. Upon receiving a tagged
packet, an 802.1Q-compliant switch can use the
information in the packet header to maintain the integrity
of VLANs, carry out priority forwarding, etc.

Data transmissions between 802.1Q-compliant switches
take place as shown below.

Switch Management Concepts

47

24-port NWay Ethernet Swi t ch User’s Guide

In the above example, step 4 is the key element. Because
the packet has 802.1Q VLAN data encoded in it ’s header,
the ingress port can make VLAN-based decisions about its
delivery – whether server #2 is attached to a port that is a
member of VLAN 2 and thus should the packet be delivered,
the queuing priority to give to the packet, etc. It can also
perform these functions for VLAN 1 packets as well, and in
fact, for any tagged packet it receives regardless of the
VLAN number.

If the ingress port in step 4 were connected to a non-

802.1Q-compliant device and was thus receiving u ntagged

48 Switch Management Concepts

24-port NWay Ethernet Swi t ch User’s Guide

packets, it would tag its own PVID onto the packet and use
this information to make forwarding decisions. Thus, the
packets coming from the non-compliant device would
automatically be placed on the ingress ports VLAN and
could only communicate with other ports that are
members of this VLAN.

Broadcast Storms

Broadcast storms are a common problem on today’s
networks. Basically, they consist of broadcast packets that
flood and/or are looped on a network causing noticeable
performance degradation and in extreme cases, network
failure. Broadcast storms can be caused by malfunctioning
NICs, bad cable connections and applications or prot ocols
that generate broadcast traffic, among others.

In effect, broadcast storms can originate fro m any number
of sources, but once they are started, they can be self­perpetuating, and can even multiply the number of
broadcast packets on the network over time. In the best
case, network utilization will be high and bandwidth
limited until the hop counts for all broadcast packets have
expired, whereupon t he packets will be discarded and the
network will return to normal. In the worst case, they will
multiply, eventually using up all the network bandwidth
(although network applications will usually crash long
before this happens), and cause a network meltdown.

Broadcast storms have long been a concern for network
administrators with routers traditionally being used to
prevent their occurrence, and if that failed, limit their
scope. However, with the advent of VLANs, switches are
now able to limit broadcast domains better and cheaper

Switch Management Concepts

49

24-port NWay Ethernet Swi t ch User’s Guide

than routers. Also, many switches, including the DES­3225G, have broadcast sensors and filters built into each
port to further control broadcast storms.

Segmenting Broadcast Domains

VLANs can be used to segment broadcast domains. They do
this by forwarding packets only to ports in the same VLAN.
Thus, broadcast packets will only be forwarded to ports
that are members of the same VLAN. Other parts of the
network are effectively shielded. Thus, the smaller the
broadcast domain, the smaller effect a broadcast storm will
have. Because VLANs are implemented at each switch port,
they can be quite effective in limiting the scope of
broadcast storms.

Eliminating Br oa dc ast Storms

SNMP agents can be programmed to monitor the number
of broadcast packets on switch ports a nd act on the data.
When the number of broadcast packets on a given port rise
past an assigned threshold, an action can be triggered.
When enabled, the usual action is to block the port to
broadcast frames, which discards all broadcast frames
arriving at the port from the attached segment. Not only
does this isolate the broadcast domain, but it actually
starts removing broadcast packets from the affected
segment. When the number of broadcast packets falls to an
acceptable level (below a falling threshold), the SNMP
agent can remove the blocking condition, returning the
port to its normal operational state.

In the DES-3225G, the default rising threshol d is set to 500
broadcast packets per second (pps), and the default falling

50 Switch Management Concepts

24-port NWay Ethernet Swi t ch User’s Guide

threshold is set to 250pps. The thresholds and actions can
easily be defined by using a normal SNMP management
program or through the console interface.

Switch Management Concepts

51

24-port NWay Ethernet Swi t ch User’s Guide

6

SING THE

U

I

Your 24-port NWay 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 set up 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.

ONSOLE

C

NTERFACE

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:

52 Using the Console Interface

24-port NWay Ethernet Swi t ch User’s Guide

♦ VT-100/ANSI compatible
♦ 9,600 b aud
♦ 8 data bits
♦ No parity
♦ One stop bit
♦ No flow control

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 for the most part 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 on or off

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. It is recommended

Using the Console Interface

53

24-port NWay Ethernet Swi t ch User’s Guide

that you use the tab key and backspace key for
moving around console.

4. Items in UPPERCASE are commands. Moving the

selection to a command and pressing Enter will
execute that comman d, e.g. APPLY, etc.

Please note that the command APPLY only app lies for the
current session. Use Save Changes from the main menu for
permanent changes. An asterisk “*” i ndicates a change has
been made but won ’t take effect until the Switch has been
rebooted.

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).
Press Ctrl+R (hold down the Ctrl key, press the R key,
and release both keys) to call up the screen, if the initial
login screen does not appear. Also Ctrl+R can be used at
any time to refresh the screen.

54 Using the Console Interface

24-port NWay Ethernet Swi t ch User’s Guide

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

Note: There is no initia l username or password. Leave the
username and password fields blank.

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

Using the Console Interface

55

24-port NWay Ethernet Swi t ch User’s Guide

Figu r e 6 -2 . Ma i n Menu

The first user automatically gets Administrator privileges
(See Table 6- 1 ). It is recommended to create at least one
Administrator-level user for the Switch.

User Accounts Management

From the screen above, move the cursor to the User
Accounts Management menu and press Enter, then the
Users Accounts Management menu appears.

1. Choose Create/Modify User Accounts from the User

Accounts Management menu and the Add/Modify User
Accounts menu appears.

2. Enter the new user name, assign an initial password,

and then confirm the new password. Determine whether
the new user should have Administrator or Normal User
privileges. (Use the space bar to toggle between the two
options).

3. Press APPLY to let the user addition take effect.

4. Press Esc. to return to the previ ous screen or Ctrl+T to

go to the root screen.

5. To see a listing of all user accounts and access levels,

press Esc. Then choose View/Delete User Accounts. The
View/Delete User Accounts screen appears.

Administrator and Normal User Privileges

There are two levels of user privileges: Administrator and
Normal User. Some menu selections available to users with
Administrator privileges may not be available to Normal

56 Using the Console Interface

24-port NWay Ethernet Swi t ch User’s Guide

Users. The main menus shown are the menus for the two
types of users:

The following table summarizes Administrator and Normal
User privileges:

Menu AdministratorNormal User

Privilege

Configuration Yes Yes, view only.
Network Monitoring Yes Yes, view only.
Community Strings and Trap

Stations
Update Firmware and

Configuration Files

User Accounts Management

Create/ M odify User Accounts Yes No
View/ Delete User Accounts Yes No
System Utilities Yes Yes
Factory Reset Yes No
Restart System Yes No

Yes Yes, view only.

Yes No

Table 6-1. Adm i nistrator and Normal Us er Privileg

After establishing a User Account with Administrator-level
privileges, press Esc. twice. Then choose the Save Changes
menu (see below). Pressing any key will return to the main
menu. You are now ready to operate the Switch.

Saving Changes

The DES-3225G has two levels of memory normal RAM and
non-volatile or NV-RAM. Settings need to be changed in all
screens by clicking on the Apply button. When this is done,

Using the Console Interface

57

24-port NWay Ethernet Swi t ch User’s Guide

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 will erase all
settings in RAM and reload them from the NV-RAM . Thus,
it is necessary to save all settings to the NV-RAM before
restarting the switch.

In order to retain any modifications made in the current
session by savi ng them i nto the NV-RAM, it is necessary to
choose Save Changes from the main menu. The following
screen will appear to indicate your new settings have been
processed:

Figure 6-3. Save Changes screen

After the settings have been saved to NV-RAM, they will
become the default settings for the switch, and they will be
used by the switch every time it is powered on, reset or
rebooted. The only exception to this is a factory reset,
which will clear all settings and restore them to their
initial values listed in the Appendix, which were present
when the s witch was purchased.

58 Using the Console Interface

24-port NWay Ethernet Swi t ch User’s Guide

Logging Onto The Switch Console
By Registered Users

To log in once you have created a registered user,

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 Administrator or Normal User access level or
privilege.

Create/Modify User Accounts

To add or change your user password:
Choose Users Accounts Management from the main

menu. The following User Accounts Management menu
appears:

Using the Console Interface

59

24-port NWay Ethernet Swi t ch User’s Guide

Figure 6-4. User Accounts Management menu

1. Choose Create/Modify User Accounts. The following

screen appears:

Figure 6-5. Add/Modify User Account screen

2. Type in your Username and press Enter.

3. If you are a new user, type in the Old Password and

press Enter.

4. 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.

5. Determine whether th e n ew user should have Normal

User or Administrator privileges.

6. Choose the APPLY command to let the password

change take effect.

60 Using the Console Interface

24-port NWay Ethernet Swi t ch User’s Guide

This method can also be used by an Administrator-level
user to change another user’s password.

View/Delete User Accounts

Access to the console, whether using the console port or
via TELNET, is controlled using a user name and password.
Up to three of these user names can be defined. The
console interface will not let you delete the current logged­in user, however, in order to prevent accidentally deleting
all of the users with Administrator privilege.

Only users with the Administrator privilege can delete
users.

To view your user password:
Choose View/Delete User Accounts from the User

Accounts Management menu. The following screen
appears:

Figur e 6 - 6 . View / Delete User Accounts screen

Using the Console Interface

61

24-port NWay Ethernet Swi t ch User’s Guide

To delete your user password:

1. Toggle the Delete field of the user you wish to remove

to Yes.

2. Press APPLY to let the user deletion take effect.

Setting Up The Switch

This section will help prepare the Switch user by
describing the Configuration, Update Firmware and
Configuration Files, Save Changes, and System Utilities
menus and their respective sub-menus.

Configuration

Choose Configurati on to access the first item on the DES­3225G main menu. The following menu appears:

62 Using the Console Interface

24-port NWay Ethernet Swi t ch User’s Guide

Figu r e 6 -7 . C on f i gu r a tion menu

You will need to change some settings to allow you to be
able to manage the Switch from an SNMP-based Network
Management System such as SNMP v1 or to be able to
access the Switch using the TELNET protocol. See the next
chapter for Web-based network management information.

Configure IP Address

The Switch needs to have an IP address assigned to it so
that an In-Band network management system or TELNET
client can find it on the network. The IP Configuration
screen allows you to change the settings for the two
different interfaces used on the Switch: the Ethernet
interface used for in-band communication, and the SLIP
interface used over the console port for out-of-band
communication.

Choose Configure IP Address to access the first item on t he
Configuration menu. The following screen appears:

Using the Console Interface

63

24-port NWay Ethernet Swi t ch User’s Guide

Figu r e 6 -8 . IP Co n f ig u r a tion screen

The fields listed under the Current Settings heading are
those that are currently being used by the switch. Those
fields listed under the Restart Settings heading are those
which will be used after the switch has been Reset. Fields
that can be set include:

♦ BOOTP Determines whether the Switch should send

out a BOOTP broadcast request when it is powered
up. The BOOTP protocol allows IP addresses,
network masks, and default gate ways 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 supplied
settings.

♦ 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 B itmask that determines the ex tent 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. If no
subnetting is being done, the va l ue sh ou ld 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.

64 Using the Console Interface

24-port NWay Ethernet Swi t ch User’s Guide

♦ Default Gateway IP address that determines where

frames with a destin ation 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 internetwork, or you do not want the
Switch to be accessible outside your local network,
you can leave this field unchanged.

Confi gure Console

You can use the Console Options screen to choose whether
to use the Switch’s RS-232C serial port for console
management or for out-of-band TCP/IP communications
using SLIP, and to set the bit rate used for SLIP
communications.

Choose Configure Console to access the last item on the
Configuration menu. The following screen appears:

Figu r e 6 -9 . C on s ol e Op t i ons screen

The following fields can be set:

Using the Console Interface

65

24-port NWay Ethernet Swi t ch User’s Guide

Settings on Restart:
♦ Console Timeout This setting for the restart of the

console is 15 mins, 30 mins, 45 mins, 60 mins, or Never.

♦ Serial Port Determines whether the serial port

should be used for out-of-band (SLIP) management or
for console management, starting from the next time
the Switch is restarted. In this field, you can toggle
between SLIP or console port type settings.

♦ Baud Rate Determines the serial port bit rate that

will be used the next time the Switch is restarted.
Applies only when the serial port is being used for
out-of-band (SLIP) management; it does not apply
when the port is used for the console port. Available
speeds are 2400, 9600, 19,200 and 38,400 bits per
second. The default setting in this Switch version is

9600.

The top of the screen displays the current settings for
Console Timeout and Serial Port as well as the Baud
Rate, Character Size, and Stop Bit for Out of Band and
Console settings, respectively.

Configure Swit ch

The Switch Configuration screen shows various pieces of
information about your Switch, and allows you to set the
System Name, System Location, and System Contact. These
settings can be retrieved from the Switch using SNMP
requests, allowing these settings to be used for network
management purposes.

Choose Configure Switch to access the seco nd item on the
Configuration menu. The following screen appears:

66 Using the Console Interface

24-port NWay Ethernet Swi t ch User’s Guide

Figu r e 6 -1 0 . S wi t ch C o n f ig u r a tion screen

The fields you can set are:
♦ System Name Corresponds to the SNMP MIB II

variable

system.sysName

, and is used to give a
name to the Switch for administrat ive purposes. The
Switch’s fully qualified domain name is often used,
provided a name has been assigned.

♦ System Location Corresponds to the SNMP MIB II

variable

system.sysLocation

, and is used to
indicate the physical location of the Switch for
administrative purposes.

♦ System Contact Corresponds to the SNMP MIB II

variable

sysContact

, and is used to give the name
and contact information for the person responsible
for administering the Switch.

Using the Console Interface

67

24-port NWay Ethernet Swi t ch User’s Guide

Adva nce d Se ttings

The Configure Advanced Switch Features screen allows
you to set an expiration time for MAC address entries and
enable or disable auto-partitioning on all ports. Click on
ADVANCED SETTINGS on the Switch Configuration
window to access the Configure Advanced Switch Features
screen:

Figure 6-11 . Co nfigure Advance d Switch Features screen

The fields you can set are:
♦ Port Auto-Par ti tion Capability on All Ports When this

function is enabled, if too many consecutive collisions
occur on an individual port, the port will be blocked off
until a good packet is seen on the wire. If a port is
partitioned, the Switch can on ly transmit data, not
receive it.

♦ Head Of Line (HOL) Blocking Prevention Enables or

disables Head-Of-Line Blocking Prevention. Head-of

68 Using the Console Interface

24-port NWay Ethernet Swi t ch User’s Guide

Line blocking occurs when a packet originating on Port
1, for instance, needs to be forwarded to Ports 2 and 3. If
Port 2 is occupied (causing the packet to be held in
memory until the port is free), the packet destined for
Port 3 will also be delayed, even though the port may be
free. Cumulatively, these delays c an h a ve a noticeable
effect on overall network performance. Enabling HOL
Blocking Prev en tion prevents Head-of-Line bl ock i ng
from occurring, meaning that the packet destined for
Port 3 gets delivered immediately.

Configure Por ts

The port configuration screen allows you to change the
port state in the case when you would like to partition a
port due to excessive collision, or for observation, device
repair, or security reasons. Great caution, however, must
be observed when partitioning a port; you should make
sure that the partitioned port is not being used as the port
to control or monitor the condition of other devices.

Figure 6-12. Port Configuration screen

Using the Console Interface

69

24-port NWay Ethernet Swi t ch User’s Guide

Items in the above window are defined a s follows:
♦ Port Specifies the port (1-22,all) that will be

configured. When all is chosen, the settings you
configure will be applied to all UTP ports.

♦ State Enables or Disables the port. This a mounts to

turning the port on or off.

♦ Speed/Duplex Selects the desired Speed and Duplex

fort the port. Possible settings include: Auto,
100M/Full, 100M/Half, 10M/Full, or 10M/Half.
Choosing Auto enables NWay auto-configuration on
the port.

♦ Flow Control Toggles flow control On or Off. Flow

control can only be used with other IEEE 802.3x­compliant devices and in a full-duplex connection. It
is useful during periods of heavy network activity
when the Switch’s buffers can receive too much
traffic and fill up faster than the Switch can forward
the information. In such cases, the Switch will
intervene and tell the transmitting device to pause
to allow the information in the port buffer to be sent.
When Auto-Negotiation is enabled in the
Speed/Duplex field above, flow control will only be
enabled if the connected device can Auto-negotiate
flow control. Confirm that Flow Control is in force
by checking the Status field.

♦ Priority selects Normal, High or Low. The DES-

3225G has two packet queues where incoming
packets wait to be processed for forwarding; a high
priority and low priority queue. The high priority
queue should only be used for data in which latency
can have adverse affects on the function of an
application, such as video or audio data, where

70 Using the Console Interface

24-port NWay Ethernet Swi t ch User’s Guide

latency can produce distorted sounds and images.
Packets in the low priority queue will not be
processed unless the High priority queue is empty.
Setting the port priority to high will deliver all
packets arriving at the port to the high priority
queue, a low setting will send them all to the low
priority qu eue. The Normal setti ngs causes the port
to examine the packet for an IE EE 802.1p/Q priority
tag. If no tag exists, the packet will be sent to the low
priority queue. If the priority tag field in the packet
header contains a value of 0-3, the packet will be
placed in the low priority queue; a value of 4-7
causes the packet to be placed in the high priority
queue.

♦ Port Lock When locked, automatic learning for all

stations connected to this port will stop and entries
in the Forwarding Table for all devices residing on
this port will age out. The only traffic this port will
allow is traffic from m achines whose MAC address is
manually entered in the Static Forwarding Table.

♦ Broadcast Storm Rising Action This setting will be

activated when Broadcast Storm Rising Threshold
(below) is met. When triggered, the port can be
configured to Do Nothing, Block or Block and Trap .
The Do Nothing setting causes the switch to operate
normally, in other words, ignore the broadcast storm
condition. The Block setting causes the port to drop
all broadcast frames, thus isolating the broadcast
storm. Block and Trap performs the same action as
Block, except it also sends a trap to the designated
Trap Recipient informing them of the situation. For
more information on broadcast storms, please refer
to the Switch Management Concepts section of this
manual.

Using the Console Interface

71

24-port NWay Ethernet Swi t ch User’s Guide

♦ Broadcast Storm Rising Threshold This setting

defines a ceiling for the number of broadcast packets
per second on this port. Once met, the Broadcast
Storm Rising Action (above) will be triggered. The
assigned number should be high enough to allow
normal broadcast packets (which comprise
significant traffic) to be let through, while being low
enough so that broadcast storms can be detected
early.

♦ Broadcast Storm Falling Action This setting will be

activated when the Broadcast Storm Rising

Threshold and then the Broadcast Storm Falling
Threshold (below) is met. This setting can be
configured to Do Nothing, F orward or Forward and
Trap. The Do Nothing setting causes the switch to

operate normally, in other words, ignore the
situation. If the port had met the Broadcast Storm
Rising Action criteria and started Blocking
broadcast packets, it will continue doing so. The
Forward setting causes the port to begin forwarding
broadcast frames, thus removing the Blocking state
imposed by the Broadcast Storm Rising Action.

Forward and Trap performs the same action as
Forward, except it also sends a trap to the

designated Trap Recipient informing them of the
situation.

♦ Broadcast Storm Falling Threshold This setting

defines the number of broadcast packets per second
on this port which will trigger the Broadcast Storm
Falling Action (above). This threshold will only
trigger an action if the Broadcast Storm Rising
Threshold has first been reached. The assigned
number should be high enough to allow normal
broadcast packets (which comprise significant

72 Using the Console Interface

24-port NWay Ethernet Swi t ch User’s Guide

traffic) to be let through as early as possible, while
being low enough so that broadcast storms are
completely eliminated.

Press CTRL+S to let the changes take effect. If you wish
these changes to be the default for the switch, return to
the main menu and choose Save Changes.

STP Port State (whether the Spanning Tree Protocol is
enabled or disabled on this port) and Status reflect the
current conditions of the port. They are read-only fields
and cannot be changed .

Confi gure Slot1 Module

This screen allows you to change the port state of the
module in slot 1 in the case when you would like to
partition a port due to excessive collision, or for
observation, device repair, or security reasons. Great
caution, however, must be observed when disabling a port,
since all data passing through the port will be discarded
by the switch.

To change the configuration of the Slot1 module shown
below:

Using the Console Interface

73

24-port NWay Ethernet Swi t ch User’s Guide

Figu r e 6 -1 3 . Sl o t 1- P o rt Co n f i gu r a t ion screen

♦ Port field specifies either Slot1-TP1, th e Port 1x por t

or Slot1-TP2, the Port 2x port on the module. For
single-port modules, only Slot1-TP1 will be available.

♦ State Enables or Disables this port.
♦ Speed/Duplex Selects the desired Speed and Duplex

fort the port. Possible settings include: Auto,
100M/Full, 100M/Half, 10M/Full, or 10M/Half.

Choosing Auto enables NWay auto-configuration on
the port.

♦ Flow Control Enables or disables IEEE 802.1x full-

duplex (only) flow control on this port. See Flow
Control in the Configure Ports section above for a
more detailed explanation.

♦ Priori ty selects Normal, High or Low. See Priority in

the Configure Ports section above for a more detailed
explanation.

74 Using the Console Interface

24-port NWay Ethernet Swi t ch User’s Guide

♦ Port Lock When locked, automatic learning for all

stations connected to this port will stop and en tries
in the Forwarding Table for all devices residing on
this port will age out. The o nly traffic this port will
allow is traffic from machines whose MAC address is
manually entered in the Static Forwarding Table.

♦ Broadcast Storm Rising Action selects an action –

Do Nothing, Block, Block and Trap – for the port
when the Broadcast Storm Rising Threshold (below)
condition is met. See Broadc ast Storm Rising Action
in the Configure Ports section of this manual for a
more detailed explanation.

♦ Broadcast Storm Rising Threshold This setting

defines a ceiling for the number of broadcast packets
per second on this port. See Broad cast Storm Rising
Threshold in the Configure Ports section of this
manual for a more detailed explanation.

♦ Broadcast Storm Falling Action This setting will be

activated when the Broadcast Storm Rising

Threshold and then the Broadcast Storm Falling
Threshold (below) is met. This setting can be
configured to Do Nothing, F orward or Forward and
Trap. See Broadcast Storm Falling Action in the
Configure Ports section of this manual for a more

detailed expl anation.

♦ Broadcast Storm Falling Threshold This setting

defines the number of broadcast packets per second
on this port which will trigger the Broadcast Storm

Falling Action (above). See Broadcast Storm Falling
Threshold in the Configure Ports section of this

manual for a more detailed explanation.

Press CTRL+S to have the changes take effect.

Using the Console Interface

75

24-port NWay Ethernet Swi t ch User’s Guide

STP Port State and Status reflect the current conditions of
the port. They are read-only fields and cannot be changed.

Confi gure Slot2 Module

This screen allows you to change the port state of the
optional 1000BASE-SX module in slot 2. This is useful in
the case when you would like to partition a port due to
excessive collision, or for observation, device repair, or
security reasons. Great caution, however, must be
observed when disabling a port , since all data passing
through the port will be discarded by the switch.

The Configure Slot2 Module screen appears as follows:

F igure 6-14. S lot2-Port Configuration screen

♦ Port field specifies either Slot1-TP1, th e Port 1x por t

or Slot1-TP2, the Port 2x port on the module. For
single-port modules, only Slot1-TP1 will be available.

♦ State Enables or Disables this port.

76 Using the Console Interface

24-port NWay Ethernet Swi t ch User’s Guide

♦ Speed/Duplex This field is read-only since the

Gigabit Ethernet module must always be set to
1000Mbps, full-duplex.

♦ Flow Control Enables or disables IEEE 802.1x full-

duplex (only) flow control on this port. See Flow
Control in the Configure Ports section above for a
more detailed explanation.

♦ Priori ty selects Normal, High or Low. See Priority in

the Configure Ports section above for a more detailed
explanation.

♦ Port Lock When locked, automatic learning for all

stations connected to this port will stop and en tries
in the Forwarding Table for all devices residing on
this port will age out. The o nly traffic this port will
allow is traffic from machines whose MAC address is
manually entered in the Static Forwarding Table.

♦ Broadcast Storm Rising Action selects an action –

Do Nothing, Block, Block and Trap – for the port
when the Broadcast Storm Rising Threshold (below)
condition is met. See Broadc ast Storm Rising Action
in the Configure Ports section of this manual for a
more detailed explanation.

♦ Broadcast Storm Rising Threshold This setting

defines a ceiling for the number of broadcast packets
per second on this port. See Broad cast Storm Rising
Threshold in the Configure Ports section of this
manual for a more detailed explanation.

♦ Broadcast Storm Falling Action This setting will be

activated when the Broadcast Storm Rising

Threshold and then the Broadcast Storm Falling
Threshold (below) is met. This setting can be

Using the Console Interface

77

24-port NWay Ethernet Swi t ch User’s Guide

configured to Do Nothing, F orward or Forward and
Trap. See Broadcast Storm Falling Action in the
Configure Ports section of this manual for a more

detailed expl anation.

♦ Broadcast Storm Falling Threshold This setting

defines the number of broadcast packets per second
on this port which will trigger the Broadcast Storm

Falling Action (above). See Broadcast Storm Falling
Threshold in the Configure Ports section of this

manual for a more detailed explanation.
Press CTRL+S to have the changes take effect.
STP Port State and Status reflect the current conditions of

the port. They are read-only fields and cannot be changed.

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 t o 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:

78 Using the Console Interface

24-port NWay Ethernet Swi t ch User’s Guide

Figure 6-15. Configure Port Mirroring screen

To configure a mirror port, select the port from where you
want to copy frames in the Source Port field. Then select
the port which receives the copies from the source port in
the Target Port field. The target port is where you will
connect a monitoring/troubleshooting device such as a
sniffer or an RMON probe.

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.

Configure Spanning Tree Protocol

The Spanning Tree Algorithm Parameters can be used for
creating alternative paths in your network. The Protocol

Using the Console Interface

79

24-port NWay Ethernet Swi t ch User’s Guide

Parameters allow you to change the behind the scene
parameters of the Spanning Tree Algorithm at the bridge
level. The parameters for this section have been fully
explained in Chapter 5’s Switch Management, see STA

Operation Levels: On the Bridge level, and User-Changeable
Parameters. It is recommended that you read these

sections, as well as the introductory section in the same
chapter entitled Spanning Tree Algorithm before changing
any of the parameters.

STP Parameter Settings

To change the Protocol Parameters:

1. Choose Configure Spanning Tree Protocol from the

Configuration menu. The following Configure
Spanning Tree Protocol menu will be displayed:

Figure 6-16. Configure Spanning Tree Protocol menu

2. Choose STP Parameters Setting to access the

following screen:

80 Using the Console Interface

24-port NWay Ethernet Swi t ch User’s Guide

Figure 6-17. STP Parameters Setting screen

The information on the screen is described as follows:
♦ Spann i ng Tree Pr otocol Enables or disables the

Spanning Tree Protocol.

♦ Time Since Topology Changes (sec) Read-only

object displays the last time changes were made to
the network topology. These changes usually occur
when backup paths are activated due to primary
path failures.

♦ Topology Change Count Read-only object displays

the number of times (since the current management
session with the device was started) changes were
made to the network topology. Changes usually
occur on the network when backup paths are
activated.

♦ Designated Root Read-only object displays the

MAC (Ethernet) address of the bridge/switch on the
network that has been chosen as the STP root.

Using the Console Interface

81

24-port NWay Ethernet Swi t ch User’s Guide

♦ Root Cost Read-only object displays the cost for

the path between the switch and the root bridge. If
the switch is the root bridge, then the root cost is
zero.

♦ Root port Read-only object identifies the port (on

the bridge) that offers the least path cost from the
bridge to the root bridge. In the event of a network
loop, data packets will pass through the root port.

♦ Max Age (sec) Read-only object indicates the

maximum age of STP information learned from the
network (on any port) before it is discarded.

♦ Forward Delay (sec) Read-only object indicates

how fast any port on the bridge c an change its
spanning state when moving towards the
forwarding state. The value determines how long
the port stays in each of the listening and learning
states, which precede the forwarding state.

♦ Hold Time (sec) Read-only object displays the time

interval during which no more than two configuration
BPDUs shall be transmitted by the bridge.

♦ Root Priority Read-only object displays the

priority number of the root bridge of the Spanning
Tree. The value is used in conjunction with the
bridge MAC address to set the bridge ID, which in
turn is used when determining t h e root bridge of a
multi-bridged network. The root bridge is
responsible for proce ssi n g data p ackets when
network loops occur. The smaller the number set,
the higher the bridge priority is. The higher the
bridge priority, the more chance the bridge has of
becoming the root bridge. A bridge priority ranges
from 0 to 65535, with 0 being the highest priority.

82 Using the Console Interface

24-port NWay Ethernet Swi t ch User’s Guide

♦ Max Age (6-40 sec) Maximum Age is a read-write

object that can be set 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.

♦ Hello Time (1-10 sec) Hello Time is a read-write

object that 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.

♦ Forward Delay (4-30 sec) The Forward Delay is a

read-write object that can be set 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) A Bridge Priority is a

read-write object that can be set from 0 to 65535.
This is the priority number of the bridge. The value
is used in conjunction with the bridge MAC address
to set the bridge ID, which in turn is used when
determining the root bridge of a multibridged
network. The root bridge is responsible for
processing data packets when network loops occur.
The smaller the number set, the higher the bridge
priority is. The higher the bridge priority, the more
chance the bridge has of becoming the root bridge.
Zero is the highest priority.

Using the Console Interface

83

24-port NWay Ethernet Swi t ch User’s Guide

STP Port Contro

To change the parameters on individual ports:

1. Choose Configure Spanning Tree Protocol from the

Configuration menu.

2. Choose STP Port Control from the Configure

Spanning Tree Protocol menu. The following screen
appears:

Fig ure 6-18 . Spanni n g Tree Pr otocol Custom S ettings screen

Items in the above window are described as follows:
♦ STP State Enables or disables the Spanning Tree

Protocol on a particular port.

♦ Cost (1-65535) Defines the cost for the connection.
♦ Priori ty (0-255) Port Priority is a read-write object

that can be set from 0 to 255. This is the priority
number of the port. The lower the port priority, the

84 Using the Console Interface

24-port NWay Ethernet Swi t ch User’s Guide

more chance the bridge has of becoming the root
port. Zero is the highest priority.

Configure Filtering and Forwarding Table

When a packet hits the Switch, it looks in the filtering and
forwarding table to decide what to do with the packet;
either to filter it off the network, or to forward it through
the port on which its destination lies.

Dynamic Filtering and Stat ic Filtering are among the two
important features of the Custom Filtering Table. They are
defined here briefly as follows. Dynamic Filtering is
defined when a dynamic entry is created by the Learning
Process as a result of observation of network traffic in the
Filtering Database. Static Filtering is defined as static
entries that may be added and removed from the Filte ring
Database by the user. They are no t aut omatically removed
by any timeout mechanism.

The Configure Filtering and Forwarding table screen
allows you to allows you to stop or start address learning,
change the way the Switch treats MAC address table
entries, and select an age-out time of the MAC address in
the selected address table. This screen also permits you to
access three additional configuration screens from the
menu at the bottom of the window.

Choose Configure Filtering and Forwarding Table from
the Configuration menu to access the following screen:

Using the Console Interface

85

24-port NWay Ethernet Swi t ch User’s Guide

Fi gure 6-1 9. Con f i gure Filtering and Forwarding table screen

The following fields at the top of the screen can be set:
♦ Lock Address Table (Stops Auto-Learning) Mostly used

for security purposes, when the forwarding table is
locked the Switch will no longer learn the MAC
addresses for new hosts. If your network configuratio n
doesn’t change, locking the forwarding table helps keep
intruders off your network since any packet coming
from an unknown source address will be dropped by the
Switch.

♦ Address Table Lookup Mode This setting allows the

user to tailor the MAC address look up procedure.
Choices are Level 0, Level 1, Level 2, Level 3, Level 4,
Level 5, Level, 6, Level 7. The higher the level, the more
MAC addresses can be learned by the Switch. However,
a side effect is that throughput will be degraded the
higher the level you select. Default is the lowest setting
offered.

86 Using the Console Interface