Cabletron Systems STHI User manual

CABLETRON SYSTEMS, P. O. Box 5005 Rochester, NH 03866-5005
STHI
INTELLIGENT
TOKEN RING STACKABLE HUB
USER’S GUIDE

NOTICE
iii
NOTICE 1
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 May, 1995 by:
Cabletron Systems, Inc.
P.O. Box 5005, Rochester, NH 038666-5005
All Rights Reserved
Printed in the United States of America
Order Number: 9031390 May, 1995
SPECTRUM , LANVIEW , Remote LANVIEW , and HubSTACK , STH, STHI, are
trademarks of Cabletron Systems, Inc.
i960 is a registered trademark of Intel Corporation.
DEC and VT100 are trademarks of Digital Equipment Corporation.
CompuServe is a registered trademark of CompuServe, Inc.
Windows is a registered trademark of Microsoft Corporation.
Printed On Recycled Pa
per

NOTICE
iv
FCC NOTICE 2
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 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 4
IMPORTANT: Before utilizing 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.

NOTICE
v
CABLETRON SOFTWARE PROGRAM LICENSE 5
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. You may not reverse engineer, decompile, or
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.
EXCLUSION OF WARRANTY
AND DISCLAIMER OF LIABILITY 6
1. EXCLUSION OF WARRANTY. Except as may be specifically provided by
Cabletron in writing, Cabletron makes no warranty, expressed or implied,
concerning the Program (including Its documentation and media).
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. IN NO EVENT
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.

NOTICE
vi
UNITED STATES GOVERNMENT
RESTRICTED RIGHTS 7
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

CONTENTS
vii
CHAPTER 1 Introduction
1.1 Contents of This Manual. . . . . . . . . . . . . . . . . . . . . . . . . . .1-1
1.2 STHI Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-1
1.2.1 LANVIEW LEDs . . . . . . . . . . . . . . . . . . . . . . . . . .1-2
1.2.2 TCU Ports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-3
1.2.3 RI & RO Ports. . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-4
1.2.4 Hub-By-Hub Bypass Control . . . . . . . . . . . . . . . . .1-5
1.2.5 Automatic Beacon Recovery Process. . . . . . . . . . .1-5
1.2.6 Support for Passive MAU Workgroups . . . . . . . . .1-5
1.2.7 Flash Downloads. . . . . . . . . . . . . . . . . . . . . . . . . . .1-6
1.2.8 IP Address Discovery . . . . . . . . . . . . . . . . . . . . . . .1-6
1.2.9 Local Management . . . . . . . . . . . . . . . . . . . . . . . . .1-8
1.2.10 Remote Network Management Capabilities. . . . . .1-8
1.3 Related Manuals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-8
1.4 Getting Help . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-8
CHAPTER 2 Requirements & Specifications
2.1 General Networking Considerations. . . . . . . . . . . . . . . . . .2-1
2.2 Operating Specifications. . . . . . . . . . . . . . . . . . . . . . . . . . .2-3
2.2.1 Hubstack Interconnect Cables. . . . . . . . . . . . . . . . .2-3
2.2.2 TCU and COM Ports . . . . . . . . . . . . . . . . . . . . . . .2-3
2.2.3 Supported MIB Groups. . . . . . . . . . . . . . . . . . . . . .2-5
2.2.4 Ring Speed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-5
2.2.5 Ring Sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6
2.2.6 Safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-6
2.2.7 Computing Hardware . . . . . . . . . . . . . . . . . . . . . . .2-7
2.2.8 Environmental Requirements . . . . . . . . . . . . . . . . .2-7
2.2.9 Physical Specifications . . . . . . . . . . . . . . . . . . . . . .2-7
CHAPTER 3 Installation
3.1 Installing the STHI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-1
3.1.1 Unpacking the STHI. . . . . . . . . . . . . . . . . . . . . . . .3-1
3.1.2 Stacking the STHI. . . . . . . . . . . . . . . . . . . . . . . . . .3-2
3.1.3 Attaching the Strain Relief Bracket . . . . . . . . . . . .3-2

CONTENTS
viii
3.1.4 Rack-Mounting the STHI . . . . . . . . . . . . . . . . . . . .3-2
3.1.5 Wall-Mounting the STHI . . . . . . . . . . . . . . . . . . . .3-3
3.1.6 Free-Standing Installations . . . . . . . . . . . . . . . . . . .3-5
3.1.7 Connecting the STHI to the Power Source. . . . . . .3-6
3.2 TPIM Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-6
3.3 Finishing the Installation. . . . . . . . . . . . . . . . . . . . . . . . . . .3-6
CHAPTER 4 Troubleshooting
4.1 LANVIEW LED Signals . . . . . . . . . . . . . . . . . . . . . . . . . .4-1
4.2 Trouble Resolution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-2
4.3 The Reset Button. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-3
4.4 NVRAM Reset Switch . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-4
CHAPTER 5 Local Management
5.1 Accessing LM. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-1
5.1.1 Dumb Terminal Configuration . . . . . . . . . . . . . . . .5-2
5.1.2 Console Cable Configuration . . . . . . . . . . . . . . . . .5-3
5.1.3 Entering LM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-3
5.2 Using LM Screens. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-4
5.2.1 Working with LM Screens . . . . . . . . . . . . . . . . . . .5-4
5.2.2 Screen Hierarchy. . . . . . . . . . . . . . . . . . . . . . . . . . .5-6
5.2.3 Screen Introductions . . . . . . . . . . . . . . . . . . . . . . . .5-6
5.3 The System Level Screen . . . . . . . . . . . . . . . . . . . . . . . . . .5-8
5.3.1 System Date and System Time. . . . . . . . . . . . . . . .5-8
5.3.2 IP Address. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-8
5.3.3 Subnet Mask . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-9
5.3.4 Enable IP Address Discovery . . . . . . . . . . . . . . . . .5-9
5.3.5 Enable Beacon Recovery . . . . . . . . . . . . . . . . . . .5-10
5.3.6 MAC Address . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-11
5.3.7 Locally Administered Address . . . . . . . . . . . . . . .5-11
5.4 The SNMP Community Names Screen . . . . . . . . . . . . . .5-11
5.4.1 Community Name. . . . . . . . . . . . . . . . . . . . . . . . .5-12
5.4.2 Access Policy . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-12
5.5 The SNMP Traps Screen . . . . . . . . . . . . . . . . . . . . . . . . .5-13

CONTENTS
ix
5.5.1 Trap Destination . . . . . . . . . . . . . . . . . . . . . . . . . .5-13
5.5.2 Trap Community Name . . . . . . . . . . . . . . . . . . . .5-13
5.5.3 Enable Traps . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-13
5.6 The Chassis Status View Screen. . . . . . . . . . . . . . . . . . . .5-14
5.6.1 The Screen Mode Screen Command. . . . . . . . . . .5-14
5.6.2 Multiplexer Configuration Fields . . . . . . . . . . . . .5-15
5.6.3 Port Configuration Fields . . . . . . . . . . . . . . . . . . .5-16
5.6.4 NEXT and PREVIOUS. . . . . . . . . . . . . . . . . . . . .5-20
5.6.5 ENABLE ALL PORTS. . . . . . . . . . . . . . . . . . . . .5-20
5.6.6 REFRESH. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-20
5.7 The Component Status Screen . . . . . . . . . . . . . . . . . . . . .5-20
5.8 The Device Statistics Screen. . . . . . . . . . . . . . . . . . . . . . .5-21
5.8.1 Screen Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-22
5.8.2 REFRESH 3SEC. . . . . . . . . . . . . . . . . . . . . . . . . .5-22
5.8.3 General Counter Fields (Group 1) . . . . . . . . . . . .5-23
5.8.4 Ring Information Fields (Group 2). . . . . . . . . . . .5-23
5.8.5 Isolating Errors Fields (Group 3) . . . . . . . . . . . . .5-25
5.8.6 Non-Isolating Errors (Group 4) . . . . . . . . . . . . . .5-26
5.9 The SNMP Tool Screen . . . . . . . . . . . . . . . . . . . . . . . . . .5-27
5.9.1 Community Name. . . . . . . . . . . . . . . . . . . . . . . . .5-28
5.9.2 OID Prepend . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-28
5.9.3 GET. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-28
5.9.4 GETNEXT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-29
5.9.5 STEP. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-29
5.9.6 WALK. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-30
5.9.7 CYCLES. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-30
5.9.8 RECALL-OID. . . . . . . . . . . . . . . . . . . . . . . . . . . .5-30
5.9.9 SET . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-30
5.9.10 REPEAT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-31
5.9.11 Firmware Image Downloads. . . . . . . . . . . . . . . . .5-31
Appendix A TPIM Specifications
A.1 Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-1
A.2 Twisted Pair TPIM Pinouts. . . . . . . . . . . . . . . . . . . . . . . . A-1
A.3 Fiber Optic TPIM Specifications . . . . . . . . . . . . . . . . . . . A-2

CONTENTS
x
A.3.1 TPIM-F2 for Multimode Fiber . . . . . . . . . . . . . . . A-3
A.3.2 TPIM-F3 for Single Mode Fiber. . . . . . . . . . . . . . A-4
Appendix B Media Specifications
B.1 Unshielded Twisted Pair (UTP) . . . . . . . . . . . . . . . . . . . . .B-1
B.1.1 UTP Cable Categories. . . . . . . . . . . . . . . . . . . . . . .B-1
B.1.2 UTP Lobe Lengths . . . . . . . . . . . . . . . . . . . . . . . . .B-2
B.2 Shielded Twisted Pair (STP). . . . . . . . . . . . . . . . . . . . . . . .B-3
B.2.1 STP Cable Categories. . . . . . . . . . . . . . . . . . . . . . .B-3
B.2.2 STP Lobe Lengths. . . . . . . . . . . . . . . . . . . . . . . . . .B-4
B.2.3 Mixed STP Cable Types. . . . . . . . . . . . . . . . . . . . .B-4
B.3 Single Mode and Multimode Fiber Optic Cabling . . . . . . .B-5

Page 1-1
CHAPTER 1
Introduction
Welcome to the Cabletron Systems STHI Intelligent Stackable Token
Ring Hub User’s Guide . Please read through this manual to gain an
understanding of the features and capabilities of the STHI. A general
knowledge of IEEE 802.5 Token Ring communications networks and their
physical layer components will be helpful.
1.1 Contents of This Manual
Chapter 1, Introduction , outlines the contents of this manual, describes
STHI features, and offers leads to further information.
Chapter 2, Requirements & Specifications , describes installation
requirements, network guidelines, and STHI operating specifications.
Chapter 3, Installation , contains instructions for installing the STHI and
making network connections.
Chapter 4, Troubleshooting , describes how to use the LANVIEW LED
system to troubleshoot network problems.
Chapter 5, Local Management , describes how to use the Local
Management application.
1.2 STHI Overview
The STHI is an SNMP compliant intelligent hub that provides basic
management functionality including port and station control, statistical
error and trap tracking, and enhanced beacon recovery for a Token Ring
LAN. Its front panel TCU (Trunk Connector Unit) ports allow for network
connections to either active stations or passive Multi-Station Access Units
(MAUs) while its TPIM (Token Ring Port Interface Module) ports allow
for ring expansions across a variety of media. Its rear panel HubSTACK
ports provide for ring expansion through connections to multiple STH
non-intelligent hubs. See Figure 1-1.

STHI Overview
Page 1-2
Figure 1-1. Front and Back Views of the STHI-24
The STHI may be installed as a fully managed stand-alone device, or it
may be stacked with up to four STH hubs, each of which adds 12 or 24
TCU ports to the LAN, bringing the total count to a maximum of 120
managed TCU ports in the stack. The STHI serves as the logical “top” of
the stack and provides full frame and error statistics for the managed ring.
The STHI fully conforms to IEEE 802.5 Token Ring specifications for
connectivity to Token Ring equipment and offers the following Token
Ring enhancement features:
• Local Management, a user interface for management control;
• Cabletron Systems’ Automatic Beacon Recovery Process (ABRP);
• Multiple Ring Out connectivity for Passive MAU workgroups;
• automatic speed fault protection;
• active filtering, equalizing, and amplify ing circuitry;
• and LANVIEW LEDs for “at-a-glance” diagnostic monitoring.
1.2.1 LANVIEW LEDs
Cabletron Systems’ LANVIEW status monitoring and diagnostics system
is an array of LEDs which helps users to diagnose power failures,
beaconing conditions, cable faults, and connection problems. Refer to
Section 4.1, LANVIEW LED Signals , for more detail.
LANVIEW®
SUPPORTING 100 OHM UTP CABLE
HubSTACK
STHI-24
TOKEN RING HUB WITH
24X 23X 22X 21X 20X 19X 18X 17X 16X 15X 14X 13X
12X 11X 10X 9X 8X 7X 6X 5X 4X 3X 2X 1X
RI
RESET
CPU ACT
MGMT
16 Mb/s
SPEED
16M4M COM RO
STACK 3STACK 2 STACK 5STACK 4
STHI-24TOKEN RING HUB LANVIEW®
WITH

STHI Overview
Page 1-3
1.2.2 TCU Ports
The four STHI models are functionally identical with the exception of the
number and type of network ports they offer:
Each STHI is equipped with TCU ports fitted with female RJ45 modular
connector jacks to support the attachment of either STP (shielded twisted
pair) or UTP (unshielded twisted pair) cabling with RJ45 connector plugs.
Models that support STP cabling use RJ45 connectors that provide a
grounded connection for the cabling shield. See Section 2.2.2, TCU and
COM Ports , for pinouts.
Lobe Port and Multiple Ring Out Port Configurations
1
Each TCU port on the STHI is internally defaulted to operate as a lobe
interface to support the insertion of a Token Ring station into a ring.
However, each TCU port may also be reconfigured via the Local
Management (LM) application (see Section 5.6.3, Port Configuration
Fields ) to function as a Ring Out port which will support connections to
non-intelligent, passive MAU (Multi-Station Access Unit) workgroups.
Refer also to Section 1.2.6, Support for Passive MAU Workgroups .
Ring Speed Fault Protection
2
STHI hubs also provide Ring Speed Fault Protection on each TCU port to
protect against beaconing conditions caused by stations inserting at the
wrong ring speed. If a ring speed mismatch is detected, the STHI blocks
the port to keep the misconfigured station isolated from the ring and
provides a simple visible LED signal (blinking red at the port’s LED) to
indicate that Ring Speed Fault Protection is blocking the port. The port
remains blocked until the ring speed mismatch condition is removed or
resolved.
Table 1-1. TCUs and Media Types per Model
STHI-22 12 unshielded RJ45 ports
STHI-24 24 unshielded RJ45 ports
STHI-42 12 shielded RJ45 ports
STHI-44 24 shielded RJ45 ports

STHI Overview
Page 1-4
Active Circuitry
3
On each TCU port, STHI hubs provide active circuitry which filters,
equalizes, and amplifies all received signals before transmitting them to
the next point on the ring. The result is enhanced signal integrity and
extended maximum station lobe cable distances.
Daughter Board Upgrade Kit
4
The following daughter board upgrade kits may be used to expand STHI
hubs from 12 to 24 TCU ports:
• TR-UTP-UGKT for STHI-22.
• TR-STP-UGKT for STHI-42.
1.2.3 RI & RO Ports
The STHI incorporates a pair of RI/RO port sockets for Token Ring Port
Interface Modules (TPIMs). This Ring In / Ring Out port pair allows for
the expansion of the main ring to other hubs. Refer to Section 5.6.3, Port
Configuration Fields , Subsection RING OUT ENABLE Mode , for the
procedure to enable RI/RO ports.
Essentially, TPIMs are media adapters which enable their host modules to
expand their network connections to other media types. The TPIM models
listed in Table 1-2 are produced by Cabletron Systems and may be
installed in the RI/RO port sockets on the STHI. Refer to Section 3.1,
Installing the STHI , for installation instructions.
Table 1-2. TPIMs, Supported Media, and Connectors
TPIM MediaType Connector
TPIM-T1 Shielded Twisted Pair DB9
TPIM-T2 Unshielded Twisted Pair RJ45
TPIM-T4 Shielded Twisted Pair RJ45
TPIM-F2 Multimode Fiber ST
TPIM-F3 Single Mode Fiber ST

STHI Overview
Page 1-5
1.2.4 Hub-By-Hub Bypass Control
Unless otherwise configured by a user, all hubs in an STH/STHI stack are
interconnected to form a continuous Token Ring. Through Local
Management, however, each hub may be individually bypassed from the
continuous ring to form its own isolated ring which does not exchange
data with the other hubs.
If an STH is bypassed from the main ring, the STH module will not receive
data-dependent services such as statistical tracking and beacon recovery,
but other physical control functions such as port configuration remain
unaffected. If the STHI is bypassed, only its TCUs are actually bypassed
from the stack’s common ring: TPIM Ring ports and management systems
maintain their connection to the stack’s common ring.
Refer to Section 5.6.2, Multiplexer Configuration Fields , for instructions
regarding bypass control.
1.2.5 Automatic Beacon Recovery Process
To guard the network against operational interruptions due to beaconing
conditions, the STHI protects itself and its attached STH hubs with
Cabletron Systems’ advanced Automatic Beacon Recovery Process. ABRP
engages more quickly and is able to treat conditions beyond the scope of
the IEEE standard beacon recovery process. The STHI automatically
partitions problematic lobes from the ring, allowing the rest of the ring to
continue operating. The hub checks partitioned Ring In/Out ports
periodically and re-enables them automatically if they have recovered;
partitioned TCU ports remain disabled until re-enabled by a user.
1.2.6 Support for Passive MAU Workgroups
By default, each TCU port is configured to its STN (station) setting to
support lobe connections to stations. Whereas a station signals a TCU to
open its interface by providing phantom current down its lobe cable, a
passive Multi-Station Access Unit cannot provide phantom current. To
allow for MAU connections, the user may reconfigure TCU ports via Local
Management to function in Ring Out mode. A TCU port in Ring Out mode
looks for the presence of data bits, rather than phantom current, to
determine link status. Refer to Section 5.6.3, Port Configuration Fields ,
Subsection RING OUT ENABLE Mode , for configuration instructions.

STHI Overview
Page 1-6
Improved Protection from Beaconing
1
By utilizing multiple Ring Out TCU ports, users can provide enhanced
reliability for existing networks which use passive MAUs because Ring
Out TCU ports allow for the separate attachment of each MAU. Rather
than daisy-chaining MAUs together as a single entity and risking their
collective isolation in case of beaconing, the user can now attach each
MAU individually, reducing the number of MAU ports that are at risk;
ABRP is able to bypass individual Ring Out-to-MAU connections on an
individual basis, leaving other workgroups unaffected. See Figure 1-2.
The Ring Out TCU configuration does not provide for the
MAU’s redundant connection to the ring. To achieve dual
attachment to a MAU, use the Ring In and Ring Out TPIM
ports.
1.2.7 Flash Downloads
New and updated firmware may be downloaded into the STHI hub’s
Flash EPROMs. This process may be executed by Cabletron’s Remote
LANVIEW/Windows, version 3.0 or later, or by any device using BOOTP
or TFTP protocols. Refer to Section 5.9.11, Firmware Image Downloads ,
for download instructions.
1.2.8 IP Address Discovery
The STHI supports IP Address Discovery. Through a BootP server (a
network device that holds a user-defined list of MAC addresses and
corresponding IP addresses), network managers may attribute an IP
address to any known MAC address. When the STHI is powered up
without an IP address and IP Address Discovery is enabled, it issues
BootP requests at user-set intervals, essentially asking “does anybody
know my name?” If the BootP server recognizes the MAC address, it tells
the STHI what IP address has been attributed to it. If no BootP sever
responds after 500 request cycles, the STHI automatically boots from its
own FLASH memory and remains without an IP address until a user
provides one through the Local Management interface.
Each STHI has on its backplate a sticker which indicates its MAC address.
NOTE

STHI Overview
Page 1-7
Figure 1-2. Improved Beacon Recovery Resolution for MAUs
(8 Stations)
(8 Stations)
(8 Stations)
(8 Stations)
STHi TCUs
Ring
Out
Ring
Out
Ring
Out
Ring
Out
Multi-Station
Access Units
Ring
In
Ring
In
Ring
In
Ring
In
When each MAU is individually connected to the STHi hub,
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.
(8 Stations)
(8 Stations)
(8 Stations)
(8 Stations)
Multi-Station
Access Units
Hub with
Ring In / Ring Out
Rin
g
Ou
t
Rin
g
Ou
t
Rin
g
Ou
t
Rin
g
Ou
t
Ring
In
Ring
In
Ring
In
Ring
In
Ring
Out
Ring
In
When MAUs are daisy-chained,
they are connected as single collective entity.
The entire chain must be bypassed
to isolate the hub from a single beaconing station.
All stations lose connection if beaconing occurs on any station.
DAISY-CHAIN MAU CONFIGURATION
RING OUT TCU MAU CONFIGURATION

Related Manuals
Page 1-8
1.2.9 Local Management
The STHI hub’s Local Management application displays packet and error
statistics for the entire stack, for each individual device, or for individual
ports, and enables the user to provide management support for the STHI
and all its attached segments.
Users with actual or emulated VT100 dumb terminals may access Local
Management out-of-band via the RJ45 COM port. Refer to Section 5.1 for
connection instructions.
1.2.10 Remote Network Management Capabilities
The STHI may be managed remotely by a variety of SNMP network
management systems including the following from Cabletron Systems:
• Cabletron Systems SPECTRUM

• Cabletron Systems Remote LANVIEW

/Windows 
• Cabletron Systems Remote LANVIEW

for SunNet  Manager
1.3 Related Manuals
Use the Cabletron Systems STH-22/24 /42/44 User’s Guide to supplement
the procedures and other technical data provided in this manual. The
procedures contained therein are referenced where appropriate, but are
not repeated in this manual.
1.4 Getting Help
To present any questions, comments, or suggestions concerning this
manual or any Cabletron Systems Product, please contact Cabletron
Systems Technical Support:
By phone [phone]
Monday-Friday; 8am - 8pm EST
By CompuServe

GO CTRON from any ! prompt
By Internet mail [email protected]
By Fax: [phone]
By BBS: [phone]

Getting Help
Page 1-9
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 2-1
CHAPTER 2
Requirements & Specifications
This chapter describes network guidelines, power requirements, and
operating specifications for the STHI. Before performing the installation,
read this chapter and confirm that the network meets the requirements
and conditions specified herein. Failure to follow these guidelines may
result in poor network performance.
Refer to Appendix A, TPIM Specifications , for TPIM specifications.
Refer to Appendix B, Media Specifications , for cable specifications.
2.1 General Networking Considerations
Take care in planning and preparing the cabling and connections for the
network. The susceptibility of the LAN’s cables to crosstalk and noise
determines the network’s error rate, and thus, the efficiency of data
propagation on the network. The quality of the connections, the length of
cables and other conditions of the installation are critical factors in
determining the quality of the network.
All devices connected to the STHI must meet IEEE 802.5 Token Ring
specifications.
Maximum Number of Stations on a Ring
1
The maximum stack composed of four 24-port STH hubs and one 24-port
STHI offers a total of 120 TCU ports, but the number of ports available on
the LAN may be increased by the use of passive Multi-Station Access
Units (see to Section 1.2.6,
Support for Passive MAU Workgroups) and
TPIM Ring In / Ring Out connections to other devices (see Section 1.2.3,
RI & RO Ports).
While there is no recommended limit to the number of TCU ports to be
made available in a stack, the recommended maximum number of stations
to be inserted simultaneously into a single ring is 255 when using STP lobe
cabling and 150 when using UTP cabling anywhere on the ring. If the ring
has been extended through RI/RO connections, consider the number of
ports on ring extensions as well as those in the stack itself.

General Networking Considerations
Page 2-2
Crosstalk 2
Crosstalk is interference caused by signal coupling between different cable
pairs contained within a multi-pair cable bundle. Multi-pair cables should
not be used for UTP lobe cabling. Avoid mixing Token Ring signals with
other applications (voice, etc.) within the same cable.
Noise 3
Noise can be caused by either crosstalk or externally induced impulses.
Outside systems (motors, switching equipment, fluorescent lighting, high
amperage equipment) may produce electrical interference causing noise.
The number and quality of cable connections also contribute considerably
to noise levels. To reduce noise induced errors, it may be necessary to
re-route cabling away from potential noise sources, or to ensure that the
electrical wiring in the area is properly wired and grounded, or to replace
connectors along affected segments.
Temperature 4
Signal attenuation varies significantly with temperature when
PVC-insulated cable is used. In areas where temperatures exceed 40˚C, it
is strongly recommended that plenum-rated cables be used instead to
ensure that signal attenuation remains within specifications.
Installation Recommendations 5
In addition to complying with the cable specifications presented in
Appendix A, TPIM Specifications, the cabling installation should comply
with the following recommendations to obtain optimum performance
from the network:
• UTP cabling should be free of splices, stubs, or bridged taps.
• Metal troughs, ducts, etc. carrying Token Ring signals should be
properly grounded.
• Cables should be routed away from sources of electrical noise, such as
power lines, fluorescent lights, electric motors, radio interference, and
heavy machinery.
• Token Ring signals should not be routed through UTP cables that exit
a building or which are adjacent to cables either exiting a building or
exposed to lightning strikes and power surges.