Cabletron Systems SmartStack STS16-20R User manual

SmartStack
STS16-20D/STS16-20R
Token Ring Switches
Installation
and
User Guide

i
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.
© October 1999 by:
Cabletron Systems, Inc.
35 Industrial Way
Rochester, NH 03867
All Rights Reserved.
Order Number: 9032956-01
(OC-7054 v. 1.1, 710001812)
SmartStack is a trademark of Cabletron Systems, Inc.
CompuServe is a registered trademark of CompuServe, Inc.
i960 microprocessor is a registered trademark of Intel Corp.
Ethernet is a trademark of Xerox Corporation.

ii
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.
VCCI Notice
This is a Class A product based on the standard of the Voluntary Control Council for
Interference by Information Technology Equipment (VCCI). If this equipment is used in
a domestic environment, radio disturbance may arise. When such trouble occurs, the user
may be required to take corrective actions.
Industry Canada Notice
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.

iii
Notice
Declaration of Conformity
Addendum
Application of Council Directive(s): 89/336/EEC
73/23/EEC
Manufacturer’s Name: Cabletron Systems, Inc.
Manufacturer’s Address: 35 Industrial Way
PO Box 5005
Rochester, NH 03867
European Representative Name: Mr. J. Solari
European Representative Address: Cabletron Systems Limited
Nexus House,
Newbury Business Park
London Road, Newbury
Berkshire RG13 2PZ, England
Conformance to Directive(s)/Product Standards: EC Directive 89/336/EEC
EC Directive 73/23/EEC
EN 55022
EN 50082-1
EN 60950
Equipment Type/Environment: Networking Equipment, for use
in a Commercial or Light
Industrial Environment.
We the undersigned, hereby declare, under our sole responsibility, that the equipment
packaged with this notice conforms to the above directives.
Manufacturer Legal Representative in Europe
Mr. Ronald Fotino Mr. J. Solari
Full Name Full Name
Principal Compliance Engineer Managing Director - E.M.E.A.
Title Title
Rochester, NH, USA Newbury, Berkshire, England
Location Location

iv
Notice
Table of Contents
1. Introduction 1
Switching Technology . . . . . . . . . . . . . . . . . . . . . . . 2
Switch of Switches . . . . . . . . . . . . . . . . . . . . . . 2
Switch of Servers . . . . . . . . . . . . . . . . . . . . . . . 3
Switch of Hubs . . . . . . . . . . . . . . . . . . . . . . . . 3
Switch of Desktops . . . . . . . . . . . . . . . . . . . . . . 3
Switch of Floors and Buildings . . . . . . . . . . . . . . . . 4
Switch of Routers . . . . . . . . . . . . . . . . . . . . . . . 4
Front Panel Details . . . . . . . . . . . . . . . . . . . . . . . . 5
The MANAGEMENT Port . . . . . . . . . . . . . . . . . . . 5
Token Ring Ports . . . . . . . . . . . . . . . . . . . . . . . 5
Reset Button . . . . . . . . . . . . . . . . . . . . . . . . . 6
System Request Button . . . . . . . . . . . . . . . . . . . . 6
Labels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Status and Activity LEDs . . . . . . . . . . . . . . . . . . . 7
Back Panel Details . . . . . . . . . . . . . . . . . . . . . . . . 9
Features and Specifications . . . . . . . . . . . . . . . . . . . 10
Features . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Specifications . . . . . . . . . . . . . . . . . . . . . . . . 13
2. Switch Overview 17
Multiple Simultaneous Conversations . . . . . . . . . . . . . . 18
Low Latency . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Address Management . . . . . . . . . . . . . . . . . . . . . . 20
Multiple Bridging Modes . . . . . . . . . . . . . . . . . . . . . 21
Source Route Switching (SRS) . . . . . . . . . . . . . . . 22
Source Route Bridging (SRB) . . . . . . . . . . . . . . . . 22
Source Route Transparent (SRT) . . . . . . . . . . . . . . 23
SRT/SRB . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Filtering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Congestion Control . . . . . . . . . . . . . . . . . . . . . . . 24
Three Switching Modes . . . . . . . . . . . . . . . . . . . . . 25
Cut-Through . . . . . . . . . . . . . . . . . . . . . . . . . 25
Store and Forward . . . . . . . . . . . . . . . . . . . . . 25
Auto (Adaptive Cut-Through) . . . . . . . . . . . . . . . . 25
Token Ring Port Operation Modes . . . . . . . . . . . . . . . 26
RI/RO-Like Connection on SmartStack STS16-20R . . . . . . 27
Transmission Priority Queues . . . . . . . . . . . . . . . . . . 28
ClearSession Support . . . . . . . . . . . . . . . . . . . . . . 28
CrossLink Connections . . . . . . . . . . . . . . . . . . . . . 29

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Notice
Spanning Tree Protocol Support . . . . . . . . . . . . . . . . 30
VLAN Support . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Dynamic Source Route Recovery . . . . . . . . . . . . . . . . 32
Management . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
SNMP . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
SmartStack Manager for Windows . . . . . . . . . . . . . 36
Telnet Management and VT100 Management (Console) . . 36
IBM LAN Network Manager . . . . . . . . . . . . . . . . . 36
RMON Support . . . . . . . . . . . . . . . . . . . . . . . . . 37
Built-in Port Counters . . . . . . . . . . . . . . . . . . . . . . 39
Stackable Architecture . . . . . . . . . . . . . . . . . . . . . . 39
Back-to-Back . . . . . . . . . . . . . . . . . . . . . . . . 39
Internal Stacker . . . . . . . . . . . . . . . . . . . . . . . 39
External Stacker . . . . . . . . . . . . . . . . . . . . . . . 39
Optional Redundant Power Supply on
SmartStack STS16-20R . . . . . . . . . . . . . . . . . . . . . 40
3. Preparing for Installation 41
Safety Recommendations . . . . . . . . . . . . . . . . . . . . 41
Safety with Electricity . . . . . . . . . . . . . . . . . . . . 41
Preventing Electrostatic Discharge Damage . . . . . . . . 42
Site Requirements . . . . . . . . . . . . . . . . . . . . . . . . 43
Environment . . . . . . . . . . . . . . . . . . . . . . . . . 43
Chassis Accessibility . . . . . . . . . . . . . . . . . . . . 43
Cooling and Airflow . . . . . . . . . . . . . . . . . . . . . 43
Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
Configuration Guidelines . . . . . . . . . . . . . . . . . . . . 45
Frame Length Limit . . . . . . . . . . . . . . . . . . . . . 45
IEEE 802.1D Spanning Tree . . . . . . . . . . . . . . . . 46
Ring Numbers . . . . . . . . . . . . . . . . . . . . . . . . 47
Sample Uses of the SmartStack STS16-20RM Family Switches 48
Deployment Scenarios . . . . . . . . . . . . . . . . . . . . 51
4. Installation 55
Installation Summary . . . . . . . . . . . . . . . . . . . . . . 55
Package Contents . . . . . . . . . . . . . . . . . . . . . . . 56
Materials needed for Installation . . . . . . . . . . . . . . . . . 57
Mounting the Chassis . . . . . . . . . . . . . . . . . . . . . . 58
Rack or Cabinet Mounting . . . . . . . . . . . . . . . . . . 58
Table-Mounting . . . . . . . . . . . . . . . . . . . . . . . 59
Cabling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
Connecting Devices to the Token Ring Ports . . . . . . . . 60
Connecting Devices to the Token Ring Ports

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Notice
Using Building Wiring . . . . . . . . . . . . . . . . . . . . 61
Checking the Installation . . . . . . . . . . . . . . . . . . . . 62
Applying Power . . . . . . . . . . . . . . . . . . . . . . . . . 63
Stacker Link Module . . . . . . . . . . . . . . . . . . . . . . 65
Installation . . . . . . . . . . . . . . . . . . . . . . . . . . 65
SmartStack STS-LM Connectors and LEDs . . . . . . . . 66
Connecting the Stacker Link Cable . . . . . . . . . . . . . 66
Working with a Stack . . . . . . . . . . . . . . . . . . . . 67
Inter-box Parameters . . . . . . . . . . . . . . . . . . . . 67
Checking the Installation . . . . . . . . . . . . . . . . . . 68
5. Accessing Switch Management 69
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
Connecting the Console . . . . . . . . . . . . . . . . . . . . . 70
Communication Problems . . . . . . . . . . . . . . . . . . 72
Diagnostic Screen . . . . . . . . . . . . . . . . . . . . . . 73
6. Switch Configuration 75
General Guidelines . . . . . . . . . . . . . . . . . . . . . . . 76
Navigating within the Menus . . . . . . . . . . . . . . . . 77
Main Menu . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
Configuration Menu . . . . . . . . . . . . . . . . . . . . . . . 79
Switch Configuration Screen . . . . . . . . . . . . . . . . . . 80
Stack Configuration Screen . . . . . . . . . . . . . . . . . 83
Module Information Screen . . . . . . . . . . . . . . . . . 84
VLAN Configuration . . . . . . . . . . . . . . . . . . . . . . . 86
VLAN Configuration Menu . . . . . . . . . . . . . . . . . 87
VLAN Configuration Screen . . . . . . . . . . . . . . . . . 88
VLAN Parameter Configuration for CRF Screen . . . . . . 89
VLAN Parameter Configuration for BRF Screen . . . . . . 91
VLAN Port Configuration . . . . . . . . . . . . . . . . . . 93
IP Configuration Screen . . . . . . . . . . . . . . . . . . . . . 94
BootP Requests and Parameters . . . . . . . . . . . . . . 96
SNMP Configuration Menu . . . . . . . . . . . . . . . . . . . 97
Spanning Tree Protocol . . . . . . . . . . . . . . . . . . . . . 97
IEEE 802.1D Spanning Tree Protocol (STP) . . . . . . . . 98
Spanning Tree for BRF Screen . . . . . . . . . . . . . . . 99
Spanning Tree for CRF Screen . . . . . . . . . . . . . . . 101
Port Spanning Tree Parameters Screen . . . . . . . . . . 104
Current Spanning Tree Information Screen . . . . . . . . . 105
Port Configuration Screen . . . . . . . . . . . . . . . . . . . . 106
Switched Port Analyzer Menu from the Configuration Menu . . 110
CrossLink . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110

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Notice
CrossLink Menu . . . . . . . . . . . . . . . . . . . . . . 112
CrossLink Configuration Screen . . . . . . . . . . . . . . 113
Setting up a CrossLink . . . . . . . . . . . . . . . . . . . 114
Current CrossLink Information Screen . . . . . . . . . . 115
Address Filtering . . . . . . . . . . . . . . . . . . . . . . . . 116
Filters and Port Security Menu . . . . . . . . . . . . . . 117
Configure Filters Screen . . . . . . . . . . . . . . . . . . 118
Configure Port Security Mode Screen . . . . . . . . . . . 120
View Port Filters Screen . . . . . . . . . . . . . . . . . . 121
Protocol Filters Menu . . . . . . . . . . . . . . . . . . . 122
Protocol Class Assignment Screen . . . . . . . . . . . . 123
Port Filtering Attributes Screen . . . . . . . . . . . . . . 124
Address Aging . . . . . . . . . . . . . . . . . . . . . . . . . 126
Address Aging Menu . . . . . . . . . . . . . . . . . . . 127
Port Address Table Aging Screen . . . . . . . . . . . . . 127
Master Address Table Aging Screen . . . . . . . . . . . 129
Password Menu . . . . . . . . . . . . . . . . . . . . . . . . 130
Console/Telnet Sessions . . . . . . . . . . . . . . . . . . . 132
Console Configuration Menu . . . . . . . . . . . . . . . 132
Serial Link Configuration Screen . . . . . . . . . . . . . 133
Creating a Console Session Using a Modem . . . . . . . 134
Stopping the Console Session . . . . . . . . . . . . . . . 134
Telnet Configuration Screen . . . . . . . . . . . . . . . . 135
Telnet Sessions Screen . . . . . . . . . . . . . . . . . . 136
Starting the Telnet Session . . . . . . . . . . . . . . . . 137
Stopping the Telnet Session . . . . . . . . . . . . . . . . 137
Involuntary Termination of the Telnet Session . . . . . . 137
Syslog Daemon Screen . . . . . . . . . . . . . . . . . . . . 139
DSRR Configuration . . . . . . . . . . . . . . . . . . . . . . 141
DSRR Group Configuration Screen . . . . . . . . . . . . 143
DSRR Configuration Screen . . . . . . . . . . . . . . . . 144
Download/Upload Menu . . . . . . . . . . . . . . . . . . . . 147
Serial Link Download Screen . . . . . . . . . . . . . . . 148
TFTP . . . . . . . . . . . . . . . . . . . . . . . . . . . . 149
TFTP Download/Upload Screen . . . . . . . . . . . . . . 150
Reset Screen . . . . . . . . . . . . . . . . . . . . . . . . . 152
7. Monitoring the Network from the Console Statistics
Menu 155
Statistics Menu . . . . . . . . . . . . . . . . . . . . . . . . 156
Switch Statistics Screen . . . . . . . . . . . . . . . . . . . . 157
Power Supply Information Screen . . . . . . . . . . . . . . . 159
Port Status Screen . . . . . . . . . . . . . . . . . . . . . . . 160

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Notice
Port Statistics Menu . . . . . . . . . . . . . . . . . . . . . . . 162
General Statistics Screen . . . . . . . . . . . . . . . . . . 163
802.5 Statistics Screen . . . . . . . . . . . . . . . . . . . 167
802.5 State Information Screen . . . . . . . . . . . . . . . 170
802.5 DTR MAC Information Menu . . . . . . . . . . . . . 172
TXI Information Screen . . . . . . . . . . . . . . . . . . . 173
Station-CPort Information Screen . . . . . . . . . . . . . . 175
Address Tables Menu . . . . . . . . . . . . . . . . . . . . . . 177
Master Address Table Screen . . . . . . . . . . . . . . . 178
Master Route Descriptor Table Screen . . . . . . . . . . . 180
VLAN Address Table Screen . . . . . . . . . . . . . . . . 182
VLAN Route Descriptor Table Screen . . . . . . . . . . . 183
Locate MAC Address Screen . . . . . . . . . . . . . . . . 184
Current Spanning Tree Information Screen . . . . . . . . . . . 185
Current Spanning Tree Information for a CRF Screen . . . 188
VLAN Statistics . . . . . . . . . . . . . . . . . . . . . . . . . 191
VLAN Statistics Screen for CRF . . . . . . . . . . . . . . 191
VLAN Statistics for BRF Screen . . . . . . . . . . . . . . 192
DSRR Status Screens . . . . . . . . . . . . . . . . . . . . . 193
DSRR Status Tables Screen . . . . . . . . . . . . . . . . 193
DSRR Neighbor Table Screen . . . . . . . . . . . . . . . 194
DSRR Acting as Backup Table Screen . . . . . . . . . . . 195
Diagnostic Test Results Screen . . . . . . . . . . . . . . . . . 196
Message Log Information Screen . . . . . . . . . . . . . . . . 197
Display Summary Screen . . . . . . . . . . . . . . . . . . . . 199
8. Monitoring the Network with SNMP 201
SNMP Setup . . . . . . . . . . . . . . . . . . . . . . . . . . 201
IP Configuration Screen . . . . . . . . . . . . . . . . . . . . . 201
SNMP Configuration . . . . . . . . . . . . . . . . . . . . . . 202
SNMP Configuration Screen . . . . . . . . . . . . . . . . 202
Community Strings Screen . . . . . . . . . . . . . . . . . 203
Trap Receivers Screen . . . . . . . . . . . . . . . . . . . 205
List of Supported Traps from a STS16-20D/STS16-20R . . 206
9. Monitoring Port Traffic 211
Switched Port Analyzer Screen . . . . . . . . . . . . . . . . . 213
10. Troubleshooting 215
Obtaining Service . . . . . . . . . . . . . . . . . . . . . . 215
Troubleshooting in a Network . . . . . . . . . . . . . . . . 215
Start of Troubleshooting Process . . . . . . . . . . . . . . 215
Choosing a Troubleshooting Procedure . . . . . . . . . . 216

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Notice
11. Getting in Touch with Technical Support 221
Problem Report Form . . . . . . . . . . . . . . . . . . . . . 222
Appendix A. Abbreviations 225
Appendix B. Cable and Pin Information 229
Connecting to the Out-of-Band Management Port . . . . 229
Out-of-Band Management Port and Cable Pin-Outs . . . 229
Twisted-Pair Cable Pin Outs . . . . . . . . . . . . . . . . 232
Cabling Recommendations . . . . . . . . . . . . . . . . 233
Cable Length and Lobe Wiring Rules
for Dedicated-Media LAN Segments . . . . . . . . . . . 234
Cable Length and Lobe Wiring Rules
for Shared-Media LAN Segments . . . . . . . . . . . . . 235

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Notice
List of Figures
Figure 1. SmartStack STS16-20D Token Ring Switch . . . . . . . . . 1
Figure 2. Location of LEDs, Switches and Connectors . . . . . . . . . 5
Figure 3. The back panel of the SmartStack STS16-20D . . . . . . . 9
Figure 4. The back panel of the SmartStack STS16-20R . . . . . . . 9
Figure 5. Multiple Conversations Through a SmartStack
STS16-20RM Switch . . . . . . . . . . . . . . . . . . . . 18
Figure 6. Typical Configuration with SmartStack STS16-20R
Switches Using Multiple Bridging Modes . . . . . . . . . . 21
Figure 7. A SmartStack STS16-20R Switch Configured
with Two VLANs . . . . . . . . . . . . . . . . . . . . . . 31
Figure 8. Example of Dynamic Source Route Recovery, Base
Configuration . . . . . . . . . . . . . . . . . . . . . . . . 32
Figure 9. Example of Dynamic Source Route Recovery,
Normal State . . . . . . . . . . . . . . . . . . . . . . . . 33
Figure 10. Example of Dynamic Source Route Recovery,
Switch 1 Failed . . . . . . . . . . . . . . . . . . . . . . . 34
Figure 11. Typical Network without the SmartStack
STS16-20D/STS16-20R . . . . . . . . . . . . . . . . . . 49
Figure 12. Relieving the Overstressed Backbone . . . . . . . . . . . 49
Figure 13. Replacing SRBs with a SmartStack STS16-20RM or
SmartStack STS16-20R . . . . . . . . . . . . . . . . . . 50
Figure 14. Delivering Dedicated Bandwidth to Individual Workstations 50
Figure 15. Scenario using a Stacker Link and a Matrix Switch . . . . 52
Figure 16. Setting Up CrossLinks . . . . . . . . . . . . . . . . . . . 53
Figure 17. Exposing the Rack Mounting Bracket . . . . . . . . . . . 58
Figure 18. Mounting the Switch in a Rack or Cabinet . . . . . . . . . 59
Figure 19. Connecting Devices to Token Ring Ports . . . . . . . . . 61
Figure 20. Connecting using Building Wiring . . . . . . . . . . . . . 62
Figure 21. The back panel of the STS16-20D . . . . . . . . . . . . . 63
Figure 22. The back panel of the STS16-20R . . . . . . . . . . . . . 64
Figure 23. SmartStack STS-LM Front Panel . . . . . . . . . . . . . 65
Figure 24. View of Console Connection . . . . . . . . . . . . . . . . 70
Figure 25. SmartStack STS16-20D/STS16-20R with four VLANs . . . 86
Figure 26. Setting Up CrossLinks . . . . . . . . . . . . . . . . . . . 110
Figure 27. Primary and Traced DSRR Port . . . . . . . . . . . . . . 142
Figure 28. TIA/EIA-232 Null-Modem Cable for 25-pin Connector . . . 231
Figure 29. EIA 232 Null-Modem Cable for 9-pin Connector . . . . . . 231
Figure 30. Straight-Through Cable . . . . . . . . . . . . . . . . . . 232
Figure 31. Data Connector-to-RJ-45 Straight-Through Cable . . . . . 232

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Notice
List of Tables
Table 1. Status LEDs and their Meanings . . . . . . . . . . . . . . . 7
Table 2. Stack-link LEDs and Their Meanings . . . . . . . . . . . . . 8
Table 3. Port LEDs and Their Meanings . . . . . . . . . . . . . . . . 8
Table 4. Back Panel Connectors . . . . . . . . . . . . . . . . . . . . 9
Table 5. Capacity Specifications . . . . . . . . . . . . . . . . . . . 13
Table 6. Performance Specifications . . . . . . . . . . . . . . . . . 14
Table 7. Specifications of Physical Characteristics . . . . . . . . . 16
Table 8. Supported MIBs . . . . . . . . . . . . . . . . . . . . . . . 35
Table 9. Supported RMON Groups . . . . . . . . . . . . . . . . . 37
Table 10. SmartStack STS-LM Network Connector . . . . . . . . . . 66
Table 11. SmartStack STS-LM LEDs . . . . . . . . . . . . . . . . . 66
Table 12. Inter-box Parameters . . . . . . . . . . . . . . . . . . . . 68
Table 13. Console Configuration Settings . . . . . . . . . . . . . . . 71
Table 14. Modem Settings . . . . . . . . . . . . . . . . . . . . . . 134
Table 15. Symptom, LED State and Recommended Procedure . . 216
Table 16. Connecting to the Management Port . . . . . . . . . . . 229
Table 17. Pin-out of the Management Port . . . . . . . . . . . . . 230
Table 18. Copper Cable Types . . . . . . . . . . . . . . . . . . . 233
Table 19. Lobe Length for 150 Ohm Shielded Media . . . . . . . . 234
Table 20. Lobe Lengths for 100 Ohm Shielded or Unshielded Cable 234
Table 21. Lobe Lengths for 100 or 120 Ohm Shielded
or Unshielded Cable . . . . . . . . . . . . . . . . . . . 235

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1
Introduction SmartStack STS16-20D/STS16-20R Token Ring Switches Installation and User Guide
1. Introduction
This chapter discusses switching technology and how the SmartStack STS16-20D
and/or SmartStack STS16-20R Token Ring Switch can be used to improve network
performance. This chapter also includes a list of features and specifications for the
SmartStack STS16-20D/STS16-20R.
The topics of this chapter are presented under the following titles:
•“Switching Technology”, starting on page 2.
•“Front Panel Details”, starting on page 5 and “Back Panel Details”starting on
page 9.
•“Features and Specifications”, starting on page 10.
The front panels of the SmartStack STS16-20D Token Ring Switch and the
SmartStack STS16-20R Token Ring Switch are exactly the same, only the product
label differs. The following figure illustrates the front panel of a SmartStack
STS16-20D Token Ring Switch.
Figure 1. SmartStack STS16-20D Token Ring Switch

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SmartStack STS16-20D/STS16-20R Token Ring Switches Installation and User Guide Introduction
Switching Technology
Demand for network bandwidth continues to grow, driven by the increasing
number of systems used in network-intensive applications. LAN segmentation has
been the prevalent method for addressing these demands and has been further
popularized by trends toward server centralization. However, the implementation
costs of LAN segmentation, as well as the real performance characteristics of
conventional network components, have served to limit growth of some Token
Ring networks. Alternative technologies for addressing bandwidth demands
present yet other inhibitors, usually relating to costs. Token Ring switching
provides users with an easy, cost-effective technique for addressing these demands.
Token Ring switches, such as the SmartStack STS16-20D/STS16-20R, increase
throughput between Token Ring segments by supporting simultaneous, parallel
conversations. Switched connections between Token Ring segments last only for
the duration of the packet—new connections can be made between different
segments for the next packet.
Token Ring switches solve congestion problems caused by high-bandwidth devices
and powerful applications as well as the number of users. Therefore, each of these
devices—servers, for example—can be assigned its own 16 Mbps segment.
In Token Ring networks, the major bottleneck is typically the throughput to high-
bandwidth devices such as servers, and between routers, bridges, and switches. An
effective solution is full-duplex communication, an option for each segment
connected to an SmartStack STS16-20D/STS16-20R port. Normally, Token Ring
operates in half-duplex communication mode, which means stations can either
receive or transmit. With full-duplex technology, two communicating stations can
transmit and receive at the same time. When packets can flow in both directions
simultaneously, effective Token Ring bandwidth doubles from 16 Mbps to 32
Mbps.
The SmartStack STS16-20D/STS16-20R can forward Token Ring frames among
multiple, shared or dedicated Token Ring LAN segments. Using a frame
forwarding technique similar to that of a multiport Token Ring transparent bridge,
the switch uses Token Ring MAC addresses to forward Token Ring frames from any
of its ports to any other.
Switch of Switches
The SmartStack STS16-20D/STS16-20R can be deployed in a variety of network
configurations, all of which provide a significant increase in network performance.
The family of Cabletron Systems Token Ring products allows users to build
network systems that can transport data efficiently and scale upwards as throughput
requirements increase. The SmartStack STS16-20D/STS16-20R delivers high-
reliability and media flexibility. These features combine to allow the SmartStack

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Introduction SmartStack STS16-20D/STS16-20R Token Ring Switches Installation and User Guide
STS16-20D/STS16-20R to be used as a switch of switches which provides media
flexibility in an Token Ring configuration.
The SmartStack STS16-20D/STS16-20R can easily connect with other SmartStack
products to deliver a broad range of network carrying capacity. Bandwidth is easily
scaled to meet all performance requirements.
Switch of Servers
With client/server applications, many client workstations may attempt to access a
single server at the same time. This traffic pattern may create bottlenecks at the
server. To further enhance performance, the SmartStack STS16-20D/STS16-20R
can deliver dedicated bandwidth to high-speed file servers. All servers perform
better with dedicated 16 Mbps bandwidth.
Even better performance can be achieved by installing multiple adapters in the
server. By connecting these adapters to the switch, multiple 16 Mbps paths to the
server are created, a solution that is only possible when using a switch.
The switch ties together all Token Ring devices lined to a local wiring center. In
networks, where a significant portion of the traffic moves locally between client
and server, the switch can be very effective.
Switch of Hubs
When network traffic increases beyond the capability of hubs, contention results.
Applications suffer and may even fail. The net effect of such a network
configuration is that all devices share a single 16 Mbps data path, thus reducing
overall network efficiency. The SmartStack STS16-20D/STS16-20R can be very
effective when used as a switch of hubs.
The SmartStack STS16-20D/STS16-20R can alleviate contention through
microsegmentation, or reducing the number of devices in each shared segment. To
provide microsegmentation, the SmartStack STS16-20D/STS16-20R divides a
single 16 Mbps segment into multiple 16 Mbps segments. As an example, a
workgroup has 16 Mbps of capacity. The 20 ports on the SmartStack STS16-20D/
STS16-20R support 10 simultaneous conversations with 20 hubs, thus providing
the workgroup with 160 Mbps bandwidth throughput, which results in a significant
gain in bandwidth. Note that on the SmartStack STS16-20D, hubs can only be
connected to the network ports 17–20.
Switch of Desktops
The SmartStack STS16-20D/STS16-20R is a cost-effective means of providing
dedicated bandwidth to individual desktop workstations. In this application, the
SmartStack STS16-20D/STS16-20R replaces a hub, providing excellent, hub-like

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SmartStack STS16-20D/STS16-20R Token Ring Switches Installation and User Guide Introduction
network management statistics. Total network capacity and throughput increase
dramatically for attached desktop workstations.
Switch of Floors and Buildings
For network managers, multistorey buildings and campuses can represent a unique
networking challenge. How can a network manager provide an efficient LAN
interconnect for users that are located on several floors of a building or in different
buildings?
Token Ring switching and the SmartStack product family can provide the best
solution. The SmartStack STS16-20D/STS16-20R provides enhanced throughput
to local wiring closets that can be connected to a switch located in the data center.
Many networks consist of users located in different buildings of a campus
environment. The switches can be used as a collapsed backbone interconnecting
multiple buildings of a campus. They can provide the connectivity solution and
enhanced throughput that such campus environments require.
Switch of Routers
Router technology has had a significant impact on the design of today’s
internetworks. Routers have become the cornerstone of most production networks.
Although well equipped to provide firewall, WAN connectivity, security, and
connection between dissimilar LANs, routers are unable to provide high throughput
between desktop devices and servers. Because of these limitations, routers and
switches perform complimentary functions in the network.
The SmartStack STS16-20D/STS16-20R can be used as a front-end to routers to
increase performance in each subnet. Communication between local clients and
servers is enhanced at the workgroup level below the router.
The SmartStack STS16-20D/STS16-20R can also be used to back-end routers. In
networks were many routers are interconnected over Token Ring and backbone
performance is not acceptable, the SmartStack STS16-20D/STS16-20R provides
nonblocking communication between the routers for enhanced network
performance. This provides protocol transparency with enhanced throughput in
each subnet between local servers and desktops, thus allowing network managers
to build logical networks as large as network layer protocol and broadcast traffic
allow.
The Switched Port Analyzer also gives a collapsed backbone network superior
network management and the ability to perform protocol analysis from a single
location. The Switch Port Analyzer provides the latest technology for monitoring
switch-based networks and helps to reduce the cost of managing these networks.

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Introduction SmartStack STS16-20D/STS16-20R Token Ring Switches Installation and User Guide
Front Panel Details
The front panel details of the switches are illustrated in Figure 2. This section lists
all the connectors, controls, and LEDs of the front panel.
Figure 2. Location of LEDs, Switches and Connectors
The MANAGEMENT Port
The 9-pin, male, Out-of-Band Management (OBM) port labeled MANAGEMENT
functions as a DTE port.
This port enables attachment of a terminal, either local or remote, through a modem
connection. The terminal can be used to configure and monitor the switch.
The Out-of-Band Management port automatically detects the baud rate of the
terminal to which it is attached.
Token Ring Ports
•Twenty shielded RJ-45 connectors for Token Ring connection.
—Support for the IBM Cabling System via 150 ohm, shielded twisted-pair
(150 ohm STP); or 100 or 120 ohm unshielded twisted-pair via Category
3, 4, or 5 cables.
—These ports allow half-duplex (HDX) or full-duplex (FDX) connections to
other switches, hubs, or end nodes.
•The SmartStack STS16-20D/STS16-20R will automatically sense what type
of Token Ring connection is being employed on each of its ports, whether it is:

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SmartStack STS16-20D/STS16-20R Token Ring Switches Installation and User Guide Introduction
—a connection to a shared-media segment via a Token Ring concentrator,
Station mode (on SmartStack STS16-20D only via the network ports
17–20)
—a connection to another Token Ring switch (on SmartStack STS16-20D
only via network ports 17–20)
—operating at 4 Mbps or at 16 Mbps
—a connection to a dedicated-media segment, directly to a Token Ring LAN
station operating in half-duplex or full-duplex mode (Port mode).
—Ports 19 and 20 on SmartStack STS16-20R can attach to a MAU/CAU RI/
RO port
The switch will automatically configure (requiring no operator action) each port to
operate at the highest possible level of capability. No special crossover cables are
required for Token Ring stations on dedicated-media segments or for switch-to-
switch connections; the same straight-through cabling is used regardless of the type
of connection. This auto-sense/auto-configure capability of the switch can be
overridden by explicit console management.
Switched Port Analyzer
Any of the Token Ring ports can be configured as an analyzer port. An analyzer
port is used to monitor any of the other ports in the same physical switch. The
activity can then be traced by a Token-Ring network analyzer attached to the
analyzer port.
Reset Button
The SmartStack STS16-20D/STS16-20R has a recessed reset button labeled RST
that is located on the front panel. Pressing the reset button resets the hardware and
software and clears all tables and memory, including the address tables. Pressing
the reset button does not clear the values stored in nonvolatile random access
memory (NVRAM).
System Request Button
This unlabeled recessed button is located on the front panel above the Reset button.
Pressing the button causes the System Request Menu to appear on the console
device attached to the MANAGEMENT port. Pressing the button for more than
five seconds will initiate a modem download of the main image.
➽Note: The system request button should be used only at the direction of service
personnel. The button is recessed to prevent accidental activation.