D-Link DES-3326 User Manual

DES-3326

24-Port Fast Ethernet

Plus 2-Port Gigabit Module

Layer 3 Switch

Second Edition (July 2002)

651ES3326025

Printed In Taiwan

RECYCLABLE

User’s Guide

Wichtige Sicherheitshinweise

1. Bitte lesen Sie sich diese Hinweise sorgfältig durch.

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

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

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

5. Das Gerät is vor Feuchtigkeit zu schützen.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Warranty service may be obtained by contacting a D-Link office within the applicable warranty period, and requesting a Return Material Authorization (RMA) number. If 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 case.

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

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

Software:

Warranty service for software products may be obtained by contacting a D-Link office within the applicable warranty period. A list of D-Link offices is provided at the back of this manual, 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 warranty service. The term "purchase" in this software warranty 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 otherwise be provided free of charge.

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

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 2002 D-Link Corporation. 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.

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 Warning

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

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

Table of Contents

Introduction .......................................................................................................................................10

Layer 3 Switching ............................................................................................................................10

The Functions of a Layer 3 Switch.................................................................................................11

Features ..........................................................................................................................................11

Ports .............................................................................................................................................11

Performance Features......................................................................................................................11

Layer 2 Features ...........................................................................................................................11

Layer 3 Switch Features................................................................................................................12

Traffic Classification and Prioritization ..........................................................................................13

Management .................................................................................................................................13

Optional Redundant Power Supply................................................................................................14

Fast Ethernet Technology ................................................................................................................14

Gigabit Ethernet Technology............................................................................................................14

Unpacking and Setup.........................................................................................................................15

Unpacking .......................................................................................................................................15

Installation ......................................................................................................................................15

Desktop or Shelf Installation .........................................................................................................15

Rack Installation...........................................................................................................................16

Power on..........................................................................................................................................17

Power Failure ................................................................................................................................17

Identifying External Components .......................................................................................................18

Front Panel......................................................................................................................................18

Rear Panel .......................................................................................................................................18

Side Panels ......................................................................................................................................19

Optional Plug-in Modules ................................................................................................................19

1000BASE-T Module.....................................................................................................................19

1000BASE-SX Fiber Module .........................................................................................................20

1000BASE-LX Fiber Module..........................................................................................................20

GBIC Two-Port Module..................................................................................................................21

LED Indicators ................................................................................................................................21

Connecting The Switch.......................................................................................................................22

Switch to End Node .........................................................................................................................22

Switch to Hub or Switch ..................................................................................................................22

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

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

Switch Management and Operating Concepts ....................................................................................24

Local Console Management .............................................................................................................24

Diagnostic (console) port (RS-232 DCE).........................................................................................24

IP Addresses and SNMP Community Names ....................................................................................25

Traps...............................................................................................................................................26

SNMP ..............................................................................................................................................27

MIBs................................................................................................................................................28

Packet Forwarding ...........................................................................................................................28

Filtering...........................................................................................................................................29

Spanning Tree .................................................................................................................................30

Link Aggregation..............................................................................................................................35

VLANs .............................................................................................................................................37

IP Addresses ....................................................................................................................................41

vii

Internet Protocols ............................................................................................................................46

Packet Headers................................................................................................................................50

The Domain Name System ...............................................................................................................54

DHCP Servers ..................................................................................................................................55

IP Routing .......................................................................................................................................55

ARP .................................................................................................................................................57

Multicasting ....................................................................................................................................57

Multicast Routing Protocols .............................................................................................................62

Routing Protocols ............................................................................................................................62

Configuring the Switch Using the Console Interface ...........................................................................87

Saving Changes..................................................................................................................................93

Advanced Setup.............................................................................................................................112

Layer 3 IP Networking....................................................................................................................121

Multicasting ..................................................................................................................................133

Port Mirroring................................................................................................................................142

Priority ..........................................................................................................................................144

Filtering.........................................................................................................................................146

Forwarding ....................................................................................................................................148

Spanning Tree ...............................................................................................................................151

Link Aggregation............................................................................................................................154

Spanning Tree ...............................................................................................................................156

Utilities..........................................................................................................................................159

Network Monitoring .......................................................................................................................167

Load Factory Defaults....................................................................................................................182

Web-Based Network Management ....................................................................................................185

Introduction ..................................................................................................................................185

Before You Start ............................................................................................................................185

General Deployment Strategy......................................................................................................185

VLAN Layout ...............................................................................................................................186

Assigning IP Network Addresses and Subnet Masks to VLANs.....................................................186

Defining Static Routes.................................................................................................................187

Getting Started ..............................................................................................................................187

Management..................................................................................................................................187

Configuring the Switch ..................................................................................................................187

User Accounts Management........................................................................................................187

Saving Changes .............................................................................................................................189

Reboot and Load Factory Defaults .................................................................................................189

USING WEB-BASED MANAGEMENT .............................................................................................190

CONFIGURING AND MONITORING................................................................................................193

Advanced Setup.............................................................................................................................208

Layer 3 IP Networking....................................................................................................................215

Multicasting ..................................................................................................................................223

Port Mirroring................................................................................................................................231

Priority ..........................................................................................................................................233

Filtering.........................................................................................................................................234

Spanning Tree ...............................................................................................................................238

Link Aggregation............................................................................................................................241

Utilities..........................................................................................................................................242

Network Monitoring .......................................................................................................................247

Technical Specifications ...................................................................................................................262

Sample Configuration File ................................................................................................................264

viii

Runtime Switching Software Default Settings...................................................................................266

Understanding and Troubleshooting the Spanning Tree Protocol......................................................267

Blocking State.............................................................................................................................267

Listening State ............................................................................................................................268

Learning State.............................................................................................................................269

Forwarding State.........................................................................................................................270

Disabled State.............................................................................................................................271

Troubleshooting STP......................................................................................................................272

Spanning Tree Protocol Failure ...................................................................................................272

Full/Half Duplex Mismatch.........................................................................................................273

Unidirectional Link .....................................................................................................................274

Packet Corruption .......................................................................................................................275

Resource Errors ..........................................................................................................................275

Identifying a Data Loop ...............................................................................................................275

Avoiding Trouble .........................................................................................................................275

Brief Review of Bitwise Logical Operations........................................................................................279

Index................................................................................................................................................280

DES-3326 Layer 3 Fast Ethernet Switch User’s Guide

INTRODUCTION

This section describes the Layer 3 functionality and Layer 2 and Layer 3 features of the DES-3326. Some background information about Ethernet/Fast Ethernet, Gigabit Ethernet, and switching technology is presented. This is intended for readers who may not be familiar with the concepts of layered switching and routing but is not intended to be a complete or in-depth discussion.

Layer 3 Switching

Layer 3 switching is the integration of two proven technologies: switching and routing. In fact, Layer 3 switches are running the same routing routines and protocols as traditional routers. The main difference between traditional routing and Layer 3 switching is the addition of a group of Layer 2 switching domains and the execution of routing routines for most packets via an ASIC – in hardware instead of software.

Where a traditional router would have one, or at best a few, Fast Ethernet ports, the DES-3326 Layer 3 switch has 24 Fast Ethernet ports and optionally, 2 Gigabit Ethernet ports. Where a traditional router would have one or two high-speed serial WAN connections, the DES-3326 relies upon a Fast Ethernet port to connect to a separate device, which in turn, connects the network to a WAN or the Internet.

The DES-3326 can be thought of as 24 Fast Ethernet Layer 2 switching domains with a wire-speed router between each domain. It can be deployed in a network between a traditional router and the intranetwork. The traditional router and its associated WAN interface would then handle routing between the intranetwork and the WAN (the Internet, for example) while the Layer 3 switch would handle routing within the LAN (between the Fast Ethernet Layer 2 domains). Any installed Layer 2 switches, and indeed the entire subnetting scheme, would remain in place.

The DES-3326 can also replace key traditional routers for data centers and server farms, routing between these locations and the rest of the network, and providing 24 ports of Layer 2 switching performance combined with wire-speed routing.

Backbone routers can also be replaced with DES-3326 and a series of DES-3326 could be linked via the optional Gigabit Ethernet ports. Routers that service WAN connections would remain in place, but would now be removed from the backbone and connected to the DES-3326 via an Ethernet/Fast Ethernet port. The backbone itself could be migrated to Gigabit Ethernet, or faster technologies as they become available.

The DES-3326 accomplishes two objectives. First as a tool to provide high-performance access to enterprise data servers and infrastructure, and second, to enhance the performance of network equipment already installed. Many network segments display poor performance, but the Ethernet wire is only carrying a fraction of its total traffic capacity. The problem is not the network, but the ability of the connected devices utilize the full capacity of the network. The DES-3326 can eliminate network bottlenecks to high-traffic areas, and improve the utilization of the network’s installed bandwidth.

DES-3326 Layer 3 Fast Ethernet Switch User’s Guide

The Functions of a Layer 3 Switch

Traditional routers, once the core components of large networks, became an obstacle to the migration toward next-generation networks. Attempts to make software-based routers forward packets more quickly were inadequate.

A layer 3 switch does everything to a packet that a traditional router does:

• Determines forwarding path based on Layer 3 information

• Validates the integrity of the Layer 3 header via checksum

• Verifies packet expiration and updates accordingly

• Processes and responds to any optional information

• Updates forwarding statistics in the Management Information Base

A Layer 3 switch can be placed anywhere within a network core or backbone, easily and cost-effectively replacing the traditional collapsed backbone router. The DES-3326 Layer 3 switch communicates with a WAN router using a standard Ethernet/Fast Ethernet port. Multiple DES-3326 switches can be linked via the optional, 2-port Gigabit Ethernet module.

Features

The DES-3326 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 (23 MDI-X 10/100 Ethernet UTP ports and one MDI-II/MDI-X port. The MDIII/MDI-X port can be switched between the two modes from the front panel.)

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

• One front panel slide-in module interface for a 2-port 1000BASE-SX, 1000BASE-LX, 1000BASET, or GBIC Gigabit Ethernet 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

Layer 2 Features

• 8.8 Gbps switching fabric capacity

DES-3326 Layer 3 Fast Ethernet Switch User’s Guide

• Store and forward switching scheme.

• Full and half-duplex for both 10Mbps and 100Mbps connections. The front-port 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.

• Supports IEEE 802.3x flow control for full-duplex mode ports.

• Supports Back-pressure flow control for half-duplex mode ports.

• Auto-polarity detection and correction of incorrect polarity on the transmit and receive twisted-

pair at each port.

• IEEE 802.3z compliant for all Gigabit ports (optional module).

• IEEE 802.3x compliant Flow Control support for all Gigabit ports (optional module).

• IEEE 802.3ab compliant for 1000BASE-T (Copper) Gigabit ports (optional module).

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

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

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

speed for 10Mbps speed.

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

• 8K active MAC address entry table per device with automatic learning and aging (10 to 9999 seconds).

• 16 MB packet buffer per device.

• Broadcast and Multicast storm filtering.

• Supports Port Mirroring.

• Supports Port Trunking – up to six trunk groups (each consisting of up to eight ports) may be set

up.

• 802.1D Spanning Tree support.

• 802.1Q Tagged VLAN support – up to 63 User-defined VLANs per device (one VLAN is reserved

for internal use).

• GVRP – (GARP VLAN Registration Protocol) support for dynamic VLAN registration.

• 802.1p Priority support with 4 priority queues.

• IGMP Snooping support.

• Layer 2 Multicast support – GMRP (GARP Multicast Registration Protocol).

Layer 3 Switch Features

• Wire speed IP forwarding.

DES-3326 Layer 3 Fast Ethernet Switch User’s Guide

• Hardware-based Layer 3 IP switching.

• IP packet forwarding rate of 6.6 Mpps.

• 2K active IP address entry table per device.

• Supports RIP – (Routing Information Protocol) version I and II.

• Supports OSPF − (Open Shortest Path First)

• Supports MD5 and Password OSPF Packet Authentication

• Supports IP version 4.

• IGMP version 1 and 2 support (RFC 1112 and RFC 2236).

• Supports PIM Dense Mode.

• Supports DVMRP.

• Supports IP multi-netting.

• Supports IP packet de-fragmentation.

• Supports Path MTU discovery.

• Supports 802.1D frame support.

Traffic Classification and Prioritization

• Based on 802.1p priority bits

• 4 priority queues

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.

• SNMP v.1 Agent.

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

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

console.

• Built-in SNMP management:

 Bridge MIB (RFC 1493)

 MIB-II (RFC 1213)

 Mini-RMON MIB (RFC 1757) – 4 groups

 CIDR MIB (RFC 2096), except IP Forwarding Table.

 802.1p MIB (RFC 2674).

 RIP MIB v2 (RFC 1724).

• Supports Web-based management.

• TFTP support.

• BOOTP support.

• BOOTP Relay Agent.

• IP filtering on the management interface.

• DHCP Client support.

• DHCP Relay Agent.

• DNS Relay Agent.

• Password enabled.

DES-3326 Layer 3 Fast Ethernet Switch User’s Guide

Optional Redundant Power Supply

The DES-3326 24+2 Fast Ethernet Layer 3 Switch supports the optional DPS-1000 (Redundant Power Supply) to provide automatic power supply monitoring and switchover to a redundant power supply (located in the chassis of the DPS-1000) in case of a failure in the DES-3326’s internal power supply.

Fast Ethernet Technology

100Mbps Fast Ethernet (or 100BASE-T) is a standard specified by the IEEE 802.3 LAN committee. It is an extension of the 10Mbps Ethernet standard with the ability to transmit and receive data at 100Mbps, while maintaining the Carrier Sense Multiple Access with Collision Detection (CSMA/CD) Ethernet protocol.

Gigabit Ethernet Technology

Gigabit Ethernet is an extension of IEEE 802.3 Ethernet utilizing the same packet structure, format, and support for CSMA/CD protocol, full duplex, flow control, and management objects, but with a tenfold increase in theoretical throughput over 100Mbps Fast Ethernet and a one hundred-fold increase over 10Mbps Ethernet. Since it is compatible with all 10Mbps and 100Mbps Ethernet environments, Gigabit Ethernet provides a straightforward upgrade without wasting a company’s existing investment in hardware, software, and trained personnel.

Gigabit Ethernet enables fast optical fiber connections and Unshielded Twisted Pair connections to support video conferencing, complex imaging, and similar data-intensive applications. Likewise, since data transfers occur 10 times faster than Fast Ethernet, servers outfitted with Gigabit Ethernet NIC’s are able to perform 10 times the number of operations in the same amount of time.

DES-3326 Layer 3 Fast Ethernet Switch User’s Guide

UNPACKING AND SETUP

This chapter provides unpacking and setup information for the Switch.

Unpacking

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

♦ One DES-3326 24-port Fast Ethernet Layer 3 Switch

♦ Mounting kit: 2 mounting brackets and screws

♦ Four rubber feet with adhesive backing

♦ One AC power cord

♦ This User’s Guide with Registration Card

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 3 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.

DES-3326 Layer 3 Fast Ethernet Switch User’s Guide

Figure 2-1. Installing rubber feet for desktop installation

Rack Installation

The DES-3326 can be mounted in an EIA standard-sized, 19-inch rack, which can be placed in a wiring closet with other equipment. To install, attach the mounting brackets on the switch’s side panels (one on each side) and secure them with the screws provided.

Figure 2- 2A. Attaching the mounting brackets to the switch

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

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

DES-3326 Layer 3 Fast Ethernet Switch User’s Guide

Power on

The DES-3326 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.

♦ 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.

DES-3326 Layer 3 Fast Ethernet Switch User’s Guide

IDENTIFYING EXTERNAL COMPONENTS

This chapter describes the front panel, rear panel, optional plug-in modules, and LED indicators of the DES-3326.

Front Panel

The front panel of the Switch consists of LED indicators, an RS-232 communication port, a slide-in module slot, one switched MDI-X/MDI-II uplink port, and 23 (10/100 Mbps) Ethernet/Fast Ethernet ports.

Figure 3-1. Front panel view of the Switch

♦ Comprehensive LED indicators display the status of the switch and the network (see the LED

Indicators section below).

♦ 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 Gigabit Ethernet ports can accommodate a 2-port

1000BASE-T Gigabit Ethernet module, a 2-port 1000BASE-SX Gigabit Ethernet module, a 2-port 1000BASE-LX Gigabit Ethernet module, or a 2-port GBIC-based Gigabit Ethernet module.

♦ One switched MDI-X/MDI-II Uplink port that can be used to connect a straight-through cable or a

crossed cable to a normal (non-Uplink) port on a switch or hub. This port is identical to the other 23 ports except for the ability to use a crossed or a straight-through cable.

♦ Twenty-three high-performance, NWay Ethernet ports all of which operate at 10/100 Mbps for

connections to end stations, servers and hubs. All ports can auto-negotiate between 10Mbps or 100Mbps, full or half duplex, and flow control.

Rear Panel

The rear panel of the switch consists of a slot for the optional DPS-1000 (Redundant Power Supply) and an AC power connector.

Figure 3-2. Rear panel view of the Switch

DES-3326 Layer 3 Fast Ethernet Switch User’s Guide

♦ 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

♦ 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 3326 24-port Fast Ethernet Layer 3 Switch is able to accommodate a range of optional plug-in modules in order to increase functionality and performance. These modules must be purchased separately.

1000BASE-T Module

Figure 3-5. 1000BASE-TX two-port module

♦ Front-panel module. ♦ Connects to 1000BASE-T devices. ♦ Supports Category 5e UTP or STP cable connections of up to 100 meters.

1000BASE-SX Fiber Module

DES-3326 Layer 3 Fast Ethernet Switch User’s Guide

Figure 3-6. 1000BASE-SX two-port module

♦ Front-panel module.

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

♦ Allows connections using multi-mode fiber optic cable in the following configurations:

Modal bandwidth

(min. overfilled launch)

Unit: MHz*km

Operating distance

Unit: meters

Channel insertion loss

Unit: dB

62.5µm 62.5µm 50µm 50µm

160 200 400 500

220 275 500 550

2.33 2.53 3.25 3.43

1000BASE-LX Fiber Module

Figure 3-7. 1000BASE-LX two-port module

♦ Front-panel module.

♦ Connects to 1000BASE-LX devices at full duplex.

♦ Supports multi-mode fiber-optic cable connections of up to 550 meters or 5 km single-mode fiber-

optic cable connections.

DES-3326 Layer 3 Fast Ethernet Switch User’s Guide

GBIC Two-Port Module

Figure 3-8. GBIC two-port module

♦ Front-panel module.

♦ Connects to GBIC devices at full duplex only.

♦ Allows multi-mode fiber optic connections of up to 550 m (SX and LX) and single-mode fiber optic

connections of up to 5 km (LX only). GBIC modules are available in –SX and –LX fiber optic media.

LED Indicators

The LED indicators of the Switch include Power, Console, and Link/Act. The following shows the LED indicators for the Switch along with an explanation of each indicator.

Figure 3-9. The LED indicators

♦ Power This indicator on the front panel should be lit 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.

♦ 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.

♦ Link/Act These indicators are located to the left and right of each port. They are lit when there is

a secure connection (or link) to a device at any of the ports. The LEDs blink whenever there is reception or transmission (i.e. Activity--Act) of data occurring at a port.

DES-3326 Layer 3 Fast Ethernet Switch User’s Guide

CONNECTING THE SWITCH

This chapter describes how to connect the DES 3326 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 5e UTP or STP cabling for 100 Mbps Fast Ethernet connections). The end node should be connected to any of the twenty-three ports (2x - 24x) of the DES-3326 or to either of the two 100BASE-TX ports on the front-panel module that came preinstalled on the switch. Port 1x can be used as an uplink port to connect to another switch using either a crossed or a straight-through cable. This port is switched between MDI-X and MDI-II to accommodate either type of cable.

Figure 4-1. Switch connected to an End Node

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 connections.

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

1. The 100 LED indicator comes ON for a 100 Mbps and stays OFF for 10 Mbps.

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

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 2x, 3x, etc.) and an Uplink (MDI-II) port. If you are using a crossover cable, the connection must be made from Uplink to Uplink (port 1x on the DES-3326), or from a crossed port to another crossed port.

DES-3326 Layer 3 Fast Ethernet Switch User’s Guide

♦ 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 5e 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 optional Gigabit module ports) using a normal straight-through cable, as shown below.

If the other device does not have an unused Uplink port, make the connection with a normal straightthrough cable from the Uplink port 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.

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

cable

10BASE-T Device

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

♦ 100 LED speed indicator is OFF.

♦ Link/Act indicator is ON.

100BASE-TX Device

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

♦ 100 LED speed indicator is ON.

♦ Link/Act is ON.

DES-3326 Layer 3 Fast Ethernet Switch User’s Guide

SWITCH MANAGEMENT AND OPERATING

CONCEPTS

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

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

Local Console Management

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

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

The DES-3326 contains a CPU, memory for data storage, flash memory for configuration data, operational programs, and SNMP agent firmware. These components allow the switch to be actively managed and monitored from either the console port or the network itself (out-of-band, or in-band).

Diagnostic (console) port (RS-232 DCE)

Out-of-band management requires connecting a terminal, such as a VT-100 or a PC running a terminal emulation program (such as HyperTerminal, which is automatically installed with Microsoft Windows) a to the RS-232 DCE console port of the Switch. Switch management using the RS-232 DCE console port is called Local Console Management to differentiate it from management performed via management platforms, such as D-View, HP OpenView, etc. Web-based Management describes management of the switch performed over the network (in-band) using the switch’s built-in Web-based management program (see Chapter 7, “Web-based Network Management”). The operations to be performed and the facilities provided by these two built-in programs are identical.

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

• Baud rate: 9,600

• Data width: 8 bits

• Parity: none

• Stop bits: 1

DES-3326 Layer 3 Fast Ethernet Switch User’s Guide

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

IP Addresses and SNMP Community Names

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

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

Figure 5-1. Boot screen

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

Figure 5-2. Switch Information screen

DES-3326 Layer 3 Fast Ethernet Switch User’s Guide

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

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

Traps

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

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

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

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

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

• Cold Start This trap signifies that the Switch has been powered up and initialized such that software settings are reconfigured and hardware systems are rebooted. A cold start is different from a factory reset in that configuration settings saved to non-volatile RAM used to reconfigure the switch.

• 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 string. The switch automatically stores the source IP address of the unauthorized user.

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

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

• Link Up This trap is sent whenever the link of a port changes from link down to link up.

• Link Down This trap is sent whenever the link of a port changes from link up to link down.

DES-3326 Layer 3 Fast Ethernet Switch User’s Guide

SNMP

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

SNMP performs the following functions:

• Sending and receiving SNMP packets through the IP protocol.

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

• Modifying the configuration of network devices.

The DES-3326 has a software program called an ‘agent’ that processes SNMP requests, but the user program that makes the requests and collects the responses runs on a management station (a designated computer on the network). The SNMP agent and the user program both use the UDP/IP protocol to exchange packets.

Authentication

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

Traps

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

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

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

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

DES-3326 Layer 3 Fast Ethernet Switch User’s Guide

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

• 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\Multicast Storm This trap is sent whenever the port reaches the threshold (in packets per second) set globally for the switch. Counters are maintained for each port, and separate counters are maintained for broadcast and multicast packets. The switch’s default setting is 128 kpps for both broadcast and multicast packets.

MIBs

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

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

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

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

Packet Forwarding

The Switch enters the relationship between destination MAC or IP addresses and the Ethernet port or gateway router the destination resides on into its forwarding table. This information is then used to forward packets. This reduces the traffic congestion on the network, because packets, instead of being

DES-3326 Layer 3 Fast Ethernet Switch User’s Guide

transmitted to all ports, are transmitted to the destination port only. Example: if Port 1 receives a packet destined for a station on Port 2, the Switch transmits that packet through Port 2 only, and transmits nothing through the other ports. This process is referred to as ‘learning’ the network topology.

MAC Address Aging Time

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

The aging time can be from 10 to 1,000,000 seconds with a default value of 300 seconds. A very long aging time can result in dynamic forwarding table entries that are out-of-date or no longer exist. This may cause incorrect packet forwarding decisions by the switch.

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

Static forwarding entries are not affected by the aging time.

Filtering

The switch uses a filtering database to segment the network and control communication between segments. It can also filter packets off the network for intrusion control. Static filtering entries can be made by either MAC address or IP address 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 or an IP Address entered into the filter table, the switch will discard the packet.

Some filtering is done automatically by the switch:

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

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

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

Some filtering requires the manual entry of information into a filtering table:

• MAC address filtering – the manual entry of specific MAC addresses to be filtered from the network. Packets sent from one manually entered MAC address can be filtered from the network. The entry may be specified as a source, a destination, or both.

• IP address filtering – the manual entry of specific IP addresses to be filtered from the network (switch must be in IP Routing mode). Packets sent from one manually entered IP address to

DES-3326 Layer 3 Fast Ethernet Switch User’s Guide

another can be filtered from the network. The entry may specified as a source, a destination, or both (switch must be in IP Routing mode).

Spanning Tree

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

The DES-3326 STP allows two levels of spanning trees to be configured. The first level constructs a spanning tree on the links between switches. This is referred to as the Switch or Global level. The second level is on a port group basis. Groups of ports are configured as being members of a spanning tree and the algorithm and protocol are applied to the group of ports. This is referred to as the Port or VLAN level.

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

On the port level, STP sets the Root Port and the Designated Ports.

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

meter Description Default

Value

Bridge Identifier

(Not userconfigurable except by setting priority below)

Priority A relative priority for each

Hello Time The length of time between

A combination of the Userset priority and the switch’s MAC address. The Bridge Identifier consists of two parts: a 16-bit priority and a 48-bit Ethernet MAC address

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

broadcasts of the hello message by the switch

32768 + MAC

32768

2 seconds

Maximum Age Timer

Forward Delay Timer

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

The amount time spent by a port in the learning and listenin

states waiting for a

20 seconds

15 seconds

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