Allied Telesis AT-GS905 User manual

Gigabit
Ethernet
Switch
AT-GS905

Installation
Guide
®
PN 613-50532-00 Rev A

Copyright ©2004 Allied Telesyn, Inc.
960 Stewart Drive Suite B, Sunnyvale, CA 94085 USA
All rights reserved. No part of this publication may be reproduced without prior written permission from Allied Telesyn, Inc.
All other product names, company names, logos or other designations mentioned herein are trademarks or registered trademarks
of their respective owners.
Allied Telesyn, Inc. reserves the right to make changes in specifications and other information contained in this document without
prior written notice. The information provided herein is subject to change without notice. In no event shall Allied Telesyn, Inc. be
liable for any incidental, special, indirect, or consequential damages whatsoever, including but not limited to lost profits, arising
out of or related to this manual or the information contained herein, even if Allied Telesyn, Inc. has been advised of, known, or
should have known, the possibility of such damages.

3
Electrical Safety and Emission
Statement
Standards: This product meets the following standards.
RFI Emission FCC Class B, EN55022 Class B, VCCI Class B, C-TICK 1
Warning: In a domestic environment this product may cause radio interference in which case the user may be
required to take adequate measures. 2
Immunity EN55024 3
Electrical Safety EN60950 (TUV), UL60950 (cULus), CE 4
Important: Appendix Bcontains translated safety statements for installing this equipment. When you see the , go
to Appendix B for the translated safety statement in your language.
Wichtig: Anhang Benthält übersetzte Sicherheitshinweise für die Installation dieses Geräts. Wenn Sie sehen,
schlagen Sie in Anhang B den übersetzten Sicherheitshinweis in Ihrer Sprache nach.
Vigtigt: Tillæg B indeholder oversatte sikkerhedsadvarsler, der vedrører installation af dette udstyr. Når De ser
symbolet , skal De slå op i tillæg B og finde de oversatte sikkerhedsadvarsler i Deres eget sprog.
Belangrijk: Appendix B bevat vertaalde veiligheidsopmerkingen voor het installeren van deze apparatuur. Wanneer
u de ziet, raadpleeg Appendix B voor vertaalde veiligheidsinstructies in uw taal.
Important: L'annexe B contient les instructions de sécurité relatives à l'installation de cet équipement. Lorsque vous
voyez le symbole , reportez-vous à l'annexe B pour consulter la traduction de ces instructions dans votre langue.
U.S. Federal Communications Commission
Declaration Of Conformity
Manufacturer Name: Allied Telesyn, Inc.
Manufacturer Address: 960 Stewart Drive, Suite B
Sunnyvale, CA 94085 USA
Manufacturer Telephone: [phone]
Declares that the product: Gigabit Ethernet Switch
Model Numbers: AT-GS905
This product complies with FCC Part 15B, Class B Limits:
This device complies with part 15 of the FCC Rules. Operation is subject to the following two conditions: (1) This
device must not cause harmful interference, and (2) this device must accept any interference received, including
interference that may cause undesired operation.
Radiated Energy
Note: This equipment has been tested and found to comply with the limits for a Class B digital device pursuant to
Part 15 of FCC Rules. These limits are designed to provide reasonable protection against harmful interference in a
residential installation. This equipment generates, uses and can radiate radio frequency energy and, if not
installed and used in accordance with instructions, may cause harmful interference to radio or television
reception, which can be determined by turning the equipment off and on. The user is encouraged to try to
correct the interference by one or more of the following measures:
- Reorient or relocate the receiving antenna.
- Increase the separation between the equipment and the receiver.
- Connect the equipment into an outlet on a circuit different from that to which the receiver is connected.
- Consult the dealer or an experienced radio/TV technician for help.
Changes and modifications not expressly approved by the manufacturer or registrant of this equipment can void
your authority to operate this equipment under Federal Communications Commission rules.
Canadian Department of Communications
This Class B digital apparatus meets all requirements of the Canadian Interference-Causing Equipment
Regulations.
Cet appareil numérique de la classe B respecte toutes les exigences du Règlement sur le matériel brouilleur du
Canada.

Electrical Safety and Emission Statement
4
Tärkeää: Liite B sisältää tämän laitteen asentamiseen liittyvät käännetyt turvaohjeet. Kun näet -symbolin, katso
käännettyä turvaohjetta liitteestä B.
Importante: l’Appendice B contiene avvisi di sicurezza tradotti per l’installazione di questa apparecchiatura. Il
simbolo , indica di consultare l’Appendice B per l’avviso di sicurezza nella propria lingua.
Viktig: Tillegg B inneholder oversatt sikkerhetsinformasjon for installering av dette utstyret. Når du ser , åpner du
til Tillegg C for å finne den oversatte sikkerhetsinformasjonen på ønsket språk.
Importante: O Anexo B contém advertências de segurança traduzidas para instalar este equipamento. Quando vir o
símbolo , leia a advertência de segurança traduzida no seu idioma no Anexo B.
Importante: El Apéndice B contiene mensajes de seguridad traducidos para la instalación de este equipo. Cuando
vea el símbolo , vaya al Apéndice B para ver el mensaje de seguridad traducido a su idioma.
Obs! Bilaga B innehåller översatta säkerhetsmeddelanden avseende installationen av denna utrustning. När du ser
, skall du gå till Bilaga B för att läsa det översatta säkerhetsmeddelandet på ditt språk.

5
Table of Contents
Electrical Safety and Emission Statement ...............................................................................................................................................3
Preface ......................................................................................................................................................................................................................7
How This Guide is Organized ............................................................................................................................................................................. 7
Document Conventions ......................................................................................................................................................................................8
Contacting Allied Telesyn ...................................................................................................................................................................................9
Online Support............................................................................................................................................................................................... 9
Email and Telephone Support.................................................................................................................................................................. 9
Returning Products....................................................................................................................................................................................... 9
For Sales or Corporate Information ........................................................................................................................................................ 9
Chapter 1
Product Description .........................................................................................................................................................................................10
Features ...................................................................................................................................................................................................................11
Components ..........................................................................................................................................................................................................12
Hardware Feature Description ........................................................................................................................................................................13
Twisted Pair Ports........................................................................................................................................................................................ 13
LEDs.................................................................................................................................................................................................................. 14
AC Power Connector.................................................................................................................................................................................. 15
A Few Ethernet Switching Basics ....................................................................................................................................................................16
MAC Address Table..................................................................................................................................................................................... 16
Duplex Mode................................................................................................................................................................................................. 17
Store and Forward....................................................................................................................................................................................... 17
Backpressure and Flow Control ............................................................................................................................................................. 17
Network Topologies ............................................................................................................................................................................................19
Power Workgroup Topology................................................................................................................................................................... 19
Collapsed Backbone................................................................................................................................................................................... 19
Chapter 2
Installation ............................................................................................................................................................................................................21
Reviewing Safety Precautions .........................................................................................................................................................................22
Selecting a Site for the Switch .........................................................................................................................................................................23
Planning the Installation ...................................................................................................................................................................................24
Unpacking the Switch ........................................................................................................................................................................................25
Using the Switch on a Desktop .......................................................................................................................................................................26
Wall- Mounting the Switch ...............................................................................................................................................................................27
Cabling the Switch ...............................................................................................................................................................................................29
Powering On the Switch ....................................................................................................................................................................................30
Warranty Registration .........................................................................................................................................................................................31

6
Chapter 3
Troubleshooting ................................................................................................................................................................................................32
Appendix A
Technical Specifications .................................................................................................................................................................................34
Physical Specifications .......................................................................................................................................................................................34
Environmental Specifications ..........................................................................................................................................................................34
Power Specifications ..........................................................................................................................................................................................34
Safety and Electromagnetic Emissions Certifications .............................................................................................................................35
Connectors .............................................................................................................................................................................................................35
RJ-45 Twisted Pair Port Pinouts ............................................................................................................................................................. 35
Appendix B
Translated Electrical Safety and Emission Information ..................................................................................................................37

7
Preface
This guide contains the hardware installation instructions for the
AT-GS905 Gigabit Ethernet Switch.
How This Guide is Organized
This manual contains the following chapters and appendices:
Chapter 1, Product Description, describes the features and
components of the switches.
Chapter 2, Installation, contains the installation instructions for the
switches.
Chapter 3, Troubleshooting, provides information on how to resolve
problems that might occur with the switches.
Appendix A, Technical Specifications, contains the technical
specifications for the switches.
Appendix B, Translated Electrical Safety and Emission Information,
contains translations of the warnings and cautions in the manual.

Preface
8
Document Conventions
This document uses the following conventions to highlight important
information:
Note
Notes provide additional information.
Warning
Warnings inform you that performing or omitting a specific action may result in
bodily injury.
Caution
Cautions inform you that performing or omitting a specific action may result in
equipment damage or loss of data.

AT-GS905 Gigabit Ethernet Switch Installation Guide
9
Contacting Allied Telesyn
This section provides Allied Telesyn contact information for technical
support as well as sales or corporate information.
Online Support You can request technical support online by accessing the Allied Telesyn
Knowledge Base from the following web site:
http://kb.alliedtelesyn.com. You can use the Knowledge Base to
submit questions to our technical support staff and review answers to
previously asked questions.
Email and
Telephone
Support
For Technical Support via email or telephone, refer to the Support &
Services section of the Allied Telesyn web site:
http://www.alliedtelesyn.com.
Returning
Products
Products for return or repair must first be assigned a Return Materials
Authorization (RMA) number. A product sent to Allied Telesyn without a
RMA number will be returned to the sender at the sender’s expense.
To obtain a RMA number, contact Allied Telesyn’s Technical Support at
our web site: http://www.alliedtelesyn.com.
For Sales or
Corporate
Information
You can contact Allied Telesyn for sales or corporate information at our
web site: http://www.alliedtelesyn.com. To find the contact
information for your country, select “Contact Us”, then “Worldwide
Contacts”.

10
Chapter 1
Product Description
The AT-GS905 Gigabit Ethernet switch is an unmanaged, Layer 2 Gigabit
Ethernet switch designed to simplify the task of creating or expanding
an Ethernet, Fast Ethernet, or Gigabit Ethernet network.
This chapter contains the follows sections:
Features on page 11
Components on page 12
Hardware Feature Description on page 13
A Few Ethernet Switching Basics on page 16
Network Topologies on page 19

AT-GS905 Gigabit Ethernet Switch Installation Guide
11
Features
AT-GS905 Gigabit Ethernet switch features include:
Five 10/100/1000 Mbps twisted pair ports
System and port LEDs
Auto MDI/MDI-X
Auto-Negotiation (IEEE 802.3u-compliant)
10/100 Mbps full or half-duplex, and 1000 Mbps full duplex
Back pressure and flow control (IEEE 802.3x-compliant)
Broadcast storm control
Full wire-speed switching with Head of Line (HOL) blocking
prevention
Support 128K byte packet buffer with the length of packet up to
1522 byte
Support two-way dynamic address learning for 4K MAC addresses

Product Description
12
Components
Figure 1 illustrates the front and back panels of the AT-GS905 switch.
Figure 1 Front and Back Panels
10/100/1000Base Twisted Pair Ports
AT-GS905
10/100/1000 Base-T Gigabit Ethernet Switch
POWER
12345
100M
1000M
LNK/ACT
FDX
23415
100-240VAC
Port LEDs

AT-GS905 Gigabit Ethernet Switch Installation Guide
13
Hardware Feature Description
The following sections describe hardware features of the AT-GS905
Gigabit Ethernet switch:
System and Port LEDs
Twisted Pair Ports
AC Power Connector
Twisted Pair
Ports
The AT-GS905 Gigabit Ethernet switch features five twisted pair ports.
Type of Connector
The twisted pair ports feature 8-pin RJ-45 connectors. (For the port
pinouts, refer to RJ-45 Twisted Pair Port Pinouts on page 35.
Speed
The ports are 10Base-T, 100Base-TX, and 1000Base-T compliant and are
capable of 10 megabits per second (Mbps), 100 Mbps, and 1000 Mbps
speeds. The ports are IEEE 802.3u Auto-Negotiation compliant. With
Auto-Negotiation, the switch automatically matches the highest
possible common speed between each switch port and each end-node.
For example, if an end-node is capable of only 10 Mbps, the switch sets
the port connected to the end-node to 10 Mbps.
Duplex Mode
Each twisted pair port on the switch can operate in either half- or full
duplex mode. The twisted pair ports are IEEE 802.3u-compliant and will
Auto-Negotiate the duplex mode setting.
Note
In order for the switch to set the duplex mode for each port
correctly, the end-nodes that you connect to the switch ports
should also use Auto-Negotiation. Otherwise, a duplex mode
mismatch can occur, affecting network performance. For further
information, refer to Duplex Mode on page 17.
Maximum Distance
Each twisted pair port has a maximum operating distance of 100 m
(328 feet).
Type of Cabling
For 10 Mbps operation, Category 3 or better 100 ohm shielded or
unshielded twisted pair cabling is required. For 100 or 1000 Mbps
operation, Category 5 and Enhanced Category 5 (5E) 100 ohm shielded
or unshielded twisted pair cabling is required.

Product Description
14
Auto-MDI
All five ports feature auto-MDI. They automatically configure themselves
as either MDI or MDI-X. This feature allows you to use either straight-
through or crossover twisted pair cables to connect devices to the ports.
LEDs The port LEDs on the front panel of the AT-GS905 switch display port
status information. Each port has four LEDs.
Figure 2 AT-GS905 Switch Port LEDs
Table 1 describes the AT-GS905 Gigabit Ethernet switch port LEDs.
Table 1 AT-GS905 Switch Port LEDs
LED State Description
POWER Green The switch is powered ON.
OFF The switch is powered OFF.
100M Green The port is operating at 100 Mbps.
1000M Green The port is operating at 1000
Mbps.
OFF When both 100M and 1000M LEDs
are OFF, the port is operating at 10
Mbps.
LNK/ACT Green A valid link has been established
between the port and the end-
node.
Flashing
Green
The port is transmitting and/or
receiving data packets.
OFF There is no link established
between the port and the end-
node.
FDX Green The port is operating in full-duplex
mode.
OFF The port is operating in half-duplex
mode.
POWER
12345
100M
1000M
LNK/ACT
FDX
1

AT-GS905 Gigabit Ethernet Switch Installation Guide
15
AC Power
Connector
AT-GS905 Gigabit Ethernet switch has a single AC power supply socket
on the back panel, which has an autoswitch AC inputs. Refer to
Technical Specifications on page 34, for the input voltage range. To
power ON or OFF the switch, you connect or disconnect the power cord.

Product Description
16
A Few Ethernet Switching Basics
An Ethernet switch interconnects network devices, such as workstations,
printers, routers, and other Ethernet switches, so that they can
communicate with each other by sending and receiving Ethernet
frames.
MAC Address
Table
Every hardware device on your network has a unique MAC address. This
address is assigned to the device by the device’s manufacturer. For
example, when you install a Network Interface Card (NIC) in a computer
so that you can connect it to the network, the NIC already has a MAC
address assigned to it by its manufacturer.
The AT-GS905 Gigabit Ethernet switch can contain up to 4,000 entries on
its MAC address table. The switch uses the table to store the MAC
addresses of the network end-nodes connected to the ports, along with
the port number on which each address was learned.
A switch learns the MAC addresses of the end-nodes by examining the
source address of each packet received on a port. It adds the address
and port on which the packet was received to the MAC table if the
address had not already been entered in the table. The result is a table
that contains all the MAC addresses of the devices that are connected to
the switch’s ports, and the port number where each address was
learned.
When the switch receives a packet, it also examines the destination
address and, by referring to its MAC address table, determines the port
on which the destination end-node is connected. It then forwards the
packet to the appropriate port and on to the end-node. This increases
network bandwidth by limiting each frame to the appropriate port when
the intended end-node is located, freeing the other switch ports for
receiving and transmitting data.
If the switch receives a packet with a destination address that is not in
the MAC address table, it floods the packet to all the ports on the switch.
If the ports have been grouped into virtual LANs, the switch floods the
packet only to those ports which belong to the same VLAN as the port
on which the packet was received. This prevents packets from being
forwarded into inappropriate LAN segments, increasing network
security. When the destination end-node responds, the switch adds its
MAC address and port number to the table.

AT-GS905 Gigabit Ethernet Switch Installation Guide
17
If the switch receives a packet with a destination address that is on the
same port on which the packet was received, it discards the packet
without forwarding it on to any port. Since both the source end-node
and the destination end-node for the packet are located on the same
port on the switch, there is no reason for the switch to forward the
packet.
Duplex Mode Duplex mode refers to how an end-node receives and transmits data. If
an end-node can receive or transmit data, but not both simultaneously,
the end-node is operating in what is referred to as half-duplex mode. If
an end-node can both receive and transmit data simultaneously, the
end-node is said to be operating in full-duplex mode. Naturally, an end-
node capable of operating in full-duplex can handle data much faster
than an end-node that can only operate in half-duplex mode.
The twisted pair ports on the AT-GS905 switch can operate in half- or
full-duplex mode for 10/100 Mbps and full-duplex for 1000 Mbps. They
are IEEE 802.3u-compliant and use Auto-Negotiation to set the duplex
mode setting for you automatically.
Store and
Forward
This Gigabit Ethernet Switch uses store and forward as the method for
receiving and transmitting frames. When a Ethernet frame is received on
a switch port, the switch does not retransmit the frame out the
destination port until it has received the entire frame and stored the
frame in a port buffer. It then examines the frame to determine if it is a
valid frame. Invalid frames, such as fragments or runts, are discarded by
the switch. This insures that only valid frames are transmitted out the
switch ports and that damaged frames are not propagated on your
network.
Backpressure
and Flow
Control
To maintain the orderly movement of data between the end-nodes, an
Ethernet switch may periodically need to signal an end-node to stop
sending data. This can occur under several circumstances. For example,
if two end-nodes are operating at different speeds, the switch, while
transferring data between the end-nodes, might need to instruct the
faster end-node to stop transmitting data to allow the slower end-node
to catch up. An example of this would be when a server operating at 100
Mbps is sending data to a workstation operating at only 10 Mbps.
How a switch signals an end-node to stop transmitting data differs
depending on the duplex mode of the end-node and switch port. A
twisted pair port operating in half-duplex mode stops an end-node from
transmitting data by forcing a collision. A collision on an Ethernet
network occurs when two end-nodes attempt to transmit data using the
same data link at the same time. A collision causes an end-node to stop
sending data, wait for a brief period of time, and then retransmit the
same data. Once the switch is ready to receive data again, the switch
stops forcing collisions. This is referred to as backpressure.

Product Description
18
A port operating in full-duplex mode uses PAUSE frames, as specified in
the IEEE 802.3x standard, to stop the transmission of data from an end-
node. Whenever the switch wants an end-node to stop transmitting
data, it issues this frame. The frame instructs the end-node to cease
transmission for a period of time specified within the frame. The switch
continues to issue PAUSE frames until it is ready again to receive data
from the end-node. This is referred to as flow control.

AT-GS905 Gigabit Ethernet Switch Installation Guide
19
Network Topologies
This section illustrates two network topologies that you can create with
the AT-GS905 Gigabit Ethernet switch: a power workgroup and
collapsed backbone. Both types of topologies are described below.
Power
Workgroup
Topology
The topology shown in Figure 3 is commonly referred to as a power
workgroup topology. Each workstation or end-node is connected
directly to a port on the switch. Each end-node has a dedicated data link
to the switch for best performance and reliability. The devices can
operate at 10 Mbps, 100 Mbps or 1000 Mbps.
Figure 3 Power Workgroup Topology
Collapsed
Backbone
In the topology illustrated in Figure 4, an AT-GS905 switch connects Fast
Ethernet switches that have Gigabit Ethernet uplinks. This type of
topology is often referred to as a collapsed backbone topology. The
switch functions as the focal point of the network and transfers an
Ethernet frame between the Fast Ethernet switches only when the
AT-GS905
10/100/1000 Base-T Gigabit Ethernet Switch
POWER
12345
100M
1000M
LNK/ACT
FDX
23415
Legend
10 Mbps
100 Mbps
AT-GS905 Gigabit Ethernet Switch
1000 Mbps

Product Description
20
destination end-node for the frame is on a different switch than the end-
node that originated the frame. This reduces the amount of unnecessary
data traffic in each workgroup, freeing up bandwidth and improving
network performance.
Figure 4 Collapsed Backbone - Hub Topology
Fast Ethernet
Switches with
AT-GS905 Gigabit Ethernet Switch
Legend
10 Mbps
100 Mbps
1000 Mbps
Gigabit Uplinks
AT-GS905
10/100/1000 Base-T Gigabit Ethernet Switch
POWER
12345
100M
1000M
LNK/ACT
FDX
23415
54321
6
7
8
54321
6
7
8
54321
6
7
8