Digital Equipment EtherWORKS Switch 8T/TX Operating and maintenance instructions

EtherWORKS Switch 8T/TX
Installation and Configuration
Part Number: EK–DEL8X–IN. A01
This guide describes how to install and configure the EtherWORKS
Switch 8T/TX.
Revision/Update Information: This is a new guide.
Digital Equipment Corporation
Maynard, Massachusetts

October 1996
Digital Equipment Corporation makes no representations that the use of its products in the manner described in this
publication will not infringe on existing or future patent rights, nor do the descriptions contained in this publication
imply the granting of licenses to make, use, or sell equipment or software in accordance with the description.
Possession, use, or copying of the software described in this publication is authorized only pursuant to a valid written
license from Digital or an authorized sublicensor.
© Digital Equipment Corporation 1996. All rights reserved.
The following are trademarks of Digital Equipment Corporation: DEC, DECnet, Digital, UNIX, EtherWORKS,
OpenVMS, PATHWORKS, ThinWire, and the DIGITAL logo.
IBM is a registered trademark of International Business Machines Corporation.
IEEE is a registered trademark of the Institute of Electrical and Electronics Engineers, Inc.
Intel is a registered trademark of Intel Corporation.
NetWare is a registered trademark of Novell, Inc.
Xerox is a registered trademark of Xerox Corporation.
All other trademarks and registered trademarks are the property of their respective holders.
FCC Class A Certification
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 in a commercial
environment. This equipment generates, uses, and can radiate radio frequency energy and, if not installed and used in
accordance with the instruction manual, may cause harmful interference to radio communications.
Any changes or modifications made to this equipment may void the user’s authority to operate this equipment.
Operation of this equipment in a residential area may cause interference in which case the user at his own expense will
be required to take whatever measures may be required to correct the interference.
VCCI Class I Compliance
( V C C I )
This product complies with CISPR 22 Class A, UL, and is eligible to bear the CE Mark label.

iii
Contents
Before You Start
About This Guide.....................................................................................................................vii
Package Contents .....................................................................................................................vii
Quick Installation......................................................................................................................ix
1 Introduction
Overview of Switching Technology........................................................................................ 1–1
EtherWORKS Switch 8TX..................................................................................................... 1–2
Full–Duplex Mode............................................................................................................. 1–2
Fast Ethernet...................................................................................................................... 1–3
Switching Methods................................................................................................................. 1–3
Cut–Through Switching..................................................................................................... 1–3
Fragment–Free Cut–Through Switching............................................................................. 1–4
Store–and–Forward Switching ........................................................................................... 1–4
Adaptive Cut–Through Switching...................................................................................... 1–4
Features.................................................................................................................................. 1–4
2 Hardware Description
Overview................................................................................................................................ 2–1
Front Panel............................................................................................................................. 2–1
Configure Button ............................................................................................................... 2–2
LEDs ................................................................................................................................. 2–3
Power LED........................................................................................................................ 2–3
Port Status Display Mode (Status) .......................................................................................... 2–3
Collision Ratio (Collision%).............................................................................................. 2–4
Port Speed (100TX)........................................................................................................... 2–5

iv
Transmit and Receive Status (TX/RX)................................................................................2–5
Full ² Duplex Status (Full Duplex) .......................................................................................2–6
Select/Link Status (Select/Link)..........................................................................................2–6
Statistical Display for System Performance.............................................................................2–7
Port Utilization Rate (Util%) ..............................................................................................2–7
Port Forwarding Ratio (Forward%).....................................................................................2–8
Port Filtering Ratio (Filter%)..............................................................................................2–8
Demonstration Display Mode (Demo).....................................................................................2–8
Diagnostics Display Mode (DIAG)..........................................................................................2–9
System Diagnostic Test.......................................................................................................2–9
Port Diagnostic Test..........................................................................................................2–10
Setting the Communication Mode (Full/Half)........................................................................2–10
Setting Autonegotiation ....................................................................................................2–11
Ethernet Ports........................................................................................................................2–11
Station Ports .....................................................................................................................2–12
Daisy–Chain Port..............................................................................................................2–12
Power Socket.........................................................................................................................2–12
3 Hardware Installation
Overview.................................................................................................................................3–1
Preinstallation Requirements...................................................................................................3–1
Hardware Installation ..............................................................................................................3–2
Stacking the DEL8X Without a Rack..................................................................................3–2
Mounting the DEL8X in a Rack..........................................................................................3–3
Connecting the DEL8X System...............................................................................................3–3
Connecting to a PC, Server, or Workstation........................................................................3–3
Connecting to Another Network Device..............................................................................3–4
Providing Power to the DEL8X...............................................................................................3–5
Verifying System Operation....................................................................................................3–6
4 Setup and Configuration
Overview.................................................................................................................................4–1
Diagnostic Tests......................................................................................................................4–1
Setting the Display Mode ........................................................................................................4–2
Port Status Display..............................................................................................................4–2
Bandwidth Utilization.........................................................................................................4–2
Packet Forwarding Ratio.....................................................................................................4–2
Packet Filtering Ratio .........................................................................................................4–2
Demonstration Function......................................................................................................4–2
Diagnostic Function............................................................................................................4–3

v
Communication Mode........................................................................................................ 4–3
Verifying Port Status .............................................................................................................. 4–4
5 Applications
Overview................................................................................................................................ 5–1
DEL8X Functions.............................................................................................................. 5–1
Collapsed Backbone for Starter Network................................................................................ 5–2
Multiport Bridge with High
²
Bandwidth Backbone................................................................. 5–3
High
²
Bandwidth File Server.................................................................................................. 5–4
High
²
Speed Link Between Switches...................................................................................... 5–5
A Troubleshooting
Overview................................................................................................................................A–1
Diagnosing DEL8X LEDs......................................................................................................A–1
System Diagnostics.................................................................................................................A–2
Power and Cooling Problems .............................................................................................A–2
Installation.........................................................................................................................A–2
Transmission Mode............................................................................................................A–2
Cabling..............................................................................................................................A–3
External Adapters ..............................................................................................................A–3
Configuration.....................................................................................................................A–3
DEL8X Integrity................................................................................................................A–3
B General Information
Overview................................................................................................................................B–1
Physical Description...............................................................................................................B–1
Conformance..........................................................................................................................B–1
Operating Environment Specifications....................................................................................B–2
Bridging Criteria ....................................................................................................................B–2
Acoustical Specifications........................................................................................................B–3
Safety Compliance .................................................................................................................B–4
Connector Pin Assignments....................................................................................................B–5
8–Pin MJ Port ....................................................................................................................B–5
Other Digital Network Adapter Products ................................................................................B–6
Ordering Information..............................................................................................................B–7

vi
C Limitations of Shared Ethernet
Single Collision Domain ........................................................................................................C–1
Failure of Alternate Solutions.................................................................................................C–2
Glossary

vii
Before You Start
About This Guide
This guide is designed for the experienced network installer. It describes how to install and
configure Digital’s EtherWORKS Switch 8T/TX (also referred to as the DEL8X or switch).
Package Contents
The EtherWORKS Switch 8T/TX package contains the items in the following list and
shown in the following figure.

viii
• The EtherWORKS Switch 8T/TX 
• An ac power cord 
• This installation and configuration guide 
• Four rubber feet 
• Rackmount brackets and screws 
LJ-5447.AI4
2
1
34
EtherWORKS Switch 8TTX
Configure
Power
Util%
Forward%
Filter%
Demo
Full/Half
Diag
Ethernet
Status
%
Collision%
30 +
20
10
5
1
100TX
TX/RX
Full Duplex
Select/Link
90+
70
50
35
20
10
5
1
%
1238
7
6
5
4
1X 2X 3X
4X 5X 6X 7X 8X 8//
or
10M/100M
Link
5

ix
Quick Installation
The EtherWORKS Switch 8T/TX contains eight 8 ² pin MJ Ethernet ports, each of which
supports 10Base ² T or 100Base ² TX connections. The transmission speed (10 Mb/s or 100
Mb/s) is detected by autosensing for any device attached to the hub. The transmission mode
(full ² and half ² duplex) is set by autonegotiation if supported by the attached device;
otherwise, the mode can be set manually using the Configure button. The smart design
built into the front display panel and configuration options provides a friendly interface that
simplifies installation and network troubleshooting.
Use the following procedure to install the DEL8X:
1. Unpack the DEL8X.
2. Choose a location close to the network device you need to connect, and within easy
reach of an electrical outlet.
3. Install the DEL8X on a desktop or mount it in a rack.
4. Connect PCs, servers, or workstations to the 8 ² pin MJ crossover ² wired (x) ports on the
DEL8X. These ports use autosensing to dynamically set the transmission speed at 10
Mb/s or 100 Mb/s. The transmission mode is dynamically set to half ² or full ² duplex
mode if the connected device supports autonegotiation (see the Full ² Duplex Mode
section in Chapter 1 and the Full ² Duplex Status section in Chapter 2 for more
information).
5. Connect to another switch or compatible hub using the straight ² wired (8//) daisy ²
chain port on the DEL8X to a standard crossover ² wired (x) port on the other device.
You may also use the DEL8X as a collapsed backbone for small networks or connect to
a network interconnection device using one of the 8 ² pin MJ ports. (Refer to Chapter 5
for sample applications.)
6. Verify network communications by ensuring the following:
• You have made all the necessary connections.
• You can access any connected resources.
• The DEL8X LEDs are functioning properly.
If you encounter any problems installing the DEL8X, refer to Chapter 3 for a detailed
description of installation procedures, or to Appendix A for troubleshooting help.

1–1
1
Introduction
Overview of Switching Technology
The Ethernet switch allows simultaneous transmission of multiple packets using an internal
high–speed data channel. This means that it can partition a network more efficiently than
bridges or routers in most environments. Therefore, the Ethernet switch is recognized as
one of the most important building blocks for today’s networking technology. See
Appendix C for information about the limitations of shared Ethernet.
The learning function in the switch stores the address and corresponding port number of
each incoming and outgoing packet in a routing table. This information is subsequently
used to filter packets whose destination address is on the same segment as the source
address. Network traffic is thereby confined to its respective domain, reducing the overall
load on the network.
The switch scans the destination address from the packet header, searches the routing table
provided for the incoming port, then forwards the packet only if required, often before fully
received. This fast forwarding makes the switch attractive for connecting servers directly to
the network, thereby increasing throughput and availability. However, the switch is most
commonly used to segment existing hubs, which usually improves overall performance. A
switching hub can be easily configured in any Ethernet network to significantly boost
bandwidth using conventional cabling and adapters.

Introduction
1–2
EtherWORKS Switch 8T/TX
The DEL8X can boost network bandwidth well beyond that of conventional shared
Ethernet. For example, when running all ports at 100 Mb/s under full–duplex mode, the
bandwidth increases to 1.6 Gb/s. It provides eight 8–pin MJ station ports for attachment to
standard Ethernet (10Base–T) or Fast Ethernet (100Base–TX) at half– or full–duplex
mode. The transmission speed for each port is automatically detected by the switch. The
transmission mode can be set by the switch using autonegotiation if the attached device also
supports this feature. Ports can be automatically configured to match the maximum
capabilities of the attached device.
When connected to a shared collision domain (such as a repeater hub or multiple
workstations), the DEL8X ports operate at half–duplex mode. However, when using a
dedicated link, the DEL8X ports can be set at full–duplex mode to maximize throughput,
allowing multiple conversations to take place simultaneously. This ensures high
throughput, even under heavy network loading.
As a device functioning on the media access control (MAC) layer, the DEL8X is protocol
independent, and therefore compatible with IEEE 802.3, IEEE 802.3u, TCP/IP, NetWare,
DECnet, and XNS protocols. The DEL8X can be configured as a standalone device to form
a work group consisting of two to eight subnetworks or workstations, it can function as a
collapsed backbone for a local area network (LAN), or it can serve as a multiport bridge.
With its low port–to–port latency and extremely high–forwarding efficiency, the DEL8X
can also be connected to other switches or compatible hubs. Moreover, where traditional
100Base–TX networks based on repeater technology restrict the maximum distance
between end nodes to 205 meters, the DEL8X divides your network into smaller and more
manageable segments, each linked to the larger network with a switch. This enables
unlimited maximum distance for communications between end nodes.
Full–Duplex Mode
When performance bottlenecks are caused by congestion at the network access point (such
as the network adapter for a high–volume file server), it may be necessary to segment the
network down to a point where a single node is attached to a switch port thereby forming a
dedicated segment. For dedicated links, using full–duplex mode can immediately double
network throughput.

Introduction
1–3
Full–duplex mode uses two independent data paths for simultaneous transmission in both
directions. These independent, parallel full–duplex paths are extended throughout the
entire switching fabric, which allows connections to be made from both halves of a full–
duplex connection to two separate half–duplex ports. In addition to autosensing the
transmission speed of the connected device (at 10 Mb/s or 100 Mb/s), the DEL8X can
autonegotiate its transmission mode at half– or full–duplex mode if the connected device
also supports this function. (See the Communication Mode section in Chapter 4 for more
information.)
Fast Ethernet
The DEL8X provides a simple cost–effective method to integrate existing networks with
Fast Ethernet. This switch provides an ideal front–end interface for small to medium
networks. By offering 100 Mb/s full–duplex connections to high–utilization devices such as
departmental servers and high–performance workstations, the DEL8X relieves the
performance bottleneck found on most client–server applications, where many client
stations compete to retrieve data from a few servers.
To install the DEL8X, use your current network infrastructure, including wiring and
network interface cards (NICs). Afterwards, you can configure and monitor the system
using the DEL8X front panel, which includes an extensive array of LEDs for monitoring
the unit's overall condition, as well as the status of each port.
Switching Methods
The DEL8X can simultaneously forward frames among up to eight different shared or
dedicated Ethernet segments. With extensive buffering, it can support connections between
any segment pair, whether 10 Mb/s or 100 Mb/s at half– or full–duplex mode. The fully
parallel internal design allows the DEL8X to easily maintain media speed frame transfer
between multiple port pairs.
The switching methods used by the DEL8X are described in the following sections.
Cut–Through Switching
The DEL8X performs “on–the–fly” cut–through switching, which sends a packet to the
other port according to the destination address scanned from the packet header. This
technique reduces the latency of packet transmission to 20 microseconds or less. Compared
to approximately 800 microseconds for a bridge or 1800 microseconds for a router, both of
which have to store the entire packet before it can be forwarded, the DEL8X can deliver a
quantum improvement to network performance.

Introduction
1–4
Fragment–Free Cut–Through Switching
This method of switching is a more conservative approach to cut–through switching by
waiting until the collision window has elapsed (that is, the first full 64 bytes have been
received) before processing the packet. This guarantees that the collision window for the
incoming frame has elapsed and that the frame will not be jammed by other stations. When
there are many stations on a segment, this method can significantly improve the utilization
of network bandwidth.
Store–and–Forward Switching
Traditional bridges and routers use a safe mode of switching called store–and–forward in
which the entire frame must be received before the bridge can perform a table lookup for
the destination node and forward the packet to the corresponding port. As a result, each
packet is delayed by approximately 800 microseconds. It may be necessary to use this
method of switching when many data errors are occurring over the network, or when
connecting to very slow devices.
Adaptive Cut–Through Switching
To ensure that you can manage any kind of network load, the DEL8X uses this method of
switching based on its smart algorithm. Adaptive cut–through switching dynamically
changes the way it handles data passing through the DEL8X based on the current CRC
error rate. These switching alternatives start with standard cut–through switching for a
clean data environment, change to fragment–free cut–through switching for a moderate
error rate, then progress to store–and–forward switching for a highly contentious
environment. By using this method, the DEL8X delivers the best networking performance
under any environment.
Features
The main features of the DEL8X are as follows:
• Eight independent 8–pin MJ 10 Mb/s or 100 Mb/s Ethernet ports
• Port 8 consists of one crossover–wired (x) port for connecting to PCs,
workstations, servers, bridges, and routers or one straight–wired port (//) for a
cascaded connection to another switch or compatible hub, thereby eliminating
the need for crossover cables
• Autosenses transmission speed (10/100 Mb/s)
• Autonegotiates transmission mode (half– or full–duplex) if supported by the
attached device
• Supports both full–duplex and half–duplex operation for all ports
• Total bandwidth of up to 1.6 Gb/s

Introduction
1–5
• Uses “on the fly” cut–through switching technique to transport packets
• Minimum latency of packet transmission (leading edge to leading edge) of
less than 20 microseconds when using cut–through switching
• Supports transparent bridging function
• Provides a 256 KB buffer for each port
• Routing table contains 4K entries per port to store MAC address for attached network
nodes
• Automatically learns MAC addresses to build the routing information database
• Uses a fast hashing scheme to retrieve information from the routing table when
making routing decisions
• Provides frame filtering and forwarding functions for each port, which are capable of
filtering and forwarding Ethernet packets at line speed
• Nonblocking crossbar switching matrix allows concurrent operation of up to eight
Ethernet segments
• Uses back pressure to eliminate frame loss by blocking traffic from end stations or
segments connected directly to the DEL8X when its buffers fill
• A LED indicator panel for monitoring the overall condition of the DEL8X, including
utilization rate and collision
• Port network status equalizer display
• Conforms to the IEEE 802.3 and IEEE 802.3u specifications (10Base–Tand 100Base–TX
standards)
• Basic configuration can be performed using the Configure button (plug and play)
• Automatic polarity detection and correction permits automatic adjustment for wiring
errors
• Transparent to all higher level protocols
• Provides self–diagnostics
• Flexible installation for the desktop or rackmount

2–1
2
Hardware Description
Overview
This chapter describes the hardware features of the EtherWORKS Switch 8T/TX. For
easier management of the switch, familiarize yourself with the front panel display LEDs,
Configure button, and ports shown in the following illustrations and described in the
following sections.
Front Panel
The front panel on the DEL8X (shown in the following figure) provides a simple interface
for configuring or monitoring network connections. It includes a Configure button  ,
power LED  , display mode LEDs  , statistical display mode LEDs  , and eight station
ports  .
25
1X 2X 3X 4X 5X 6X 7X 8X or 8//
10M/100M
1
12345678
EtherWORKS Switch 8TTX
Ethernet
Configure
Power
Status
Util%
Forward%
Filter%
Demo
Diag
Full/Half
35
50
70
90+
%
1
Link
5
10
20
%Full Duplex
TX/RX
1
5
10
20
30+
Collision%
100TX
Select/Link
LJ-5449.AI4
4
3

Hardware Description
2–2
Configure Button
The Configure button, located on the left of the front panel (  in the previous and next
figures), is used to select the following configuration functions:
• Port status (displays the status of ports during normal operation)
• System performance (displays the relative bandwidth utilization rate, forwarding
ratio, or filtering ratio for each port)
• Demonstration (verifies that all LEDs are functioning properly)
• Diagnostics (tests the status of various system components)
• Full– and half–duplex mode (sets port communication to full–duplex or half–
duplex operation)
To set system performance or diagnostic mode, use the following procedures:
_____________________________ Note________________________________
The term “long press” means to press the Configure button for more than 2
seconds, then release it. The term “short press” means to press the Configure
button, then immediately release it. If the Configure button is not pressed within
10 seconds, the system returns to normal operation.
____________________________________________________________
1. To start the configuration, use a long press on the Configure button. The LEDs
will light to show the selected configuration function. (Refer to the related sections
in this chapter and in Chapter 4 for complete details.)
2. To scan through the configuration functions,use a short press on the Configure
button. (Refer to the Communication Mode section in Chapter 4 for information
on how to select full– and half–duplex communications.)
3. To accept and implement the current settings, use a long press on the Configure
button.

Hardware Description
2–3
LEDs The LEDs shown in the following figure indicate:
• The unit is receiving power 
• The current display mode 
• The statistical display for system performance 
• The demonstration, diagnostics, and full
²
and half
²
duplex display modes 
LJ-5448.AI4
Ethernet
Configure
Power
Status
Util%
Forward%
Filter%
Demo
Diag
Full/Half
%
14 2 3 5
Power LED
The power LED indicates the conditions described in the following table:
LED Activity Condition Indication
Blinking light ON Unit is receiving power
No light OFF Power is disconnected, no power received
Port Status Display Mode (Status)
The port status display LED (  in the previous figure) shows the port status for the
DEL8X.
When this LED lights (see the following table), the port status display LEDs (shown in the
next figure) provide the information described in the following sections.

Hardware Description
2–4
LED Activity Condition Indication
Steady light ON Port status display mode is active
No light OFF Port status display is inactive
12345678
35
50
70
90+
%
1
Link
5
10
20
Full Duplex
TX/RX
1
5
10
20
30+
Collision%
100TX
Select/Link
LJ-5450.AI4
Collision Ratio (Collision%)
For half
² duplex transmission, collisions occur when two or more devices connected to a
DEL8X attempt to transmit data simultaneously on the network. When a collision occurs,
the devices pause, then retransmit after a pseudo ² random wait period. Because wait periods
differ among devices, successive collisions become increasingly improbable. For full ²
duplex transmissions, no collisions occur because the port serves as a dedicated link for the
attached device.
The collision LEDs assist the network manager in monitoring the percentage of packet
collisions occurring relative to the total packets transmitted by each port. The collision
LEDs are labeled by row to indicate the percentage of collisions encountered by the
corresponding port. When collisions reach a level marked on the LED display, the
corresponding LED lights. For example, if packet collision reaches 1%, the LED labeled
1% will light. However, if collisions go beyond 30%, the LED labeled 30% and all the
other LEDs before it (1, 5, 10, and 20) also light in rapid succession (see the previous
figure and the following table).
Label% Color
30% Red
20% Amber
10% Amber
5% Green
1% Green

Hardware Description
2–5
__________________________ Note_____________________________
If any port displays a high collision rate, check to see if any of the connected
devices are malfunctioning or if a loop has been formed in your network
connections. Otherwise, you may need to reconfigure your network to balance the
traffic load.
____________________________________________________________
Port Speed (100TX)
All DEL8X ports can operate at either 10 Mb/s or 100 Mb/s. Network access speed is
automatically sensed by the system and displayed by this LED (see the following table):
LED Activity Condition Indication
No light OFF Port is set at 10 Mb/s
Steady light ON Port is set at 100 Mb/s
__________________________ Note_____________________________
The DEL8X can detect transmission speed even if the attached device does not
support autonegotiation.
____________________________________________________________
Transmit and Receive Status (TX/RX)
The following table describes the transmit and receive status LEDs when traffic is
traversing the port:
LED Activity Condition Indication
Blinking light ON Port is transmitting or receiving packets; frequency
of blinking is proportional to the traffic passing
through the port
No light OFF No packets are traversing this port

Hardware Description
2–6
Full
²
²
Duplex Status (Full Duplex)
The following table describes the full ² duplex status LEDs when communications have been
set to this mode for the indicated port:
LED Activity Condition Indication
Steady light ON Port is set for full
² duplex operation
No light OFF Port is set for half ² duplex operation
Select/Link Status (Select/Link)
The following table describes the Select/Link status LEDs during a valid network
connection associated with the port:
LED Activity Condition Indication
Steady light ON Valid link has been established on this port
No light OFF No valid link has been established on this port
__________________________ Note _____________________________
If the Select/Link LED does not light when a device is connected to its
corresponding port, make sure that both the DEL8X and the connected device
are powered on. Verify that the cable length (standard, straight–through cable)
does not exceed 100 meters. Use crossover cables only if no crossover
²
wired (x)
port is available to cascade switches.
____________________________________________________________