Cabletron Systems TDRMIM-42A, TDRMIM-22A User Manual

TDRMIM-22A/42A

TM

TOKEN RING DUAL REPEATER MIM

USER’S GUIDE

SW1

OFF ON

Switchblock SW1

TDRMIM Quick Reference Card

Front

Panel

Side View of the TDRMIM

12345678

1
2
3
4
5
6
7
8

FNB Ring 1 Speed Default:
[Leave OFF]
[Unused]
[Unused]

Ring Ports 1 Ring In
Ring Ports 1 Ring Out

Keying

Fiber Optic

Ring Ports 2 Ring In

Sequence

Ring Ports 2 Ring Out

Motherboard

Daughterboard

ON = 16 Mbps; OFF = 4 Mbps

ON = 802.5
OFF = ctron

Switchblock SW1 with Factory Default Settings

TRANSMIT +

RECEIVE ­RECEIVE +

TRANSMIT -

RJ45 Lobe Port Pinouts

8
7
6
5
4
3
2
1

QR-1

ALL LED SIGNALS

ERR
ERR

BYP
BYP

MGMT

MGMT

16 MB
16 MB

IN USE

IN USE

IN USE

G

R

G

G

Y

G

Normal operation
Hardware error condition, or reset in process
Module Bypass—No ports inserted in FNB rings
FNB interfaces active
Management control in effect

(hardware default switches overridden)
Hardware defaults in effect
16 Mbps ring speed in effect
4 Mbps ring speed in effect
Ring active

Ring active but bypassed from FNB
Ring inactive (no lobes connected)

12

12

12

12

12

PEN
PEN

LNK

LNK

G

R

G

R

G

G

Port enabled and transmitting
Port linked but disabled by management
Port in standby state
Speed Fault on linked port
Port disabled and not linked

Ring Port set enabled
Ring Port set disabled
Ring Port set linked
Ring Port set disabled, or autowrapped, or

not linked

LEGEND:

= GREEN

G

= RED = off

R

QR-2

= YELLOW

Y

G

R

= Blinking GREEN

= Blinking RED

NOTICE

NOTICE

Cabletron Systems reserves the right to make changes in specifications and other
information contained in this document without prior notice. The reader should in
all cases consult Cabletron Systems to determine whether any such changes have
been made.

The hardware, firmware, or software described in this manual is subject to change
without notice.

IN NO EVENT SHALL CABLETRON SYSTEMS BE LIABLE FOR ANY
INCIDENTAL, INDIRECT, SPECIAL, OR CONSEQUENTIAL DAMAGES
WHATSOEVER (INCLUDING BUT NOT LIMITED TO LOST PROFITS)
ARISING OUT OF OR RELATED TO THIS MANUAL OR THE INFORMATION
CONTAINED IN IT, EVEN IF CABLETRON SYSTEMS HAS BEEN ADVISED OF,
KNOWN, OR SHOULD HAVE KNOWN, THE POSSIBILITY OF SUCH
DAMAGES.



Copyright July, 1995 by:
Cabletron Systems, Inc.
P.O. Box 5005, Rochester, NH 03866-0505

All Rights Reserved.

1

Printed in the United States of America.

Order Number 9031428 July, 1995.

FNB, MMAC, TRXMIM, TRBMIM, TDRMIM, TRMIM, TRMM-2,
4

are trademarks of Cabletron Systems, Inc.

Flexible Network Bus, Multi Media Access Center, SPECTRUM, LANVIEW

and

Remote LANVIEW

IBM

is a registered trademark of International Business Machines Corporation.

DEC

and

VT100

CompuServe

are trademarks of Digital Equipment Corporation.

is a registered trademark of CompuServe, Inc.

are registered trademarks of Cabletron Systems, Inc.

and

TRMM-

,

Printed on Recycled Paper

i

NOTICE

FCC NOTICE

This device complies with Part 15 of the FCC rules. Operation is subject to the
following two conditions: (1) this device may not cause harmful interference, and
(2) this device must accept any interference received, including interference that
may cause undesired operation.

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

WARNING: Changes or modifications made to this device which are not expressly
approved by the party responsible for compliance could void the user’s authority
to operate the equipment.

DOC NOTICE

2

3

This digital apparatus does not exceed the Class A limits for radio noise emissions
from digital apparatus set out in the Radio Interference Regulations of the
Canadian Department of Communications.

Le présent appareil numérique n’émet pas de bruits radioélectriques dépassant les
limites applicables aux appareils numériques de la class A prescrites dans le
Règlement sur le brouillage radioélectrique édicté par le ministère des
Communications du Canada.

CABLETRON SYSTEMS, INC. PROGRAM LICENSE AGREEMENT

IMPORTANT: Before using this product, carefully read this License Agreement.

This document is an agreement between you, the end user, and Cabletron Systems,
Inc. (“Cabletron”) that sets forth your rights and obligations with respect to the
Cabletron software program (the “Program”) contained in this package. The
Program may be contained in firmware, chips or other media. BY UTILIZING THE
ENCLOSED PRODUCT, YOU ARE AGREEING TO BECOME BOUND BY THE
TERMS OF THIS AGREEMENT, WHICH INCLUDES THE LICENSE AND THE
LIMITATION OF WARRANTY AND DISCLAIMER OF LIABILITY. IF YOU DO
NOT AGREE TO THE TERMS OF THIS AGREEMENT, PROMPTLY RETURN
THE UNUSED PRODUCT TO THE PLACE OF PURCHASE FOR A FULL
REFUND.

4

ii

NOTICE

CABLETRON SOFTWARE PROGRAM LICENSE

1. LICENSE. You have the right to use only the one (1) copy of the Program

provided in this package subject to the terms and conditions of this License
Agreement.

You may not copy, reproduce or transmit any part of the Program except as
permitted by the Copyright Act of the United States or as authorized in
writing by Cabletron.

2. OTHER RESTRICTIONS.

disassemble the Program.

3. APPLICABLE LAW. This License Agreement shall be interpreted and

governed under the laws and in the state and federal courts of New
Hampshire. You accept the personal jurisdiction and venue of the New
Hampshire courts.

You may not reverse engineer, decompile, or

EXCLUSION OF WARRANTY AND DISCLAIMER OF LIABILITY

1. EXCLUSION OF WARRANTY.

Cabletron in writing, Cabletron makes no warranty, expressed or implied,
concerning the Program (including Its documentation and media).

Except as may be specifically provided by

5

6

CABLETRON DISCLAIMS ALL WARRANTIES, OTHER THAN THOSE
SUPPLIED TO YOU BY CABLETRON IN WRITING, EITHER EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO IMPLIED WARRANTIES
OF MERCHANTABLITY AND FITNESS FOR A PARTICULAR PURPOSE,
WITH RESPECT TO THE PROGRAM, THE ACCOMPANYING WRITTEN
MATERIALS, AND ANY ACCOMPANYING HARDWARE.

2. NO LIABILITY FOR CONSEQUENTIAL DAMAGES

SHALL CABLETRON OR ITS SUPPLIERS BE LIABLE FOR ANY DAMAGES
WHATSOEVER (INCLUDING, WITHOUT LIMITATION, DAMAGES FOR
LOSS OF BUSINESS, PROFITS, BUSINESS INTERRUPTION, LOSS OF
BUSINESS INFORMATION, SPECIAL, INCIDENTAL, CONSEQUENTIAL,
OR RELIANCE DAMAGES, OR OTHER LOSS) ARISING OUT OF THE USE
OR INABILITY TO USE THIS CABLETRON PRODUCT, EVEN IF
CABLETRON HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
DAMAGES. BECAUSE SOME STATES DO NOT ALLOW THE EXCLUSION
OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL
DAMAGES, OR ON THE DURATION OR LIMITATION OF IMPLIED
WARRANTEES IN SOME INSTANCES THE ABOVE LIMITATIONS AND
EXCLUSIONS MAY NOT APPLY TO YOU.

. IN NO EVENT

iii

NOTICE

UNITED STATES GOVERNMENT RESTRICTED RIGHTS

The enclosed product (a) was developed solely at private expense; (b) contains
“restricted computer software” submitted with restricted rights in accordance
with Section 52227-19 (a) through (d) of the Commercial Computer Software ­Restricted Rights Clause and its successors, and (c) in all respects is proprietary
data belonging to Cabletron and/or its suppliers.

For Department of Defense units, the product is licensed with “Restricted Rights”
as defined in the DoD Supplement to the Federal Acquisition Regulations, Section

52.227-7013 (c) (1) (ii) and its successors, and use, duplication, disclosure by the
Government is subject to restrictions as set forth in subparagraph (c) (1) (ii) of the
Rights in Technical Data and Computer Software clause at 252.227-7013. Cabletron
Systems, Inc., 35 Industrial Way. Rochester, New Hampshire 03866

7

iv

CONTENTS

CHAPTER 1 Introduction

1.1 Using This Manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2

1.2 About the TDRMIM. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-2

1.2.1 Ring In/Ring Out Ports . . . . . . . . . . . . . . . . . . . . . .1-3

1.2.2 Lobe Ports. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-4

1.2.3 Cluster Switching . . . . . . . . . . . . . . . . . . . . . . . . . .1-5

1.2.4 Automatic Configuration at Power-Up. . . . . . . . . . 1-7

1.2.5 Support for Passive MAU Workgroups . . . . . . . . . 1-8

1.2.6 Interaction with Other MIMs in the MMAC . . . . .1-8

1.2.7 LANVIEW LEDs . . . . . . . . . . . . . . . . . . . . . . . . .1-10

1.2.8 Network Management. . . . . . . . . . . . . . . . . . . . . . 1-10

1.3 Supplemental Information . . . . . . . . . . . . . . . . . . . . . . . . 1-10

1.3.1 Related Manuals . . . . . . . . . . . . . . . . . . . . . . . . . .1-10

1.3.2 Recommended Reading . . . . . . . . . . . . . . . . . . . . 1-10

1.3.3 Getting Help . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-11

CHAPTER 2 Requirements and Specifications

2.1 General Cabling Considerations. . . . . . . . . . . . . . . . . . . . . 2-1

2.1.1 Maximum Number of Stations on a Ring. . . . . . . .2-1

2.1.2 Crosstalk and Noise . . . . . . . . . . . . . . . . . . . . . . . .2-1

2.1.3 Installation Recommendations . . . . . . . . . . . . . . . .2-2

2.1.4 Network Performance Requirements . . . . . . . . . . . 2-2

2.2 UTP Cabling Specifications . . . . . . . . . . . . . . . . . . . . . . . . 2-3

2.2.1 UTP Cable Categories. . . . . . . . . . . . . . . . . . . . . . .2-3

2.2.2 UTP Cable Lengths to Stations. . . . . . . . . . . . . . . .2-5

2.3 STP Cabling Specifications . . . . . . . . . . . . . . . . . . . . . . . .2-5

2.3.1 STP Cable Categories. . . . . . . . . . . . . . . . . . . . . . . 2-5

2.3.2 STP Cable Lengths to Stations . . . . . . . . . . . . . . . . 2-6

2.4 Fiber Optic Cable Specifications . . . . . . . . . . . . . . . . . . . . 2-7

2.5 TDRMIM Operating Specifications . . . . . . . . . . . . . . . . . . 2-8

2.5.1 Switchblock SW1 . . . . . . . . . . . . . . . . . . . . . . . . . .2-8

2.5.2 Media Filters. . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-10

2.5.3 Connector Types. . . . . . . . . . . . . . . . . . . . . . . . . .2-10

2.5.4 Ring Sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-11

v

CONTENTS

2.5.5 LANVIEW LEDs . . . . . . . . . . . . . . . . . . . . . . . . .2-12

2.6 Other Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-12

2.6.1 Hardware Specifications. . . . . . . . . . . . . . . . . . . .2-12

2.6.2 Environmental Requirements . . . . . . . . . . . . . . . .2-12

2.6.3 Safety Issues . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-12

2.6.4 Service. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-13

CHAPTER 3 Installation

3.1 General Considerations. . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1

3.2 Installation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-1

3.2.1 Unpacking the TDRMIM . . . . . . . . . . . . . . . . . . . . 3-2

3.2.2 Setting Configuration Switches . . . . . . . . . . . . . . .3-2

3.2.3 Installing the TDRMIM into an MMAC . . . . . . . . 3-2

3.2.4 Boot-Up Check . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-3

3.2.5 Connecting Twisted Pair Cabling. . . . . . . . . . . . . .3-4

3.2.6 Connecting Ring In/Ring Out Cables. . . . . . . . . . . 3-7

3.2.7 Pre-Operational Testing . . . . . . . . . . . . . . . . . . . . .3-7

CHAPTER 4 Testing and Troubleshooting

4.1 Installation Checkout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1

4.2 LANVIEW LED Signals . . . . . . . . . . . . . . . . . . . . . . . . . .4-2

APPENDIX A Introduction to Port Switching

A.1 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-1

A.2 The Flexible Network Bus (FNB). . . . . . . . . . . . . . . . . . . A-1

A.3 Without Port Switching. . . . . . . . . . . . . . . . . . . . . . . . . . . A-1

A.4 With Port Switching . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-2

A.5 Configuration Specifications . . . . . . . . . . . . . . . . . . . . . . A-5

vi

CHAPTER 1

Introduction

Welcome to the

Media Interface Module User’s Guide

Token Ring Dual Port Repeater/Concentrator Switching

. This manual is a reference for the
installation and troubleshooting of Cabletron Systems’ TDRMIM-22A and
TDRMIM-42A modules, represented in Figure 1-1.

The TDRMIM is an active cluster-switching twisted pair concentrator with
dual multimode fiber Ring In/Out repeater ports for Token Ring
expansions. The IEEE 802.5 compliant and IBM compatible TDRMIM is
designed for installation into any Cabletron Systems Multi Media Access
Center (MMAC) equipped with a Flexible Network Bus (FNB).

TDRMIM-22A

1
x

2
x

3
x

4
x

5
x

6
x

SN

RING 1 16Mb
RING 2 16Mb
RING 3 16Mb
RING 4 16Mb

AUX 1 16Mb
AUX 2 16Mb

1
2
3
4
5
6

7
8
9
10
11
12

R

I
N
G

P
O
R
T
S

1

BYP

LNK PEN

RI

LNK PEN

RO

ERR
MGMT
IN USE
IN USE
IN USE
IN USE
IN USE
IN USE

TX

RX

TX

RX

TDRMIM-42A

1
x

2
x

3
x

4
x

5
x

6
x

SN

RING 1 16Mb
RING 2 16Mb
RING 3 16Mb
RING 4 16Mb

AUX 1 16Mb
AUX 2 16Mb

1
2
3
4
5
6

7
8
9
10
11
12

R

I
N
G

P
O
R
T
S

1

BYP

LNK PEN

RI

LNK PEN

RO

ERR
MGMT
IN USE
IN USE
IN USE
IN USE
IN USE
IN USE

TX

RX

TX

RX

Figure 1-1. TDRMIM -22A and TDRMIM-42A

7
x

8
x

9
x

10

x

11

x

12

x

DUAL FIBER REPEATER

LNK PEN

RI

R

I
N
G

P
O
R
T
S

LNK PEN

2

RO

UTP TOKEN RING

TX

RX

TX

RX

7
x

8
x

9
x

10

x

11

x

12

x

DUAL FIBER REPEATER

LNK PEN

RI

R

I
N
G

P
O
R
T
S

LNK PEN

2

RO

STP TOKEN RING

TX

RX

TX

RX

Page 1-1

Using This Manual

1.1 Using This Manual

Prior to installing and operating the TDRMIM, read through this manual
completely. If you are not familiar with port switching and four-ring FNB
applications, read Appendix A,
manual assumes users to have a working knowledge of Token Ring (IEEE

802.5) networks.

Introduction to Port Switching

. This

Chapter 1,

Introduction

, describes how to use this document, provides an
overview of the features and capabilities of the TDRMIM, and concludes
with a list of related manuals.

Chapter 2,

Requirements and Specifications

, lists the network
requirements that must be met before installation, and provides detailed
specifications for the TDRMIM.

Chapter 3,

Installation

, contains instructions for installing the TDRMIM

into an MMAC and attaching Token Ring station cabling.

Chapter 4,

Testing and Troubleshooting

, describes diagnostic checks to
assist in the correction of post-installation problems, and provides
detailed descriptions of LANVIEW LEDs, Cabletron Systems’ visual
diagnostic and status monitoring system.

Appendix A,

Introduction to Four-Ring FNB Functionality,

discusses the

concepts of port switching and port assignment.

1.2 About the TDRMIM

The TDRMIM expands MMAC connectivity through two sets of
multimode fiber optic Ring In and Ring Out ports and twelve active lobe
ports. Designed for use with the TRMM-2 and TRMM-4 Token Ring
Management Modules, it provides MMAC users with the ability to extend
FNB backplane rings through other devices to form collapsed backbone
configurations, and increases connectivity in the hub by 12 lobe ports. The
TDRMIM also offers the following features:

• Complete compatibility with all Token Ring MIMs

• Cluster switching

• Automatic speed fault protection

• Full back-up path redundancy protection from ring out cable faults

• Full signal retiming on Ring In and Ring Out ports

• Active lobe ports for twisted pair connections

Page 1-2

About the TDRMIM

IN USE

RING 2 16Mb

• Cable fault Autowrap on fiber optic trunk ports

• Multi Ring Out connectivity for passive MAU workgroups

• LANVIEW LEDs for “at-a-glance” diagnostic monitoring

1.2.1 Ring In/Ring Out Ports

The dual multimode fiber Ring Port sets (Ring Ports 1 and Ring Ports 2)
support two fully redundant ring extensions to other hubs up to 2 Km
away from the MMAC. As shown in Figure 1-2, each Ring Port set consists
of four ST connectors—a pair of Transmit and Receive ports for Ring In
and another pair for Ring Out.

7
8
9
10
11
12

R
I
N

G
P

O
R

T
S

1

LNK PEN

RI

LNK PEN

RO

LNK PEN

IN USE
IN USE
IN USE
IN USE

TX

RX

TX

RX

1 Ring Ports set = 4 cable connections

Transmit

Ring In

Receive

Transmit

ST Connectors

Ring Out

Receive

Ring Ports 1

1
x

2
x

3
x

4
x

5
x

6
x

7
x

RING 3 16Mb
RING 4 16Mb

AUX 1 16Mb
AUX 2 16Mb

1
2
3
4
5
6

Figure 1-2. One Ring Port Set

With these Ring Ports, two otherwise isolated Token Rings may be joined
via two cable sets—one Ring In and one Ring Out. This is known as a fully
redundant connection because, as both cable sets contain a Transmit line
and a Receive line, either cable set is capable of maintaining the connection
without the other. Under normal operating conditions, only half of each
cable set is active—the Transmit line on the Ring Out set and the Receive
line on the Ring In set. If either cable set fails, the other maintains the ring
connection by automatically activating the second line in its
Receive/Transmit pair to provide a backup path.

Refer to Section 1.2.3,
assignments.

Cluster Switching

, for details about FNB Ring

Page 1-3

About the TDRMIM

Repeater Circuitry

The Ring Port sets provide circuitry that completely retimes and repeats
all received signals before transmitting them to the next point on the ring.
This enhances signal integrity and makes adjusted ring length (ARL)
computations unnecessary: maximum trunk cable distances are extended
to 2 Km.

Ring Speed Fault Protection

TDRMIMs provide ring speed fault protection on each Ring Port to protect
against beaconing conditions caused by ring speed mismatches between
the host hub’s ring and the ring on the externally connected hub. If there
is a mismatch between the ring speeds of the incoming signal and the
destination ring, the TDRMIM keeps the Ring Port looped back on itself to
protect the hub from the conflict. When the speed mismatch condition is
eliminated, the port comes out of loopback mode.

1.2.2 Lobe Ports

1

2

Each TDRMIM is equipped with 12 lobe ports—female RJ45 modular
connector jacks—for TCU (Trunk Coupling Unit) or Multi Ring Out
connections. TDRMIM-22A supports UTP cabling (Unshielded Twisted
Pair) and TDRMIM-42A supports STP (Shielded Twisted Pair). The RJ45
connectors used in the TDRMIM-42A (for STP cabling) provide a
grounded connection for the cabling shield.

Refer to Section 1.2.3,

Cluster Switching

, for details about port-to-FNB

Ring assignments.

TCU and Multi Ring Out Configurations

BY default, each lobe port on the TDRMIM operates as a TCU to support
the insertion of a Token Ring station into a ring; however the Local
Management (LM) application on a management module (such as
TRMM-4) may be used to reconfigure any of these TCU ports to function
as Multi Ring Out ports to support the connection of passive network
devices. See Section 1.2.5,

Support for Passive MAU Workgroups

.

1

Active Circuitry

Each lobe port provides circuitry which filters, equalizes, and amplifies all
received signals before transmitting them to the next point on the ring. The

Page 1-4

2

About the TDRMIM

82

result is enhanced signal integrity and extended maximum lobe cable
distances. For length specifications for UTP and STP lobe cables, see
Section 2.2.2,

Lengths to Stations

UTP Cable Lengths to Stations

.

and Section 2.3.2,

STP Cable

Ring Speed Fault Protection

TDRMIMs provide Ring Speed Fault Protection on each lobe port to
protect against beaconing conditions caused by stations inserting at the
wrong ring speed. If there is a mismatch between the ring speeds of the
incoming signal and the destination ring, the TDRMIM keeps the lobe port
looped back on itself to keep the misconfigured station from disrupting
the ring. When the mismatch condition is eliminated, the port comes out
of loopback mode.

1.2.3 Cluster Switching

The ports of the TDRMIM are permanently grouped into two Clusters:
Cluster 1 comprises lobe ports 1-6 and Ring Ports 1, Cluster 2 comprises
lobe ports 7-12 and Ring Ports 2 (see Figure 1-3). These Clusters switch as
collective units; rather than taking port assignments on a port-by-port
basis, TDRMIMs take assignments on a per-Cluster basis and switch their
corresponding ports collectively. The TDRMIM is therefore called a
cluster-switching MIM.

3

93
104
115
126

1

LNK

PEN

TX

RI

RX

LNK

PEN

LNK

PEN

Lobe Ports 1-6

Ring Ports 1

Lobe Ports 7-12

LNK

PEN

Ring Ports 2

Cluster 1

Cluster 2

X
2

X
3

X
4

X
5

X
6

X

7
X

8
X

9
X

10

X

11

X

12

X

Figure 1-3. Port Clusters of the TDRMIM

and

and

Page 1-5

About the TDRMIM

Port-Switching MIMs

As with port-switching MIMs, the cluster-switching TDRMIM requires
the support of a port-assigning management module such as the TRMM-2
or TRMM-4 to switch its connections. With this support, the Clusters may
be individually assigned to any of the four vertically stacked FNB rings
(illustrated in Figure 1-4) on the MMAC backplane.

TRMM-4

CRM2-R/T

TSXMIM

TDRMIM

TRXMIM

TRXMIM

TRXMIM

TRXMIM

FNB ring 1
FNB ring 2
FNB ring 3
FNB ring 4

Figure 1-4. FNB Expanded to Four Rings by Port Switching MIMs

To assign and change a Cluster’s FNB connection from one ring to another,
simply issue a new port assignment through the network management
interface provided by a port-assigning management module such as the
TRMM-2/TRMM-4 or through a remote management system (see Section

1.2.8,

Network Management

). The TDRMIM receives such commands

and switches the specified Cluster’s connection internally.

Either Cluster may be assigned to any of the four FNB rings. When a
Cluster is switched, all stations and ring extensions attached through the
Cluster’s lobe ports and ring ports are thereby transplanted onto the
newly assigned ring. Therefore, when preparing to switch a Cluster’s ring
assignment, take care to consider the number of stations currently inserted
on the proposed destination ring and the number inserted through the
Cluster to be switched. If the total number of stations inserted in these two
locations exceeds the maximum station limit for a single ring, do not
execute the switch. Also, make sure that the rings are operating at the
same ring speed.

NOTE

When using the TDRMIM in an MMAC managed by a TRMM-2,
which has a permanent interface with FNB ring 1, the firmware on
the TRMM-2 rejects instructions to switch either Cluster onto

Page 1-6

About the TDRMIM

FNB 1 while the TRMM-2’s STATION port interface is operating
through that Cluster. For if allowed, such a switch would create the
prohibited condition of redundant management on FNB 1.

1.2.4 Automatic Configuration at Power-Up

The management module in the TDRMIM’s host MMAC stores all
user-configured ring assignments and speed settings in its battery-backed
NVRAM (Non-Volatile Random Access Memory). Upon TDRMIM reset,
the MMAC’s resident management module reissues its stored
configurations to the TDRMIM so that all ring assignments and speed
settings established before power-down are reinstated at next power-up.

Instructions from a management module always override the TDRMIM’s
hardware defaults. However, there are two conditions under which the
TDRMIM will not receive management configuration instructions:

• no functional management module is present in the hub; or

• the TDRMIM is not recognized by the management module—either
the TDRMIM is powering up for the first time in its current hub slot,
or the latest hub configuration has been cleared from the management
module’s NVRAM.

If the TDRMIM does not receive management configuration instructions
at start-up, it uses its hardware defaults for ring speed and ring
assignment configurations.

Hardware Default Configuration

The TDRMIM’s default ring speed for FNB Ring 1 is user-configurable.
Use Switch #1 on SW1 (see Section 2.5.1,

Switchblock SW1

) to select a
default ring speed of either 4 Mbps or 16 Mbps for FNB Ring 1. All other
rings default to 16 Mbps.

The TDRMIM’s default ring assignments are factory set (are not
user-configurable): Cluster 1 defaults to FNB ring 1 and Cluster 2 defaults
to FNB ring 2. Because of these default assignments, even in the absence of
a port-assigning management module to address FNB rings 2-4, all
contiguously installed TDRMIMs connect to each other across both FNB
ring 1 and FNB ring 2. Therefore, in addition to the usual Token Ring on
FNB ring 1, TDRMIM defaults provide for a second fully viable (though
possibly unmanaged) Token Ring on FNB ring 2.

1

Page 1-7

About the TDRMIM

1.2.5 Support for Passive MAU Workgroups

The TDRMIM’s RJ45 lobe ports default to their TCU configuration to
support station connections, but they also offer a Multi Ring Out override
to support connections to passive MAU (Multi-Station Access Unit)
workgroups. Because a passive MAU cannot provide the phantom current
that a station sends down its lobe cable to signal a TCU to open its
interface, the Multi Ring Out configuration directs the port to look for the
presence of data bits rather than for phantom current to determine link
status. Use a management interface to activate the Multi Ring Out
override on selected lobe ports.

NOTE

The LANVIEW LED output for a Multi Ring Out port is quite
different from the output for a TCU port. See Section 4.2 for a
discussion of this and all other LED signal details.

Improved Protection from Beaconing

Multi Ring Out lobe ports provide enhanced reliability for networks that
use passive MAUs by allowing for the separate attachment of each MAU.
Whereas Ring In/Ring Out MAU connection schemes daisy-chain MAUs
together as a single entity and risk their collective isolation in case of
beaconing (see Figure 1-5), the Multi Ring Out method attaches each MAU
individually to its own lobe port. The Beacon Recovery process can then
bypass problematic ring-to-MAU connections individually, leaving all
other workgroups unaffected. The Multi Ring Out configuration thereby
reduces the number of MAU ports that are at risk of collective isolation in
case of beaconing on a MAU port.

1.2.6 Interaction with Other MIMs in the MMAC

1

When configured with identical ring speed settings, Token Ring MIMs
connect to each other via the continuous FNB rings on the MMAC
backplane.

FNB ring 1 is always available in all MMAC slots, but FNB rings 2, 3, and
4 are extended across the MMAC only where there are multi-ring modules
to carry them. Because single-ring MIMs do not have port-switching
capability and

cannot

support connections across FNB rings 2, 3, or 4, any
single-ring MIM installed between multi-ring MIMs will break the continuity of
FNB rings 2, 3, and 4. To maintain ring continuity, install all MIMs with

multiple ring access (all port-switching or cluster-switching MIMs) in the
right-most slots of the MMAC where they will have contiguous contact
with each other and with the hub’s management module.

Page 1-8

About the TDRMIM

DAISY-CHAIN CONFIGURATION

When MAUs are daisy-chained, they are connected as a single
collective entity. To isolate the hub from a beaconing MAU station,
the entire chain must be bypassed. All MAU stations lose their
connection to the hub if beaconing occurs on just one MAU station.

Ring
Out

Ring
Out

Ring
Out

Ring
Out

Ring

Out

Ring

In

Ring

In

Ring

In

Ring

In

Ring

In

(8 Stations)

(8 Stations)

(8 Stations)

(8 Stations)

MULTI RING OUT CONFIGURATION

When each MAU is individually connected to the TDRMIM, only
one MAU must be bypassed to isolate the hub from a beaconing

MAU station. The stations on that MAU still go down, but the
remaining MAUs and their stations stay operational.

Multi-Station

Access Units

Ring

Out

Ring

Out

Ring

Out

Ring

Out

Figure 1-5. Improved Beacon Recovery Resolution for MAUs

Ring

In

Ring

In

Ring

In

Ring

In

(8 Stations)

(8 Stations)

(8 Stations)

(8 Stations)

Ring
Out

Ring
Out

Ring
Out

Ring
Out

Multi-Station

Access Units

Page 1-9

Supplemental Information

1.2.7 LANVIEW LEDs

The LANVIEW LED system comprises several LEDs, located on the front
panel of the TDRMIM. Operating as an “at-a-glance,” visual diagnostic
and status monitoring system, they light, blink, and flash in various colors
to indicate various network and module-specific conditions, thereby
facilitating the quick diagnosis of physical layer network problems. The
system is discussed in detail in Section 4.2, LANVIEW LED Signals.

1.2.8 Network Management

With a management module installed in slot 1 of the MMAC, the
TDRMIM and other modules in the hub can be monitored and controlled
through a variety of network management tools including Cabletron
Systems’ Remote LANVIEW/Windows and SPECTRUM packages for
remote management, as well as the Local Management interface built into
each management module. Any Token Ring management module may be
used to manage the TDRMIM’s port Clusters on FNB ring 1, but only a
management module that supports port switching can fully manage both
port Clusters on two separate FNB rings.

1.3 Supplemental Information

1.3.1 Related Manuals

Use the manuals listed below to supplement the procedures and technical
data provided in this manual.

Cabletron Systems TRXMIM-22A/24A/42A/44A User’s Guide

(PN 9031265)

Cabletron Systems TRMM-2 Dual Port Token Ring Management
Model User’s Guide (PN 9031287)

Cabletron Systems TRMM-2 Local Management User’s Guide
(PN 9031389)

1.3.2 Recommended Reading

For further information regarding the implementation of Token Ring
networks, refer to the following publications:

Local Area Networks, Token Ring Access Method, IEEE Standard

802.5 (1989)

Page 1-10

Supplemental Information

Commercial Building Wiring Standard, EIA Standard Proposal No.
1907-B (if approved, to be published as EIA/TIA-568)

LAN Troubleshooting Handbook, Mark Miller (1989, M&T

Publishing)

1.3.3 Getting Help

If you need additional support related to Cabletron Systems Token Ring
products, or if you have any questions, comments, or suggestions related
to this manual, please contact Cabletron Systems Technical Support:

By phone: [phone]

Monday-Friday; 8am - 8pm EST

By CompuServe: GO CTRON from any ! prompt

By Internet mail: [e-mail]

By Fax: [phone]

By BBS: [phone]

By FTP: ctron.com (134.141.197.25)

Login: anonymous
Password: your email address

By United States Cabletron Systems, Inc.

Postal Service: P.O. Box 5005

Rochester, NH 03866-5005

Page 1-11

CHAPTER 2

Requirements and Specifications

Before installing the TDRMIM, review the recommendations and
requirements outlined in this chapter. Failure to follow these guidelines
could result in poor network performance.

2.1 General Cabling Considerations

Take care in planning and preparing the cabling and connections for the
network. The reliability of data transmission on the network depends on
the LAN’s susceptibility to error-inducing crosstalk and noise. The quality
of the LAN’s connections and cables are critical factors in determining
susceptibility.

All devices connected to the TDRMIM must meet IEEE 802.5 Token Ring
specifications.

2.1.1 Maximum Number of Stations on a Ring

The recommended maximum number of stations in a single ring is 250
stations if only STP lobe cabling is used. If UTP cabling is used anywhere
on the ring, the recommended maximum is 150 stations.

The number of lobe ports available through the hub may be increased

TIP

2.1.2 Crosstalk and Noise

Crosstalk is interference caused by electrical signal coupling between
different cable pairs contained within a multi-pair cable bundle. Crosstalk
and other externally induced electrical impulses may cause error-inducing
noise. Outside systems (motors, switching equipment, fluorescent
lighting, high amperage equipment) may produce electrical interference
(noise). The number and quality of cable connections also contribute
considerably to noise levels. To eliminate noise-induced errors, re-route
cabling away from potential noise sources, ensure that electrical wiring is
properly wired and grounded, and replace connectors along affected
segments.

by the use of passive MAUs (refer to Section 1.2.5).

Page 2-1

General Cabling Considerations

2.1.3 Installation Recommendations

For optimum network performance, make sure that twisted pair cabling
installations comply with the following recommendations:

• Keep UTP cabling free of splices, stubs, or bridged taps.

• Do not use more than two punch-down blocks between TCU ports

and wall outlets.

• Properly ground all metal troughs, ducts, etc. carrying Token Ring

cabling.

• Route cables away from sources of electrical noise, such as power

lines, fluorescent lights, electric motors, radio interference, and heavy
machinery.

• Do not route Token Ring signals through UTP cables that exit a

building or that are adjacent to cables either exiting a building or
exposed to lightning strikes and power surges.

• Where practical, use dedicated cable for Token Ring signals.

• Avoid using multi-pair cable bundles for UTP lobe cabling.

• Avoid mixing Token Ring signals with other application signals

(voice, etc.) within the same metallic cable bundle. Do not bundle UTP
cables for Token Ring signals with cables carrying other applications
which may impress high voltages (greater than 5 volts) with sharp rise
or fall times.

• Make sure that work-area wall plates and outlets used for the Token

Ring network are clearly labeled, “Token Ring Only.”

• To ensure that cable attenuation remains within specifications, use

only plenum-rated cables in areas where temperatures exceed 40˚C.
(The attenuation of PVC-insulated cable varies significantly with
temperature. Check the cable manufacturer’s specifications.)

2.1.4 Network Performance Requirements

Token Ring network cabling must meet the following performance
requirements:

Page 2-2

UTP Cabling Specifications

Table 2-1. Token Ring Network Performance Requirements

Maximum

Total

Signal

Attenuation

Maximum

Total

Ambient

Noise

Minimum

NEXT*

loss

per 100 m

≤ 14.5dB ≤ 20 dBmV ≥ 30.5 dB

*NEXT = Near-End Crosstalk

All STP cables of IBM Type 1, 2, 6, and 9 meet Token Ring network
performance requirements. All category 5, all category 4, and some
category 3 (see Section 2.2.2, UTP Cable Lengths to Stations) UTP cables
also meet these requirements. However, signal integrity relies not only
upon the quality of the cable but also upon the quality of the connections.
The connectors or terminators used add considerable losses and may drive
signal attenuation below performance requirements. Choose and install
connectors with care.

To reduce total signal attenuation, reduce lobe lengths and upgrade cables
and connectors.

2.2 UTP Cabling Specifications

The TDRMIM-22A supports D-inside wiring (DIW) voice grade UTP cable
as described in EIA SP-1907B and below. All category 5, all category 4,
and some (see Section 2.2.2, UTP Cable Lengths to Stations) category 3
UTP cables meet Token Ring network performance requirements.

2.2.1 UTP Cable Categories

The TDRMIM-22A supports UTP cables classified as category 3, 4, and 5.

UTP cable is categorized according to the following specifications.

Page 2-3

UTP Cabling Specifications

Table 2-2. UTP Cable Category Specifications

UTP

Cat.

Operating

Frequency

Electrical

Impedance

Signal

Attenuation

per 100m

NEXT

loss

(@ ≥100m)

3 4 MHz ≤ 100Ω ±15% ≤ 5.6 dB ≥ 32 dB

16 MHz ≤ 100Ω ±15% ≤ 13.1 dB ≥ 23 dB*

4 4 MHz ≤ 100Ω ±15% ≤ 4.3 dB ≥ 47 dB

16 MHz ≤ 100Ω ±15% ≤ 8.9 dB ≥ 38 dB

5 4 MHz ≤ 100Ω ±15% ≤ 4.3 dB ≥ 63 dB

16 MHz ≤ 100Ω ±15% ≤ 8.2 dB ≥ 44 dB

*below Token Ring performance requirement of ≥ 30.5 dB.

Category 3 usually consists of four Unshielded Twisted Pairs of 24 AWG
solid wire for data or voice communication. (IBM Type 3 is coincidentally
the same as UTP Category 3.) It is typically used to wire cable runs within
the walls of buildings. In some installations, pre-existing UTP building
wiring can be used for Token Ring cabling.

At 16 Mbps ring speeds, some Category 3 cable does not meet the

WARNING

performance requirements of a Token Ring network. This may
impose lower limits on lobe cable distances and ring node counts.
See Table 2-2.

Categories 4 and 5 are higher quality versions of Category 3. They use the
same gauge of wire but demonstrate superior performance due to
improvements in material quality and assembly (e.g. more twists per foot).

Because Near-End Crosstalk (NEXT) contributes the majority of its

WARNING

detrimental effects near the end of a lobe cable, the quality of jumper
cables and patch cables is most critical. Seek the highest practical
grade. The quality of connectors and terminators is also critical.

Telephone battery and ringing voltages used in UTP telephone

WARNING

circuits could present a shock hazard and can damage Token Ring
equipment if connected to Token Ring cabling. DO NOT connect

UTP cabling to any non-Token Ring network conductors
(telephone, etc.) or ground. If in doubt, test wiring before using.

Page 2-4

STP Cabling Specifications

2.2.2 UTP Cable Lengths to Stations

The physical length of the cable connecting a station to a TCU port on the
concentrator is referred to as the lobe length. The maximum lobe length
attainable with the concentrator, under ideal conditions, is shown in Table
2-3. Cable routing, connector attenuation, noise, and crosstalk can
adversely affect the maximum lobe length.

Table 2-3. UTP Maximum Lobe Lengths.

Maximum Lengths

UTP

Category

@ 4 Mbps @ 16 Mbps

meters (feet) meters (feet)
3 200 (656) 100* (328)*
4 225 (738) 110 (360)
5 250 (820) 120 (393)

*for cable with NEXT loss ≥ 30.5 dB per 100m

Some UTP category 3 cables fail to meet the performance minimums
required to support a Token Ring network. Whereas category 3 allows for
near end crosstalk (NEXT) loss as low as 23 dB per 100 m at 16 Mbps,
Token Ring performance requirements demand a NEXT loss of at least

30.5 dB. When using Category 3 cables, consider safeguarding against
worst case conditions (running at 16 Mbps and using category 3 cable with
the category’s lowest qualifying NEXT loss—23 dB) by keeping lobe
lengths shorter than the recommended maximum to keep crosstalk
interference within acceptable levels.

2.3 STP Cabling Specifications

The TDRMIM-42A supports all STP cables classified as IBM Types 1, 2, 6,
and 9. All cables meeting the criteria for classification as IBM Type 1, 2, 6,
or 9 meet Token Ring network performance requirements.

2.3.1 STP Cable Categories

The supported STP cable types meet the following specifications:

Page 2-5

STP Cabling Specifications

Table 2-4. STP Cable Type Specifications.

IBM

Type

Operational

Frequency

Impedance

Attenuation per...

1000 m (1000 ft)

1 & 2 4 MHz ≤ 150Ω ±15% ≤ 22 dB (≤ 6.7 dB)

16 MHz ≤ 150Ω ±15% ≤ 45 dB (≤ 13.7 dB)

6 & 9 4 MHz ≤ 150Ω ±15% ≤ 33 dB (≤ 10.0 dB)

16 MHz ≤ 150Ω ±15% ≤ 66 dB (≤ 20.0 dB)

IBM Type 1 consists of two shielded twisted pairs (STP) of 22 AWG solid
wire for data. It is often used for the longest cable runs within the walls of
buildings.

IBM Type 2 consists of six pairs of unshielded twisted pairs of 24 AWG
solid wire and a shield casing. The two pairs carried within the shield
casing are used to carry Token Ring data. The four pairs carried outside of
the shield casing are typically used for voice communication. Type 2 is
frequently used to wire cable runs within the walls of buildings.

IBM Type 6 consists of two STP of 26 AWG stranded wire for data.
Because of its high attenuation, Type 6 is used only in patch panels or to
connect devices to/from wall jacks. Attenuation for Type 6 cable is 3/2 x
Type 1 cable (attenuation for 66 m of Type 6 = attenuation for 100 m of
Type 1).

IBM Type 9 is similar to Type 1, but uses 26 AWG solid wire. Like Type 6,
because of its high attenuation, Type 9 is used only in patch panels or to
connect devices to/from wall jacks. Attenuation for Type 9 cable is 3/2 x
Type 1 cable (66 m of Type 9 = 100 m of Type 1).

2.3.2 STP Cable Lengths to Stations

The physical length of the cable connecting a station to a TCU port on the
concentrator is referred to as the lobe length. The maximum lobe length
attainable with the concentrator, under ideal conditions, is shown in Table
2-5. Cable routing, connector attenuation, noise and crosstalk can
adversely affect the maximum lobe length.

Page 2-6

Fiber Optic Cable Specifications

Table 2-5. STP Maximum Lobe Lengths.

Maximum Length

STP

Types

@ 4 Mbps @ 16 Mbps

meters (feet) meters (feet)
1 & 2 300 (984) 150 (492)
6 & 9 200 (656) 100 (328)

Mixed STP Cable Types 1

If cable types are to be mixed in the installation, compensations must be
made for the different cable attenuations. For example, Type 6 & 9 cables
can be run for only 2/3 the distance of Type 1: 100 meters (Type 1) ≈ 66
meters (Types 6, 9).

2.4 Fiber Optic Cable Specifications

Table 2-6 defines total signal attenuation tolerances for multimode fiber
cabling. Each connector on the cable system contributes significant
additional attenuation. Maximum drive distances define maximum
allowable cable length.

Table 2-6. Signal Tolerances for Multi-mode Fiber Optic Cable

Cable T ype

Acceptable

Attenuation

50/125 µm 13.0 dB or less 2 km (2187.2 yards)

62.5/125 µm 16.0 dB or less
100/140 µm 19.0 dB or less

Typical Signal Attenuation Rate: ≤ 2.5 dB/km.

NOTE

The attenuation values shown include the attenuation attributable
to cables, connectors, patch panels, and reflection losses due to
impedance mismatches in the segment.

Maximum

Drive Distance

Page 2-7

TDRMIM Operating Specifications

2.5 TDRMIM Operating Specifications

This section describes the operating specifications for each of the active
Token Ring concentrator modules. Cabletron Systems reserves the right to
change these specifications at any time without notice.

2.5.1 Switchblock SW1

The TDRMIM has a switchblock called SW1 (see Figure 2-1). Use its
switches (see Figure 2-2) to configure the following:

• Default Speed of FNB ring 1: 4 or 16 Mbps

• Default Ring Assignments (Cascade): ON (both Clusters on FNB
ring 1) or OFF (Cluster 1 on FNB ring 1 and Cluster 2 on FNB ring 2)

• Fiber Optic Keying Sequence of each Ring port: 802.5 or Ctron

SW1

Switchblock SW1

Motherboard

Daughterboard

Figure 2-1. Location of SW1.

Front

Panel

Page 2-8

12345678

OFF ON

1

FNB Ring 1 Speed Default:

TDRMIM Operating Specifications

ON = 16 Mbps; OFF = 4 Mbps
2
3
4
5
6
7
8

[Leave OFF]
[Unused]
[Unused]

Ring Ports 1 Ring In
Ring Ports 1 Ring Out

Keying

Fiber Optic

Ring Ports 2 Ring In

Sequence

Ring Ports 2 Ring Out

ON = 802.5
OFF = ctron

Figure 2-2. Switchblock SW1 with Factory Default Settings

Default Ring Speed of FNB Ring 1 1

Use Switch #1 to set the default ring speed for FNB ring 1: ON for
16 Mbps, and OFF for 4 Mbps. All other rings default to 16 Mbps.

This switch setting is relevant only in the absence of configuration
commands from a management module.

NOTE

The ring speed setting is a factor in determining maximum lobe
length. Refer to Section 2.2.2 and Section 2.3.2 for details.

Cascade Switch 2

Do not move Switch #2 out of the OFF position.

Keying Sequence of each Ring In and Ring Out Port 3

Use Switches #5, 6, 7, & 8 to select the fiber optic keying sequence—802.5
or Ctron—for each corresponding Ring In or Ring Out port. All Cabletron
devices with Fiber Optic ports support Ctron sequencing.

NOTE

There is currently no 802.5 standard for interoperability between
vendors for trunk (RI/RO) ports. The TDRMIM’s 802.5 keying
sequence may not support all devices from all vendors.

Page 2-9

TDRMIM Operating Specifications

2.5.2 Media Filters

When connecting Token Ring stations that are not equipped with a Type 3
Media Filter to the TDRMIM-22A (UTP), install a Type 3 Media Filter
(such as the Cabletron Systems TRMF or TRMF-2) in line with the lobe
cable at the Token Ring station connection.

2.5.3 Connector Types

TCUs for Twisted Pair Cabling 1

The TDRMIM’s lobe ports are internally crossed-over to provide
connection of straight-through station lobe cabling. Figure 2-3 shows the
pinouts required for RJ45 lobe connections.

8

TRANSMIT +

RECEIVE ­RECEIVE +

TRANSMIT -

7
6
5
4
3
2
1

Figure 2-3. Lobe Port Pinouts.

Each RJ45 connector is encased in a metallic shield that provides a means
of connection for the STP cable shield. When STP patch cabling is used,
contacts within the female RJ45 maintain shield continuity by contacting
the metallic casing of the male RJ45 on the STP lobe cable.

Shielded patch cables that adapt a shielded RJ45 to a Data Connector
(MIC) are available from Cabletron Systems in eight-foot lengths. These
adapter/patch cables permit connection to an existing patch panel
equipped with MIC connectors. (See Figure 2-4)

Page 2-10

RJ45 Plug

TDRMIM Operating Specifications

MIC Connector

Black

18

Green

Orange

Transmit -..... Pin 3.......to......Black....... Transmit -

Receive +..... Pin 4....... to ......Blue.........Receive +

Receive -..... Pin 5....... to ......Green.....Receive -

Transmit +..... Pin 6....... to......Orange... Transmit +

Blue

Figure 2-4. STP Adapter/Patch Cable (PN 9372057-8)

ST Connectors for Fiber Optic Cabling 1

The Ring Port sets incorporate ST (Stab & Twist) connectors for fiber optic
cable connections.

2.5.4 Ring Sequence

When multiple Token Ring MIMs (set to the same ring speed) are installed
in adjacent slots within an MMAC, they are attached via the FNB and
create a larger ring network. Multiple Token Ring MIMs are automatically
attached (when possible) at power on, but the configuration can be
modified via network management software, attaching or detaching
adjacent MIMs.

The ring sequence for the stations on each ring (the order in which stations
are logically arranged on the ring) is determined by the physical location
of each station connection in the MMAC. It progresses in ascending slot
and port number order. There is a separate ring sequence for each ring,
and the sequence changes each time a station inserts or de-inserts from a
ring.

To determine the ring sequence, consider only those ports inserted into the
specified ring. Begin with the lowest numbered (right-most) slot and list
(in numerical order) each port inserted into the ring. Repeatedly move to
the next slot (one position to the left) and list the inserted ports in
numerical order until all ports inserted into the ring have been listed. The

Page 2-11

Other Specifications

order is continuous, wrapping directly from the MMAC’s last inserted
port to the first—from the bottom of the list, right back to the top.

2.5.5 LANVIEW LEDs

There are a number LEDs on the front panel of each TDRMIM. Each
individually labelled LED uses a simple combination of colors and
ON/OFF states to provide information about its attributed component.
These components include ring speeds (16Mb) for each ring, ring in use
(IN USE) for each ring, module-level bypass (BYP), module error (ERR),
management (MGMT) or default mode, and port status (PORT) for each
port. Section 4.2, LANVIEW LED Signals, discusses in detail the function
of each LANVIEW LED.

2.6 Other Specifications

2.6.1 Hardware Specifications

Ports: 12 RJ45 active TCUs and

Backplane Connections: FNB rings 1-4
Lobe Cables Supported:

TDRMIM-42A: IBM Type 1, 2, 6, 9 (STP)
TDRMIM-22A: EIA/TIA category 3, 4, 5 (UTP)

RI/RO Cables Supported: Multi-mode fiber

Physical Dimensions: 11.5"H x 2"W x 13.4"D

2.6.2 Environmental Requirements

Operating Temperature: 5º to 40º C

Storage Temperature: -30º to 90º C

Relative Humidity: 5% to 95% non-condensing

8 Multi-mode Fiber Optic STs
forming 2 RI/RO port sets

2.6.3 Safety Issues

NOTE

It is the responsibility of the vendor of the system to which the
TDRMIM will be a part to ensure that the total system meets
allowed limits of conducted and radiated emissions.

Page 2-12

Other Specifications

This product conforms to the following standards:

Safety 1

• UL 1950

• CSA C22.2 No.950

• EN 60950

EMI 2

• FCC Part 15 Class A

• EN 55022 Class A

• VCCI Class I

EMC 3

• EN 50082-1

• IEC 801-2

• IEC 801-3

• IEC 801-4

2.6.4 Service

MTBF

(Mean Time Between Failure): 603,339 hrs.

Page 2-13

CHAPTER 3

Installation

This chapter explains how to install the TDRMIM into a Cabletron
Systems MMAC product and to connect network devices to the
TDRMIM’s lobe ports.

This unit must be installed by qualified personnel only. Failure to

!

CAUTION

3.1 General Considerations

Before installing and operating the TDRMIM, confirm that the network
meets the requirements listed in Chapter 2, Requirements and
Specifications. Consider the following guidelines at installation:

follow instructions could result in the presence of a shock hazard.

• Install the TDRMIM into any slot in the MMAC except the rightmost,
Slot 1.

• Install a Power Supply Module (PSM) in the MMAC’s power supply
slot. Use two power supply modules with an MMAC-8FNB for power
supply redundancy.

Multiple Token Ring products within an MMAC automatically
interconnect at power on unless the MMAC has no FNB; without the FNB,
the individual MIMs do not interconnect, but rather form independent
Token Ring LANs.

NOTE

Establishing a network path between a Token Ring network and another
network type (i.e., FDDI or Ethernet) requires the use of a bridging device.

The FNB is a full-height, full-width backplane that links Cabletron
Systems Token Ring products. To provide greater configuration
flexibility for MMAC-3s and MMAC-8s, upgrade them with an
FNB. Contact Cabletron Systems’ Technical Support for more
information.

3.2 Installation

Contact Cabletron Systems Technical Support if problems are discovered
during unpacking or installation.

Page 3-1

Installation

3.2.1 Unpacking the TDRMIM

Unpack and visually inspect the TDRMIM for damage:

Electrostatic Discharge (ESD) can damage the module. Take

!

CAUTION

1. Carefully remove the TDRMIM from the shipping box. Save the box
and materials for future transport.

2. Remove the TDRMIM from its static resistant bag and set it on top of
the bag in a static free area. This will help to prevent ESD damage.

3.2.2 Setting Configuration Switches

Refer to Section 2.5.1, Switchblock SW1, and set the switches to configure
the TDRMIM to the desired parameters. The switchblock controls the
default rings speed for FNB ring 1 and the keying sequence for each ring
port.

precautions against ESD. When handling the module, hold only the
edges of the board or the metal front panel. Avoid touching the
components or surface of the board.

3.2.3 Installing the TDRMIM into an MMAC

The installer should be prepared to monitor the LANVIEW LEDs as

TIP

TIP

Install the TDRMIM into the MMAC as follows:

1. Remove the coverplate from the selected MMAC slot and slide the
TDRMIM into the MMAC chassis (see Figure 3-1). Be sure that the
card is in the card guides at the top and bottom of the chassis.

2. Ensure complete insertion of the module into the MMAC by
tightening the knurled knobs. Failure to firmly secure the MIM may
result in its improper operation.

described in Section 3.2.4. Because the sequence may proceed
rapidly, please read Section 3.2.4 to prepare for this task before
actually installing the TDRMIM.

Although the TDRMIM may be “hot swapped” when servicing,
Cabletron Systems recommends powering-down the hub before
installing any module, whenever practical.

Page 3-2

MMAC M8 FNB

S

Installation

TRMM-4

SN

RESET

CPU

LWRPLWRP
NSRTNSRT
16Mb16Mb
XMTXMT
RCVRCV

R

R

I

I

N

N

G

G

TDRMIM-22A

1

2

SN

ERR

LWRPLWRP

MGMTBYP

RING1 16Mb

NSRTNSRT

INUSE
INUSERING2 16Mb

16Mb16Mb

RING3 16Mb

INUSE

XMTXMT

INUSERING4 16Mb

RCVRCV

INUSEAUX1 16Mb
INUSEAUX2 16Mb

R

R

I

I

71

N

N

82

G

G

93
104

3

4

115
126

1

LNKPEN

X
2

TX

X

RI

R

RX

3

I
N

X

G
P
O

LNKPEN

R

4

T
S

X

C

1

O
M

5

TX

1

X

RO

6

RX

X

C
O
M

LNKPEN

7

2

X

TX

8

RI

X

R

RX

I
N
G

TOKENRING

9

P
O

X

R
T
S
2

10

LNKPEN

X

TX

11

RO

X

RX

12

X

DUALFIBER REPEATER

UTP TOKEN RING

Figure 3-1. Installing the TDRMIM into the MMAC

KNURLED KNOB

3.2.4 Boot-Up Check

Table 3-1 describes the LANVIEW LED activity for three instances of
TDRMIM operation. The first represents the moment of power-on. The
second and third both represent possible post boot-up modes:
management mode and default mode.

Because this is presented to assist in installation, it is assumed that no lobe
cables are attached to the TDRMIM at the moment of power-up. For more
detailed information on the significance of LANVIEW LED activity, see
Section 4.2, LANVIEW LED SIGNALS.

Table 3-1. LANVIEW LED Activity at First Boot-up

After Default

boot-up

(management

module

not present)

LED label

At moment of

Power-on

After

Management

Module

boot-up

ERR off off off
BYP YELLOW YELLOW YELLOW
MGMT off GREEN off

Page 3-3

Installation

Table 3-1. LANVIEW LED Activity at First Boot-up (Continued)

After Default

boot-up

(management

module

not present)

determined by

Switch #1

YELLOW

LED label

At moment of

Power-on

Ring 1 16 Mb determined by

Switch #1

other rings

YELLOW determined by

16 Mb

After

Management

Module

boot-up

determined by

management

management
IN USE (all) off off off
Port (all) RED off off
PEN (all) GREEN determined by

GREEN

management
LNK (all) off off off

Boot-up may take a few minutes. When the Port LEDs turn from RED to
off, boot-up is complete. If the boot-up does not proceed as described
above, refer to Chapter 4, Testing and Troubleshooting.

The LED activity presented above represents a power-up with no

TIP

cables connected to the TDRMIM. See Section 4.2 to determine
appropriate activity for other start-up conditions.

Because port assignments can be made only by a management module, the
TDRMIM goes through a bypass period at each boot-up to provide a
window of opportunity during which a management module may
announce its intention to make these assignments. During this boot-up
period, the TDRMIM holds itself in full bypass mode by setting all ports
to loop-back to prevent them from connecting to any ring. After the
boot-up procedure is complete—the TDRMIM either has been
programmed by management or has gone to default mode—the TDRMIM
returns to normal operations.

3.2.5 Connecting Twisted Pair Cabling

The physical lobe connection from the TDRMIM to the Token Ring station
does not require the use of a crossover cable. To provide the necessary

Page 3-4

Installation

signal crossover or null modem effect, the TCU and Token Ring station
connectors are wired so that the transmit pair from the TDRMIM connects
to the receive pair in the station and the receive pair from the TDRMIM
connects to the transmit pair in the station. Table 3-2 provides a
cross-reference of pinouts for connections that may be encountered along
the length of lobe cabling.

Table 3-2. Twisted Pair Cabling Connector/Signal Pinout Cross-reference

Connector TX+ TX– RX+ RX–

NOTE

RJ11 6-pin

modular connector

RJ45 8-pin

modular connector

Data Connector

(MIC) genderless

DB9 9-pin

D-shell connector

5234

6345

OBRG

9516

A Type 3 Media Filter must be used when connecting the UTP
lobe cable from either of the active UTP TDRMIMs
(TDRMIM-22A/24A) to a Token Ring station that is not equipped
with an internal filter. A Type 3 Media Filter, such as the Cabletron
Systems TRMF, provides impedance matching from the Type 3
(UTP) lobe cabling to the Type 1 (STP) interface provided with
many Token Ring stations.

The twisted pair cabling used with the TDRMIM-42A/44A requires
shielded RJ45 connections to attain the maximum lobe lengths listed in
Chapter 2, Installation Requirements & Specifications. Shielded patch
cables that adapt a shielded RJ45 to a Data Connector (MIC) are available
from Cabletron Systems. These adapter/patch cables permit connection to
a pre-existing patch panel equipped with data connectors (see Figure 3-2).

Page 3-5

Installation

TDRMIM-42A

RX+

RX–

TX+

TDRMIM-22A

RX+

RX–

TX+

TX–

TCU port

RJ45 jack

6

6

3

3

4

4

6

6

3

3

4

4

5

5

STP lobe cable

TX+

TX–

RX+

UTP Lobe Cable

TX+

TX–

RX+

RX–

RJ45 plugs

MIC coupling

TX+

TX–

RX+

Token Ring Station

TX+

TX–

RX+

RX–

O

B

R

6

3

4

5

STP jumper cable

TX+

O

TX–

B

RX+

R

TYPE 3

MEDIA

FILTER

(internal

or

external)

TX+

9

5

TX–

RX+

1

6

RX–

NIC port

female DB9

TX+

9

TX–

5

RX+

1

Token Ring Station

TX+

9

5

TX–

1

RX+

TX–

TCU port

RJ45 jack

RX–

5

5

RJ45 plug

shield

ShieldShield

RX–

G

MIC / MIC

RX–

G

RX–

6

ShieldShield

shield

Male DB9 NIC port

Female DB9

6

RX–

Figure 3-2. Token Ring Lobe Cable Wiring Schematic

Attaching Twisted Pair Cabling at the Module 1

To attach station cable to the TDRMIM:

1. Insert the male RJ45 connector from one end of the station’s lobe cable
into any TCU port on the front of the TDRMIM.

2. If a patch panel is being used, attach the other end of the cable to the
appropriate patch panel jack.

Repeat the above steps for each station.

Attaching Twisted Pair Cabling at the Station 2

Connect stations to the TDRMIM using Type 3 patch cables. Attach one
end of the patch cable at the wall plate and the other to the station port.

Page 3-6

Installation

TX

RX

3.2.6 Connecting Ring In/Ring Out Cables

The fiber cable ends should be color-coded so that the colors are switched
at either end of the cable (as in Figure 3-3) ensuring that if the user keeps
the color/port connection consistent, the cables will be properly crossed
over (as in Figure 3-4).

RECEIVETRANSMIT

RECEIVE

TRANSMIT

Figure 3-3. Cross-Coded Cable Ends

TX

TRANSMIT TRANSMIT

RX

RECEIVE RECEIVE

Figure 3-4. Coded Cable Ends Crossed-Over

To attach fiber cable to the TDRMIM:

1. Designate one cable label color to represent transmit and another to

represent receive.

2. Carefully remove any rubber end protectors from the cable tips.

3. Remove any port covers from the ST connectors.

4. Connect one cable end marked with the designated transmit color to

the ST connector labeled “transmit” on the TDRMIM, and connect the
other end marked with the same color to the transmit connector on the
device to be connected.

5. Connect the receive cable ends in the same manner.

3.2.7 Pre-Operational Testing

The TDRMIM should now be ready for operation. Before placing the
network into service, proceed to Chapter 4, Testing and Troubleshooting,

Page 3-7

Installation

and test the installation thoroughly to ensure that all stations are able to
receive and that data is being relayed without error. Verify also that the
networking software is configured properly to match the installed
network.

Page 3-8

CHAPTER 4

Testing and Troubleshooting

This section contains procedures to verify that the connections between
the TDRMIM and the Token Ring stations are functioning properly. A
description of the LANVIEW LED system is also provided.

4.1 Installation Checkout

Perform the following check to confirm proper installation of the
TDRMIM:

1. Confirm that power settings for all connected Token Ring stations and

the MMAC match the AC power source (120 Vac or 240 Vac) and are
powered on.

2. Trace the ring path through the network to be sure that there are no

breaks in the ring and that it is free from logical design errors. While
tracing the ring:

a. Check that all cable connections at patch panels, at wall plates, at

stations, and at the MIM are secure.
b. Verify the pinouts for each connection.
c. Use cable testers to check all cable conductors for continuity.

3. Check network ring speeds:
a. Verify that ring speeds match the station and cable specifications

defined in Chapter 2, Installation Requirements &
Specifications.

b. Confirm that all MIMs and stations in the ring network are set to

the same ring speed.

c. Check that the MIMs in the MMAC are grouped together

according to network type and switching type (i.e.: all Ethernet
MIMs far left, all port switching Token Ring MIMs far right, all
single-ring Token Ring MIMs in between).

4. Confirm that neither the maximum cable length for EACH station nor
the maximum number of stations are exceeded.

Page 4-1

LANVIEW LED Signals

RI

When these checks have been successfully cleared, the TDRMIM is ready
for normal operation. If further problems are encountered, contact
Cabletron Systems Technical Support.

4.2 LANVIEW LED Signals

LANVIEW is Cabletron Systems’ built-in visual diagnostic and status
monitoring system. Using LANVIEW, network trouble shooting
personnel can quickly scan the LANVIEW LEDs (shown in Figure 4-1) to
determine network status, diagnose network problems, and isolate faulty
nodes or trunk segments.

TDRMIM-22A

SN

BYP
RING 1 16Mb
RING 2 16Mb
RING 3 16Mb
RING 4 16Mb

AUX 1 16Mb
AUX 2 16Mb

1
2
3
4
5
6

1
x

2
x

7
8
9
10
11
12

LNK

ERR
MGMT
IN USE
IN USE
IN USE
IN USE
IN USE
IN USE

PEN

TX

Figure 4-1. TDRMIM LANVIEW LEDs

NOTE

“Linked” describes a state of electromechanical connection between
a concentrator module’s TCU port and a station. “Inserted”
indicates a data connection between a station and a LAN, typically
through a TCU port.

Page 4-2

LANVIEW LED Signals

E

ERRB

B

M

M

ERR—Error 1

RR

R

This LED should be off during normal operations.

If the LED is RED, there is a hardware failure within
the module. If this occurs, contact Cabletron Systems
Technical Support.

BYP—Bypass 2

YP

If the LED is off, at least one port is inserted into the
FNB rings.

YP

G

If the LED is GREEN, no ports are inserted into the
FNB rings. This occurs under the following
conditions:

• The module is executing normal start-up
procedure.

• No ports are linked to the TDRMIM.

• All linked ports are currently disabled by
management.

• All rings in use are bypassed from the FNB.

• Management has placed the entire module in
bypass mode.

MGMT—Management Mode

GMT

When this LED is OFF during normal operations, the
TDRMIM is without management control and is
operating on hardware default settings.

This LED may also be OFF during normal boot-up
before communications have been established
between the TDRMIM and a management module.

GMT

G

When this LED is GREEN, the TDRMIM has received
configuration information (such as port assignments
and ring speeds) from a management module in
slot 1.

3

Page 4-3

LANVIEW LED Signals

1

1

I

I

I

1

1

Y

16MB—Ring Speed 4

6 MB

Y

YELLOW indicates that the ring speed is set to 16
Mbps.

6 MB

OFF indicates that the ring speed is set to 4 Mbps.

IN USE—Ring In Use 5

These LEDs indicate the status of network communications on the
associated ring. They do not reflect ring activity that excludes this
TDRMIM (e.g. on rings bypassed from the TDRMIM), nor do they indicate
whether a Ring Port connection has been made to an FNB ring.

N USE

OFF indicates that no lobe ports are inserted into the
associated ring.

N USE

G

GREEN indicates that at least one lobe port on the
module is successfully inserted into the associated
ring.

N USE

G

BLINKING GREEN indicates at least one lobe port is
inserted into the ring, but the ring itself is bypassed
from the FNB by management command.

#—port Status (Lobe Ports Only)

This LED indicates the status of the connection at the TCU. The function
of the LED is different for TCU station ports than for TCU Ring Out ports.
Lobe port #12 was arbitrarily chosen to model the LED samples below.

At power-on, all ports are temporarily disabled, suspending insertion
until the module comes out of bypass mode and returns to normal
operations. When the TDRMIM is ready, the ports will be switched to their
assigned rings and all suspended ports will be inserted accordingly.

At power-on, the LEDs operate as follows:

2

2

R

R

RED indicates that the port is not linked.

Cycling between GREEN and YELLOW indicates
that the port is linked.

6

Page 4-4

LANVIEW LED Signals

1

1

1

1

1

1

1

P

PENL

During normal operation, the LEDs for TCU ports operate as follows:

2

G

GREEN indicates that the TCU port is inserted into its
assigned ring.

2

G

BLINKING GREEN indicates that a Token Ring
station is phantom linked to the port, but the TCU
port is disabled by management command.

2

R

BLINKING RED indicates that a Speed Fault was
detected (a station was trying to insert into the ring at
the wrong ring speed) and the TCU port has been
looped back to prevent mis-insertion and beaconing.

2

R

RED indicates that the TCU port is disabled by
management command.

During normal operation, the LEDs for Multi Ring Out ports operate as
follows:

2

G

GREEN indicates that the Multi Ring Out port is
active (carrying data) and inserted into the ring.

2

R

BLINKING RED indicates that the Multi Ring Out
port is in a normal inactive state. This is equivalent to
OFF for a lobe port during normal operation. Refer to
Section 1.2.5, Support for Passive MAU
Workgroups, for an explanation of the operational
difference between a Ring Out port and a lobe port.

2

R

RED indicates that the Multi Ring Out port is
disabled by management command.

PEN—Port Enabled (Ring In/Ring Out Ports Only)

EN

OFF indicates that the associated RI or RO port is
disabled.

G

GREEN indicates that the associated RI or RO port is
enabled.

LNK—Linked (Ring In/Ring Out Ports Only) 8

NK

OFF indicates that the associated RI or RO port is
disabled or autowrapped.

Page 4-5

7

LANVIEW LED Signals

L

NK

G

GREEN indicates that the associated RI or RO port is
linked.

Page 4-6

APPENDIX A

Introduction to Port Switching

A.1 Introduction

This appendix introduces the concepts of port switching, port assignment,
and the four-ring Flexible Network Bus (FNB). These concepts are
fundamental to the basic functionality of a growing number of Cabletron
Systems Token Ring products.

A.2 The Flexible Network Bus (FNB)

The FNB is a data bus that spans the entire width of the backplane of the
Multi Media Access Center (MMAC). Its Ring In / Ring Out connections
between each adjacent hub slot allow for the formation of continuous data
channels across the MMAC.

A.3 Without Port Switching

Creation of Multiple FNB Rings

When used with Media Interface Modules (MIMs) that do not support
port switching (such as TRMIM and TRRMIM), the FNB offers a single
row of Ring In / Ring Out connections between each adjacent hub slot.
These MIMs are typically linked together across the FNB to form a single
Token Ring LAN. MIMs with left/right- wrapping abilities may
discontinue FNB connections between MIMs, effectively segmenting the
single FNB ring into smaller, isolated FNB ring segments, as illustrated in
Figure A-1.. Each resulting FNB segment functions as its own LAN.

Page A-1

With Port Switching

TRMIM

FNB ring

segment B

FNB ring wrapped at TRMMIM’s right FNB interface.

Figure A-1. FNB Segmentation Produces Two Isolated FNB Rings

Management of Segmented FNB Rings

TRMIM

TRMIM

TRMMIM

TRMIM

TRMIM

TRMIM

TRMM

FNB ring
segment A

When the FNB is segmented, as shown in Figure A-1., the modules on one
segment are isolated from modules on another FNB segment, and
management interfaces with one ring are isolated from other FNB
segments as well. Therefore, to receive full management support, each
FNB segment requires its own management interface; but as management
modules are added to the MMAC to manage these rings, the number of
slots available for concentrator modules is decreased, creating greater
power demands, and increasing the overall cost per port in the MMAC.

A.4 With Port Switching

Each port-switching MIM (e.g., TRXMIM), makes use of additional pins in
its FNB connector to create four vertically stacked, parallel FNB rings (as
illustrated in Figure A-2.). Therefore, whereas each single-ring (non
port-switching) MIM (e.g., TRMIM) provides access to only one ring (one
segment of the FNB), each port-switching MIM, provides access to four
FNB rings.

Page A-2

Port-Switching MIMs

TRMM-4

CRM2-R/T

Port-switching MIMs can assign ports on an individual basis to connect to
any of four FNB rings, thereby providing multiple users with access to
multiple rings through a single MIM.

TSXMIM

Figure A-2. Four Vertically Stacked FNB Rings

TDRMIM

TRXMIM

TRXMIM

TRXMIM

TRXMIM

FNB ring 1
FNB ring 2
FNB ring 3
FNB ring 4

Refer to Figure A-3. for a comparative illustration of the connectivity
afforded by each kind of MIM.

Port Assignment and Port Switching

Port assignments are made via a network management interface (such as
the Local Management application provided with port-assigning
management modules like the TRMM-2/-4). The switching
(reassignment) of a port from one ring to another requires no physical
reconfiguration of lobe cables: instead, the connection is changed
internally by the port-switching MIM (as represented in Figure A-4.).
Note, however, that port assignments cannot be issued without a
port-assigning management module. To account for management
absences, all port-switching MIMs have default port assignments.

With Port Switching

Page A-3

With Port Switching

TRMIM

TRMIMs TRXMIMs

TRMIM

TRMIM

TRMIM

TRXMIM

TRXMIM

TRXMIM

TRMM-2

External
Mgmt.
Interface

Segmented

FNB ring 1

Figure A-3. Mixed MIMs (In this example, only FNB ring 1 and the

Segment are managed.)

Management

For a management module to fully manage a ring, it requires a
network-monitoring interface with the ring. Whereas single-ring
management modules have only one network interface, port-assigning
management modules provide for multiple ring interfaces, making it
possible for a single management module to fully manage any or all of the
rings in the hub. (The TRMM-2 can manage two Token Rings and the
TRMM-4 can manage four.) This leaves all other hub slots available for
concentrator modules, eliminating the power demands of additional
management modules, and actually reducing the overall cost per port in
the MMAC. Meanwhile, port switching increases the number of Token
Rings in the hub and makes them easier to access.

FNB ring 1
FNB ring 2
FNB ring 3
FNB ring 4

Page A-4

TRXMIM-44A

SN

RING 1 16Mb

RING 3 16Mb

1913
2014
2115
2216
2317
2418

-PORTS-

13

X

14

X

15

X

16

X

17

X

18

X

Port assignments made by the Management

ERR

BYP

MGMT
INUSE
INUSERING 2 16Mb
INUSE
INUSERING 4 16Mb
INUSEAUX 1 16Mb

INUSEAUX 2 16Mb
71
82
93
104
115
126

1
X

2
X

3
X

4
X

5
X

6
X

Module are executed internally by the multi-ring
(port-switching or cluster-switching) MIM.

FNB ring 1

FNB ring 2

19

X

20

X

21

X

22

X

23

X

24

X

SWITCHING STP

TOKEN RING

7
X

8
X

9
X

10

X

11

X

12

X

FNB ring 3

FNB ring 4

Electronic reassignment of port 24 from ring 2 to ring 4

Figure A-4. Port Assignment and Port Switching

Terminology

The four vertically stacked FNB rings are referred to as FNB rings 1, 2, 3,
and 4. FNB ring 1 is the same ring that is used by all earlier generation,
single-ring MIMs and was addressed in earlier manuals as “the FNB ring,”
or simply “the FNB.” The term “the FNB” now refers collectively to the
MMAC backplane’s communications bus which supports FNB rings,
interconnects MIMs, and carries all user-data.

A.5 Configuration Specifications

Single-ring MIMs and port switching MIMs are compatible and
interconnectable across FNB ring 1. However, as shown in Figure A-3.,
single-ring MIMs cannot support communications across FNB rings 2, 3,
or 4.

If installed in a slot between port switching MIMs, a single-ring MIM will
isolate the additional FNB rings established on either side of the
single-ring MIM; avoid this configuration. All port switching MIMs

Configuration Specifications

Page A-5

Configuration Specifications

should be grouped together in the right-most slots of the MMAC as shown
in Figure A-3.

Single-ring MIMs still have the ability to segment FNB ring 1 (as shown in
Figure A-3.). They still view the FNB as having only one ring and are not
affected by the utilization of FNB rings 2, 3, or 4 by other MIMs in the
MMAC.

Port switching MIMs do not have the ability to wrap (segment) the FNB;
they are automatically and internally connected to the MIMs adjacent to
them via the MMAC chassis. However, a neighboring single-ring MIM
may wrap the connection between itself and a port-switching MIM to
isolate the port-switching MIMs from other MIMs in the hub.

Page A-6