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Document:	DECrepeater 90FA Owner's Manual
Order Number:	EK-DEFAR-OM
Revision:	B01
Pages:	76
Original Filename:

OCR Text

DECrepeater 90FA
Owner’s Manual
Order Number: EK–DEFAR–OM. B01

Revision/Update Information:

Digital Equipment Corporation
Maynard, Massachusetts

This is a revised manual.

First Edition, September 1992
Second Edition, January 1994
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 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.
Restricted Rights: Use, duplication, or disclosure by the U.S. Government is subject to restrictions
as set forth in subparagraph (c) (1) (ii) of the Rights in Technical Data and Computer Software
clause at DFARS 252.227-7013.
© Digital Equipment Corporation 1992, 1994. All rights reserved.
FCC NOTICE: The equipment described in this manual generates, uses, and may emit radio
frequency energy. The equipment has been type tested and found to comply with the limits for
a Class A computing device pursuant to Subpart J of Part 15 of FCC Rules, which are designed
to provide reasonable protection against such radio frequency interference when operated in a
commercial environment. Operation of this equipment in a residential area may cause interference,
in which case the user at his own expense may be required to take measures to correct the
interference.
The following are trademarks of Digital Equipment Corporation: BI, DEC, DECbridge, DECconnect,
DECmcc, DECnet, DECserver, Digital, LAT, MicroVAX, ThinWire, ULTRIX, UNIBUS, VAX,
VAX–11/780, VAX–11/785, VAX 3600, VAX 3900, VAX 6000, VAX 6300, VAX 6400, VAX 9000,
VAXcluster, VAX DOCUMENT, VAXELN, VAXstation, VMS, VT, and the DIGITAL logo.
ST is a registered trademark of American Telephone & Telegraph Company.
All other trademarks and registered trademarks are the property of their respective holders.

This document was prepared using VAX DOCUMENT Version 2.1.

Contents
About This Manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

vii

1 Overview
Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
LEDs and Connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1–1
1–2

2 Configuring the DECrepeater 90FA
Configuration Rules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Segment Length Constraints . . . . . . . . . . . . . . . . . . . . . . . . . .
Network Constraints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Installed Fiber Constraints . . . . . . . . . . . . . . . . . . . . . . . . . . .

2–1
2–1
2–2
2–5

3 Installation
Site Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Standalone Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Mount the DECrepeater 90FA on a Wall . . . . . . . . . . . . . . . . .
Standalone Installation Connections . . . . . . . . . . . . . . . . . . . .
Backplane Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3–1
3–1
3–2
3–4
3–6

4 Managing the DECrepeater 90FA
Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Components Needed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Accessing MOP from VMS Systems . . . . . . . . . . . . . . . . . . . . . . . .
Accessing a Bridge Repeatedly . . . . . . . . . . . . . . . . . . . . . . . . .
Accessing MOP from ULTRIX Systems . . . . . . . . . . . . . . . . . . . . .
Console Carrier User Interface . . . . . . . . . . . . . . . . . . . . . . . . . . .
Console Carrier Command Language . . . . . . . . . . . . . . . . . . . . . . .
Description of Command Parameters . . . . . . . . . . . . . . . . . . . .
Description of Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4–1
4–1
4–2
4–3
4–3
4–4
4–4
4–6
4–7

iii

Typical Management Techniques . . . . . . . . . . . . . . . . . . . . . . . . . .
Remote Network Management with the DECbridge 90 . . . . . .
Management Disconnect . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Management Session . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Example of a Typical Management Session . . . . . . . . . . . .
If Problems are Reported . . . . . . . . . . . . . . . . . . . . . . . . . .
To Disable a Port . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
To Reset the Repeater . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Error Messages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Standalone Configuration Management . . . . . . . . . . . . . . . . . . . . .

4–13
4–14
4–14
4–15
4–15
4–16
4–17
4–17
4–18
4–20

5 Troubleshooting
Port Partitioning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DECrepeater 90FA Standalone Troubleshooting . . . . . . . . . . . . . .
DECrepeater 90FA Backplane Troubleshooting . . . . . . . . . . . . . . .

5–1
5–3
5–8

A Specifications and Parts List
AUI Connector Pin Assignments . . . . . . . . . . . . . . . . . . . . . . . . . .
Parts List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

A–4
A–5

B Management Details
Designating a Hub Manager . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Annotating the Bridge Address Table . . . . . . . . . . . . . . . . . . . . . .
Using the WGB Address Table for Work Group Management . . . .

B–1
B–2
B–3

C Related Documentation
Ordering Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Continental USA and Puerto Rico . . . . . . . . . . . . . . . . . . . . . .
New Hampshire, Alaska, and Hawaii . . . . . . . . . . . . . . . . . . .
Outside the USA and Puerto Rico . . . . . . . . . . . . . . . . . . . . . .
Digital Personnel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

C–1
C–1
C–1
C–1
C–2

Index
Figures
1–1
2–1
2–2
3–1
3–2
3–3
3–4
4–1
4–2

DECrepeater 90FA LEDs and Connectors . . . . . . . . . .
DECrepeater 90FA Repeater Path . . . . . . . . . . . . . . .
DECrepeater 90FA Typical DEChub 90 Configuration
...........................................
Removing the Back Cover . . . . . . . . . . . . . . . . . . . . . .
Mounting Screws . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Standalone Installation . . . . . . . . . . . . . . . . . . . . . . . .
Installing the DECrepeater 90FA into the DEChub
90 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Sample Configuration . . . . . . . . . . . . . . . . . . . . . . . . .
Typical Network Topology Map . . . . . . . . . . . . . . . . . .

1–2
2–3
2–4
3–2
3–3
3–5
3–7
4–13
4–15

Tables
1–1
2–1
4–1
4–2
4–3
5–1
5–2
5–3
5–4
A–1
A–2
A–3
A–4
A–5
A–6

DECrepeater 90FA LEDs and Connectors . . . . . . . . . .
Segment Lengths . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Ethernet Circuit Names for Systems . . . . . . . . . . . . . .
Summary of DECbridge 90FA Commands . . . . . . . . . .
DECbridge 90 Messages . . . . . . . . . . . . . . . . . . . . . . . .
DECrepeater 90FA Status Indicators . . . . . . . . . . . . . .
DECrepeater 90FA Fiber-Link Indicators . . . . . . . . . .
Troubleshooting a DECrepeater 90FA Standalone
Unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Troubleshooting a DECrepeater 90FA in a DEChub 90
Backplane . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Physical Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . .
Operating Environment . . . . . . . . . . . . . . . . . . . . . . . .
Shipping Environment . . . . . . . . . . . . . . . . . . . . . . . . .
Power Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . .
DECrepeater 90FA Input . . . . . . . . . . . . . . . . . . . . . . .
Parts List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1–3
2–1
4–2
4–5
4–18
5–2
5–2
5–3
5–8
A–1
A–2
A–2
A–3
A–3
A–5

About This Manual
This manual describes how to install, operate, and maintain the DECrepeater 90FA
repeater. The DECrepeater 90FA is a three-port repeater designed to function as
a standalone unit or as a managed unit in a DEChub 90 backplane.
In this manual, the DECrepeater 90FA unit may be referred to as the
DECrepeater 90FA or the repeater.

Organization
This manual contains five chapters and three appendices.
Chapter

Description

Provides an overview of the DECrepeater 90FA and briefly describes
the product’s features.

Describes the configuration rules and conditions of operation for the
DECrepeater 90FA in a ThinWire Ethernet system or fiber-optic
network.

Describes how to install the DECrepeater 90FA.

Describes how to manage the DECrepeater 90FA.

Provides basic troubleshooting information.

Appendix A

Provides the physical dimensions, environmental (operating and
shipping) specifications, electrical specifications, and a parts list.

Appendix B

Provides more detailed information on management issues.

Appendix C

Provides a list of related documentation and ordering information.

vii

Conventions
The following conventions are used in this manual:
Convention

Meaning

Note

Provides general information.
A number in a black circle in text refers to the
corresponding number in an accompanying figure.

[]

In command descriptions, brackets indicate
optional elements.

variables

In command descriptions, italic type indicates a
variable that you supply.

SHOW ADDRESS

In text, commands are shown in all uppercase
letters to differentiate them from regular text. For
VMS operating systems, you can enter commands
in either uppercase or lowercase letters. For
ULTRIX operating systems, commands must be
entered as indicated in the examples.

DECbridge>

Text that the system displays on the screen is
shown in monospaced type.

SHOW REPEATER 1

Text that you enter is shown in bold monospaced
type.

viii

1
Overview
This chapter describes the DECrepeater 90FA repeater and briefly summarizes
the features of this repeater.
The DECrepeater 90FA is a three-port repeater designed for IEEE 802.3 standard
CSMA/CD networks. The DECrepeater 90FA has one ThinWire port, one
fiber-optic port, and one 15-pin AUI port. The ThinWire port complies with the
IEEE 802.3 standard for 10Base2 networks; the fiber-optic port complies with
the IEEE 802.3 standard for 10Base-FL networks; and the AUI port complies
with the IEEE 802.3 standard for Attachment Unit Interfaces. The 10Base-FL
standard allows backward compatibility of the DECrepeater 90FA to Fiber Optic
Inter Repeater Link (FOIRL) compliant products.
The DECrepeater 90FA can operate in a standalone configuration or as
a managed repeater when installed in a DEChub 90 backplane with a
DECbridge 90 series bridge.
When operating as a standalone unit, the DECrepeater 90FA is an unmanaged
repeater with a separate power supply connected to the repeater by a cable with
a 7-pin connector. The auto-ranging power supply is modular and accommodates
either a North American 120-volt or an international 240-volt wall outlet.

Features
The following list summarizes the main features of the DECrepeater 90FA:
•

One ThinWire (10Base2) port

•

One fiber-optic link (10Base-FL) port

•

One 15-pin AUI Ethernet port

•

Standalone or installable in a DEChub 90 backplane

•

Manageable when installed in a DEChub 90 backplane

For detailed information about how to configure the DECrepeater 90FA, see
Chapter 2, Configuring the DECrepeater 90FA. For detailed information about
how to install and use the DECrepeater 90FA, see Chapter 3, Installation.

Overview 1–1

LEDs and Connectors
The front panel of the DECrepeater 90FA contains several indicator lights (LEDs)
and connectors. These LEDs and connectors are described in Table 1–1 and are
shown in Figure 1–1.
Figure 1–1 DECrepeater 90FA LEDs and Connectors
9

1
2
3

4
5
6

11
7
8

10
P J - D1 2 0
RE DUCE . 4 5
O RG

LJ-02371-TI0

1–2 Overview

Table 1–1 DECrepeater 90FA LEDs and Connectors
DC OK monitors the voltage.
On: The +5.0 Vdc and +12.0 Vdc voltage is normal.
Off: The voltage is abnormal (as when a power failure occurs).

Network activity indicator monitors the network activity.
On: There is network activity.
Off: There is no network activity.

Port 0 status indicator monitors the status of port 0.
On: Port 0 is functional.
Off: Port 0 is not functioning or has been partitioned.
Flashing: Port 0 has been partitioned by management.

Port 1 status indicator monitors the status of port 1. See Table 5–1 in
Chapter 5, Troubleshooting, for more information.
On: Port 1 is functional.
Off: Port 1 is not functioning or has been partitioned.
Flashing: Port 1 has been partitioned by management.

Fiber-link status indicator monitors the optical link status of port 1.
See Table 5–2 in Chapter 5, for more information.
On: The link is operational.
Off: The link is not functioning.

Port 2 AUI status indicator monitors the status of port 2.
On: The port is operational.
Off: The port is not functioning.
Flashing: The port has been partitioned by management.

Fiber-optic transmit connector connects to the receive port of the other
fiber-optic device.

Fiber-optic receive connector connects to the transmit port of the other
fiber-optic device.

Port 0 network connector (BNC) connects the repeater to the work
group ThinWire segment. Not used when the repeater is installed in the
DEChub 90 backplane.

Port 2 Backbone Port AUI connector provides AUI connection to the
backbone port of the DECrepeater 90FA.

Power connector receives +5.0 V and +12.0 V from the DECrepeater 90FA
power supply. Not used when the repeater is installed in the DEChub 90
backplane.
Backplane connector provides network and power connections to the
DECrepeater 90FA when it is installed in the DEChub 90 backplane.
Back cover covers the backplane connector and mounting assembly. (Use
with standalone units only.)

Overview 1–3

2
Configuring the DECrepeater 90FA
This chapter contains some of the basic configuration rules and guidelines
that must be followed to correctly install the typical DECrepeater 90FA
configurations. For more detailed information about installing IEEE 802.3
compliant multisegment LANs, refer to Section 13 of the IEEE 802.3i-1990
standard.

Configuration Rules
The two basic constraints in IEEE 802.3 LAN configurations are segment lengths
and the number of repeaters between data terminal equipment (DTE). To ensure
the proper operation of the IEEE 802.3 physical layer and access methodology,
the network size must meet the round trip propagation delay budget.

Segment Length Constraints
Table 2–1 specifies the maximum segment lengths for the four possible types of
media.
Table 2–1 Segment Lengths
Media Type
Mixing (coaxial)
Link

AUI

Maximum Segment Length (Meters)

10Base2 (ThinWire)

185

10Base5

500

10BaseT (twisted-pair)

100

FOIRL (fiber)

1000

10Base-FL (fiber)

2000

Transceiver cable

Configuring the DECrepeater 90FA 2–1

Network Constraints
The overall network is constrained by the following IEEE 802.3 rules:
1. The transmission path between any two DTEs may consist of up to five
segments and four repeater sets (Figure 2–1).
When a network consists of five segments and four repeater sets, a maximum
of three of these segments may be mixing (coaxial) segments.
2. The total of all segments (up to five) shall not exceed 2500 meters.
Figure 2–1 shows an example of the maximum number of repeaters on a path
using coaxial segments and 10Base-FL segments.

2–2 Configuring the DECrepeater 90FA

Figure 2–1 DECrepeater 90FA Repeater Path
DECrepeater 90FL

Fiber-Optic Link
Segment 500 m

Fiber-Optic Link
Segment 500 m
DECrepeater 90FA

Coax
10Base5
Segment
500 m

DECrepeater 90FA

AUI

10Base-FL
Link Segment
100 m
MAU
AUI

DECrepeater 90FA

AUI

10Base2
Segment
185 m
MAU
AUI

DTE

LJ-02372-TI0

Configuring the DECrepeater 90FA 2–3

Figure 2–2 shows a DEChub 90 extended LAN configuration.
Figure 2–2 DECrepeater 90FA Typical DEChub 90 Configuration
DEC h u b 9 0
1

DECr epeater 90FL

P o w er
S uppl y

Fiber-Optic Link Segment
1000 m

Fiber-Optic Link S e g m e n t
1000 m
DECbridge 90FL

DECr epeater 90FA
D EChub 90
1

DEChub 90
7

Power
Supply

10BaseT
(Twisted-Pair)
Link Segment
100 m

Fiber-Optic
Link Segment
500 m
MAU

P ow er
S u ppl y

Fiber-Optic
Link Segment
500 m

10BaseT
(Twisted-Pair)
Link Segment
100 m

MAU

AUI
DTE

DTE

DTE
(ThinWire)
Mixing Segment
185 m
DTE
LJ-02373-TI0

2–4 Configuring the DECrepeater 90FA

In this configuration, the requirements of the network extend beyond the five
segments and four repeaters allowed by the IEEE 802.3 rules. This configuration
is supported by using a bridge to create an extended LAN. The two LANs on
either side of the bridge may each contain up to five segments and four repeaters;
however, they are able to communicate with one another as if they were on a
single LAN.

Installed Fiber Constraints
In addition to following the IEEE 802.3 rules that ensure proper protocol
operation, the user must also ensure that the fiber-optic cable plant is properly
designed. Although the IEEE 802.3 standard allows for a maximum length of
1000 meters (FOIRL) or 2000 meters (10Base-FL), the fiber-optic segments may
be limited by the following characteristics of installed fiber:
•

Power budget

•

Link-loss

•

Wavelength

•

Bandwidth

The maximum link distance could be further restricted by the number of splices,
interconnects, and cross-connect administration points. Refer to the DECconnect
System Fiber Optic Planning and Configuration guide for instructions on how to
calculate the link certification value for each segment.

Configuring the DECrepeater 90FA 2–5

3
Installation
Before you install the DECrepeater 90FA repeater, it is recommended that you
read this entire manual to become familiar with the features and configuration
rules of the DECrepeater 90FA. If problems occur during installation, refer
to Chapter 5, Troubleshooting. For additional information that may be useful
during installation, refer to Appendix A, Specifications and Parts List.
The DECrepeater 90FA may be installed on a desk top or table, mounted on a
wall by its back cover, or installed in a DEChub 90 backplane. The only tool
required for installation is a screwdriver. The screwdriver is used to remove the
back cover, which covers the backplane connector and mounting assembly, and to
mount the repeater or the power supply on the wall.

Site Considerations
The DECrepeater 90FA and its power supply can be placed in various locations,
including office areas, computer rooms, or wiring closets, as long as the
environmental requirements are met. These requirements are provided in
Table A–2, Operating Environment, in Appendix A.

Standalone Installation
To install the DECrepeater 90FA on a desk top or table, make sure that the
air circulation around the DECrepeater 90FA does not become obstructed by
papers or other materials. Refer to the environmental specifications provided in
Table A–2 in Appendix A.

Installation 3–1

Mount the DECrepeater 90FA on a Wall
To install the DECrepeater 90FA as a standalone wall-mount unit, perform the
following procedure:
1. Remove the cover (if necessary).
a. Insert a small screwdriver into the top mounting hole on the cover
(Figure 3–1).
b. Lift the internal latch with the screwdriver, then pull the cover away and
down from the top of the unit.
Figure 3–1 Removing the Back Cover

LJ-00320-TI0

3–2 Installation

2. Use the mounting holes on the back cover to determine the placement for the
mounting screws on the wall (Figure 3–2).
3. Secure the back cover to the wall using the mounting screws.
Figure 3–2 Mounting Screws

LJ-00701-TI0

Installation 3–3

The screws should be tight enough to provide resistance if you try to remove
the back cover from the wall. However, do not make the screws so tight that
the cover is distorted or cannot be removed from the wall.
4. Remove the back cover from the wall.
5. Attach the back cover to the repeater.
6. Mount the repeater onto the mounting screws.

Standalone Installation Connections
To make the DECrepeater 90FA standalone installation connections, perform the
following procedure and refer to Figure 3–3:
1. Connect the cable from the power supply to the 7-pin power connector on the
DECrepeater 90FA. Align the power symbol on the dc power connector with
the power symbol on the DECrepeater 90FA and push straight in.
2. Connect the DECrepeater 90FA to the power source.
For 120/240 V power outlets, connect the power supply cord to the modular
power supply, then to the wall outlet.
3. If desired, connect the Ethernet ThinWire segment to a T-connector; connect
the T-connector to the port 0 BNC network connector. Terminate the
T-connector using a 50-ohm terminator or extend the Ethernet segment
to the next device.
The port 0 status activity LED should be on or flashing to indicate the
amount of traffic on the network. The LED intensity varies with the amount
of traffic: the more traffic, the brighter the LED will appear.
4. Connect the AUI cable to port 2, if required by the application.
5. Connect the fiber-optic cables to port 1 using 2.5-millimeter ST type bayonet
connectors, if required by the application.
The DECrepeater 90FA is now installed.

3–4 Installation

Figure 3–3 Standalone Installation

50- Ohm
Ter m i nator
T- C onnector

Fiber Link

To Fiber
Network
LJ-02374-TI0A

Installation 3–5

Backplane Installation
To install the DECrepeater 90FA in the DEChub 90 backplane, perform the
following procedure:
1. Remove the back cover (if necessary).
a. Insert a small screwdriver into the top mounting hole located on the
cover.
b. Lift the internal latch with the screwdriver and pull the cover away and
down from the top of the unit (Figure 3–1).
2. Install the DECrepeater 90FA into slot 7 or 8 of the backplane.
Place the lower mounting tab, located on the back of the repeater, into slot 7
or 8 of the backplane (Figure 3–4).
3. Rock the repeater into place. You will hear a click when the repeater is
secured in the slot.
4. Supply power to the backplane if this is a new installation.
5. Connect the AUI cable to port 2, if required by the application.
6. Attach the fiber-optic cables to port 1, if required by the application.
The DECrepeater 90FA is now installed.
Note
The DECrepeater 90FA can be installed into or removed from the
DEChub 90 backplane while power is supplied to the backplane
(hot swap).

3–6 Installation

Figure 3–4 Installing the DECrepeater 90FA into the DEChub 90

LJ-02375-TI0

Installation 3–7

4
Managing the DECrepeater 90FA
This chapter provides information about managing the DECrepeater 90FA
repeater on a network using the Maintenance Operations Protocol (MOP) for
VMS or ULTRIX operating systems. This chapter also describes the management
functions, commands, techniques, and messages.
The DECrepeater 90FA is managed online using a DECbridge 90 series unit in a
DEChub 90 backplane. All commands that affect the DECrepeater 90FA are part
of the DECbridge 90 series command set.

Functions
Online management allows the user to perform the following functions:
•

Identify all repeaters in the DEChub 90.

•

Examine port status (enabled, disabled, properly operating, or inoperative) of
repeater ports that share the DEChub 90 backplane with a bridge.

•

Examine the work group address database entries 1 to 200, annotated with
the repeater port to which each is attached, if any.

•

Reset any repeater in the DEChub 90 backplane.

•

Enable or disable a repeater port.

•

Define the bridge password.

See the Description of Commands section of this chapter for additional
information about command syntax.

Components Needed
The following components are needed to manage a DECrepeater 90FA online:
•

DEChub 90 backplane

•

DECbridge 90 series work group bridge

•

DECrepeater 90FA

Managing the DECrepeater 90FA 4–1

Accessing MOP from VMS Systems
The MOP console carrier on a VMS operating system is included as part of
the Network Control Program (NCP) facility, which requires a DECnet license.
You do not need increased user privileges to use the NCP facility; however, to
establish a console carrier session, you must know the following:
•

The Ethernet address of the bridge used for management

•

The Ethernet name of the circuit containing the bridge

The circuit name is needed because a VMS operating system may have more than
one Ethernet interface. The Ethernet address is located on the front panel label
on a DECbridge 90 series unit.
Table 4–1 lists the Ethernet circuit names, based on system types, that apply.
Table 4–1 Ethernet Circuit Names for Systems
System

Ethernet Circuit Name

VAX 6000 and VAX 9000 XMI computers

mna-0

BI-based systems (VAX 6300 and VAX 6400 computers)

bna-0

VAX 4000 computer series

isa-0

MicroVAX systems and VAX 3600 and VAX 3900
computers

qna-0

VAXstation 2000 and VAXstation 3000 computer series

sva-0

VAX–11/780 and VAX–11/785 computers (UNIBUS)

una-0

4–2 Managing the DECrepeater 90FA

Example:
If the bridge address is 08-00-2B-01-23-45 and the Ethernet circuit name is
sva-0, a typical VMS system command line to establish the session from a
VAXstation 3100 computer is:
$ MCR NCP CONNECT VIA SVA-0 PHYSICAL ADDRESS 08-00-2B-01-23-45
When you establish the connection, the following message appears on the screen:
Console connected (press CTRL/D when finished)

Accessing a Bridge Repeatedly
If you need to access a specific bridge repeatedly, you can enter the Ethernet
address for the bridge in the NCP database by choosing an arbitrary address
in area 13. Bridge names in the NCP database may have a maximum of six
characters.
Example:
If you name your bridge DBRG1 on address 13.87 and access it from a VAX 6400
computer (the Ethernet circuit name is bna-0), you could use the following
commands:
$ NCP
NCP> DEFINE NODE DBRG1 ADDRESS 13.87 HARDWARE
08-00-2B-01-23-45
SERVICE CIR BNA-0
NCP> SET NODE DBRG1 ALL
To access the bridge, enter the following:
$ NCP CONNECT NODE DBRG1

Accessing MOP from ULTRIX Systems
On ULTRIX operating systems, the console carrier is a separate utility included
as part of the MOP option. This option is part of the regular distribution,
however, it is not selected by default and is not included in the basic installation.
You can install the MOP option from the original distribution media using the
setld utility. You must have superuser privileges to invoke console carrier.
Once the MOP option is installed, each bridge to be managed must be given a
name and a dummy node number using the addnode utility. For example:
# addnode 13.1 DBRG1

Managing the DECrepeater 90FA 4–3

After the name and node number are assigned, you can establish the link at any
time using the ccr command:
# ccr -n DBRG1 -h 08-00-2B-01-23-45 -c sva-0
In this example, the -h qualifier is followed by the station address of the
DECbridge unit to be attached. The -c qualifier is followed by the name of the
Ethernet circuit to use for the connection. Ethernet circuit names, based on
system type, apply. Refer to Table 4–1 for circuit names.

Console Carrier User Interface
The DECbridge 90 is not shipped with a pre-set password; therefore, no password
prompt appears on the screen when you connect for the first time. For secure
operation of the DECbridge 90, you should define a password using the DEFINE
BRIDGE PASSWORD command.
The password prompt is represented by the pound sign (#). If you do not define a
password, then the password prompt does not appear on the screen when you log
in.
You have three attempts to enter a password; if all three attempts fail, then you
must disconnect and try again.
After you enter the correct password, or if there is no password, the DECbridge
console carrier management banner and prompt will appear on the screen as
follows:
Copyright © Digital Equipment Corporation 1991.
DEWGB V2.0 08-00-2B-2D-9B-81
EPROM V2.7 ©1991,92 Digital Equip Corp 25-JUN-92
DECbridge>

Console Carrier Command Language
You can type a question mark (?) at any point in the command line to show a list
of the options available at that point in the command line. The system accepts
unique command abbreviations.
Table 4–2 summarizes the DECbridge commands that apply to the
DECrepeater 90FA. For a complete list of commands, refer to the DECbridge 90
Owner’s Manual or the DECbridge 90FL Owner’s Manual.

4–4 Managing the DECrepeater 90FA

Table 4–2 Summary of DECbridge 90FA Commands
Command
1

DEFINE

Argument and Parameter
BRIDGE AGE age
BRIDGE FLOOD
ENABLE
DISABLE
BRIDGE HUB MANAGEMENT
ENABLE
DISABLE
BRIDGE PASSWORD password string
BRIDGE SPANNING TREE
ENABLE
DISABLE
PORT port number
ENABLE
DISABLE
PROTOCOL protocol number
FILTER ALL protocol identifier
FILTER BACKBONE protocol identifier
FILTER GROUP protocol identifier
FILTER WORKGROUP protocol identifier
FORWARD protocol identifier
NONE

DISPLAY

No arguments or parameters are needed

LIST

BRIDGE
PROTOCOL protocol number

SET

ALL
BRIDGE AGE age
BRIDGE FLOOD
ENABLE
DISABLE
BRIDGE HUB_MANAGEMENT
ENABLE
DISABLE

1 Changes made with the DEFINE command change only the default settings, which are assumed on
power-up or reset. DEFINE commands do not change the currently active values.
2 The SET commands change only the currently active values, but do not affect the defaults that are

assumed on power-up or reset.

(continued on next page)

Managing the DECrepeater 90FA 4–5

Table 4–2 (Cont.) Summary of DECbridge 90FA Commands
Command

Argument and Parameter
BRIDGE SPANNING TREE
ENABLE
DISABLE
PORT port number
ENABLE
DISABLE
PROTOCOL protocol number
FILTER ALL protocol identifier
FILTER BACKGROUND protocol identifier
FILTER GROUP protocol identifier
FILTER WORKGROUP protocol identifier
FORWARD
NONE
REPEATER

SHOW

ADDRESS [start index,[stop index]
BRIDGE
PORT port number
REPEATER hub slot number

Description of Command Parameters
A start index or stop index for an address is a decimal index into the work group
forwarding database in the range of 1 to 200.
A slot number is a single number ranging from 1 to 8 that identifies a hub slot
containing a DECrepeater 90FA. When two DEChub units are connected together,
the hub number (1 or 2) is specified before the slot number. For example, the
hub slot number 2,4 refers to the fourth slot from the left in the second DEChub,
which is the hub that does not contain the DECbridge 90.
A password string is a string of a maximum of 16 characters.
A port number is either a DECbridge 90 port, or the number of a port on a
repeater that is installed in the DEChub backplane with the bridge. The bridge
backbone port is the single digit 1. The work group port is 2. A port is identified
by a hub slot number and the port number within the slot.

4–6 Managing the DECrepeater 90FA

Description of Commands
This section describes the commands used by the DECrepeater 90FA. The
examples used to explain the commands are based on the configuration shown in
Figure 4–1, Sample Configuration.
DEFINE BRIDGE HUB_MANAGEMENT DISABLE
SET BRIDGE HUB_MANAGEMENT DISABLE
Disables all repeater management through the DECbridge 90 unit for
DECrepeater 90FA units in the DEChub 90 backplane. When disabled, you
receive an error message with the SHOW REPEATER, SET PORT, or SHOW
PORT commands on repeater ports. You do not receive port number information
from the SHOW ADDRESS command.
DEFINE BRIDGE HUB_MANAGEMENT ENABLE
SET BRIDGE HUB_MANAGEMENT ENABLE
Reverses the affect of the SET or DEFINE BRIDGE HUB_MANAGEMENT
DISABLE commands.
DEFINE BRIDGE PASSWORD password string
Lets you change the password string. You are prompted twice for a new password.
The password may be a maximum of 16 characters and does not appear on the
screen. The system saves the new password. There is no corresponding SET
command because the DEFINE BRIDGE PASSWORD takes effect immediately.
The MOP option provides a mechanism for setting and checking passwords.
This mechanism is intended to provide protection against accidental tampering
with parameters and is not intended as a security feature. No attempt is made
to prevent compromise of the password by malicious users. The DECbridge 90
should not be used in applications that depend on the prevention of any
unauthorized modifications to the parameters.
LIST BRIDGE
Displays the nonvolatile bridge-wide parameters.

Managing the DECrepeater 90FA 4–7

SET PORT [hub number,] slot number,port number DISABLE
Disables the attachment of a specific repeater port in the DEChub backplane.
The port status indicator on the selected DECrepeater 90 flashes, indicating
that the port was disconnected by the network manager. There is no equivalent
DEFINE command for disabling repeater ports.
Example 1:
The expected response to a SET PORT DISABLE command for a
DECrepeater 90FA appears as follows:
DECbridge>SET PORT 1,3,1 DISABLE
Hub 1 slot 3 port 1 segment counter 0 status: disabled-operational
SET PORT [hub number,] slot number, port number ENABLE
Reverses the effect of SET PORT DISABLE for DECrepeater 90 ports.
Example 2:
The expected response to a SET PORT ENABLE command for a DECrepeater 90FA
appears as follows:
DECbridge>SET PORT 1,3,1 ENABLE
Hub 1 slot 3 port 1 segment counter 0 status: no carrier loopback

SET REPEATER [hub number,]slot number RESET.
Resets a specific repeater. There is no output response to this command. All
disabled ports are enabled.

4–8 Managing the DECrepeater 90FA

SHOW ADDRESS [start index,[stop index]]
Displays the station address in a selected range (1 to 200) of entries in the
address database. The start index value always appears; however, other entries
in the range appear only if they are not empty. Addresses in this database are
all in the work group. If indexes are omitted, the addresses of all stations in the
work group are listed.
When the DECbridge 90 unit is used with a DECrepeater 90 series repeater,
the hub slot number and repeater port to which each station is attached will
also appear on the screen. Note that it may take several minutes for the SHOW
ADDRESS command to accurately reflect the correct repeater port number for
stations recently added to the network or station that have been moved from one
port to another. See Appendix B, Management Details, for further information
about the SHOW ADDRESS command.
Example 1:
This command displays all addresses contained within the hub configuration.
Address 5 and address 7 show the same hub, slot, and port because both devices
are daisy chained on the same port.
DECbridge>SHOW ADDRESS
Address 1: 08-00-2B-0F-19-23
Address 2: 08-00-2B-10-20-30 hub 2 slot 8 port 4
Address 5: 08-00-2B-10-6A-31 hub 2 slot 3 port 3
Address 6: 08-00-2B-A6-43-17 hub 1 slot 3 port 5
Address 7: 08-00-2B-16-23-4C hub 2 slot 3 port 3
Example 2:
The expected response to a SHOW ADDRESS command to a nonexisting address
appears as follows:
DECbridge>SHOW ADDRESS 3
Address 3: unused
Example 3:
The expected response of a SHOW ADDRESS command to a valid address
appears as follows:
DECbridge>SHOW ADDRESS 2
Address 2: 08-00-2B-10-20-30 hub 2 slot 8 port 4

Managing the DECrepeater 90FA 4–9

Example 4:
The expected response of a SHOW ADDRESS command for a range of addresses
appears as follows:
DECbridge>SHOW ADDRESS 2,6
Address 2: 08-00-2B-10-20-30 hub 2 slot 8 port 4
Address 5: 08-00-2B-10-6A-31 hub 2 slot 3 port 3
Address 6: 08-00-2B-A6-43-17 hub 1 slot 3 port 5
SHOW PORT [hub number,] slot number, port number
Shows whether the port is enabled or disabled and shows the operational status
of the port. Hub numbers can be 1 or 2; slot numbers can be 1 to 8. For the
DECrepeater 90T, port numbers are 1 to 8; for the DECrepeater 90C, port
numbers are 1 to 6; for the DECrepeater 90FL, port numbers are 1 to 4; for the
DECrepeater 90A, port numbers are 1 to 3.
Example 1:
The expected response to a SHOW PORT command appears as follows:
DECbridge>SHOW PORT 3,2
Hub 1 slot 3 port 2 segment counter 0 status: disabled-no carrier loopback

The hub was not defined in the command; therefore, the default (1) was used.
Example 2:
A SHOW PORT command for hub 2 appears as follows:
DECbridge>SHOW PORT 2,3,2
Hub 2 slot 3 port 2 segment counter 0 status: operational
SHOW REPEATER [[hub slot number,]slot number]
Shows the type of repeater and the port status for each port on that repeater.
The hub number can be 1 or 2, and slot numbers can be 1 to 8. If you do not
include parameters, information is shown for all repeaters in both hubs.

4–10 Managing the DECrepeater 90FA

Example 1:
The expected response to a SHOW REPEATER command appears as follows:
DECbridge>SHOW REPEATER
Hub 1 slot 3 twisted pair, repeater, rev.1, 8 ports.
Hub 1 slot 4 ThinWire repeater, rev.1, 6 ports.
Hub 2 slot 3 ThinWire repeater, rev.1, 6 ports.
Hub 2 slot 6 twisted pair repeater, rev.1, 8 ports.
Hub 2 slot 8 twisted pair repeater, rev.1, 8 ports.
Note that both the DECrepeater 90T and DECrepeater 90C repeaters are
installed in the hub.
Example 2:
The response to a SHOW REPEATER command to a slot that contains a device
other than a repeater appears as follows:
DECbridge>SHOW REPEATER 1
No repeater responds.
Example 3:
The response to a SHOW REPEATER command to an empty slot appears as
follows:
DECbridge>SHOW REPEATER 7
No repeater responds.
Example 4:
The response to a SHOW REPEATER command for a particular repeater appears
as follows:
DECbridge>SHOW REPEATER 3
Hub 1 slot 3 twisted pair, rev.1, 8 ports.
Hub 1 slot 3 port 0 segment counter 0 status: operational
Hub 1 slot 3 port 1 segment counter 1 status: no carrier loopback
Hub 1 slot 3 port 2 segment counter 0 status: disabled
Hub 1 slot 3 port 3 segment counter 0 status: operational
Hub 1 slot 3 port 4 segment counter 1 status: no carrier loopback
Hub 1 slot 3 port 5 segment counter 1 status: no carrier loopback
Hub 1 slot 3 port 6 segment counter 1 status: no carrier loopback
Hub 1 slot 3 port 7 segment counter 1 status: no carrier loopback
Hub 1 slot 3 port 8 segment counter 1 status: no carrier loopback

Managing the DECrepeater 90FA 4–11

Example 5:
The response to a SHOW REPEATER command for hub 2, slot 3 appears as
follows:
DECbridge>SHOW REPEATER 2,3
Hub 2 slot 3 ThinWire, rev.1, 6 ports.
Hub 2 slot 3 port 0 segment counter 0 status: operational
Hub 2 slot 3 port 1 segment counter 1 status: no carrier loopback
Hub 2 slot 3 port 2 segment counter 1 status: no carrier loopback
Hub 2 slot 3 port 3 segment counter 1 status: no carrier loopback
Hub 2 slot 3 port 4 segment counter 1 status: no carrier loopback
Hub 2 slot 3 port 5 segment counter 0 status: operational
Hub 2 slot 3 port 6 segment counter 1 status: no carrier loopback

Example 6:
The response to a SHOW REPEATER command for hub 2, slot 7 appears as
follows:
DECbridge>SHOW REPEATER 2,7
Hub 2 slot 7 AUI, rev.1, 1 port.
Hub 2 slot 7 port 0 segment counter 0 status: operational
Hub 2 slot 7 port 1 segment counter 1 status: no carrier loopback

Example 7:
The response to a SHOW REPEATER command for hub 2, slot 7 appears as
follows:
DECbridge>SHOW REPEATER 2,7
Hub 2 slot 7 Fiber, rev.1, 4 port.
Hub 2 slot 7 port 0 segment counter 0 status: operational
Hub 2 slot 7 port 1 segment counter 1 status: operational
Hub 2 slot 7 port 2 segment counter 2 status: operational
Hub 2 slot 7 port 3 segment counter 3 status: operational
Hub 2 slot 7 port 4 segment counter 4 status: operational

Example 8:
The response to a SHOW REPEATER command when the DECbridge 90 is not
the hub manager or the DECbridge 90 is still in the power-up stage appears as
follows:
DECbridge>SHOW REPEATER
The DECbridge 90 is not the designated hub manager.
There is a 60-second delay after power-up before the DECbridge takes control of
the hub.

4–12 Managing the DECrepeater 90FA

Figure 4–1 Sample Configuration
DECser v er 90L
08-00-2B-0F-19-23

DECbridge 90
08-00-2B-1D-07-21
1

H4005

DECr epeat er 90T
P o we r
Supply

DECr epeat er 90C

AUI
Cable
BC16M
ThinWire
Cable

VT 4 2 0

Di s k Ser ver

08-00-2B-A6-43-17

BC16E
Cable
1

D ECr epeat er 90C
P o we r
Supply

D ECr epeat er 90T
D ECr epeat er 90F L

08-00-2B-10-6A-31

08-00-2B-16-23-4C

08-00-2B-10-20-30
LJ-02153-TI0

Typical Management Techniques
The DECrepeater 90FA can be managed as a standalone unit using LEDs,
or online within a group of repeaters installed in a DEChub 90. The
DECrepeater 90FA comes with LEDs that indicate system status in a standalone

Managing the DECrepeater 90FA 4–13

configuration. In a DEChub 90 environment, the repeater may be managed using
LEDs as well as online management.

Remote Network Management with the DECbridge 90
You can manage a DECrepeater 90FA with a DECbridge 90 work group bridge
and a DEChub 90 backplane. The DECbridge 90 unit communicates across the
DEChub 90 backplane to any repeaters in the DEChub. You can also connect two
DEChub 90 backplanes together and manage the repeaters in both DEChub 90
backplanes using one DECbridge 90 unit.
The DECbridge unit communicates with the DECrepeater 90FA units using
unique signals on the DEChub backplane. The two DEChub 90 backplanes are
connected with two cables:
1. ThinWire coaxial cable to carry the work group Ethernet signals
2. DECconnect office cable to carry the management signals
Note
If two DEChub backplanes are being managed by one bridge, the
backplanes must be connected BNC to BNC using ThinWire cable (part
number BC16M-xx where xx stands for length) and a DECconnect office
cable (part number BC16E-xx).

Management Disconnect
A port can be partitioned at any time by the management protocol. The
management protocol can be used only for the repeater ports mounted in the
DEChub 90 backplane and connected to a DECbridge 90. When a port is
disconnected by the management protocol, it can be reconnected either by turning
the power off and then on again, or by using the management protocol. If the
port LED flashes approximately twice a second, the port is partitioned by the
management protocol.
Whether your configuration is a standalone or a DEChub 90 installation, you
should create a network topology map to help facilitate management tasks.
Figure 4–2 shows a typical network topology map.

4–14 Managing the DECrepeater 90FA

Figure 4–2 Typical Network Topology Map
DEChub 90
Slot 1

DECrepeater 90T

Slot 2

DECrepeater 90C

Slot 7

DECrepeater 90FA

Port 1

Node - Address - Username

Port 1

Node - Address - Username

Port 1

Node - Address - Username

Port 2

Node - Address - Username

Port 2

Node - Address - Username

Port 2

Node - Address - Username

Port 3

Node - Address - Username

Port 3

Node - Address - Username

Port 3

Node - Address - Username

Port 4

Node - Address - Username

Port 4

Node - Address - Username

Port 4

Node - Address - Username

Port 5

Node - Address - Username

Port 5

Node - Address - Username

Port 5

Node - Address - Username

Port 6

Node - Address - Username

Port 6

Node - Address - Username

Port 6

Node - Address - Username

Port 7

Node - Address - Username

Port 7

Node - Address - Username

Port 7

Node - Address - Username

Port 8

Node - Address - Username

Port 8

Node - Address - Username

Port 8

Node - Address - Username
LJ-02377-TI0

Management Session
To perform online management commands, establish a MOP console carrier
session with the bridge from any remote node. After you connect to the bridge,
the following prompt appears on the screen:
DECbridge>
When a bridge goes through a power cycle or is reset, the bridge begins to poll
repeaters for status. This process includes a special algorithm to determine
which repeater ports have stations that are attached. The time to complete this
algorithm depends on the number of repeaters and the network activity. You
should allow time before proceeding to manage the hub. For the same reason, it
can take time for the system to report on stations or repeaters that are moved in
the hub. See Appendix B, Management Details, for more information.
Example of a Typical Management Session
The following steps show how you can use the SHOW REPEATER and SHOW
ADDRESS commands in a typical management session.
1. Determine what repeaters are in the hub.
DECbridge>SHOW REPEATER
Hub 1 slot 5 ThinWire repeater, rev.0, 8 ports.
In this example, there is a ThinWire repeater (DECrepeater 90C) in the same
hub (hub 1) as the bridge (if this is a 2-hub configuration). The repeater is in
slot 5 with 6 ThinWire ports.

Managing the DECrepeater 90FA 4–15

2. Determine what stations are connected to the repeaters in the hub.
DECbridge>SHOW ADDRESS
Address 1: 08-00-2B-19-94-FB
Address 2: 08-00-2B-1E-2D-0C hub 1 slot 5 port 3
This indicates that a station with address 08-00-2B-1E-2D-0C is connected to
the repeater in slot 5 on port 3. At this point, without physical examination,
you have enough information to construct a network map.
3. Determine the status of all ports on the repeater.
DECbridge>SHOW REPEATER 5
Hub 1 slot 5 twisted pair, rev.1, 6 ports.
Hub 1 slot 5 port 0 segment counter 0 status: operational
Hub 1 slot 5 port 1 segment counter 0 status: excessive collisions
Hub 1 slot 5 port 2 segment counter 0 status: excessive length collision
Hub 1 slot 5 port 3 segment counter 0 status: operational
Hub 1 slot 5 port 4 segment counter 0 status: excessive length collision
Hub 1 slot 5 port 5 segment counter 0 status: excessive length collision
Hub 1 slot 5 port 6 segment counter 0 status: excessive length collision
Hub 1 slot 5 port 7 segment counter 0 status: excessive length collision
Hub 1 slot 5 port 8 segment counter 0 status: excessive length collision
Continue to use the SHOW REPEATER command for each port on the
repeater.
If Problems are Reported
The following table describes the status messages and the most common causes.
Message

Most Common Cause

Operational

Cable connected, everything OK.

Excessive length collision

Cable fault, usually either a port that is not connected
to anything or an open cable. In the case of 10BaseT,
the remote station may be powered down (no link
beat).

Excessive collisions

Cable fault, usually either a port that is not connected
to anything or an open cable. In the case of 10BaseT,
the remote station may be powered down (no link
beat).

No carrier loopback

Cable fault, usually a shorted cable.

Transmit carrier drop out

Cable fault, usually a shorted cable.

Jabber

Stations connected to this port continue to transmit;
expect a faulty station.

4–16 Managing the DECrepeater 90FA

The operational condition is normal. All other conditions cause the repeater
to automatically partition the port. When the condition clears, the repeater
automatically reconnects the port and reports it as operational unless it is
partitioned by management.
To help solve intermittent problems, the repeater reports a segmentation count.
This count runs from 0 to 15 and then latches at 15. Every time you enter the
SHOW REPEATER command, this count is set to zero.
If this count is not zero, you can tell that a port has partitioned since the last
SHOW REPEATER command. This partitioning occurs normally if users turn
stations on and off, or if cables are connected and disconnected from the repeater
during installation and reconfiguration. If none of these normal causes have
occurred, there may be an intermittent problem with cabling or attached stations.
To Disable a Port
The following commands allows the manager to disable a particular port on a
repeater. This may be useful if stations attached to that port are causing network
difficulties.
DECbridge>SET PORT 5,1 DISABLE
Hub 1 slot 5 port 1 segment counter 0 status: disabled-no carrier
loopback
To Reset the Repeater
The following command resets the repeater to power-up condition. This includes
restoring any ports that have been partitioned by the manager as well as
resetting the segmentation counters.
DECbridge>SET REPEATER 5 RESET

Managing the DECrepeater 90FA 4–17

Error Messages
Table 4–3 lists the DECbridge 90 error messages and a description of each
message. For a complete list of messages, refer to either the DECbridge 90
Owner’s Manual or the DECbridge 90FL Owner’s Manual.
Table 4–3 DECbridge 90 Messages
Error Message

Description

Address n: unused

Address number n does not contain a station address.

Confirmation error - password
not changed

The second entry or verification of the new password
provided to the DEFINE BRIDGE PASSWORD
command did not match the first entry.

DECbridge 90 is not the
designated hub manager

The DECbridge 90 was not the designated hub
manager when either the SHOW PORT or SHOW
REPEATER command was issued. This occurs when
•

The bridge is reset and, for 60 seconds, the
DECbridge is not the hub manager.

•

Another DECbridge unit is acting as the current
hub manager.

•

A fault exists in the BC16E cable or in the
connections between two DEChub backplanes.

•

A fault exists in the power supply of one of
the DEChub units. This prevents repeater
management communication.

Hub management disabled

A SHOW PORT or SHOW REPEATER command was
issued to a DECbridge 90 for which repeater management is disabled. Enable repeater management with
the SET BRIDGE HUB_MANAGEMENT ENABLE
command before trying again.

Hub number and slot number
[ [hub], slot]. Hub is 1 or 2, slot
is 1-15

One or more parameters provided to the SHOW
REPEATER command were out of range. The hub
number must be either 1 or 2. The slot number must
be between 1 and 15.

Hub h slot s - port number out of
range

The port number provided to the SHOW PORT
command was out of range for the device in hub
h slot s. Use the SHOW REPEATER command to
determine the number of ports for the device and to
specify a port number within that range.
(continued on next page)

4–18 Managing the DECrepeater 90FA

Table 4–3 (Cont.) DECbridge 90 Messages
Error Message

Description

Hub h slot s not a repeater

The device does not use the same management
protocol as the DECrepeater 90 series repeaters.
The device ports, if any, cannot be managed by the
DECbridge 90 unit.

Hub h slot s unrecognized type

The repeater type in hub h slot s is not known to
the DECbridge 90. The repeater ports can still be
managed with the DECbridge 90.

No repeater responds

There is no repeater installed in the requested hub
slots, or the repeater is not functioning.

No such port

The bridge port number provided to the SHOW PORT
command was invalid. Valid numbers are 1 and 2.

Password too long - not changed

A password longer than 16 characters was given to the
DEFINE BRIDGE PASSWORD command.

Port number [[hub,]slot,]port

One of the parameters provided to a SET PORT or
DEFINE PORT command was not a valid hub, slot, or
port number.

Station address number
[first [,last] ] in range 1-200

One or more parameters provided to the SHOW
ADDRESS command was invalid. The valid range is 1
to 200.

Unsupported by this hardware
revision

This occurs when you attempt to execute a SET or
DEFINE BRIDGE FLOOD command on a bridge with
a firmware revision of 1 (DECbridge 90 V1.4) but
have loaded V2.5 or a later version flash EPROM. The
old hardware revision does not support flood mode.
These version numbers appear in the MOP console
connection banner.

???

A command or parameter was not recognized. Enter ?
to display valid commands.

180501

A loopback diagnostic has run and passed on the
backbone port. If the backbone port is not receiving
any messages, this diagnostic is run every 10 minutes.

180201

A loopback diagnostic has run and passed on the work
group port. If the work group port is not receiving any
messages, this diagnostic is run every 10 minutes.

1805:00-00-00-00
01

A loopback diagnostic has run and failed on the
backbone port. The diagnostic is tried every 5 seconds
until the test passes.
(continued on next page)

Managing the DECrepeater 90FA 4–19

Table 4–3 (Cont.) DECbridge 90 Messages
Error Message

Description

1802:00-00-00-00
01

A loopback diagnostic has run and failed on the work
group port. The diagnostic is tried every 5 seconds
until the test passes.

Standalone Configuration Management
The recommended process for managing a small standalone network is as follows:
•

Maintain records indicating which stations are connected to each port on each
repeater. It may be desirable to draw a network topology map (Figure 4–2).

•

Observe the LEDs on the repeater for network status. Refer to Chapter 1,
Table 1–1, for a description of each LED and its function.
Note
After you power up a standalone DECrepeater 90FA, all LEDs, except
the network activity LED, stay on if there are no active connections, or
if there is no hardware or network activity. After an active station is
connected to one of the ports, the LED for the active port stays on and all
other ports turn off.

4–20 Managing the DECrepeater 90FA

5
Troubleshooting
This chapter provides troubleshooting information for the DECrepeater 90FA
repeater when used as a standalone unit or when installed in the DEChub 90
backplane.
Before you start to troubleshoot a problem:
1. Verify the installation of the repeater. The installation must meet the
configuration rules provided in Chapter 2, Configuring the DECrepeater
90FA.
2. Note the fault condition.
3. Isolate the problem.

Port Partitioning
Any messages or data packets received from any port by the DECrepeater 90FA
are transmitted to all ports. The port status LEDs display the following port
partition status:
On

The port is not partitioned.

Off

The port is autopartitioned.

Flashing

The port is partitioned by management.

Each port is automatically controlled by the repeater function and can be
partitioned for any of the reasons shown in Table 5–1 and Table 5–2.

Troubleshooting 5–1

Table 5–1 DECrepeater 90FA Status Indicators
LED

Fault

Non-Fault

Ports 0 through
2 flashing

–

Partitioned by management.

Port 0 off

Open cables
Shorted cables
Cables not properly connected

Port not connected.

Port 1 off

Link problem (see Table 5–2)

Link not connected.

Port 2 off

AUI cable not connected to MAU
MAU not functioning
Coaxial cable not terminated

Port not connected.

Table 5–2 DECrepeater 90FA Fiber-Link Indicators
LED

Fault

Correction

Port 1 off

Cables not connected

Connect fiber cables.

Transmit/receive not connected

Cross over the cables (transmit to
remote receive; receive to remote
transmit).

Lack of idle signal

Power up the remote repeater/DTE.

Low light

Reduce attenuation of the fiber
segment. Consider cable type, link
loss, and connector loss variables.

5–2 Troubleshooting

DECrepeater 90FA Standalone Troubleshooting
To troubleshoot a DECrepeater 90FA standalone installation, refer to Table 5–3
for a list of possible error conditions and the corrective action.
Table 5–3 Troubleshooting a DECrepeater 90FA Standalone Unit
If...

Then...

Do this...

All LEDs are off.

Check the ac power connection.

Check that the power
supply is properly plugged
into the power outlet.
Check the power to the
power outlet.

Check the power supply.

Check the 7-pin connector
at the repeater unit. If
the connections are okay,
replace either the power
supply or both the power
supply and power cord.

There is low network activity or
no network activity.

Ensure that network
activity is present.

If the network activity LED still
fails to light

Turn the repeater off and
on by unplugging and
replugging the power
supply. Check that the
network activity LED
comes on momentarily.

If the network activity LED
lights momentarily, the LED
portion of testing has passed. If
the network LED fails to light

Replace the repeater.

If port 0 is connected, the port
may be segmented or the LED
may have failed.

Remove all network
connections to the
repeater. Power the
repeater off and on by
unplugging and replugging
the power supply. All port
status LEDs should come
on and, in the absence of
network activity, remain
on.

The network activity
LED is off.

The port 0 status LED
is off.

(continued on next page)

Troubleshooting 5–3

Table 5–3 (Cont.) Troubleshooting a DECrepeater 90FA Standalone Unit
If...

A fiber-link LED is off.

Port 1 status LED is off.

Then...

Do this...

If the port 0 status LED does not
light and/or remain on

Replace the repeater.

If the port 0 status LED does
remain on, the port may be
segmented when connected to
the network.

Terminate port 0 with a Tconnector and two 50-ohm
terminators. Reconnect a
front panel fiber segment
carrying network activity.
The repeater activity LED
will light.

If port 0 status LED does not
remain on

Replace the repeater.

If the port 0 status LED does
remain on

Remove the T-connector
and the terminators, and
reconnect the ThinWire
segment.

If the port 0 status LED turns
off, either the ThinWire cable is
open, shorted, not terminated
properly, or the external
equipment is transmitting
incorrect data.

Ensure the operation
of external equipment
and cable, or replace the
it with a known good
segment carrying valid
traffic.

Ensure the cable to the receive
channel of the port in question
is good, and that the external
equipment is transmitting the
idle signal.

Reconnect the same cables
and external device to
another repeater port.

If the fiber-link LED for the
new port comes on, the fiber-link
LED of the original port is faulty.

Replace the repeater.

The fiber port may be
segmented, or the LED may
have failed.

Ensure that network
activity is present (a
segmented port will
require data to return
to normal status). The
repeater activity LED
should be on.
(continued on next page)

5–4 Troubleshooting

Table 5–3 (Cont.) Troubleshooting a DECrepeater 90FA Standalone Unit
If...

No traffic is received
from or by an external
device connected to a
fiber port with both
fiber-link and port
status LEDs on.

Then...

Do this...

If the fiber-link LED is on

Remove all network
connections from the
repeater. Turn the
repeater off and on. Check
that all the port status
LEDs come on. There will
be no activity; therefore,
the port status LEDs
should remain on.

If all port status LEDs do not
remain on

Replace the repeater.

If all port status LEDs do remain
on, the port in question may
be segmenting in use. This
occurs if the port in question
does not receive the idle signal
from the external device, or the
external device is transmitting
improperly.

Reconnect the port in
question. The fiber-link
LED should come on and
the status LED should
remain on.

If the fiber-link LED does not
come on

Refer to the fiber-link
troubleshooting section of
this table.

If the fiber-link LED does come
on but the port status LED turns
off

Confirm the operation
of the external device.
Connect the same device to
another fiber port.

If the fiber-link and status LEDs
of the second port are both
on, the fault is internal to the
transmitter of the original port.

Replace the repeater.

It is possible that the external
device is not receiving the idle
signal from the repeater.

Use a single cable to loop
the transmit channel of
the port in question to the
receive channel of another
repeater port.
(continued on next page)

Troubleshooting 5–5

Table 5–3 (Cont.) Troubleshooting a DECrepeater 90FA Standalone Unit
If...

The port 2 status LED
is off.

Then...

Do this...

If the fiber-link LED of the
receiving port lights, the idle
signal is present.

Check the cable to the
external device, and check
the external device for
correct operation.

If the fiber-link LED of the
receiving port does not come on

Replace the cable with a
known good cable.

If the fiber-link LED of the
receiving port still fails to come
on

Replace the repeater.

Port 2 is either segmented or the
LED has failed.

Check to see if port 2
status LED is defective.
Remove all front panel
connections and the port
0 connection. Power
the repeater off and on.
Ensure that the port 2
status LED lights and
remains on.

If port 2 status LED does not
light and remain on

Replace the repeater.

If port 2 status LED lights and
remains on

Restore all port connections on the repeater.

Check port 0 and port 1 status
LEDs. If both port status LEDs
are off

Check to see that port 0 or
1 are properly connected
to active network
segments. Using previous
troubleshooting steps,
ensure that either port 0
or port 1 is functioning
before troubleshooting port
2.

If either port 0 or port 1 status
LEDs are on, and port 2 status
LED goes off, it is likely that
port 2 is segmented. Correction
of the segmentation fault should
correct the problem.

Check the AUI connection.
Ensure that the cable is
properly connected and the
slide latches are secured.

(continued on next page)

5–6 Troubleshooting

Table 5–3 (Cont.) Troubleshooting a DECrepeater 90FA Standalone Unit
If...

Then...

Do this...

If the AUI connection is secure

Check that the MAU is
being powered by the
repeater. (Most MAUs
have a Power OK LED.)

If the MAU is not powered by
the repeater

Replace the repeater.

If the MAU is powered by the
repeater, the fault is probably
due to an improper MAU
connection to the medium.

Ensure that the medium is
correctly attached and that
it is properly terminated.
Correction of the medium
attachment should resolve
the problem.

Troubleshooting 5–7

DECrepeater 90FA Backplane Troubleshooting
To troubleshoot a DECrepeater 90FA installed in a DEChub 90 configuration,
refer to Table 5–4 for a list of possible error conditions and the corrective action.
Table 5–4 Troubleshooting a DECrepeater 90FA in a DEChub 90 Backplane
If...

Then...

Do this...

The power LED is off.

The repeater does not have
correct operating voltage.

Check the power LED on
the DEChub 90 power
supply.

If the power LED on the
DEChub 90 is off, there is a
problem with the DEChub 90
power supply.

See the troubleshooting
procedures in the DEChub
90 Owner’s Manual.

If the power LED on the
DEChub 90 power supply is on,
check the power LEDs on other
modules. If all power LEDs are
off, the DEChub 90 has a power
distribution problem.

See the troubleshooting
procedures in the DEChub
90 Owner’s Manual.

If there is power to other
modules, ensure that the
repeater is correctly seated
in either slot 7 or 8 of the
DEChub 90. (Slots 7 and 8
are the only ones that provide
the +12.0 V necessary to operate
the DECrepeater 90FA.)

Reseat module in slot 7 or
8.

If the power LED turns on
when reseated in the same slot,
the repeater was not properly
installed. Problem should be
corrected.

Return to normal
operation.

If the power LED turns on
when reseated in another slot,
but not when installed in the
original slot, there is a power
distribution problem to that slot
within the DEChub 90.

See the troubleshooting
procedures in the DEChub
90 Owner’s Manual.

(continued on next page)

5–8 Troubleshooting

Table 5–4 (Cont.) Troubleshooting a DECrepeater 90FA in a DEChub 90
Backplane
If...

The network activity
LED is off.

The port 0 status LED
is off.

Then...

Do this...

If the repeater does not turn
on in either slot 7 or 8, check
those slots with another known
good module. If the known good
module powers up, and the
repeater does not, the repeater is
defective.

Replace the repeater.

The repeater or any other unit
in the DEChub 90 may not be
connected to an active segment.

Connect a known active
segment to any unit in
the DEChub 90. Look for
an indication of network
activity on any unit in the
DEChub 90.

If the repeater is connected to a
known active segment and the
network activity LED is off, the
repeater is defective.

Replace the repeater. (See
the following port 0 status
section.)

Port 0 may be segmented or the
LED may be defective.

Remove all front panel
fiber port connections.
Power the repeater off and
on by reseating the unit in
the DEChub 90. Ensure
that the port 0 status LED
lights and remains on.

If the port 0 status LED does not
light and remain on

Plug the repeater into
another slot in the
DEChub 90. If possible,
choose a known good slot.

If the port 0 status LED does not
light and remain on

Replace the repeater.

If the port 0 status LED does
light and remain on, there is a
problem with the DEChub 90.

See the troubleshooting
procedures in the DEChub
90 Owner’s Manual.
(continued on next page)

Troubleshooting 5–9

Table 5–4 (Cont.) Troubleshooting a DECrepeater 90FA in a DEChub 90
Backplane
If...

Port fiber-link LED is
off.

Port 1 status LED is off.

Then...

Do this...

If any other units in the DEChub
90 indicate network activity, the
repeater activity LED should be
on. If the port 0 status LED is
on and the activity LED is off,
port 0 is not receiving traffic.

Replace the repeater.

If the port 0 status LED is on,
and the activity LED is on, the
front panel fiber ports should be
reconnected.

Reconnect the front panel
fiber ports.

Ensure the cable to the receive
channel of the port in question
is good, and that the external
equipment is transmitting the
idle signal.

Reconnect the same cables
and external device to
another repeater port.

If the fiber-link LED for the new
port comes on, the original port
fiber-link LED has failed.

Replace the repeater.

The fiber port may be
segmented or the LED may
have malfunctioned.

Disconnect all front panel
fiber connections to the
repeater. Power the unit
off and on by removing and
reseating it in the DEChub
90.

All port status LEDs should
light momentarily. (If there is no
activity on the DEChub 90, they
will light and stay on.) If any
port status LED does not light
momentarily

Replace the repeater.

(continued on next page)

5–10 Troubleshooting

Table 5–4 (Cont.) Troubleshooting a DECrepeater 90FA in a DEChub 90
Backplane
If...

Then...

Do this...

If all port status LEDs do light
momentarily, the ports should be
reconnected one at a time.

Reconnect each fiber port
receive channel. Note
that the external device
will not be receiving the
idle signal and should
not be transmitting
data; therefore, the port
fiber-link and status
LEDs should light as
each receive channel is
connected.

If the fiber-link LED lights and
the port status LED does not
come on

Reconnect the receive
channel of a different port
on the repeater.

If the fiber-link LED lights and
the port status LED fails to light

Ensure that the external
equipment is operating
properly. Connect the
transmit channel of a
known good device to the
receive channel of the
ports in question.

If the fiber-link LED lights and
the port status LED remains off

Check that the repeater
network activity LED is
on. An unconnected port
will be segmented and will
require good data to be
transmitted before it is
unsegmented. Connecting
the receive channel of
a port should establish
the link; however, a good
packet of data must be
available for transmission
to unsegment and return
the port to normal status.

If the fiber-link LED lights and
the port status LED remains off
while the repeater activity LED
is on

Replace the repeater.

(continued on next page)

Troubleshooting 5–11

Table 5–4 (Cont.) Troubleshooting a DECrepeater 90FA in a DEChub 90
Backplane
If...

No traffic is received
from or by an external
device connected to a
fiber port with both
fiber-link and port
status LEDs on.

The port 2 status LED
is off.

Then...

Do this...

If the fiber-link and status LEDs
both come on

Connect the transmit
channel of the port to the
external equipment.

If the port status LED fails to
remain on

Ensure that the external
equipment is operating
properly. Replace the
equipment with a known
good device.

If the port status LED fails to
remain on, the port transmitter
may be sending the idle signal,
but may not be passing data.

Replace the repeater.

It is possible that the external
device is not receiving the idle
signal from the repeater.

Use a single cable to loop
the transmit channel of
the port in question to the
receive channel of another
repeater port.

If the fiber-link monitor LED of
the receiving port lights, the idle
signal is present.

Check the cable to the
external device, and check
the external device for
correct operation.

If the fiber-link LED of the
receiving port does not come on

Replace the cable with a
known good cable.

If the fiber-link LED of the
receiving port still fails to come
on

Replace the repeater.

Port 2 is either segmented or the
LED is defective.

Check to see if the port 2
status LED is defective.
Remove all front panel
connections. Power the
repeater off and on by
reseating the unit in the
DEChub 90. Ensure that
the port 2 status LED
lights. (On an active
DEChub 90, the light will
come on momentarily.)
(continued on next page)

5–12 Troubleshooting

Table 5–4 (Cont.) Troubleshooting a DECrepeater 90FA in a DEChub 90
Backplane
If...

Then...

Do this...

If port 2 status LED does not
light, at least momentarily

Replace the repeater.

If port 2 status LED does light,
even if only momentarily

Restore all port connections on the repeater.

Check the port 0 status LED. If
the port 0 status LED is off

Check to see that the
repeater is properly
installed in the DEChub
90. Using previous
troubleshooting steps,
ensure that the port
0 status LED and
network activity LED
are functioning before
troubleshooting port 2.

If the repeater is properly
installed in the DEChub 90
and the port 2 status LED goes
off, then it is likely that port
2 is segmented. Correction of
the segmentation fault should
correct the problem.

Check the AUI connection.
Ensure that the cable is
properly connected and the
slide latches are secured.

If the AUI connection is secure

Check that the MAU is
being powered by the
repeater. (Most MAUs
have a Power OK LED.)

If the MAU is not powered by
the repeater

Replace the repeater.

If the MAU is powered by the
repeater, the fault is probably
due to an improper MAU
connection to the medium.

Ensure that the medium is
correctly attached and that
it is properly terminated.
Correction of the medium
attachment should resolve
the problem.

Troubleshooting 5–13

A
Specifications and Parts List
This appendix provides the specifications and parts list for the DECrepeater 90FA
repeater.
Specifications for the DECrepeater 90FA are divided into the following categories:
•

Physical dimensions

•

Environmental (operating and shipping) specifications

•

Power specifications

Table A–1 lists the physical dimensions of the DECrepeater 90FA.
Table A–1 Physical Dimensions
Dimension

Measurement

Height

3.5 cm (1.4 in)

Width

28.0 cm (11.0 in)

Depth

14.0 cm (5.5 in)

Weight

.77 kg (1.7 lb)

Specifications and Parts List A–1

Table A–2 lists the operating environment specifications for the
DECrepeater 90FA.
Table A–2 Operating Environment
Condition

Value

Temperature

5°C to 50°C (41°F to 122°F)

Maximum rate of change

20°C/hr (36°F/hr)

Relative humidity

10% to 95% (noncondensing)

Wet-bulb temperature

32°C (90°F) maximum

Dew point

2°C (36°F) minimum

Altitude

Sea level to 2.4 km (8000 ft)

Air flow

Convectively cooled. A minimum of 10 cm (4 in) of space must
be provided on both ends of the unit for adequate air flow.

The DECrepeater 90FA is designed to operate in an office environment or
equipment room environment such as telephone closets or satellite equipment
rooms. It is not intended to operate in an air plenum.
Table A–3 lists the shipping environment specifications for the DECrepeater
90FA.
Table A–3 Shipping Environment
Condition

Value

Temperature

-40°C to 66°C (-40°F to 151°F)

Relative humidity

10% to 95% (noncondensing)

Altitude

Sea level to 4.9 km (16,000 ft)

A–2 Specifications and Parts List

Table A–4 lists the power specifications for the DECrepeater 90FA.
Table A–4 Power Specifications
Specification

Value

Voltage (domestic)

104 Vac to 128 Vac (nominal 120 Vac)

Voltage (international)

208 Vac to 256 Vac (nominal 240 Vac)

AC cord length

6 ft

Current at 120 V

.25 A

Current at 240 V

.125 A

Frequency

50 Hz to 60 Hz

Power consumption

Output voltage 1

5.1 Vdc

Output voltage 2

12.0 Vdc

DC cord length

8 ft

Output current

1.8 A

The DECrepeater 90FA features either a self-contained power supply or
self-contained power supply and power cord option.
Table A–5 lists the DECrepeater 90FA voltage and current specifications.
Table A–5 DECrepeater 90FA Input
Specification

Value

Input voltage

4.75 to 5.25 Vdc, 12.0 Vdc

Input current

1.7 A

Specifications and Parts List A–3

AUI Connector Pin Assignments
The following table shows the assignment of circuits to connector pins in
accordance with the IEEE 802.3 standard.
Pin

Circuit

Use

DO-A

Data Out circuit A

DO-B

Data Out circuit B

DO-S

Data Out circuit Shield

DI-A

Data In circuit A

DI-B

Data In circuit B

DI-S

Data In circuit Shield

CO-A

Control Out circuit A

CO-B

Control Out circuit B

CO-S

Control Out circuit Shield

CI-A

Control In circuit A

CI-B

Control In circuit B

CI-S

Control In circuit Shield

Voltage Common

Voltage Plus

Voltage Shield

Shell

Protective Ground (Conductive Shell)

Note
Voltage Plus and Voltage Common use a single, twisted-pair cable in the
AUI cable.

A–4 Specifications and Parts List

Parts List
Table A–6 lists the replacement parts for a DECrepeater 90FA.
Table A–6 Parts List
Replacement Part

Part Number

DECrepeater 90FA

DEFAR-MA

Fiber-optic cables

BN24E series

Power supply (120/240 Vac)

H7827-AA

Specifications and Parts List A–5

B
Management Details
This appendix supplements the management information in Chapter 4; it
provides the following information for managing a DECrepeater 90FA in a
DEChub backplane:
•

Designating a hub manager

•

Annotating the bridge address table

•

Using the work group bridge address table for work group management

Designating a Hub Manager
The protocol used on the DEChub management bus allows for only a single
manager unit to access the management bus. When a DECbridge 90 series unit
is first powered up or reset, the bridge waits 60 seconds before it is established as
the designated hub manager. This delay ensures that there is no other manager
unit in use in the hub.
During the 60 seconds, you cannot remotely manage the DECrepeater 90FA. This
restriction does not apply to the repeaters themselves. A repeater inserted into
the hub is immediately manageable by whatever unit is currently the designated
hub manager.
If you receive the following message after a DECbridge unit has been running for
60 seconds, then there is something wrong.
The DECbridge unit is not the designated hub manager.
When this message appears, check the following:
•

If you are using two hubs, be sure that the BNE16 or DECconnet office cable
is wired correctly, and that it is not shorted or broken.

•

If you are using only one hub, the MMJ connector should be disconnected.

Only one DECbridge unit is allowed in the hub. If more than one is inserted, only
one is able to manage the repeaters. The other unit issues the message.

Management Details B–1

If you do not want a specific DECbridge 90 series unit to be the designated hub
manager, use the DEFINE BRIDGE HUB_MANAGEMENT DISABLE command
to disable the hub management features.
You can use the SHOW REPEATER and SET or SHOW PORT commands without
restriction once the DECbridge unit is the designated hub manager. There is,
however, an additional delay before the SHOW ADDRESS command has complete
information.
The DEFINE commands do not take effect until the next SET ALL or RESET
bridge commands are used. To have the command take effect immediately, you
must also issue the corresponding SET command.

Annotating the Bridge Address Table
The DECbridge 90 series unit SHOW ADDRESS command lists the repeater slot
number and port number for every station in the work group that is connected
to the same DEChub with a repeater. However, when changes are made to the
network topology, there is a time lapse before the changes appear in the bridge
address table. The algorithm for creating this information for every station in the
work group is as follows:
•

Tell the repeaters to wait for a message from this station.

•

Wait as long as 90 seconds for the station to transmit a message.

•

Ask the repeaters what port the message came from.

If a station does not transmit a message within 90 seconds, the algorithm
proceeds to the next station. In a typical network situation, this information
is complete in a few minutes. After a bridge is newly installed or reset, this
information should be complete after approximately 10 minutes of operation.
If some stations do not often transmit messages, the DECbridge can hang
on those stations as long as 90 seconds each before going to the next one. If you
add a station or move a station to another port, it could take about 10 minutes
before the SHOW ADDRESS command recognizes this move.
If you remove a station from the network entirely, it should take a full
address age time (default is 30 minutes) for the DECbridge unit to notice the
removal. If you remove several stations at once, the DECbridge unit hangs on
each of these stations for 90 seconds, until they age out of the bridge address
database. In this case, it usually takes the full address age time (30 minutes)
before the port number annotations are complete.

B–2 Management Details

As a worst case example, if it takes 60 seconds for each of the recommended 200
stations to transmit a message, it could take 200 minutes to complete the address
database annotations. However, the DECbridge 90 unit tries to expedite the
transmission as follows:
•

If the station remains quiet after waiting 30 seconds for a message, the
DECbridge unit attempts to generate a response using the IEEE XID request.

•

If the IEEE XID request fails, the DECbridge unit tries a MOP system-ID
request.

For these reasons, the DECbridge unit never hangs for more than 30 seconds
on an IEEE conforming station, or for more than 60 seconds on any Digital
station that predates the IEEE specifications. If you are monitoring messages
and protocols on your work group Ethernet, you occasionally see these messages.

Using the WGB Address Table for Work Group
Management
The work group bridge Ethernet address table is dynamic: Ethernet addresses
are added to the table when a device first transmits on the network; addresses
are removed when a device does not retransmit for a user-specified period, from
1 to 32767 seconds (about 10 hours). The default is 15 minutes. When a device
is learned or relearned after it has timed out, the address is listed in the lowest
empty entry of the address table.
This continuous learning, timeout, and relearning of the Ethernet addresses
means that devices in a particular work group may or may not be in the address
table at any moment. If they are in the address table, they may not be in a
consistent database location. Devices such as personal computers or laptop
computers that are removed and reconnected elsewhere, timeout from the address
table. When the device is reconnected, the addresses for these devices are stored
in a different address table location.
Because the address table is dynamic, the network manager cannot easily
compare printouts of the work group bridge address table to determine work
group changes on a day-to-day or week-to-week basis.

Management Details B–3

C
Related Documentation
This appendix lists related documentation and provides ordering information.
Document Title

Order Number

DECbridge 90 Owner’s Manual

EK-DEWGB-OM

DECbridge 90FL Owner’s Manual

EK-DEWGF-OM

DEChub 90 Owner’s Manual

EK-DEHUB-OM

Open DECconnect Building Wiring Components
and Application Catalog

EB-K2407-42

DECconnect System Planning and Configuration
Guide

EK-DECSY-CG

Ordering Information
Customers may order documents by phone or mail.

Continental USA and Puerto Rico
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Related Documentation C–1

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C–2 Related Documentation

Index
A
Address number, 4–6
Attached Unit Interface (AUI)
See AUI.
AUI
connector, 1–3
connector pin assignments, A–4
port, 1–1
AUI status indicator, 1–3

B
Backplane, 1–1
connector, 1–3
installation, 3–6 to 3–7
Bridge names
maximum length, 4–3

C
Commands
abbreviations, 4–4
additional, 4–17
arguments and parameters, 4–5
console carrier, 4–4 to 4–6
parameter descriptions, 4–6
Configuration rules
DECrepeater 90FA, 2–1 to 2–5
extended LAN, 2–4
network, 2–2
number of repeaters, 2–1
segment length, 2–1

Connections
backplane, 3–6 to 3–7
power supply, 3–4
standalone, 3–4 to 3–5
ThinWire, 3–4
Connector
AUI, 1–3
backplane, 1–3
fiber-optic receive cable, 1–3
fiber-optic transmit cable, 1–3
port 0 network (BNC), 1–3
power, 1–3
Console carrier
commands, 4–4 to 4–6
to establish a session from ULTRIX,
4–3 to 4–4
to establish a session from VMS, 4–2
to 4–3
user interface, 4–4
Constraints
installed fiber, 2–5
network, 2–2
segment length, 2–1

D
DC OK indicator, 1–3
DEChub 90 backplane
See backplane.
DECrepeater 90FA
backplane troubleshooting, 5–8 to
5–13
configuration rules, 2–1
environmental specifications, A–1

Index–1

DECrepeater 90FA (cont’d)
features, 1–1
managed in backplane, 1–1
operating environment, A–2
physical dimensions, A–1
power specifications, A–3
replacement parts, A–5
shipping environment, A–2
standalone troubleshooting, 5–3 to 5–7
unmanaged as standalone, 1–1
voltage specifications, A–3

E
Error messages
DECbridge 90, 4–18 to 4–20
Ethernet
addresses, 4–2
arbitrary address, 4–3
circuit names, 4–2

F
Fiber-link status indicator, 1–3
Fiber-optic receive connector, 1–3
Fiber-optic transmit connector, 1–3

H
Help command, 4–4
Hub slot number, 4–6

I
IEEE 802.3
AUI compliant, 1–1
CSMA/CD networks, 1–1
FOIRL compliant, 1–1
multisegment LANs, 2–1
ThinWire compliant, 1–1
Indicators
AUI status, 1–3
DC OK, 1–3
fiber-link status, 1–3
network activity, 1–3
port 0 status, 1–3

Index–2

Indicators (cont’d)
port 1 status, 1–3
Installation
backplane, 3–6 to 3–7
environmental requirements, 3–1
standalone, 3–1
tool, 3–1
wall-mount, 3–2 to 3–5

L
LEDs and connectors, 1–2 to 1–3

M
Maintenance Operations Protocol (MOP)
See MOP.
Management
annotating bridge address, B–2 to B–3
components, 4–1
designating a hub manager, B–1 to
B–2
from remote network, 4–14
port partitioning, 4–14
problems, 4–16 to 4–17
session, 4–15 to 4–16
techniques, 4–13
topology map, 4–14
using bridge address table, B–3
MOP
access from ULTRIX, 4–3
access from VMS, 4–2
functions, 4–1 to 4–4

N
Network (BNC) connector, 1–3
Network activity indicator, 1–3
Network Control Program (NCP), 4–2
Networks
10Base2, 1–1
10Base-FL, 1–1
CSMA/CD, 1–1

port numbers, 4–10
show command, 4–10
slot numbers, 4–10

P
Password
at login, 4–3
defining, 4–3
length, 4–7
security, 4–3
Port
AUI, 1–1
fiber-optic, 1–1
number, 4–6
ThinWire, 1–1
Port 0 network (BNC) connector, 1–3
Port 0 status indicator, 1–3
Port 1 status indicator, 1–3
Port partitioning, 5–1
Power supply
auto-ranging, 1–1
connector, 1–3
output voltage, A–3
120 Vac, 1–1
240 Vac, 1–1

R
Repeaters
disabling ports, 4–8

S
Standalone installation, 3–1 to 3–5

T
Troubleshooting
DECrepeater 90FA in DEChub 90
backplane, 5–8 to 5–13
DECrepeater 90FA standalone, 5–3 to
5–7

U
ULTRIX access to MOP, 4–3

V
VMS access to MOP, 4–2

W
Wall-mount installation, 3–2 to 3–5

Index–3