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AT-S25
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Allied Telesis AT-S25 User Manual

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◆
User’s Guide
Management
Software
AT-S25
AT-8316F/MT, AT-8316F/VF, AT-8316F/SC, AND AT-8324 FAST ETHERNET SWITCHES
VERSION 2.0.2
PN 613-10844-00 Rev E
Copyright © 2003 Allied Telesyn, Inc. 960 Stewart Drive Suite B, Sunnyvale, CA 94085 USA
All rights reserved. No part of this publication may be reproduced without prior written permission from Allied Telesyn, Inc.
Microsoft is a registered trademark of Microsoft Corporation, Netscape Navigator is a registered trademark of Netscape Communications Corporation. All other product names, company names, logos or other designations mentioned herein are trademarks or registered trademarks of their respective owners.
Allied Telesyn, Inc. reserves the right to make changes in specifications and other information contained in this document without prior written notice. The information provided herein is subject to change without notice. In no event shall Allied Telesyn, Inc. be liable for any incidental, special, indirect, or consequential damages whatsoever, including but not limited to lost profits, arising out of or related to this manual or the information contained herein, even if Allied Telesyn, Inc. has been advised of, known, or should have known, the possibility of such damages.

Table of Contents

List of Figures ........................................................................................................................................................................................................ 8
List of Tables ........................................................................................................................................................................................................11
Preface ....................................................................................................................................................................................................................12
How This Guide is Organized ...........................................................................................................................................................................13
Document Conventions ....................................................................................................................................................................................14
Contacting Allied Telesyn .................................................................................................................................................................................15
Online Support ............................................................................................................................................................................................. 15
E-mail and Telephone Support .............................................................................................................................................................. 15
For Sales or Corporate Information ...................................................................................................................................................... 15
Where to Find Web-based Guides .................................................................................................................................................................16
Obtaining Management Software Updates ...................................................................................................................................... 16
Upgrading AT-S25 Version 1.5.6.2 or Earlier to Version 2.0.2 or Later ..............................................................................................17
TFTP Guidelines............................................................................................................................................................................................ 18
Using TFTP to Download the AT-S25 Version 2.0.2 Image File to the Master Switch of the Stack ................................ 19
Using XModem to Download the AT-S25 Version 2.0.2 Image File .......................................................................................... 19
Section I Overview
Chapter 1
Overview ................................................................................................................................................................................................................26
Local Management Session ..............................................................................................................................................................................28
Telnet Management Session ............................................................................................................................................................................29
Web Browser Management Session ..............................................................................................................................................................30
SNMP Management Session ............................................................................................................................................................................31
Management Access Levels .............................................................................................................................................................................32
...................................................................................................................................................................................................25
Section II Local and Telnet Management Sessions
Chapter 2
Starting a Local or Telnet Management Session ................................................................................................................................34
Local Management Session ..............................................................................................................................................................................35
Starting a Local Management Interface.............................................................................................................................................. 35
Quitting from a Local Interface .............................................................................................................................................................. 37
.............................................................................................33
3
Table of Contents
Telnet Management Session ........................................................................................................................................................................... 38
Starting a Telnet Management Interface ........................................................................................................................................... 38
Quitting from a Telnet Management Interface................................................................................................................................ 39
Selecting a Switch Module in the Stack ...................................................................................................................................................... 40
Chapter 3
Basic Switch Parameters ................................................................................................................................................................................ 41
When Does a Switch Need an IP Address? ................................................................................................................................................. 42
How Do You Assign an IP Address?...................................................................................................................................................... 42
Configuring an IP Address and Switch Name ........................................................................................................................................... 45
Activating the BOOTP and DHCP Services ................................................................................................................................................. 46
Resetting a Stack .................................................................................................................................................................................................. 48
Pinging a Remote System ................................................................................................................................................................................ 49
Configuring the AT-S25 Software Security Features .............................................................................................................................. 50
Configuring the Management Passwords......................................................................................................................................... 51
Configuring Management Access ........................................................................................................................................................ 52
Configuring SNMP Community Strings and Trap IP Addresses ......................................................................................................... 54
Returning the AT-S25 Software to the Factory Default Values ........................................................................................................... 56
Viewing the AT-S25 Version Number and Basic Switch Information ............................................................................................... 58
Chapter 4
Port Parameters ................................................................................................................................................................................................. 59
Configuring Port Parameters .......................................................................................................................................................................... 60
Displaying Port Status ........................................................................................................................................................................................ 64
Chapter 5
Port Security ........................................................................................................................................................................................................ 67
Port Security Overview ...................................................................................................................................................................................... 68
Automatic...................................................................................................................................................................................................... 68
Limited............................................................................................................................................................................................................ 68
Secure ............................................................................................................................................................................................................. 70
Lock All Ports ................................................................................................................................................................................................ 71
Configuring Limited Security Level .............................................................................................................................................................. 72
Activating a Port Security Level ..................................................................................................................................................................... 75
Chapter 6
Port Trunking ...................................................................................................................................................................................................... 77
Port Trunking Overview .................................................................................................................................................................................... 78
Port Trunking Guidelines ......................................................................................................................................................................... 78
Creating a Port Trunk ......................................................................................................................................................................................... 82
Creating a 10/100 Port Trunk ................................................................................................................................................................. 82
Creating a Gigabit Port Trunk................................................................................................................................................................. 83
Modifying a Port Trunk ...................................................................................................................................................................................... 85
Modifying a Trunk Name .................................................................................................................................................................................. 86
Deleting a Port Trunk ......................................................................................................................................................................................... 87
Chapter 7
Port Mirroring ..................................................................................................................................................................................................... 88
Port Mirroring Overview ................................................................................................................................................................................... 89
Creating a Port Mirror ........................................................................................................................................................................................ 90
Chapter 8
STP and RSTP ....................................................................................................................................................................................................... 92
STP and RSTP Overview ..................................................................................................................................................................................... 93
Bridge Priority and the Root Bridge ..................................................................................................................................................... 94
Mixed STP and RSTP Networks ............................................................................................................................................................ 100
Spanning Tree and VLANs ........................................................................................................
............................................................. 100
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AT-S25 Management Software User’s Guide
Enabling or Disabling STP or RSTP .............................................................................................................................................................. 101
STP and RSTP Parameters .............................................................................................................................................................................. 102
Configuring STP ................................................................................................................................................................................................. 105
Configuring a Bridge’s STP Settings .................................................................................................................................................. 105
Configuring a Port’s STP Settings ....................................................................................................................................................... 107
Displaying Port’s STP Status and Setting .................................................................................................................................................. 109
Configuring RSTP .............................................................................................................................................................................................. 110
Configuring a Bridge’s RSTP Settings................................................................................................................................................ 110
Configuring a Port’s RSTP Settings .................................................................................................................................................... 111
Displaying Port’s RSTP Status and Settings ............................................................................................................................................. 114
Displaying a Port’s RSTP Settings ....................................................................................................................................................... 114
Displaying a Port’s RSTP Status ........................................................................................................................................................... 115
Chapter 9
Virtual LANs ....................................................................................................................................................................................................... 117
VLAN Overview .................................................................................................................................................................................................. 118
Port-based VLAN Overview ........................................................................................................................................................................... 120
VLAN Name................................................................................................................................................................................................. 120
VLAN Identifier .......................................................................................................................................................................................... 120
Untagged Ports ......................................................................................................................................................................................... 121
Port VLAN Identifier................................................................................................................................................................................. 121
General Rules to Creating a Port-based VLAN ............................................................................................................................... 121
Drawbacks to Port-based VLANs ........................................................................................................................................................ 122
Port-based VLAN Example .................................................................................................................................................................... 123
Tagged VLAN Overview .................................................................................................................................................................................. 125
VLAN Name................................................................................................................................................................................................. 126
VLAN Identifier .......................................................................................................................................................................................... 126
Tagged and Untagged Ports ................................................................................................................................................................ 126
Port VLAN Identifier................................................................................................................................................................................. 126
General Rules to Creating a Tagged VLAN...................................................................................................................................... 126
Tagged VLAN Example ........................................................................................................................................................................... 127
Basic VLAN Mode Overview .......................................................................................................................................................................... 129
Creating a Port-based or Tagged VLAN .................................................................................................................................................... 130
Modifying a VLAN ............................................................................................................................................................................................. 134
Displaying VLAN Information ....................................................................................................................................................................... 137
Deleting a VLAN ................................................................................................................................................................................................. 138
Deleting All VLANs ............................................................................................................................................................................................ 140
Displaying PVIDs ................................................................................................................................................................................................ 141
Specifying a Management VLAN ................................................................................................................................................................. 143
Switching the VLAN Mode ............................................................................................................................................................................. 145
Chapter 10
MAC Address Table ........................................................................................................................................................................................ 146
MAC Address Overview .................................................................................................................................................................................. 147
Viewing MAC Addresses ................................................................................................................................................................................. 149
Viewing All MAC Addresses.................................................................................................................................................................. 149
Viewing Static MAC Addresses Only ................................................................................................................................................. 151
Viewing Multicast MAC Addresses Only .......................................................................................................................................... 152
Viewing MAC Addresses on Base Ports Only.................................................................................................................................. 153
Viewing MAC Addresses by Port & Module .................................................................................................................................... 154
Viewing the MAC Addresses of a VLAN ............................................................................................................................................ 155
Identifying a Port or a Module Number by MAC Address .................................................................................................................. 156
Deleting MAC Addresses ................................................................................................................................................................................ 157
Deleting All Dynamic MAC Addresses ....................................................................................................................................................... 158
Adding Static and Multicast MAC Addresses .......................................................................................................................................... 159
Changing the Aging Time .............................................................................................................................................................................. 160
5
Table of Contents
Chapter 11
Class of Service .................................................................................................................................................................................................161
Class of Service Overview ...............................................................................................................................................................................162
Configuring CoS .................................................................................................................................................................................................163
Show Port VLANs & Priorities ........................................................................................................................................................................165
Chapter 12
IGMP Snooping ................................................................................................................................................................................................166
IGMP Snooping Overview .............................................................................................................................................................................. 167
Activating IGMP Snooping .............................................................................................................................................................................169
Displaying a List of Host Nodes ....................................................................................................................................................................172
Displaying a List of Multicast Routers ........................................................................................................................................................173
Chapter 13
Ethernet Statistics ...........................................................................................................................................................................................174
Displaying Port Statistics ................................................................................................................................................................................175
Displaying Switch Statistics ...........................................................................................................................................................................177
Chapter 14
File Downloads and Uploads .....................................................................................................................................................................178
Obtaining Software Updates .........................................................................................................................................................................180
Transferring Files from a Local Management Interface .......................................................................................................................181
Downloading An Image File ................................................................................................................................................................. 182
Downloading Configuration File......................................................................................................................................................... 184
Uploading Configuration File to TFTP Server................................................................................................................................. 185
Transferring Files Using HyperTerminal Interface .................................................................................................................................186
Section III Web Browser Management
Chapter 15
Starting a Web Browser Management Interface .............................................................................................................................189
Web Browser Management Interface ........................................................................................................................................................190
Starting a Web Browser Interface ....................................................................................................................................................... 190
Browser Tools ............................................................................................................................................................................................. 192
Quitting from a Web Browser Management Interface................................................................................................................ 192
Chapter 16
Basic Switch Parameters ..............................................................................................................................................................................193
Configuring an IP Address and Switch Name .........................................................................................................................................194
Activating the BOOTP and DHCP Services ...............................................................................................................................................198
Resetting a Switch .............................................................................................................................................................................................199
Viewing System Information .........................................................................................................................................................................200
Configuring the SNMP Parameters and Trap IP Addresses ................................................................................................................202
Pinging a Remote System ..............................................................................................................................................................................204
Returning the AT-S25 Software to the Factory Default Values .........................................................................................................205
Chapter 17
Port Parameters ...............................................................................................................................................................................................206
Configuring Port Parameters ........................................................................................................................................................................207
Displaying Port Status and Statistics ..........................................................................................................................................................210
Chapter 18
Port Security ......................................................................................................................................................................................................214
Displaying the Port Security Level ..............................................................................................................................................................215
....................................................................................................................................188
6
AT-S25 Management Software User’s Guide
Chapter 19
Port Trunks ........................................................................................................................................................................................................ 216
Creating a Port Trunk ....................................................................................................................................................................................... 217
Modifying a Port Trunk ................................................................................................................................................................................... 219
Deleting a Port Trunk ....................................................................................................................................................................................... 220
Displaying Port Trunks .................................................................................................................................................................................... 221
Chapter 20
Port Mirroring ................................................................................................................................................................................................... 222
Creating a Port Mirror ...................................................................................................................................................................................... 223
Deleting a Port Mirror ...................................................................................................................................................................................... 225
Viewing Source and Destination Ports ...................................................................................................................................................... 226
Chapter 21
STP and RSTP .................................................................................................................................................................................................... 227
Enabling or Disabling STP or RSTP .............................................................................................................................................................. 228
STP and RSTP Parameters .............................................................................................................................................................................. 230
Configuring STP ................................................................................................................................................................................................. 233
Configuring a Bridge’s STP Settings .................................................................................................................................................. 233
Configuring a Port’s STP Settings ....................................................................................................................................................... 234
Displaying STP Status and Settings ............................................................................................................................................................ 235
Displaying Bridge’s STP Status and Settings .................................................................................................................................. 235
Displaying Port’s STP Status and Settings ....................................................................................................................................... 235
Configuring RSTP .............................................................................................................................................................................................. 237
Configuring a Bridge’s RSTP Settings................................................................................................................................................ 237
Configuring a Port’s RSTP Settings .................................................................................................................................................... 238
Displaying RSTP Status and Settings ......................................................................................................................................................... 240
Displaying Bridge’s RSTP Status and Settings................................................................................................................................ 240
Displaying Port’s RSTP Status and Settings .................................................................................................................................... 240
Chapter 22
Virtual LANs ....................................................................................................................................................................................................... 242
Creating a VLAN ................................................................................................................................................................................................. 243
Modifying a VLAN ............................................................................................................................................................................................. 245
Deleting VLANs .................................................................................................................................................................................................. 247
Displaying VLANs .............................................................................................................................................................................................. 248
Changing a PVID Value ................................................................................................................................................................................... 250
Setting the Switch’s VLAN Mode ................................................................................................................................................................. 252
Chapter 23
MAC Address Table ........................................................................................................................................................................................ 254
Viewing the MAC Address Table ................................................................................................................................................................. 255
Adding Static and Multicast MAC Addresses .......................................................................................................................................... 258
Deleting MAC Addresses ................................................................................................................................................................................ 259
Changing the Aging Time .............................................................................................................................................................................. 260
Chapter 24
Class of Service ................................................................................................................................................................................................ 262
Configuring CoS ................................................................................................................................................................................................ 263
Chapter 25
IGMP Snooping ................................................................................................................................................................................................ 265
Configuring IGMP Snooping ......................................................................................................................................................................... 266
Displaying a List of Host Nodes and Multicast Routers ....................................................................................................................... 269
Appendix A
AT-S25 Default Settings .............................................................................................................................................................................. 272
Index
..................................................................................................................................................................................................................... 274
7

List of Figures

Figure 1: System Booting Window ......................................................................................................................................................... 20
Figure 2: ATI Diagnostics Menu ............................................................................................................................................................... 21
Figure 3: AT-S25 Properties Window ..................................................................................................................................................... 22
Figure 4: COM1 Properties Window ....................................................................................................................................................... 22
Figure 5: Local Management Window - Send File Menu ................................................................................................................ 23
Figure 6: Send File Pop-Up Window ....................................................................................................................................................... 23
Figure 7: XModem File Send Window ................................................................................................................................................... 24
Figure 8: Connecting a Terminal or PC to the RS-232 Terminal Port .......................................................................................... 35
Figure 9: Main Menu .................................................................................................................................................................................... 37
Figure 10: Administration Menu ................................................................................................................................................................ 43
Figure 11: Passwords Menu ......................................................................................................................................................................... 51
Figure 12: System Config Menu ................................................................................................................................................................. 52
Figure 13: Advanced Configuration Menu ............................................................................................................................................. 54
Figure 14: SNMP Configuration Menu ..................................................................................................................................................... 55
Figure 15: Diagnostics Menu ....................................................................................................................................................................... 58
Figure 16: Example of Port Configuration Menu .................................................................................................................................. 61
Figure 17: Ports Menu .................................................................................................................................................................................... 64
Figure 18: Port Status Window ................................................................................................................................................................... 65
Figure 19: Port Groupings on an AT-8324 Switch ................................................................................................................................ 69
Figure 20: Port Groups on an AT-8316F/MT or AT-8316/VF Switch .............................................................................................. 69
Figure 21: Port Groups on an AT-8316F/SC Switch ............................................................................................................................. 70
Figure 22: Port Security Menu ..................................................................................................................................................................... 72
Figure 23: Port Security Limited-Mode Menu ....................................................................................................................................... 73
Figure 24: Port Security Menu ..................................................................................................................................................................... 75
Figure 25: Port Trunk Example .................................................................................................................................................................... 78
Figure 26: Port Groupings on an AT-8324 Switch ................................................................................................................................ 79
Figure 27: Port Groups on an AT-8316F/MT or AT-8316/VF Switch .............................................................................................. 79
Figure 28: Port Groups on an AT-8316F/SC Switch ............................................................................................................................. 79
Figure 29: Port Trunking Menu ................................................................................................................................................................... 82
Figure 30: Port Mirroring Menu .................................................................................................................................................................. 90
Figure 31: Point-to-Point Ports ................................................................................................................................................................... 98
Figure 32: Edge Port ....................................................................................................................................................................................... 99
Figure 33: Point-to-Point and Edge Point ............................................................................................................................................... 99
Figure 34: VLAN Fragmentation .............................................................................................................................................................. 100
Figure 35: Spanning Tree Menu .............................................................................................................................................................. 101
Figure 36: STP Menu .................................................................................................................................................................................... 105
Figure 37: STP Port Parameters Menu ................................................................................................................................................... 107
Figure 38: Configure STP Port Settings Menu .................................................................................................................................... 108
8
AT-S25 Management Software User’s Guide
Figure 39: Display STP Port Configuration Window ......................................................................................................................... 109
Figure 40: RSTP Menu ................................................................................................................................................................................. 110
Figure 41: RSTP Port Parameters Menu ................................................................................................................................................ 111
Figure 42: Configure RSTP Port Settings Menu ................................................................................................................................. 112
Figure 43: Display RSTP Port Configuration Window ...................................................................................................................... 115
Figure 44: Display RSTP Port State Window ........................................................................................................................................ 116
Figure 45: Port-based VLAN Example .................................................................................................................................................... 123
Figure 46: Tagged VLAN Example .......................................................................................................................................................... 127
Figure 47: VLAN Menu ................................................................................................................................................................................ 130
Figure 48: VLAN Definition Menu ........................................................................................................................................................... 130
Figure 49: Create VLAN Menu .................................................................................................................................................................. 131
Figure 50: Modifying VLAN Menu ........................................................................................................................................................... 134
Figure 51: Show All VLANs Window ....................................................................................................................................................... 137
Figure 52: Delete VLAN Menu .................................................................................................................................................................. 138
Figure 53: Configure Port Priorities Menu ........................................................................................................................................... 141
Figure 54: Show Port VLANs and Priorities Window ........................................................................................................................ 142
Figure 55: System Config Menu .............................................................................................................................................................. 145
Figure 56: MAC Menu .................................................................................................................................................................................. 149
Figure 57: Show all MAC addresses Window ...................................................................................................................................... 150
Figure 58: Show all static MAC addresses Window .......................................................................................................................... 151
Figure 59: Show all multicast MAC addresses Window .................................................................................................................. 152
Figure 60: Show MAC addresses on base ports Window ............................................................................................................... 153
Figure 61: Configure Port Priorities Menu ........................................................................................................................................... 163
Figure 62: Show Port VLANs & Priorities Window ............................................................................................................................. 165
Figure 63: IGMP Snooping Configuration Menu ............................................................................................................................... 169
Figure 64: View Multicast Hosts List Window ..................................................................................................................................... 172
Figure 65: View Multicast Routers List Window ................................................................................................................................. 173
Figure 66: Ethernet Statistics Menu ....................................................................................................................................................... 175
Figure 67: Display Port Statistics Window ........................................................................................................................................... 175
Figure 68: Display Module Statistics Window .................................................................................................................................... 177
Figure 69: Downloads & Uploads Menu ............................................................................................................................................... 182
Figure 70: Local Management Window ................................................................................................................................................ 186
Figure 71: Send File Window .................................................................................................................................................................... 186
Figure 72: XModem File Send Window ................................................................................................................................................ 187
Figure 73: Entering an IP Address in the URL Field .......................................................................................................................... 190
Figure 74: Home Page ................................................................................................................................................................................. 191
Figure 75: Exit Confirmation Window ................................................................................................................................................... 192
Figure 76: Configuration - General Window ....................................................................................................................................... 194
Figure 77: Monitoring - General Window ............................................................................................................................................ 200
Figure 78: Configuration - SNMP Window ........................................................................................................................................... 202
Figure 79: Monitoring - Ping Client Window ...................................................................................................................................... 204
Figure 80: Configuration - Factory Default Window ........................................................................................................................ 205
Figure 81: Configuration - Port Settings Window ............................................................................................................................. 207
Figure 82: Example of Settings for Port(s) Window .......................................................................................................................... 208
Figure 83: Port Monitoring Page ............................................................................................................................................................. 210
Figure 84: Port Status Window ................................................................................................................................................................ 211
Figure 85: Port Statistics Window ........................................................................................................................................................... 213
Figure 86: Port Security Menu .................................................................................................................................................................. 215
Figure 87: Port Trunking Tab Window .................................................................................................................................................. 217
Figure 88: Port Trunking Window - Create .......................................................................................................................................... 218
Figure 89: Example of Port Trunking Window - Modify .................................................................................................................. 219
Figure 90: Port Mirroring Window .......................................................................................................................................................... 223
Figure 91: Port Mirroring Window .......................................................................................................................................................... 224
Figure 92: Configuration - Spanning Tree Window ......................................................................................................................... 228
Figure 93: STP Configuration Spanning Tree Window .................................................................................................................... 233
9
List of Figures
Figure 94: STP Settings Window .............................................................................................................................................................. 234
Figure 95: Monitoring - Spanning Tree Window ............................................................................................................................... 235
Figure 96: Monitoring - STP Settings Window ................................................................................................................................... 236
Figure 97: RSTP Configuration Spanning Tree Window ................................................................................................................. 238
Figure 98: RSTP Settings Window ........................................................................................................................................................... 239
Figure 99: Monitoring - Spanning Tree Window ............................................................................................................................... 240
Figure 100: Monitoring - RSTP Settings Window ................................................................................................................................. 241
Figure 101: Configuration - VLAN Window ............................................................................................................................................ 243
Figure 102: Add VLAN Window .................................................................................................................................................................. 243
Figure 103: View/Update VLAN Window ................................................................................................................................................ 245
Figure 104: Monitoring - VLAN Window ................................................................................................................................................. 248
Figure 105: View VLAN Window ................................................................................................................................................................. 248
Figure 106: COS Setting Window .............................................................................................................................................................. 250
Figure 107: Configuration - General Window ....................................................................................................................................... 252
Figure 108: MAC Address Window ............................................................................................................................................................ 255
Figure 109: Example of MAC Address Table .......................................................................................................................................... 256
Figure 110: Add Static MAC Address window ...................................................................................................................................... 258
Figure 111: Configuration - General Window ....................................................................................................................................... 260
Figure 112: COS Setting Window .............................................................................................................................................................. 263
Figure 113: Configuration - IGMP Window ............................................................................................................................................ 266
Figure 114: Monitoring - IGMP Window .................................................................................................................................................. 269
Figure 115: View Multicast Hosts List Window ..................................................................................................................................... 270
Figure 116: View Multicast Routers List Window ................................................................................................................................. 271
10

List of Tables

Table 1: Basic Switch Parameters 43 Table 2: Port Configuration Parameters 61 Table 3: Port Status Parameters 65 Table 4: Trunked Ports on 10/100 Mbps and 100 Mbps Expansion Modules 81 Table 5: Port Mirroring Parameters 90 Table 6: Bridge Priority Value Increments 94 Table 7: Auto-Detect Port Costs 95 Table 8: Port Priority Value Increments 96 Table 9: STP and RSTP Parameters 102 Table 10: Port Assignments of the Port-based VLAN Example 124 Table 11: Show all MAC address Parameters 150 Table 12: Show all multicast MAC addresses Parameters 152 Table 13: IGMP Snooping Configuration Parameters 170 Table 14: View Multicast Hosts List Parameters 172 Table 15: View Multicast Routers List Parameters 173 Table 16: Port and Module Statistics Parameters 176 Table 17: Configuration - General Window Parameters 195 Table 18: Monitoring - General Window Parameters 201 Table 19: Port Setting Parameters 208 Table 20: Port Status Parameters 211 Table 21: Port Statistics Parameters 213 Table 22: STP and RSTP Parameters 230 Table 23: MAC Address Parameters 255 Table 24: MAC Address Table Parameters 256 Table 25: COS Setting Parameters 264 Table 26: View Multicast Hosts List Parameters 270 Table 27: View Multicast Routers List Parameters 271
11

Preface

This guide contains instructions on how to configure an AT-8300 Series switch or AT-8300 Series stack using the AT-S25 management software.
The Fast Ethernet switches in the AT-8300 Series include the following:
❑ AT-8316F/MT
❑ AT-8316F/VF
❑ AT-8316F/SC
❑ AT-8324
12

How This Guide is Organized

This manual is divided into three sections.
Section I: Overview
This section contains just one chapter. It reviews the different ways that you could access the AT-S25 management software on a switch.
Section II: Local and Telnet Management
The chapters in this section explain how to manage an AT-8300 Series stack from a local management interface or a Telnet management interface.
A local management interface is established by connecting a terminal or PC to the RS-232 Terminal Port on the front panel of the Master switch of the stack.
A Telnet management interface is established using the Telnet application protocol. This type of management interface can be performed from any workstation on your network that has the application protocol.
AT-S25 Management Software User’s Guide
Section III: Web Browser Management
The chapters in this section explain how to manage a stack using a web browser, such as Microsoft® Internet Explorer or Netscape® Navigator, from a workstation on your network.
13
Preface

Document Conventions

This document uses the following conventions:
Note
Notes provide additional information.
Warning
Warnings inform you that performing or omitting a specific action may result in bodily injury.
Caution
Cautions inform you that performing or omitting a specific action may result in equipment damage or loss of data.
14
AT-S25 Management Software User’s Guide

Contacting Allied Telesyn

This section provides Allied Telesyn contact information for technical support as well as sales or corporate information.

Online Support You can request technical support online by accessing the Allied Telesyn

Knowledge Base from the following web site: http://kb.alliedtelesyn.com. You can use the Knowledge Base to submit questions to our technical support staff and review answers to previously asked questions.
E-mail and Telephone
Support
For Sales or
Corporate
Information
For Technical Support via E-mail or telephone, refer to the Support & Services section of the Allied Telesyn web site: http://www.alliedtelesyn.com.
You can contact Allied Telesyn for sales or corporate information at our web site: http://www.alliedtelesyn.com. To find the contact information for your country, select Contact Us, then Worldwide Contacts.
15
Preface

Where to Find Web-based Guides

The installation and user guides for all Allied Telesyn products are available in Portable Document Format (PDF) on our web site at http://www.alliedtelesyn.com. You could view the documents on-line or download them onto a local workstation or server.
Obtaining
Management
Software
Updates
New releases of management software for our managed products can be downloaded from the Allied Telesyn web site: http://www.alliedtelesyn.com.
16
AT-S25 Management Software User’s Guide

Upgrading AT-S25 Version 1.5.6.2 or Earlier to Version 2.0.2 or Later

This section contains the procedures for upgrading an image file to AT-S25 Version 2.0.2 or later.
Caution
The configuration file in the AT-S25 Version 1.5.6.2 or earlier version is not compatible with the AT-S25 Version 2.0.2 or later versions of code; therefore, the user needs to save the configuration settings such as the static MAC addresses, VLAN settings, port configuration settings, etc. before downloading the latest version of code. Once the latest version of code is downloaded, these settings must be reconfigured manually.
Note
You cannot perform this procedure from a Telnet or Web Browser management interface.
Note
The switch will not forward Ethernet traffic during the software download and initialization process.
Two methods that you could use to download the image file are the TFTP and XModem methods.
❑ TFTP Method: This method is used to upgrade the software to the
switch modules that are part of a stacked configuration or to the entire stack at once. This method may be performed from either a local or a remote host PC.
❑ XModem Method: This method is used to upgrade the software to
an individual switch module of a stack or to a stand-alone switch module. If the switch module is a member of a stack, the stacking cable(s) must be disconnected from the module before starting this procedure. This method may be performed from a local host PC only.
Note
For faster transfer, the TFTP method is preferable. For guidelines or background information on how to upgrade the software using TFTP, refer to TFTP Guidelines on page 18.
17
Preface

TFTP Guidelines In the legacy code of AT-S25 Version 1.5.6.2 or an earlier version and

Version 1.5.6.3, the TFTP server software runs on the switch, so the user has to use the Put command of the TFTP client software on a PC to download an image file to the switch. However, AT-S25 Version 2.0.2 and after is designed to use the TFTP client software on the switch. As a result, the user must run TFTP server on the PC to download the image file to the switch when Version 2.0.2 or later is the current software. For further information on software downloads, refer to Chapter 14: File Downloads and Uploads on page 178.
TFTP software is available from various sources and is included in SNMP, which can be purchased through Allied Telesyn. A command line version, is included in most UNIX variants, Windows 2000, Windows NT, and Windows XP. Please consult the documentation or the manufacturer of the software for instructions on how to use the software.
Note
This is a two-step method used to upgrade the software to the switch modules that are part of a stacked configuration or to the entire stack at once. This method may be performed from either a local or a remote host PC.
Regardless of the manufacturer, all TFTP client software will need the following information:
Host - This is the IP address of the switch to which you are downloading the software.
Binary or ANSI - You will need to specify binary mode (-i) for the file transfer.
Put - The Put command is used to download a new software image file to the switch.
Source file - When using the Put command to download software to the stack, enter the path and filename of the file to be downloaded onto the switch. The filename must be “ATS25_V1563.IMG” or “ATS25_V202.IMG”, for example, depending on the new software image that is being downloaded.
Destination file - When using the Put command to download the software from a stack, the filename must be “ats25.img”. (No path should be specified for this file.)
Example:
tftp -i 149.35.1.1 put c:\ats25_v1563.img ats25.img
tftp -i 149.35.1.1 put c:\ats25_v202.img ats25.img
18
AT-S25 Management Software User’s Guide
Using TFTP to
Download the
AT-S25 Version
2.0.2 Image File to the Master Switch of the
Stack
In a network consisting of several AT-8316F or AT-8324 switches, you could simplify the upgrade procedure with the two-step process below:
❑ First, download Version 1.5.6.3 image file “ATS25_V1563.IMG” to
the Master switch of the stack.
❑ Secondly, download Version 2.0.2 image file “ATS25_V202.IMG” to
the Master switch of the stack. In turn, the Master switch will automatically download the new image file to all the Slave switches.
To download the AT-S25 Version 2.0.2 image file to the Master switch, the process is as follows:
1. Download the AT-S25 Version 1.5.6.3 image file to the Master switch via TFTP.
2. Make sure that the source image file you are downloading is for Version 1.5.6.3 “ATS25_V1563.IMG”.
After Version 1.5.6.3 is downloaded to the Master switch; the Master switch in turn will download the image file of this version to all the Slave switches in the stack when it boots up.
Using XModem
to Download
the AT-S25
Version 2.0.2
Image File
When it is rebooted, verify that the current software version is “1.5.6.3”, and that all the Slave switches also booted up correctly.
3. Download the source image file for Version 2.0.2 “ATS25_V202.IMG” to the stack via TFTP.
4. Allow the stack to reboot automatically.
This section contains the procedure for upgrading a switch module running Version 1.5.6.2 or an earlier version to Version 2.0.2 from a local management interface using the XModem protocol. (You could also load the new software using TFTP, as explain in the previous section.)
Note
This method is used to upgrade the software to an individual switch module of a stack or to a stand-alone switch module. If the switch module is a member of a stack, the stacking cable(s) must be disconnected from the module before starting this procedure. This method may be performed from a local host PC only.
Note
Hilgraeve HyperTerminal software is used in this XModem procedure.
19
Preface
Note
The ATS25_V1563.IMG file is not required when using the XModem method.
To download the AT-S25 Version 2.0.2 image file “ATS25_V202.IMG” using the XModem method, perform the following procedure:
1. In HyperTerminal, verify that your current port settings are set as follows:
- Bits per second = “9600”
- Data bits = “8”
- Parity = “None”
- Stop bits = “1”
- Flow control = “None”
2. Start the AT-S25 management software. The System Booting window as shown in Figure 1 is running.
Figure 1 System Booting Window
20
AT-S25 Management Software User’s Guide
3. Immediately hit any key to run the system diagnostics. The ATI Diagnostics menu in Figure 2 is displayed.
Figure 2 ATI Diagnostics Menu
Note
The current terminal speed is 9600 baud. For faster transfer, select the highest speed available.
4. Type Z to change the terminal speed.
5. Type 5 to select the new speed at 115200.
6. From the local management interface menu, select Disconnect from the Call menu or click the Disconnect icon .
21
Preface
7. From the local management interface menu bar, select Properties from the File menu or click the Properties icon . The AT-S25
Properties window in Figure 3 is displayed.
Figure 3 AT-S25 Properties Window
8. Click the Configure button. The Properties window of the connecting COM in Figure 4 is displayed.
Figure 4 COM1 Properties Window
9. From the Bits per second pull-down list, select 115200; and click OK. You are returned to the AT-S25 Properties.
10. In the AT-S25 Properties window, click OK. You are now returned to the ATI Diagnostics menu in the HyperTerminal window.
22
AT-S25 Management Software User’s Guide
11. From the local management interface menu, select Connect from the Call menu or click the Call icon .
12. In the HyperTerminal window, hit any key to activate the ATI Diagnostics menu.
13. In the ATI Diagnostics menu, type X to select XMODEM download updated System Software, and press the Enter key.
The following prompt is displaying, indicating that the system is ready for the download:
The System is now ready for download. Please start your XMODEM transfer.
14. From the HyperTerminal main window, select the Send icon or select the Transfer menu, and then select Send File... from the pull-
down menu, as shown in Figure 5.
Figure 5 Local Management Window - Send File Menu
The Send File pop-up window in Figure 6 is displayed.
Figure 6 Send File Pop-Up Window
15. Click the Browse button to specify the location and the file to be downloaded onto the switch.
16. Click on the Protocol filed and select the transfer protocol as either Xmodem or, for faster download, 1K XModem.
The image file you are downloading is “ATS25_V202.IMG”.
17. Click Send.
23
Preface
The software immediately begins to download onto the switch. The Xmodem File Send window in Figure 7 displays current status of the software download. The download process take a couple minutes to complete.
Figure 7 XModem File Send Window
Once the download process is completed, the following prompt is displayed:
XMODEM transfer has successfully completed. Now writing to Flash PROM.
Please wait for FLASH writes to complete.
This may take up to 1 minute.
Do not reset, do not remove power.
The system will automatically reboot.
When the image file is downloaded to all the modules in the stack, make sure to set the terminal speed back to the default of 9600 by performing the following steps:
1. From the local management interface menu, select Disconnect from the Call menu or click the Disconnect icon .
2. From the local management interface menu bar, select Properties from the File menu or click the Properties icon . The AT-S25
Properties window in Figure 3 on page page -22 is displayed.
3. Click the Configure button. The Properties window of the connecting COM in Figure 4 on page 22 is displayed.
4. From the local management interface menu, select Connect from the Call menu or click the Call icon .
5. Click the Restore Defaults button, the Bits per second field is displayed with 9600 as its setting; and click OK.
The system is now rebooted and you are returned to the AT-S25 management software login menu.
24

Section I

Overview

The chapter in this section provides a brief overview of the AT-S25 management software. It explains some of the functions that you could perform with the management software and reviews the different methods for accessing the AT-S25 software on an AT-8316F or an AT-8324 Fast Ethernet Switch.
25

Chapter 1

Overview

The AT-S25 management software is intended for an AT-8300 Series stack of AT-8316F and AT-8324 Fast Ethernet Switches. The software is used to monitor and adjust a stack’s operating parameters. Functions that you could perform with the software include:
❑ Enable and disable ports
❑ Configure port parameters, such as port speed and duplex mode
❑ Create virtual LANs (VLANs)
❑ Create port trunks and port mirrors
❑ Assign an Internet Protocol (IP) address and subnet mask
❑ Activate and configure Spanning Tree Protocol (STP) and
Rapid Spanning Tree Protocol (RSTP)
❑ Configure port security
❑ Configure IGMP Snooping
❑ Configure and View MAC Addresses
❑ Configure Class of Service
❑ File Uploads and Downloads
The AT-S25 management software comes pre-installed on the AT-8300 Series switch with default settings for all operating parameters. If the default settings are adequate for your network, you could use the switch or stack as an unmanaged Fast Ethernet switch simply by connecting the units to your network, as explained in the hardware installation guide, and powering ON the devices.
26
AT-S25 Management Software User’s Guide
Note
The default settings for the management software can be found in Appendix A, AT-S25 Default Settings on page 272.
To actively manage an AT-8300 Series stack, such as to change or adjust the operating parameters, you must access the switch’s AT-S25 management software. The AT-S25 software has a menu interface that makes it very easy to use.
There are four different ways that you can access the AT-S25 management software. They are briefly described in the following sections of the this chapter:
❑ Local Management Session on page 28
❑ Telnet Management Session on page 29
❑ Web Browser Management Session on page 30
❑ SNMP Management Session on page 31
27
Section I: Overview

Local Management Session

You establish a local management session with an AT-8300 Series stack by connecting a terminal or a PC with a terminal emulator program to the RS-232 Terminal port on the Master switch of the stack, using a straight-through RS-232 cable. This type of management interface is referred to as “local” because you must be physically close to the stack, such as in the wiring closet where the stack is located.
Once the session is started, you will see a menu from which you could make selections to configure and monitor the stack. You can configure all of the switches in a stack from a local management session.
Note
For instructions on starting a local management interface, refer to Starting a Local Management Interface on page 35.
28

Telnet Management Session

Any management workstation on your network that has the Telnet application protocol can be used to manage an AT-8300 Series stack. This type of management session is referred to in this guide as a remote management because you do not have to be in the wiring closet where the stack is located. You can manage a stack from any workstation on the network that has the application protocol.
To establish a Telnet management interface with a stack, you must assign it an IP address. Initially assigning an IP address to a stack is only possible through a local management session.
Note
For instructions on how to start a Telnet management session, refer to Starting a Telnet Management Interface on page 38.
A Telnet management session gives you complete access to all of a stack’s operating parameters. You can perform nearly all the same functions from a Telnet management session as you can from a local management session.
AT-S25 Management Software User’s Guide
29
Section I: Overview

Web Browser Management Session

You can also use a web browser to manage an AT-8300 Series stack. This too is referred to as remote management because you can manage a stack from any workstation on your network that has a web browser.
Note
For instructions on starting this type of management session, refer to Starting a Web Browser Interface on page 190.
30

SNMP Management Session

Another way to remotely manage a AT-8300 Series stack is with an SNMP management program. A familiarity with Management Information Base (MIB) objects is necessary for this type of management.
The AT-S25 software supports the following MIBs:
❑ SNMP MIB-II (RFC 1213)
❑ Bridge MIB (RFC 1493)
❑ Interface Group MIB (RFC 1573)
❑ Ethernet MIB (RFC 1643)
❑ Remote Network MIB (RFC 1757)
❑ Allied Telesyn Managed Switch MIB (atiStackSwitch.mib)
You must download the Allied Telesyn managed switch MIB file from the Allied Telesyn web site and compile the file with your SNMP program. For instructions, refer to your SNMP management documentation.
AT-S25 Management Software User’s Guide
Note
A stack must have an IP address in order to be managed with an SNMP program. Initially assigning an IP address is only possible from a local management session.
31
Section I: Overview

Management Access Levels

An AT-8300 Series stack has two levels of management access. They are:
❑ Manager: When you log in as a Manager, you can view and
configure all of a switch’s operating parameters.
The username for Manager access is “manager” and the default password is “friend”.
❑ Operator: When you log in as an Operator, you can only view the
operating parameters, but you cannot change values.
The username for Operator access is “operator” and the default password is “operator”.
Note
The user names and the passwords are case sensitive.
32

Section II

Local and Telnet Management Sessions

The chapters in this section explain how to manage an AT-8300 Series stack from a local or Telnet management session. The chapters include:
❑ Chapter 2: Starting a Local or Telnet Management Session on
page 34
❑ Chapter 3: Basic Switch Parameters on page 41
❑ Chapter 4: Port Parameters on page 59
❑ Chapter 5: Port Security on page 67
❑ Chapter 6: Port Trunking on page 77
❑ Chapter 7: Port Mirroring on page 88
❑ Chapter 8: STP and RSTP on page 92
❑ Chapter 9: Virtual LANs on page 117
❑ Chapter 10: MAC Address Table on page 146
❑ Chapter 11: Class of Service on page 161
❑ Chapter 12: IGMP Snooping on page 166
❑ Chapter 13: Ethernet Statistics on page 174
❑ Chapter 14: File Downloads and Uploads on page 178
33

Chapter 2

Starting a Local or Telnet Management Session

This chapter contains the procedure for starting a local or Telnet management session on an AT-8300 Series stack. The sections in the chapter are:
❑ Local Management Session on page 35
❑ Telnet Management Session on page 38
34

Local Management Session

STATUS
RESET
F
AULT
R
PS
PWR
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
1
6
1
7
18
19
20
21
22
23
2
4
19X
21X 23X
20
X
22
X
24
X
R
S-
232
TER
M
IN
AL
PORT
100M LINK /
A
CTIVITY
P
O
RT AC
T
I
V
I
TY
L/A
L/A
D/C
D/C
L/A
D/C
1
0
M
LIN
K
/ ACTIV
I
T
Y
HALF DUP /
COL
F
ULL
DU
P
To start a local management session on an AT-8300 Series stack, you connect a terminal or personal computer with a terminal emulator program to the RS-232 Terminal Port on the Master switch in the stack, using a straight-through RS-232 cable. Once you have started the session, you will be able to manage all of the switches in the stack.
A local management interface is so named because you must be close to the switch, usually within a few meters, to start this type of management interface. This typically means that you must be in the wiring closet where the switch is located.
The stack does not need an IP address to be managed from a local management interface. Furthermore, running a local management session does not interfere with the flow of Ethernet traffic through the stack.
AT-S25 Management Software User’s Guide
Starting a Local
To start a local management interface, perform the following procedure:
Management
Interface
1. Connect one end of a straight-through RS-232 cable with a DB-9 connector to the RS-232 Terminal Port on the Master switch in the stack.
M
ASTER
Figure 8 Connecting a Terminal or PC to the RS-232 Terminal Port
The master switch is the switch assigned the Stack ID value of 1. For information on Stack ID switch settings, refer to the
AT-8316F/MT, AT-8316F/VF, AT-8316F/SC, and AT-8324 Installation Guide.
35
Section II: Local and Telnet Mangement
2. Connect the other end of the cable to an RS-232 port on a terminal or
3. Configure the terminal or terminal emulator program as follows:
Note
Do not connect the terminal to the RS-232 port on a slave switch. To start a local management interface on a stack, you must connect the terminal to the RS-232 port on the master switch.
PC with a terminal emulator program.
❑ Baud rate: 9600 bps
❑ Data bits: 8
❑ Parity: None
❑ Stop bits: 1
❑ Flow control: None
Note
The port settings are for a DEC VT100 or ANSI terminal, or an equivalent terminal emulator program.
When prompted for the user name and password, enter one of the following options:
4. When prompted for a user name and password, do one of the following:
❑ For Manager access, type manager as the user name. The default
password is “friend”.
❑ For Operator access, type operator as the user name. The default
password is “operator”.
Note
The user names and passwords are case sensitive.
The user names cannot be changed. For instructions on how to change a password, refer to Configuring the Management Passwords on page 51. For information on the two access levels, refer to Management Access Levels on page 32.
36
AT-S25 Management Software User’s Guide
The Main Menu window is displayed in Figure 9.
Quitting from a
Local Interface
Figure 9 Main Menu
To select a menu item, type the corresponding letter or number.
Pressing the Esc key or typing the letter “R” in a submenu or window returns you to the previous menu.
To quit a local management interface, return to the Main Menu and type Q for Quit.
Note
You should always exit from a management session when you are finished managing a stack. This can prevent unauthorized individuals from making changes to a stack’s configuration should you leave your management station unattended.
Note
If the console is not active for specified period of time, the console will time out.
Note
You cannot operate both a local management session and a Telnet management session on the same stack simultaneously. Failure to properly exit from a management session may block future management sessions.
37
Section II: Local and Telnet Mangement

Telnet Management Session

You can use the Telnet application protocol from a workstation on your network to manage an AT-8300 Series stack. This type of management is referred to as remote management because you do not have to be physically close to the switch to start the interface, as with a local management session. Any workstation on your network that has the application protocol can be used to manage the switch.
In terms of functionally, there are almost no differences between managing a switch locally through the RS-232 Terminal Port and remotely with the Telnet application protocol. You see the same menu selections and have nearly the same management capabilities.
Starting a Telnet management session requires that an IP address be assigned to the stack. Initially assigning an IP address to a stack is possible only through a local management session.
Once you have started a Telnet management interface on an AT-8300 Series stack, you have management access to all the switches that reside in the stack.
Starting a Telnet
Management
Interface
To start a Telnet management interface, specify the IP address of the Master switch of the stack in the Telnet application protocol.
Note
For instructions on how to configure the IP Address on the Master switch, refer to Configuring an IP Address and Switch Name on page 45.
When prompted for a user name and password, do one of the following:
❑ For Manager access, type manager as the user name. The default
password is “friend”.
❑ For Operator access, type operator as the user name. The default
password is “operator”.
Note
The user names and passwords are case sensitive.
The user names cannot be changed. For instructions on how to change a password, refer to Configuring the Management Passwords on page 51. For information on the two access levels, refer to Management Access Levels on page 32.
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AT-S25 Management Software User’s Guide
The Main Menu of a Telnet management session is identical to the Main Menu of a local management session, shown in Figure 9 on page 37. You can perform nearly all the same functions from a Telnet management session as you can from a local management session.
The menus also function the same. To make a selection, type its corresponding number or letter. To return to a previous menu, type R or press the Esc key.
Note
You could run only one Telnet management interface on a stack at a time. Additionally, you cannot run both a Telnet management session and a local management session on the same stack at the same time.
Quitting from a
Telnet
Management
Interface
To end a Telnet management interface, return to the Main Menu and type Q for Quit.
39
Section II: Local and Telnet Mangement

Selecting a Switch Module in the Stack

Most of the procedures in this guide have you select the switch module in the stack on which you want to perform the procedure.
For example, to display the status of the ports on the third switch module, you would perform the following procedure:
1. From the Main Menu, type M to select M - Select another module.
The prompt message is displayed:
Select Module ID: [1 to 8] ->
2. Enter 3 for the switch module ID, and press the Enter key.
Note
The number of each switch module in the menu corresponds to the Stack ID setting on the switch. The Stack ID setting is assigned with the Stack ID switch on the back panel of the switch. For the location of the Stack ID switch and information on how to set this switch, refer to the AT-8316F/MT, AT-8316F/VF, AT-8316F/SC and AT-8324 Installation Guide.
40

Chapter 3

Basic Switch Parameters

This chapter contains a variety of information and procedures. There is a discussion on when to assign an IP address to a switch and the different ways that you could go about it. There are also procedures for resetting the switch, activating the original switch default settings, and more.
Sections in the chapter include:
❑ When Does a Switch Need an IP Address? on page 42
❑ Configuring an IP Address and Switch Name on page 45
❑ Activating the BOOTP and DHCP Services on page 46
❑ Configuring SNMP Community Strings and Trap IP Addresses
on page 54
❑ Pinging a Remote System on page 49
❑ Configuring the AT-S25 Software Security Features on page
50
❑ Configuring SNMP Community Strings and Trap IP Addresses
on page 54
❑ Returning the AT-S25 Software to the Factory Default Values
on page 56
❑ Viewing the AT-S25 Version Number and Basic Switch
Information on page 58
41
Section II: Local and Telnet Mangement

When Does a Switch Need an IP Address?

If you want to remotely manage an AT-8300 Series stack, you must assign it an IP address. The IP address is assigned to the Master switch of the stack and is shared by all the switches in the stack.
When you assign a stack an IP address, you must also assign it a subnet mask. The stack uses the subnet mask to determine which portion of an IP address represents the network address and which the node address.
You must also assign the stack a gateway address if there is a router between the stack and the remote management workstation. This gateway address is the IP address of the router through which the stack and management station will communicate.
If you do not intend to remotely manage an AT-8300 Series stack, then you do not need to assign it an IP address. The stack will operate fine without an IP address and you will still be able to manage it completely from a local management session.
How Do You
Assign an IP
Address?
Once you have decided which, if any, stacks on your network need an IP address, you have to access the AT-S25 software and assign the addresses. There are actually two ways in which an AT-8300 Series stack can obtain an IP address.
The first method is for you to assign the IP configuration information manually. The procedure for this is explained in Configuring an IP Address and Switch Name on page 45. Initially assigning an IP address to a switch can only be done through a local management interface.
The second method is for you to activate the BOOTP and DHCP services on the stack and have the stack automatically download its IP configuration information from a BOOTP or DHCP server on your network. This procedure is explained in Activating the BOOTP and DHCP Services on page 46.
42
AT-S25 Management Software User’s Guide
The basic switch parameters can be found in the Administration Menu, as shown in Figure 10.
Figure 10 Administration Menu
Table 1 lists the basic switch parameters used in the Administration Menu.
Table 1 Basic Switch Parameters
PARAMETER DESCRIPTION
1 - IP Address
2 - Subnet Mask
3 - Default Gateway
4 - System Name
This parameter specifies the IP address of the stack. You must specify an IP address if you intend to remotely manage the stack using a Telnet utility, an SNMP management program, or a Web browser.
This parameter specifies the subnet mask. You must specify a subnet mask if you assigned an IP address to the stack.
This parameter specifies the default router’s IP address. This address is required if you intend to remotely manage the stack from a management station that is separated from the stack by a router.
This parameter specifies a name for the stack (for example, Sales).
The value range is 1 to 39 alphanumeric characters. This parameter is optional.
NOTE: Assigning names to the different stacks in your network can make it easier for you to identify them. This can help you avoid performing a configuration procedure on the wrong stack.
43
Section II: Local and Telnet Mangement
PARAMETER DESCRIPTION
5 - Administrator
6 - Comments
7 - BOOTP/DHCP
8 - Set Passwords
9 - Reset Switch
P - Ping a Remote System
This parameter specifies the name of the network administrator responsible for managing the stack. The value range is 1 to 39 alphanumeric characters. This parameter is optional.
This parameter specifies additional information about the stack, such as its location (for example, 4th Floor ­wiring closet 402B). The value range is 1 to 39 alphanumeric characters. This parameter is optional.
This selection activates and deactivates the BOOTP and DHCP services on the stack. For information on this selection, refer to Activating the BOOTP and DHCP Services on page 46.
This parameter is used to change the Manager and Operator login passwords. For instructions, refer to Configuring the Management Passwords on page
51.
This selection resets the stack.
For information on this selection, refer to Pinging a
Remote System on page 49.
D - Downloads & Uploads Menu
For information on this selection, refer to Chapter 15, File Downloads and Uploads on page 178.
44
AT-S25 Management Software User’s Guide

Configuring an IP Address and Switch Name

The procedure in this section explains how to manually assign an IP address, subnet mask, and gateway address to an AT-8300 Series stack from a local or Telnet management interface. (If you want the stack to obtain its IP configuration from a DHCP or BOOTP server on your network, go to the procedure Activating the BOOTP and DHCP Services on page 46.)
This procedure also explains how to assign a name to a stack, along with other optional information, such as the name of the administrator responsible for maintaining the unit and any comments; for example, the location of the stack.
To manually assign an IP address and other information, perform the following procedure:
1. From the Main Menu, type 4 to select Administration Menu.
The Administration Menu as shown in Figure 10 on page 43 is displayed.
2. Make sure that the BootP/DHCP parameter is Disabled.
3. Enter or modify the parameters in the window as desired.
For information on these parameters, refer to Table 1 on page 43.
Changes to the parameters take effect immediately on the switch.
4. After you have set the parameters, type S to select Save Configuration changes.
Note
A change to a parameter in this menu, including the IP address, subnet mask, and gateway address, is immediately activated on a stack.
45
Section II: Local and Telnet Mangement

Activating the BOOTP and DHCP Services

The BOOTP and DHCP application protocols were developed to simplify network management. They are used to automatically assign IP configuration information to the devices on your network, such as an IP address, subnet mask, and a default gateway address.
An AT-8300 Series switch supports these protocols and can obtain its IP configuration information from a BOOTP or DHCP server on your network. If you activate this feature, a stack seeks its IP address and other IP configuration information from a BOOTP or DHCP server on your network whenever you reset or power ON the device.
Naturally, for this to work there must be a BOOTP or DHCP server residing on your network and you must configure the service by entering in the Master switch’s MAC address.
BOOTP and DHCP services typically allow you to specify how the IP address is to be assigned to the switch. Choices are static and dynamic. If you choose static, the server will always assign the same IP address to the switch when the switch is reset or powered ON. This is the preferred configuration. Since the BOOTP and DHCP services always assigns the same IP address to a switch, you will always know which IP address to use when you need to remotely manage a particular switch.
If you choose dynamic, the server will assign any unused IP address that it has not already assigned to another device. This means that a switch might have a different IP address each time you reset or power cycle the device, making it difficult for you to remotely manage the unit.
Note
The BOOTP and DHCP option is disabled by default on the switch.
To activate or deactivate the BOOTP and DHCP protocols on the switch, perform the following procedure:
1. From the Main Menu, type 4 to select Administration Menu.
The Administration Menu in Figure 10 on page 43 is displayed.
2. Type 7 to select BOOTP/DHCP.
The following prompt is displayed:
BOOTP/DHCP (E-Enabled, D-Disabled):
3. Type E to enable BOOTP and DHCP services on the switch or D to disable the services and press the Enter key. The default is disabled. For information on these parameters, refer to
46
AT-S25 Management Software User’s Guide
For information on this parameter setting, refer to Table 1 on page 43.
Note
If you activated BOOTP/DHCP, the switch immediately begins to query the network for a BOOTP or DHCP server. The switch will continue to query the network for its IP configuration until it receives a response.
47
Section II: Local and Telnet Mangement

Resetting a Stack

To reset a stack, perform the following procedure:
1. From the Main Menu, type 4 to select Administration Menu.
2. From the Administration Menu, type 9 to select Reset Switch.
3. Type Y to reset the switch or N to cancel this procedure.
The Administration Menu as shown in Figure 10 on page 43 is displayed.
The following prompt is displayed:
Do you want to proceed with the switch reboot? [Yes/No] ->
The switch reloads its operating system, a task requiring a minimum of 20 seconds to complete.
For information on this parameter setting, refer to Table 1 on page 43.
Caution
The stack will not forward traffic while it is reloading its operating software. Some data traffic may be lost.
48

Pinging a Remote System

You could instruct the switch to ping a remote device on your network. This procedure is useful in determining whether a valid link exists between the switch and another device.
To ping a network device, perform the following procedure:
1. From the Main Menu, type 4 to select Administration Menu.
The Administration Menu as shown in Figure 10 on page 43 is displayed.
2. From the Administration Menu, type P to select Ping a Remote System.
The following prompt is displayed:
Please enter an IP address ->
3. Enter the IP address of the end node you wish the switch to ping and press the Enter key.
AT-S25 Management Software User’s Guide
The results of the ping command are displayed on the screen. To stop the ping, press any key.
For information on this parameter setting, refer to Table 1 on page 43.
49
Section II: Local and Telnet Mangement

Configuring the AT-S25 Software Security Features

The AT-S25 software has several security features that can help prevent unauthorized individuals from changing the parameter settings of an AT-8300 Series stack. The security features are:
Manager and Operator Passwords - The management software has two standard, management login accounts:
❑ For Manager access, type manager as the user name. The default
password is “friend”.
❑ For Operator access, type operator as the user name. The default
password is “operator”.
Note
The user names cannot be changed and the passwords are case sensitive. For instructions on how to change a password, refer to Configuring the Management Passwords on page 51. For information on the two access levels, refer to Management
Access Levels on page 32.
Console Timeout - This parameter causes the management software to
automatically end a management interface if it does not detect any activity from the local or remote management station after the specified period of time. This security feature can prevent unauthorized individuals from using your management station should you step away from your system while configuring a stack. The default for the console timeout value is 10 minutes. For instructions on how to set this security feature, refer to Configuring Management Access on page 52.
SNMP Access - You can also disable the SNMP management feature on a stack, and so prevent individuals from managing a stack remotely using a SNMP management program. For instructions on how to set this security feature, refer to Configuring Management Access on page 52.
Web Access - You can disable the web browser management feature on a stack, and so prevent individuals from managing it remotely using a web browser. For instructions on how to set this security feature, refer to Configuring Management Access on page 52.
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AT-S25 Management Software User’s Guide
Configuring the
Management
Passwords
There are two levels of management access on an AT-8300 Series stack: Manager and Operator. When you log in as a Manager, you can view and configure all of a stack’s operating parameters. When you log in as an Operator, you can only view the operating parameters; you cannot change any values.
You log in as a Manager or an Operator by entering the appropriate password when you start an AT-S25 management software.
❑ The default login password for Manager access is “friend”.
❑ The default password for Operator access is “operator”.
Note
The passwords are case sensitive.
To change the Manager or Operator password, perform the following procedure:
1. From the Main Menu, type 4 to select Administration Menu.
The Administration Menu as shown in Figure 10 on page 43 is displayed.
2. From the Administration Menu, type 8 to select Set Passwords. The Passwords Menu in Figure 11 is displayed.
Figure 11 Passwords Menu
3. Type 1 to change the Manager password, or type 2 to change the Operator password.
4. When prompted, enter the current Manager or Operator password.
5. When prompted, enter the new Manager or Operator password.
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6. When prompted, re-enter the new Manager or Operator password.
For information on these parameters, refer to Table 1 on page 43.
Note
The password can be from 0 to 15 alphanumeric characters. The passwords are case sensitive.
Caution
You should not use spaces or special characters, such as asterisks (*) and exclamation points (!), in a password if you will be managing the stack from a web browser. Many web browsers cannot handle special characters in passwords.
Configuring
Management
Access
To configure the console timer, web access, SNMP access, and TFTP server security features of the AT-S25 management software, perform the following procedure:
1. From the Main Menu, type 5 to select System Config Menu.
The System Config Menu in Figure 12 is displayed.
Figure 12 System Config Menu
2. To configure the console timer, type 2 to select Console Disconnect Timer Interval and, when prompted, enter a value of from 1 to 60 minutes. The default is 10 minutes.
For example, if you specify 2 minutes, the AT-S25 management software automatically ends a management interface if it does not detect any activity from the local or telnet management station after 2 minutes.
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AT-S25 Management Software User’s Guide
3. To configure SNMP access, type 3 to select SNMP Access. When prompted, type E to enable SNMP management access or D to disable it. By default, SNMP Access is Disabled.
With the SNMP Access disabled, no one will be able to manage the stack remotely using an SNMP management program.
4. To configure web browser access, type 4 to select Web Server Access. When prompted, type E to enable web access or D to disable web access. By default, Web Server Access is Enabled.
If the Web Server Access is disabled, no one will be able to manage the stack remotely using a web browser.
5. After you have made the desired changes, type S to select Save Configuration changes.
6. Your changes are immediately activated on the stack.
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Configuring SNMP Community Strings and Trap IP Addresses

To configure the SNMP community strings for the switch and to assign up to four IP addresses of management stations to receive traps from the switch, perform the following procedure:
1. From the Main Menu, type 5 to select System Config Menu.
The System Config Menu as shown in Figure 12 on page 52 is displayed.
2. From the System Config Menu, type A to select Advanced Configuration.
The Advanced Configuration menu in Figure 13 is displayed.
Figure 13 Advanced Configuration Menu
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AT-S25 Management Software User’s Guide
3. From the Advanced Configuration window, type 2 to select SNMP Configuration. The SNMP Configuration menu in Figure 14 is displayed.
Figure 14 SNMP Configuration Menu
4. Enter or modify the parameters as desired.
To change a value, type its corresponding number and, when prompted, enter the new value.
❑ To set a switch’s SNMP community strings, use the parameters
described below:
1 - GET Community 2 - SET Community 3 - TRAP Community
❑ To specify the IP addresses of up to four management
workstations on your network to receive traps from the switch, use the selections below:
4 - Trap Receiver 1 5 - Trap Receiver 2 6 - Trap Receiver 3 7 - Trap Receiver 4
5. After making your changes, type S to select Save Configuration changes.
Changes to the SNMP parameters are immediately activated on the switch.
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Section II: Local and Telnet Mangement

Returning the AT-S25 Software to the Factory Default Values

The procedure in this section returns all AT-S25 software parameters to their default values. This procedure also deletes any VLANs that you have created on the switch.
Note The AT-S25 software default values can be found in Appendix A, AT-S25 Default Settings on page 272.
To return the AT-S25 management software to its default settings, perform the following procedure:
1. From the Main Menu, type 5 to select System Config Menu.
The System Config Menu as shown in Figure 12 on page 52 is displayed.
2. From the System Config Menu, type 6 to select Reset Configuration to Factory Defaults.
The following prompt is displayed:
The switch will reboot after set to factory default.
Do you want to proceed? [Yes/No] ->
3. Type Y for yes or N for no.
The following prompt is displayed:
Do you want to reset static IP, Subnet and Gateway as well? [Yes/No] ->
4. If you type Y for yes, all switch parameters including the IP address, subnet mask, and gateway address are changed to their default values. If you type N for no, all switch parameters excluding the IP address, subnet mask, and gateway address are changed to their default values.
The following prompt is displayed when Y is selected:
Configuration is set to factory default!
Reboot the switch..
The operating parameters are returned to their default values and the switch is reset.
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AT-S25 Management Software User’s Guide
Caution
If the switch is being managed remotely and its configuration has DHCP Enabled, this parameter will be set to Disabled after resetting the switch to Factory Defaults. This action will result in the loss of management until either the IP address is manually set or DHCP is enabled again via the serial port.
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Viewing the AT-S25 Version Number and Basic Switch Information

The procedure in this section displays the following switch information:
❑ AT-S25 Version Number
❑ Application Software Version
❑ Application Software Build Date
❑ MAC Address
❑ Stack Info Menu
1. To display the information, type 8 to select Diagnostics Menu from the Main Menu.
The Diagnostics Menu window in Figure 15 is displayed.
Figure 15 Diagnostics Menu
2. To view the stacking information, type 4 to select Stack Info Menu.
The information in this Diagnostics Menu window and the sub-windows is for viewing purposes only.
58

Chapter 4

Port Parameters

The chapter contains the procedures for viewing and changing the parameter settings for the individual ports on a switch.
This chapter contains the following procedures:
❑ Configuring Port Parameters on page 60
❑ Displaying Port Status on page 64
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Configuring Port Parameters

To configure the parameter settings for a port on a switch, perform the following procedure:
1. From the Main Menu, type 1 to select Ports Menu.
2. From the Ports Menu, type M if you wish to select a module other than the one currently displayed.
The prompt message is displayed:
Select Module ID: [1 to 8] ->
3. Enter the ID of the module you wish to select, and press the Enter key.
4. From the Ports Menu, type 1 to select Port Configuration.
The following prompt is displayed:
Start Port to configure [1 - 24] ->
5. Enter the number of the port you wish to configure and press the Enter key. To configure a range of ports, enter the first port of the range.
The following prompt is displayed:
End Port to configure [1 - 24] ->
6. To configure only one port, enter the same port number in Step 4 and Step 5, then press the Enter key. To configure a range of ports, enter the last port number in the range.
Note
Only a continuous range of ports can be entered at once.
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AT-S25 Management Software User’s Guide
The Port Configuration menu in Figure 16 is displayed.
Figure 16 Example of Port Configuration Menu
Note
The example Port Configuration window in the figure above is for a 10/100 Mbps twisted pair port. The window for a fiber optic port will contain a subset of the parameters.
7. Enter or modify the parameters in the window as desired.
Changes to the parameters take effect immediately on the switch.
Table 2 lists the parameters used in the Port Configuration window:
Table 2 Port Configuration Parameters
PARAMETER DESCRIPTION
1 - State
2 - Broadcast Filter
Sets the current state of the selected port or the first port in the selected range.
Settings for this parameter are:
• Enable (default): The port forwards frames.
• Disable: The port will not forward frames.
Sets the selected port to receive broadcast traffic.
Settings for this parameter are:
• Enable: The port discards all ingress broadcast frames.
• Disable (default): The port forwards all ingress
broadcast frames.
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PARAMETER DESCRIPTION
3 - Negotiation
Configures a port for Auto-Negotiation or to manually set a port’s speed and duplex mode.
Settings for this parameter are:
• Auto: Sets a port’s speed and duplex mode automatically. (default)
• Manual: Set a port’s speed and duplex mode manually.
If you select Auto, the switch will set both speed and duplex mode for the port automatically.
If you select Manual, two additional selections are displayed in the window:
4 - Duplex ..............Half
5 - Speed .............. 10MB
You use these two selections to set the port’s duplex and speed mode.
Settings for these 2 selections are:
4 - Duplex:
• Full = Full-duplex
F - Flow Control
• Half = Half-duplex
5 - Speed:
• 0010 = 10MB
• 0100 = 100MB
• 1000 = 1000MB (Optional uplink port only)
Sets flow control on the port. This parameter only applies to ports operating in full-duplex mode.
A port using flow control transmits a special pause packet to stop the end node from sending frames when the port’s buffer is full and it cannot receive any more packets. The pause packet notifies the end node to stop transmitting for a specified period of time.
Possible settings for this parameter are:
• Enable
• Disable (default)
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AT-S25 Management Software User’s Guide
PARAMETER DESCRIPTION
B - Back Pressure
Sets back pressure on the port. This parameter only applies to ports that are operating in half-duplex mode.
A port operating with back pressure transmits a JAM pattern to halt the transmission of packets from the end node when the port’s buffer is full and it cannot receive any more packets.
Possible settings for this parameter are:
• Disable (default)
• Enable
8. Once you have set the port parameters, type S to select Save Configuration changes.
Configuration changes take effect immediately on the switch.
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Displaying Port Status

To display the status of the ports on the switch, perform the following procedure:
1. From the Main Menu, type 1 to select Ports Menu.
The Ports Menu in Figure 17 is displayed.
Figure 17 Ports Menu
2. From the Ports Menu window, type M if you want to select a module in the stack other than the one currently displayed.
The following prompt is displayed:
Select Module ID: [1 to 8] ->
3. Enter the ID of the module you want to select, and press the Enter key.
4. From the Ports Menu window, type 4 to select Port Status.
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AT-S25 Management Software User’s Guide
The Port Status window is displayed. Figure 18 is an example of the window.
Figure 18 Port Status Window
Table 3 lists the parameters appeared in the Port Configuration window. These parameters are for viewing purposes only.
Table 3 Port Status Parameters
PARAMETER DESCRIPTION
PortName/ UplinkType
State
Nego
The name of the port or, in the case of an optional uplink port, the uplink model (AT-A14, AT-A15, AT-A17, AT-A18, or AT-A19).
The current state of the port.
Possible settings for this parameter are:
• Enable (default)
• Disable
The status of Auto-Negotiation on the port.
Possible settings for this parameter are:
• Auto - Indicates that the port is using Auto­Negotiation to set operating speed and duplex mode.
• Manual - Indicates that the operating speed and duplex mode have been set manually.
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Section II: Local and Telnet Mangement
PARAMETER DESCRIPTION
Link
Speed
Duplex
PVID
The status of the link between the port and the end node connected to the port.
Possible settings for this parameter are:
• Up - indicates that a valid link exists between the port and the end node.
• Down - indicates that the port and the end node have not established a valid link.
The operating speed of the port.
Possible settings for this parameter are:
• 10 Mbps = 10 MB
• 100 Mbps = 100 MB
• 1000 Mbps = 1 GB (Optional uplink ports only)
The duplex mode of the port.
Possible settings for this parameter are:
• Half-duplex
• Full-duplex
The port VLAN identifier assigned to the port.
FlowCtrl
STP_State
The flow control setting for the port.
Possible settings for this parameter are:
• Enable
• Disable
The current operating STP status of the port.
Possible settings for this parameter are:
• Disable
• Blocking
• Listening
• Learning
• Forwarding
66

Chapter 5

Port Security

This chapter contains the procedures for setting port security. The sections in this chapter include:
❑ Port Security Overview on page 68
❑ Configuring Limited Security Level on page 72
❑ Activating a Port Security Level on page 75
Note
You can set port security only from a local management session. You cannot set it from a Telnet management session.
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Port Security Overview

The port security feature can enhance the security of your network. You can use the feature to control which network devices can forward frames through the stack.
There are four levels of port security. Only one security level can be active on an AT-8300 Series stack at a time. The security levels are:
❑ Automatic
❑ Limited
❑ Secure
❑ Lock All Ports
Note
Only one security level can be active on a stack at a time. You cannot assign different security levels on different switches in the same stack.
Automatic This mode disables port security. Each switch in the stack learns and
adds addresses to the dynamic MAC Address Table as it receives frames on the ports. MAC addresses of inactive nodes are deleted from the table according to the aging timer.
Note
The Automatic security mode is the default security level for a stack.
Limited This security level allows you to manually specify the maximum number
of dynamic MAC addresses a group of ports on a switch can learn. Once a group has learned its maximum limit, the ports within the group discard ingress frames with source MAC addresses not already stored in the MAC Address Table.
Before using this security level, please note the following:
❑ The maximum number of MAC addresses that a group of ports
can learn applies to the entire group, not to the individual ports.
❑ Once this mode is activated, the switches in the stack delete all
MAC addresses in the dynamic MAC Address Tables and immediately begin learning new addresses, adding them to the dynamic MAC Address Tables until a group reaches the maximum limit.
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AT-S25 Management Software User’s Guide
❑ The MAC address aging time is disabled under this security level.
Once a dynamic MAC address has been learned on a port and added to a MAC Address Table, it remains in the table and is not purged unless one member of the group experiences a link down condition or the switch is power cycled.
❑ Static MAC addresses are retained and are not included in the
count of maximum addresses that can be learned by a port group. You can continue to add static MAC addresses to a port even if the group in which the port is a member has already learned its maximum number of dynamic MAC addresses.
Port Groupings
As noted earlier, a maximum limit of MAC addresses applies to a port group. It cannot be set on a per port basis, except for some optional uplink ports. Different port groups on a switch can have different maximum limits.
Port groupings differ depending on the switch model. An AT-8324 Switch has five port groups, as illustrated in Figure 19.
10BASE-T / 100BASE-TX FAST ETHERNET SWITCH
Group 4
Group 5
A
1X 3X 5X 7X
B
2X 4X 6X 8X
Group 1
Ports 1 to 8
10BASE-T / 100BASE-TX
9X 11X 13X 15X
10X 12X 14X 16X
Group 2
Ports 9 to 16
17X 19X 21X 23X
18X 20X 22X 24X
L/A
100M LINK / ACTIVITY 10M LINK / ACTIVITY
D/C
FULL DUP
1234567891011121314151617181920212223
L/A
D/C
L/A
D/C
Group 3
Ports 17 to 24
PORT ACTIVITY
HALF DUP/
COL
STATUS
RS-232
TERMINAL PORT
FAULT
MASTER
RPS
PWR
24
RESET
Figure 19 Port Groupings on an AT-8324 Switch
The AT-8316F/MT and AT-8316F/VF switches have four groups, as shown in Figure 20.
100BASE-FX FAST ETHERNET SWITCH
Group 3
Group 4
A
L/A
L/A
L/A
L/A
L/A
D/C
D/C
B
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
D/C
D/C
D/C
Group 1
Ports 1 to 8
100BASE-FX
L/A
L/A
L/A
L/A
L/A
L/A
D/C
D/C
D/C
D/C
D/C
D/C
L/A
L/A
L/A
D/C
D/C
Group 2
Ports 9 to 16
PORT ACTIVITY
L/A
ACTIVITY
100M LINK
D/C
FULL DUP
HALF DUP/ COL
L/A
L/A
D/C
D/C
D/C
RS-232
TERMINAL PORT
STATUS
FAULT
MASTER
RPS
PWR
RESET
Figure 20 Port Groups on an AT-8316F/MT or AT-8316/VF Switch
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Section II: Local and Telnet Mangement
The AT-8316F/SC switch also has four groups, as shown in Figure 21.
Group 1
Ports 1 to 8
Group 3
Group 4
100BASE-FX FAST ETHERNET SWITCH
A
B
L/A
L/A
D/C
D/C
L/A
L/A
D/C
D/C
100BASE-FX
L/A
L/A
D/C
D/C
L/A
L/A
D/C
D/C
Group 2
Ports 9 to 16
87654321
L/A
L/A
L/A
D/C
D/C
L/A
L/A
D/C
D/C
L/A
D/C
D/C
RXTXRXTXRXTXRXTXRXTXRXTXRXTXRXTX
161514131211109
L/A
L/A
D/C
D/C
RXTXRXTXRXTXRXTXRXTXRXTXRXTXRXTX
L/A
LINK / ACTIVITY
FULL DUP /
D/C
HALF DUP
COL
TERMINAL PORT
FAULT
RPS
PWR
RESET
STATUS
RS-232
PORT ACTIVITY
Figure 21 Port Groups on an AT-8316F/SC Switch
Here is an example of Limited port security. Let’s assume you are configuring Limited port security on an AT-8324 switch and you specified that Group 1 on the switch could learn up to 50 dynamic MAC addresses. This means that Ports 1 to 8 on the switch could learn a group total of 50 dynamic MAC addresses. Once 50 dynamic addresses are learned, the ports in the group will not learn any more and will discard packets with new source addresses.
It should be noted that in some circumstances some ports in a group might not learn any MAC addresses at all. For instance, referring again to our example, if Ports 1 to 6 in Group 1 were to learn a total of 50 addresses before Ports 7 and 8 had received any packets, the latter ports would not be allowed to learn any addresses, even when they receive packets, because the group total has already been reached. This needs to be taken into account when using Limited port security.
Limited port security also applies to optional uplink ports. If the optional expansion card contains only one uplink port, then the group maximum applies to the one port. If the expansion card contains multiple uplink ports, then the maximum total of MAC addresses applies to all the ports on the card.
Secure This security level instructs the stack to forward frames based only on
static MAC addresses. When this security level is activated, the stack deletes all dynamic MAC addresses and disables the MAC Address Tables in the switches in the stack so that no addresses can be learned.
The stack also deletes all static MAC addresses from the MAC Address Tables. After activating this security level, you must enter the static MAC addresses of the nodes whose frames the stack should forward. The stack will forward frames only from those nodes whose MAC addresses you enter in as static MAC addresses. Frames from nodes whose MAC addresses are not entered as static addresses will be discarded.
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AT-S25 Management Software User’s Guide
Lock All Ports This security level causes the stack to stop learning new dynamic MAC
addresses. The stack forwards frames based on the dynamic MAC addresses that it has already learned and any static MAC addresses that the network administrator has entered. You can add more static MAC addresses once this security level is activated.
The MAC aging time is disabled in this security level; no dynamic MAC addresses are deleted from the MAC Address Table, even those belonging to inactive end nodes.
Note
For background information on MAC addresses and aging time, refer to MAC Address Overview on page 147.
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Configuring Limited Security Level

Perform the following procedure if you intend to activate the Limited security level on the stack. This procedure explains how to set the maximum number of MAC addresses the port groups can learn. (The default is 100.) You must set these values before you activate Limited security level. If you want to set the stack to the Automatic, Secured, or Lock All Ports security level, skip this procedure and go to Activating a
Port Security Level on page 75.
Note
This procedure can only be performed from a local management session. You cannot perform it from a Telnet management session.
1. From the Main Menu, type 1 to select Ports Menu.
2. From the Ports Menu, type 5 to select Port Security.
The Port Security menu in Figure 24 is displayed.
Figure 22 Port Security Menu
3. From the Port Security menu, type 2 to select Port Security Limited- Mode menu.
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AT-S25 Management Software User’s Guide
The Port Security Limited-Mode menu in Figure 23 is displayed.
Figure 23 Port Security Limited-Mode Menu
4. From the Port Security Limited-Mode menu, type M if you want to configure the Limited security level on a switch other than the one currently managing.
The prompt message is displayed:
Select Module ID: [1 to 8] ->
5. Enter the ID of the module you want to select, and press the Enter key.
6. From the Port Security Limited-Mode menu, type 2 to select Set MAC Threshold.
A prompt similar to the following is displayed:
Select Port Group ID [1 to 5] ->
7. Enter the number of the port group where you want to specify a new MAC address limit. The port groupings for the AT-8300 Series switches can be found in Port Groupings on page 69.
The following prompt is displayed:
Enter the MAC threshold value -> [1 to 1024] ->
8. Enter the maximum number of dynamic MAC addresses you want the port group to be able to learn and press the Enter key. The range is 1 to 1024 addresses. The default is 100.
9. Repeat this procedure starting with Step 4 to specify MAC address limits on other port groups.
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Section II: Local and Telnet Mangement
10. Type 1 to select Display MAC Threshold.
11. Examine the MAC limits. Check to be sure that they are correct. If you
12. Type S to select Save Configuration Changes.
13. Once you have configured the maximum limits, go to the next
The current MAC address limits for the port groups are displayed.
assigned different values to different port groups, be sure that the different values apply to the correct groups. If necessary, repeat this procedure to change any MAC address limits.
procedure to activate the Limited security level.
74

Activating a Port Security Level

The following procedure explains how to activate a port security level on a stack.
Note
Before activating the Limited security level, configure the maximum number of MAC addresses each port group can learn. For instructions, refer to Configuring Limited Security Level on page
72.
Note
This procedure can only be performed from a local management session. You cannot perform it from a Telnet management session.
You can perform this procedure on any switch in a stack. All switches in the stack are automatically changed to the same security level. Only one security level can be active in a stack at a time.
AT-S25 Management Software User’s Guide
To activate port security on a stack, perform the following procedure:
1. From the Main Menu, type 1 to select Ports Menu.
2. From the Ports Menu, type 5 to select Port Security.
The Port Security menu in Figure 24 is displayed.
Figure 24 Port Security Menu
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Section II: Local and Telnet Mangement
3. From the Port Security menu, type 1 to select Port Security Mode:
4. Select the desired security level by typing the appropriate letter. For
5. Type S to select Save Configuration Changes.
Automatic.
The following prompt is displayed:
Enter new mode (A-Automatic, L-Limited, S-Secured, K-locKed) :
a description of the security levels, refer to Port Security Overview on page 68.
A change to the security level is immediately activated on a stack.
76

Chapter 6

Port Trunking

This chapter contains the procedures for creating and deleting port trunks. Sections in the chapter include:
❑ Port Trunking Overview on page 78
❑ Creating a Port Trunk on page 82
❑ Modifying a Port Trunk on page 85
❑ Modifying a Trunk Name on page 86
❑ Deleting a Port Trunk on page 87
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Section II: Local and Telnet Mangement

Port Trunking Overview

Port trunking is an economical way for you to increase the bandwidth between two switches. A port trunk is a group of 2 to 8 ports that have been grouped together to function as one logical path. A port trunk increases the bandwidth between switches and is useful in situations where a single physical data link between switches is insufficient to handle the traffic load.
A port trunk always sends packets from a particular source to a particular destination over the same link within the trunk. A single link is designated for flooding broadcasts and packets of unknown destination.
The example in Figure 25 consists of a port trunk of four data links between two AT-8324 Switches.
10BASE-T / 100BASE-TX FAST ETHERNET SWITCH
A
B
1X 3X 5X 7X
2X 4X 6X 8X
10BASE-T / 100BASE-TX
9X 11X 13X 15X
10X 12X 14X 16X
17X 19X 21X 23X
18X 20X 22X 24X
PORT ACTIVITY
L/A
100M LINK / ACTIVITY 10M LINK / ACTIVITY
D/C
HALF DUP/
FULL DUP
1234567891011121314151617181920212223
L/A
D/C
L/A
D/C
COL
FAULT
MASTER
RPS
PWR
24
RESET
STATUS
RS-232
TERMINAL PORT
Port Trunking
Guidelines
10BASE-T / 100BASE-TX FAST ETHERNET SWITCH
A
B
1X 3X 5X 7X
2X 4X 6X 8X
10BASE-T / 100BASE-TX
9X 11X 13X 15X
10X 12X 14X 16X
17X 19X 21X 23X
18X 20X 22X 24X
PORT ACTIVITY
L/A
100M LINK / ACTIVITY 10M LINK / ACTIVITY
D/C
HALF DUP/
FULL DUP
1234567891011121314151617181920212223
L/A
D/C
L/A
D/C
COL
STATUS
RS-232
TERMINAL PORT
FAULT
MASTER
RPS
PWR
24
RESET
Figure 25 Port Trunk Example
When creating a port trunk, observe the following guidelines:
Selecting the Number of Ports in a Trunk
A port trunk can consist of 2 to 8 ports. .
Selecting Ports from the Same Switch in a Stack
The ports of a port trunk must be from the same switch in a stack. A port trunk cannot consist of ports from different switches in a stack.
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AT-S25 Management Software User’s Guide
Using Ports from the Same Group
The ports on the AT-8300 Series switch are divided into groups. When selecting ports for a trunk, the selected ports must be members of the same group.
The AT-8324 Switch has five groups, as illustrated in Figure 26.
10BASE-T / 100BASE-TX FAST ETHERNET SWITCH
A
B
1X 3X 5X 7X
2X 4X 6X 8X
10BASE-T / 100BASE-TX
9X 11X 13X 15X
10X 12X 14X 16X
17X 19X 21X 23X
18X 20X 22X 24X
PORT ACTIVITY
L/A
100M LINK / ACTIVITY 10M LINK / ACTIVITY
D/C
HALF DUP/
FULL DUP
1234567891011121314151617181920212223
L/A
D/C
L/A
D/C
COL
STATUS
RS-232
TERMINAL PORT
FAULT
MASTER
RPS
PWR
24
RESET
Group D
Group E
Group A
Ports 1 to 8
Group B
Ports 9 to 16
Group C
Ports 17 to 24
Figure 26 Port Groupings on an AT-8324 Switch
The AT-8316F/MT and AT-8316F/VF switches have four groups, as shown in Figure 27.
100BASE-FX FAST ETHERNET SWITCH
Group C
Group D
A
L/A
L/A
L/A
L/A
L/A
B
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
D/C
D/C
D/C
D/C
Group A
Ports 1 to 8
100BASE-FX
L/A
L/A
L/A
L/A
L/A
L/A
D/C
D/C
D/C
D/C
D/C
D/C
D/C
L/A
L/A
L/A
D/C
D/C
Group B
Ports 9 to 16
PORT ACTIVITY
L/A
ACTIVITY
100M LINK
D/C
FULL DUP
HALF DUP/ COL
L/A
L/A
D/C
D/C
D/C
RS-232
TERMINAL PORT
STATUS
FAULT
MASTER
RPS
PWR
RESET
Figure 27 Port Groups on an AT-8316F/MT or AT-8316/VF Switch
The AT-8316F/SC switch also has four groups, as shown in Figure 28.
Group A
Ports 1 to 8
Group C
100BASE-FX FAST ETHERNET SWITCH
A
B
L/A
L/A
D/C
D/C
L/A
L/A
D/C
D/C
100BASE-FX
L/A
L/A
L/A
D/C
L/A
D/C
D/C
D/C
L/A
L/A
D/C
D/C
L/A
L/A
D/C
D/C
L/A
L/A
D/C
D/C
PORT ACTIVITY
87654321
L/A
D/C
L/A
RXTXRXTXRXTXRXTXRXTXRXTXRXTXRXTX
LINK / ACTIVITY
FULL DUP /
HALF DUP
D/C
161514131211109
COL
L/A
D/C
RXTXRXTXRXTXRXTXRXTXRXTXRXTXRXTX
Group B
Group D
Ports 9 to 16
Figure 28 Port Groups on an AT-8316F/SC Switch
RS-232
TERMINAL PORT
STATUS
FAULT
RPS
PWR
RESET
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Section II: Local and Telnet Mangement
As an example of a port trunk on an AT-8324 Switch, you could use Ports 4 and 5 as one port trunk, since the ports are members of the same group. However, you could not use Ports 7, 8, 9, and 10 because they belong to different groups.
Creating Only One Trunk Per Group
Each port group can support one port trunk. For example, the AT-8324 Ethernet switch, which has three port groups, assuming no expansion modules, can support three port trunks, one port trunk for each port group. The addition of two expansion modules would enable the switch to support two more port trunks, one for each module.
Cabling Based on Port Number
When cabling a trunk, the order of the connections must be the same on both nodes. The lowest numbered port in a trunk must be connected to the lowest numbered port of the trunk on the other device, the next lowest numbered port must be connected to the next lowest numbered port on the other device, and so on.
For example, assume that you are connecting a trunk between two AT-8324 Switches. On the first AT-8324 Switch you had chosen Ports 12, 13, 14, 15 from port group 2 for the trunk. On the second AT-8324 Switch you had chosen Ports 21, 22, 23, and 24 from port group 3. To maintain the order of the port connections, you connect Port 12 on the first AT­8324 Switch to Port 21 on the second AT-8324, Port 13 to Port 22, and so on.
Configuring the Port Parameters of a Port Trunk
The ports of a trunk automatically assume the speed and duplex mode of the lowest numbered port in the trunk. For example, if you create a trunk consisting of Ports 4, 5, 6, and 7, Port 4’s configuration is automatically propagated to Ports 5, 6, and 7. You cannot configure the ports of a trunk individually. They can be configured only as a unit.
Configuring VLANs
All ports in a trunk must belong to the same VLAN.
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AT-S25 Management Software User’s Guide
Creating Port Trunks on 10/100 Mbps and 100 Mbps Expansion Modules
The ports on an expansion card that contains two or more 10/100 Mbps or 100 Mbps twisted pair or fiber optic ports can be grouped together to form a port trunk, as shown in Table 4.
Table 4 Trunked Ports on 10/100 Mbps and 100 Mbps Expansion
Modules
Number of Ports on
Port Trunks
Expansion Module
1
2
4
Does not support port trunking.
One port trunk consisting of two ports.
One trunk consisting of two, three or four ports.
Creating Port Trunks on One Gigabit Expansion Modules
If a switch contains two expansion modules and each module has one gigabit port, you can group the two ports into one trunk. This is the only instance where you can create a port trunk from different port groups on a switch. Both gigabit modules must be installed in the same switch and both modules must be of the same medium type (i.e., either both fiber or both twisted pair).
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Creating a Port Trunk

This section contains the procedure for creating a port trunk on the switch. Be sure to review the guidelines in Port Trunking Overview on page 78 before performing the procedure.
Caution
Do not connect the cables to the ports in a port trunk until after you have configured the trunk with the management software. Connecting the cables before configuring the software will create a loop in your network topology, possibly resulting in broadcast storms and poor network performance.
Creating a
10/100 Port
Trunk
To create a 10/100 port trunk, perform the following procedure:
1. From the Main Menu, type 1 to select Ports Menu.
2. From the Ports Menu, type 3 to select Port Trunking.
The Port Trunking menu in Figure 29 is displayed.
Figure 29 Port Trunking Menu
3. To create the port trunk on a switch in the stack other than the one you are currently managing, type M.
The prompt message is displayed:
Select Module ID: [1 to 8] ->
4. Enter the ID of the module you wish to select, and press the Enter key.
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AT-S25 Management Software User’s Guide
5. From the Port Trunking menu, type 1 to select Create 10/100 Trunk.
The prompt similar to the following is displayed.
Enter Trunk Number -> [1 to 5] ->
6. Enter the port group containing the ports to be in the trunk and press the Enter key. (For port groupings, refer to Using Ports from the Same Group on page 79.)
The following prompt appears:
Enter Trunk Name ->
7. Enter a name for the trunk and press the Enter key. The name can be up to 10 alphanumeric characters.
A prompt similar to the following appears:
Enter trunk ports [1 - 8] ->
8. Specify the ports of the trunk. You can specify the ports individually (e.g., 1,2,3,4), as a range (e.g., 1-4), or both (e.g., 1-2,5,7).
Creating a
Gigabit Port
Trunk
9. Type S to select Save Configuration Changes.
10. Configure the ports on the remote switch for port trunking.
11. Connect the cables to the ports of the trunk on the switch.
The port trunk is ready for network operation.
To create a Gigabit port trunk, perform the following procedure:
1. From the Main Menu, type 1 to select Ports Menu.
2. From the Ports Menu, type 3 to select Port Trunking.
The Port Trunking menu in Figure 29 on page 82 is displayed.
3. To create the port trunk on a switch in the stack other than the one you are currently managing, type M.
The prompt message is displayed:
Select Module ID: [1 to 8] ->
4. Enter the ID of the module you want to select, and press the Enter key.
5. From the Port Trunking menu, type 2 to select Create Gigabit Trunk.
The following prompt is displayed.
Enter Trunk Name ->
6. Enter a name for the trunk and press the Enter key. The name can be up to 10 alphanumeric characters.
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7. Type S to select Save Configuration Changes.
8. Configure the ports on the remote switch for port trunking.
9. Connect the cables to the ports of the trunk on the switch.
10. Enter the ports that will constitute the port trunk; then press the Enter
The port trunk is ready for network operation.
A prompt similar to the following appears:
Enter trunk ports [1 - 8] ->
Enter Trunk Number -> [1 to 2] ->
key.
You can specify the ports individually (e.g., 24,25) or as a range (e.g., 24-25).
Once you have specified the port(s) of the trunk, the following menu selection appears in the window:
Enter trunk ports [1 - 8] ->
Press any key to continue.
84

Modifying a Port Trunk

To add or remove ports from a 10/100 Mbps port trunk, perform the following procedure:
1. From the Main Menu, type 1 to select Ports Menu.
2. From the Ports Menu, type 3 to select Port Trunking.
The Port Trunking menu in Figure 29 on page 82 is displayed.
3. To modify a port trunk on a switch other than the one currently selected, type M.
The following prompt is displayed:
Select Module ID: [1 to 8] ->
4. Enter the ID of the module you want to select, and press the Enter key.
5. From the Port Trunking menu, type 3 to select Modify 10/100 Trunk Ports.
AT-S25 Management Software User’s Guide
The following prompt is displayed.
Enter Trunk Number -> [1 to 5] ->
6. Enter the number of the port trunk you want to modify; then press the Enter key.
The following prompt is displayed:
Enter trunk ports [1 - 8] ->
7. Enter the new port list for the trunk port. The new ports will overwrite the old ports. You can specify the ports individually (e.g., 1,2,3,4), as a range (e.g., 1-4), or both (e.g., 1-2,5,7).
8. Press any key to continue.
9. Type S to select Save Configuration Changes.
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Modifying a Trunk Name

To modify the name of a port trunk, perform the following procedure:
1. From the Main Menu, type 1 to select Ports Menu.
2. From the Ports Menu, type 3 to select Port Trunking.
The Port Trunking menu in Figure 29 on page 82 is displayed.
3. To modify a port trunk on a module other than the one currently selected, type M.
The following prompt is displayed:
Select Module ID: [1 to 8] ->
4. Enter the ID of the module you want to select, and press the Enter key.
5. From the Port Trunking menu, type 4 to select Modify Trunk Name.
The following prompt is displayed.
Enter Trunk Number -> [1 to 6] ->
6. Enter the number of the port trunk you want to modify and press the Enter key.
The following prompt is displayed.
Enter Trunk Name ->
7. Enter the new name for the port trunk. The name can be up to 30 alphanumeric characters.
8. Type S to select Save Configuration Changes.
86

Deleting a Port Trunk

Caution
Disconnect the cables from the port trunk on the switch before performing the following procedure. Deleting a port trunk without first disconnecting the cables can create loops in your network topology, which can result in broadcast storms and poor network performance.
To delete a port trunk from the switch, perform the following procedure:
1. From the Main Menu, type 1 to select Ports Menu.
2. From the Ports Menu, type 3 to select Port Trunking.
The Port Trunking menu in Figure 29 on page 82 is displayed.
3. To delete a port trunk from a module other than the one currently selected, type M.
The prompt message is displayed:
AT-S25 Management Software User’s Guide
Select Module ID: [1 to 8] ->
4. Enter the ID of the module you want to select, and press the Enter key.
5. From the Port Trunking menu, type 5 to select Delete trunk.
The following prompt is displayed.
Enter Trunk Number -> [1 to 6] ->
6. Enter the number of the trunk you want to delete.
The following prompt is displayed.
Are you sure you want to delete the trunk (Y/N) ->
7. Type Y for Yes to delete the port trunk or N for No to cancel this procedure.
If Y is selected, the port trunk is deleted from the switch.
8. Type S to select Save Configuration changes.
87

Chapter 7

Port Mirroring

This chapter contains the procedures on how to create a port mirror. Sections in the chapter include:
❑ Port Mirroring Overview on page 89
❑ Creating a Port Mirror on page 90
88

Port Mirroring Overview

The port mirroring feature allows you to unobtrusively monitor the traffic being received and transmitted on a port on a switch by having the traffic copied to another switch port. You could connect a network analyzer to the port where the traffic is being copied and monitor the traffic on the other ports without impacting network performance or speed.
Observe the following guidelines when creating a port mirror:
❑ The port whose traffic is to be copied is called the source port. The
port where the traffic is to be copied and where the network analyzer will be located is called the destination port.
❑ You can mirror only one port in a stack at a time.
❑ There can be only one destination port.
❑ The destination port cannot be a member of a port trunk.
AT-S25 Management Software User’s Guide
❑ The source port and the destination port can be located on
different switches in a stack.
❑ The source port and the destination port must be operating at the
same speed. For example, you cannot use a 10/100 Mbps port to monitor traffic on a 1000 Mbps GBIC port.
❑ The source port and the destination port must be in the same
VLAN in order to see broadcast, multicast, and flooded traffic on the destination mirror port. If these packets are being sent and received on a tagged port, they will have the tag removed before delivery to the destination mirror port.
❑ Unicast packets that are received on a tagged port will have the
tag removed before delivery to the destination mirror port. Unicast packets sent out a tagged port will have the tag inserted before delivery to the destination port.
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Creating a Port Mirror

To create a port mirror, perform the following procedure:
1. From the Main Menu, type 1 to select Ports Menu.
2. From the Ports Menu, type 2 to select Port Mirroring.
The Port Mirroring menu in Figure 30 is displayed.
Figure 30 Port Mirroring Menu
3. Type 1 to select Enable/Disable.
The following prompt is displayed.
Enter Enable (E)/Disable (D):
4. Type E to enable the port mirroring feature or D to disable the port mirroring feature. The default is disabled. Press the Enter key.
5. If the port mirroring is enabled, several new options are added to the Port Mirroring menu.
Table 5 lists the parameters used in the Port Mirroring Menu.
Table 5 Port Mirroring Parameters
PARAMETER DESCRIPTION
2 - Destination Module
3 - Destination Port
Use this option to specify the switch in the stack where the destination port is located.
Use this selection to specify the destination port on the switch. This is the port where the traffic from the source port will be copied to.
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PARAMETER DESCRIPTION
4 - Source Module
5 - Source Port
Use this option to specify the switch in the stack containing the source port.
Use this option to specify the source port. This is the port whose traffic will be copied to the destination port. You can specify only one port.
6. Configure the options in the menu as needed. Refer to the table above for option definitions.
7. Type S to select Save Configuration changes.
The port mirror is immediately activated on the switch. You can now connect a data analyzer to the destination port to monitor the traffic on the source port.
91

Chapter 8

STP and RSTP

This chapter provides background information on the Spanning Tree Protocol (STP) and Rapid Spanning Tree Protocol (RSTP). The chapter also contains procedures on how to adjust the STP and RSTP bridge and port parameters. The sections in this chapter include:
❑ STP and RSTP Overview on page 93
❑ Enabling or Disabling STP or RSTP on page 101
❑ Configuring STP on page 105
❑ Displaying Port’s STP Status and Setting on page 109
❑ Configuring RSTP on page 110
❑ Displaying Port’s RSTP Status and Settings on page 114
Note
For detailed information on the Spanning Tree Protocol, refer to IEEE Std 802.1d. For detailed information on the Rapid Spanning Tree Protocol, refer to IEEE Std 802.1w.
92

STP and RSTP Overview

A significant danger to Ethernet network performance is the existence of a data loop in a network topology. A data loop exists when two or more nodes on a network can transmit data to each other over more than one data link. The problem that data loops pose is that data packets can become caught in repeating cycles, referred to as broadcast storms, that needlessly consume network bandwidth and significantly reduce network performance.
STP and RSTP prevent data loops from forming by ensuring that only one path exists between the end nodes in your network. Where multiple paths exist, these protocols place the extra paths in a standby or blocking mode, leaving only one main active path.
STP and RSTP can also activate a redundant path if the main path goes down. So not only do these protocols guard against multiple links between segments and the risk of broadcast storms, but they can also maintain network connectivity by activating a backup redundant path in case a main link fails.
AT-S25 Management Software User’s Guide
Where the two protocols differ is in the time each takes to complete the process commonly referred to as convergence. When a change is made to the network topology, such as the addition of a new bridge, a spanning tree protocol must determine whether there are redundant paths that must be blocked to prevent data loops, or activated to maintain intercommunications between the various network segments. This process is referred to as convergence.
With STP, convergence can take a minute or more to complete in a large network. This can result in lost data packets from the loss of intercommunication between various parts of the network during the convergence process.
RSTP is much faster. RSTP can complete a convergence in seconds, and so greatly diminish the impact the process can have on your network.
Note
RSTP is the default Active Protocol version. The Spanning Tree feature is disabled by default.
Both STP and RSTP are using the same database; therefore, they are using the same parameters. Any changes made to the common parameters will be take effect on both protocols such as: Bridge Priority, Bridge Hello Time,….”
The following subsections provide a basic overview on how STP and RSTP operate and describe the available parameters.
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Bridge Priority
and the Root
Bridge
The first task that bridges perform when a spanning tree protocol is activated on a network is the selection of a root bridge. A root bridge distributes network topology information to the other network bridges and is used by the other bridges to determine if there are redundant paths in the network.
A root bridge is selected by a combination of a bridge priority number, also referred to as the bridge identifier, and sometimes the bridge’s MAC address. The bridge with the lowest bridge priority number in the network is selected as the root bridge. If two or more bridges have the same bridge priority number, of those bridges the one with the lowest MAC address is designated as the root bridge.
The bridge priority number can be changed on an AT-8316F or an AT­8324 Switch. You could designate which switch on your network you wish as the root bridge by giving it the lowest bridge priority number. You might also consider which bridge should function as the backup root bridge in the event you need to take the primary root bridge off­line, and assign that bridge the second lowest bridge identifier number.
Bridge priority has a range of 0 to 61440 in multiples of 4096. The management software divides the range into increments. You specify the increment that represents the desired bridge priority value. The range is divided into sixteen increments, as shown in the following table.
Table 6 Bridge Priority Value Increments
Increment
Bridge
Priority
Increment
Bridge
Priority
00832768
1 4096 9 36864
2 8192 10 40960
3 12288 11 45056
4 16384 12 49152
5 20480 13 53248
6 24576 14 57344
7 28672 15 61440
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Path Costs and Port Costs
Once the Root Bridge has been selected, the bridges must determine if the network contains redundant paths and, if one is found, they must select a preferred path while placing the redundant paths in a backup or blocking state.
Where there is only one path between a bridge and the root bridge, the bridge is referred to as the designated bridge and the port through which the bridge is communicating with the root bridge is referred to as the root port.
If redundant paths exist, the bridges that are a part of the paths must determine which path will be the primary, active path, and which path(s) will be placed in the standby, blocking mode. This is accomplished by an determination of path costs. The path offering the lowest cost to the root bridge becomes the primary path and all other redundant paths are placed into blocking state.
Path cost is determined through an evaluation of port costs. Every port on a bridge participating in STP has a cost associated with it. The cost of a port on a bridge is typically based on port speed. The faster the port, the lower the port cost. The exception to this is the ports on the root bridge, where all ports have a port cost of 0.
Path cost is simply the cumulation of the port costs between a bridge and the root bridge.
The port costs of the ports on an AT-8316F or an AT-8324 Switch are adjustable through the management software. For either STP or RSTP, the port costs have a range of from 0 to 20 000 000. This range allows you to have more control over path costs.
These port costs also feature an Auto-Detect feature. This features allows either STP or RSTP to automatically set the port cost according to the speed of the port, assigning a lower value for higher speeds. Auto­Detect is the default setting on the ports when the switch is operating in either STP or RSTP. Table 7 lists the ports cost with Auto-Detect.
Table 7 Auto-Detect Port Costs
Port Speed Port Cost
10 Mbps 2 000 000
100 Mbps 200 000
1000 Mbps 20 000
You could override Auto-Detect and set the port cost manually.
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Port Priority
If two paths have the same port cost, the bridges must select a preferred path. In some instances this can involve the use of the port priority parameter. This parameter can be used as a tie-breaker when two paths have the same cost.
The port priority has a range of from 0 to 240. As with the bridge priority, this range is broken into increments, in this case multiples of 16. When you specify a port priority for a port, you enter the increment of the desired value.
Table 8 Port Priority Value Increments
Increment
Bridge
Priority
Increment
Bridge
Priority
008128
1169144
2 3210160
3 4811176
4 6412192
5 8013208
6 9614224
7 112 15 240
Forwarding Delay and Topology Changes
If there is a change in the network topology due to a failure, removal, or addition of any active components, the active topology also changes. This may trigger a change in the state of some blocked ports. However, a change in a port state is not activated immediately.
It might take time for the root bridge to notify all bridges that a topology change has occurred, especially if it is a large network. If a topology change is made before all bridges have been notified, a temporary data loop could occur, and that could adversely impact network performance.
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To forestall the formation of temporarily data loops during topology changes, a port designated to change from blocking to forwarding passes through two additional states, listening and learning, before it begins to forward frames. The amount of time a port spends in these states is set by the forwarding delay value. This value states the amount of time that a port spends in the listening and learning states prior to changing to the forwarding state.
During a reconvergence and for a short period of time thereafter, the switch’s FDB aging time is shortened considerably. This is done to minimize the impact of possible path changes to host machines due to the topology change. The side effect of this is an increase in flooding, and may result in a small amount of packet loss.
The forwarding delay value is adjustable on the AT-8316F or AT-8324 Switch through the management software. The appropriate value for this parameter will depend on a number of variables, with the size of your network being a primary factor. For large networks, you should specify a value large enough to allow the root bridge sufficient time to propagate a topology change throughout the entire network. For small networks, you should not specify a value so large that a topology change is unnecessarily delayed, which could result in the delay or loss of some data packets.
Hello Time and Bridge Packet Data Units (BPDU)
The bridges that are part of a spanning tree domain communicate with each other using a bridge broadcast frame that contains a special section devoted to carrying STP or RSTP information. This portion of the frame is referred to as the Bridge Packet Data Unit (BPDU). When a bridge is brought on-line, it will issue a BPDU in order to determine whether a root bridge has already been selected on the network. and if not, whether it has the lowest bridge priority number of all the bridges and should therefore become the root bridge.
The root bridge will periodically transmit a BPDU to determine whether there have been any changes to the network topology and to inform other bridges of topology changes. The frequency with which the root bridge sends out a BPDU is called the Hello Time. This is a value that you could set on the AT-8316F or AT-8324 Switch. The interval is measured in seconds and the default is 2 seconds. Consequently, if an AT-8316F or an AT-8324 Switch is selected as the Root Bridge of a spanning tree domain, it will transmit a BPDU every two seconds.
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Point-to-Point Ports and Edge Ports
Part of the task of configuring RSTP is defining the port types on the bridge. This relates to the device(s) connected to the port. With port type defined, RSTP can reconfigure a network much quicker than STP when a change in network topology is detected.
There are two possible selections: Point-to-Point and Edge Port.
If a bridge port is operating in full-duplex mode, than the port is functioning as point-to-point. Figure 31 illustrates two AT-8324 Switches that have been interconnected with one data link. With the link operating in full-duplex, the ports are said to be point-to-point ports.
Note
This section applies only to RSTP.
10BASE-T / 100BASE-TX FAST ETHERNET SWITCH
A
B
1X 3X 5X 7X
2X 4X 6X 8X
10BASE-T / 100BASE-TX
9X 11X 13X 15X
10X 12X 14X 16X
17X 19X 21X 23X
18X 20X 22X 24X
PORT ACTIVITY
L/A
100M LINK / ACTIVITY 10M LINK / ACTIVITY
D/C
HALF DUP/
FULL DUP
1234567891011121314151617181920212223
L/A
D/C
L/A
D/C
COL
FAULT
MASTER
RPS
PWR
24
RESET
STATUS
RS-232
TERMINAL PORT
Point-to-Point Ports (Full-duplex Mode)
10BASE-T / 100BASE-TX FAST ETHERNET SWITCH
A
B
1X 3X 5X 7X
2X 4X 6X 8X
10BASE-T / 100BASE-TX
9X 11X 13X 15X
10X 12X 14X 16X
17X 19X 21X 23X
18X 20X 22X 24X
Figure 31 Point-to-Point Ports
PORT ACTIVITY
L/A
100M LINK / ACTIVITY 10M LINK / ACTIVITY
D/C
HALF DUP/
FULL DUP
1234567891011121314151617181920212223
L/A
D/C
L/A
D/C
COL
FAULT
MASTER
RPS
PWR
24
RESET
STATUS
RS-232
TERMINAL PORT
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If a port is operating in half-duplex mode and is not connected to any further bridges participating in STP or RSTP, then the port is an edge port. Figure 32 illustrates an edge port on an AT-8324 Switch. The port is connected to an Ethernet hub, which in turn is connected to a series of Ethernet workstations. This is an edge port because it is connected to a device operating at half-duplex mode and there are no participating STP or RSTP devices connected to it.
10BASE-T / 100BASE-TX FAST ETHERNET SWITCH
A
B
1X 3X 5X 7X
2X 4X 6X 8X
7
8
9X 11X 13X 15X
10X 12X 14X 16X
Edge Port
54
6
10BASE-T / 100BASE-TX
2
3
17X 19X 21X 23X
18X 20X 22X 24X
1
PORT ACTIVITY
L/A
100M LINK / ACTIVITY 10M LINK / ACTIVITY
D/C
HALF DUP/
FULL DUP
1234567891011121314151617181920212223
L/A
D/C
L/A
D/C
COL
STATUS
RS-232
TERMINAL PORT
FAULT
MASTER
RPS
PWR
24
RESET
Figure 32 Edge Port
A port can be both point-to-point and edge at the same time. It would operate in full-duplex and have no STP or RSTP devices connected to it. Figure 33 illustrates a port functioning both as point-to-point and edge.
10BASE-T / 100BASE-TX FAST ETHERNET SWITCH
A
B
1X 3X 5X 7X
2X 4X 6X 8X
10BASE-T / 100BASE-TX
9X 11X 13X 15X
10X 12X 14X 16X
17X 19X 21X 23X
18X 20X 22X 24X
PORT ACTIVITY
L/A
100M LINK / ACTIVITY 10M LINK / ACTIVITY
D/C
HALF DUP/
FULL DUP
1234567891011121314151617181920212223
L/A
D/C
L/A
D/C
COL
STATUS
RS-232
TERMINAL PORT
FAULT
MASTER
RPS
PWR
24
RESET
Point-to-Point and Edge Port
Workstation (Full-duplex Mode)
Figure 33 Point-to-Point and Edge Point
Determining whether a bridge port is point-to-point, edge, or both, can be a bit confusing. For that reason it might be best not to change the default values for this RSTP feature unless in have a good grasp of the concept. In most cases, the default values will work fine.
Note
If you are sure that there are RSTP participating bridges attached to a particular port, you should set that port’s edge port status to ‘NO’ to prevent possible bridge loops.
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Mixed STP and
RSTP Networks
Spanning Tree
and VLANs
RSTP IEEE 802.1w is fully compliant with STP IEEE 802.1d. Your network can consist of bridges running both protocols. STP and RSTP in the same network should be able to operate together to create a single spanning tree domain.
There is no reason not to activate RSTP on an AT-8316F or an AT-8324 Switch even when all other switches are running STP. The AT-8316F or AT-8324 Switch can combine its RSTP with the STP of the other switches. An AT-8316F or AT-8324 Switch will monitor the traffic on each port for BPDU packets. Ports that receive RSTP BPDU packets will operate in RSTP while ports receiving STP BPDU packets will operate in STP.
The spanning tree implementation on an AT-8316F or an AT-8324 Switch is a single-instance spanning tree. The switch supports just one spanning tree. You could not define multiple spanning trees.
The single spanning tree encompasses all ports on the switch. If the ports are divided into different VLANs, the spanning tree crosses the VLAN boundaries. This point can pose a problem in networks containing many VLANs that span different switches and are connected with untagged ports. What can happen is that STP will block a data link because it detects a data loop. This can cause fragmentation of your VLANs.
This issue is illustrated in Figure 34. Two VLANs, Sales and Production, span two AT-8324 Switches. Two links consisting of untagged ports interconnect the separate parts of each VLAN. If STP is activated on the switch, one of the links would be disabled. This problem can be avoided by not activating spanning tree or by connecting VLANs using tagged instead of untagged ports. (For information on tagged and untagged ports, refer to Chapter 10, Virtual LANs on page 117.
Sales
VLAN
10BASE-T / 100BASE-TX FAST ETHERNET SWITCH
A
1X 3X 5X 7X
B
2X 4X 6X 8X
10BASE-T / 100BASE-TX FAST ETHERNET SWITCH
A
1X 3X 5X 7X
B
2X 4X 6X 8X
Sales VLAN
9X 11X 13X 15X
10X 12X 14X 16X
9X 11X 13X 15X
10X 12X 14X 16X
10BASE-T / 100BASE-TX
10BASE-T / 100BASE-TX
Production
VLAN
17X 19X 21X 23X
18X 20X 22X 24X
17X 19X 21X 23X
18X 20X 22X 24X
Production
VLAN
PORT ACTIVITY
L/A
100M LINK / ACTIVITY 10M LINK / ACTIVITY
D/C
HALF DUP/
FULL DUP
1234567891011121314151617181920212223
L/A
D/C
L/A
D/C
PORT ACTIVITY
L/A
100M LINK / ACTIVITY 10M LINK / ACTIVITY
D/C
HALF DUP/
FULL DUP
1234567891011121314151617181920212223
L/A
D/C
L/A
D/C
COL
COL
FAULT
MASTER
RPS
PWR
24
24
RS-232
TERMINAL PORT
RESET
STATUS
FAULT
MASTER
RPS
PWR
RESET
STATUS
RS-232
TERMINAL PORT
Figure 34 VLAN Fragmentation
100
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