Cabletron Systems SPECTRUM 2.2 User Manual

Title Page

Bridge/Router Interface (BRIM)

User’s Guide

Notice

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

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

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

Virus Disclaimer

Cabletron has tested its software with current virus checking technologies. However, because no anti­virus system is 100% reliable, we strongly caution you to write protect and then verify that the
Licensed Software, prior to installing it, is virus-free with an anti-virus system in which you have
conÞdence.

Cabletron Systems makes no representations or warranties to the effect that the Licensed Software is
virus-free.

Copyright © 1999 by Cabletron Systems, Inc. All rights reserved.

Printed in the United States of America.

Order Number: 9031617-04 April 1999

Cabletron Systems, Inc.
P.O. Box 5005
Rochester, NH 03866-5005

SPECTRUM , MiniMMAC , FNB , Multi Media Access Center , and DNI are registered trademarks,

and Portable Management Application , IRM , IRM2 , IRM3 , IRBM , ESXMIM , ETSMIM , EMME ,

EMM-E6 , ETWMIM , FDMMIM , FDCMIM , MicroMMAC , MRXI , MRXI-24 , NB20E , NB25E , NB30 ,
NB35E , NBR , SEHI , STHI , TRBMIM , TRMM , TRMM-2 , TRMM-4 , TRMMIM , TRXI , Media
Interface Module , MIM , and Flexible Network Bus are trademarks of Cabletron Systems, Inc.

UNIX and OPENLOOK are trademarks of Unix System Laboratories, Inc. OSF/Motif and Motif are

trademarks of the Open Software Foundation, Inc. X Window System is a trademark of X Consortium,
Inc. Ethernet and XNS are trademarks of Xerox Corporation. Apple and AppleTalk are registered
trademarks of Apple Computer, Inc. Banyan is a registered trademark of Banyan Systems, Inc.

DECnet is a registered trademark of Digital Equipment Corporation. Novell is a registered trademark

of Novell, Inc. CompuServe is a registered trademark of CompuServe. Sun Microsystems is a
registered trademark, and Sun , SunNet , and OpenWindows are trademarks of Sun Microsystems,
Inc.

i

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(Applicable to licenses to the United States Government only.)

1. Use, duplication, or disclosure by the Government is subject to restrictions as set forth in
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252.227-7013.

Cabletron Systems, Inc., 35 Industrial Way, Rochester, New Hampshire 03867-0505.

2. (a) This computer software is submitted with restricted rights. It may not be used, reproduced, or

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(e) This Notice shall be marked on any reproduction of this computer software, in whole or in part.

ii

Chapter 1 Introduction

Using the BRIM UserÕs Guide..................................................................................... 1-2

Related Manuals............................................................................................................ 1-3

BRIM Management Applications ...............................................................................1-3

Software Conventions .................................................................................................. 1-4

Using the Mouse ....................................................................................................1-4

Common Device Window Fields......................................................................... 1-6

Using Window Buttons......................................................................................... 1-7

Getting Help .................................................................................................................. 1-8

Using On-line Help................................................................................................ 1-8

Accessing On-line Documentation...................................................................... 1-8

Getting Help from the Cabletron Systems Global Call Center .......................1-9

Contents

Chapter 2 Bridging

Bridging Basics .............................................................................................................. 2-1

About Transparent Bridging ................................................................................ 2-1

About Source Route Bridging .............................................................................. 2-2

About Source Route-Transparent Bridges.......................................................... 2-3

About Source Route-Translational Bridges ........................................................ 2-4

Viewing and Managing Bridging Interfaces............................................................. 2-5

The Bridge Status Window.......................................................................................... 2-7

Accessing Bridge Status Window Options......................................................... 2-9

Enabling and Disabling Bridging .............................................................................2-14

Enabling and Disabling Individual Interfaces................................................. 2-14

Enabling and Disabling All Installed Interfaces.............................................. 2-14

Bridge Statistics ........................................................................................................... 2-15

Performance Graphs............................................................................................ 2-15

ConÞguring Performance Graphs.............................................................. 2-17

Bridge Detail Breakdown ............................................................................2-18

Bridge Port Detail Breakdown.................................................................... 2-19

Interface Statistics ................................................................................................2-20

CSMACD Statistics .............................................................................................. 2-23

PPP Link Statistics ............................................................................................... 2-25

Dot5 Errors............................................................................................................ 2-28

Source Route Statistics ........................................................................................2-31

Spanning Tree ..............................................................................................................2-34

Bridge Level.......................................................................................................... 2-35

Bridge Port Level .................................................................................................2-37

ConÞguring Spanning Tree ................................................................................ 2-39

iii

Contents

Changing Bridge Priority ............................................................................2-39

Changing the Spanning Tree Algorithm Protocol Type ..........................2-39

Changing Hello Time ................................................................................... 2-40

Changing Max Age Time .............................................................................2-40

Changing Forwarding Delay Time............................................................. 2-40

Changing Port Priority.................................................................................2-41

Changing Path Cost......................................................................................2-41

Filtering Database .......................................................................................................2-41

ConÞguring the Filtering Database................................................................... 2-45

Special Filter Databases.............................................................................................. 2-47

Ethernet and Token Ring Special Filter Database Windows .........................2-48

Special Filter Database Window........................................................................ 2-49

DeÞning and Editing Filters in the Special Database .....................................2-51

Changing the Receive Ports................................................................................ 2-52

Changing the Port Filtering Action ...................................................................2-52

Setting the Port Filtering Action................................................................. 2-52

Clearing the Port Filtering Action ..............................................................2-53

Enabling and Disabling a Filter .........................................................................2-53

Saving a Set of Filters to a File............................................................................ 2-53

Interface ConÞguration ..............................................................................................2-54

Bridge Methods ....................................................................................................2-55

Setting the Bridge Method.................................................................................. 2-56

Protocol Transmission Methods.........................................................................2-56

Source Route ConÞguration ......................................................................................2-57

Source Routing Information............................................................................... 2-58

Source Route ConÞguration ...............................................................................2-59

Making and Setting Changes .............................................................................2-62

Using the Find Source Address Feature................................................................... 2-63

Using the Port Source Addresses Window..............................................................2-64

Setting the Aging Time ........................................................................................2-65

Using the Token Ring Bridge and Port ConÞguration Windows......................... 2-65

Duplex Modes.............................................................................................................. 2-70

Setting the Duplex Mode ............................................................................. 2-72

Ethernet Port ConÞguration............................................................................... 2-72

Fast Ethernet Port ConÞguration....................................................................... 2-73

Setting the Operational Mode for the FE-100TX ......................................2-76

Setting the Operational Mode for the FE-100FX ......................................2-77

SONET Port ConÞguration........................................................................................2-77

SONET/SDH ConÞguration ..............................................................................2-77

SONET/SDH Statistics........................................................................................ 2-79

ConÞguring SmartTrunking ......................................................................................2-85

ConÞguring Broadcast Suppression......................................................................... 2-88

Token Ring Bridge Mode ........................................................................................... 2-89

Setting Token Ring Bridge Mode .......................................................................2-90

Setting Bridge Translation.......................................................................................... 2-91

Enabling and Disabling Auto and Dual Translate Modes .............................2-92

ConÞguring Token Ring Packet Translation ....................................................2-93

ConÞguring Novell Token Ring Packet Translation................................ 2-93

The IBM Translation Table.................................................................................. 2-94

The SNAP Translation Table...............................................................................2-96

iv

ConÞguring SNAP Translation................................................................... 2-96

Using the Novell Translation Window ....................................................................2-97

Using the Physical View Windows for the ETWMIM ...........................................2-99

Ethernet Port Physical View............................................................................... 2-99

Token Ring Port Physical View........................................................................ 2-101

Chapter 3 FDDI Applications

Accessing the FDDI Menu ........................................................................................... 3-2

The ConÞguration Window......................................................................................... 3-2

Connection Policy Window......................................................................................... 3-5

Station List Window ..................................................................................................... 3-8

FDDI Performance Window...................................................................................... 3-10

Setting the Time Interval..................................................................................... 3-11

Contents

Chapter 4 WAN Applications

Accessing the WAN Status Windows ........................................................................ 4-1

Viewing WAN Interface Status ...................................................................................4-2

ConÞguring the Synchronous Connection......................................................... 4-3

ConÞguring T-1 Ports............................................................................................ 4-5

Using the T1 FracTable ConÞguration Window ........................................ 4-7

ConÞguring the Fractional Table........................................................... 4-8

Restoring a Fractional Table................................................................... 4-9

Changing the Interface Line Coding .................................................... 4-9

Displaying the WAN Logical View .......................................................................... 4-10

Changing WAN Logical Settings ....................................................................... 4-11

Viewing the WAN Port Admin/Status.................................................................... 4-12

Synchronous Admin/Status............................................................................... 4-12

T1 Admin/Status .................................................................................................4-13

Enabling and Disabling WAN T1 Interfaces............................................. 4-14

Displaying Synchronous Port Statistics................................................................... 4-14

Chapter 5 ATM Configuration

Accessing the ATM Connections Window................................................................ 5-1

ConÞguring Connections............................................................................................. 5-3

Adding a New Connection................................................................................... 5-4

Deleting a Connection........................................................................................... 5-5

Index

v

Contents

vi

Chapter 1

Introduction

Using this guide; related manuals; management applications available for BRIMs; software
conventions; getting help; contacting Cabletron Systems Global Call Center

Welcome to the Cabletron SystemsÕ SPECTRUM

Bridge/Router Interface (BRIM) UserÕs Guide . We have designed this guide

to serve as a reference for using SPECTRUM Element Manager for all types
of BRIMs.

Cabletron SystemsÕ Bridge/Router Interface Modules (BRIMs) provide ßexible,
integrated bridging functionality (including trafÞc Þltering by destination, source,
type Þeld, and 64-byte data offset, and support for the Spanning Tree Algorithm)
or routing functionality to the network hub. By accommodating several media
types and topologies, these network interfaces connect to any standard Local Area
Network (LAN) or Wide Area Network (WAN).

Since BRIMs plug into CabletronÕs Intel i960-based products (e.g., EMM-E6,
ESXMIM, MicroMMAC, and MicroMMAC-T), SPECTRUM Element Manager
views the hub and bridge/router as a single entity. The following BRIMs are
supported by SPECTRUM Element Manager:

BRIM-A6
BRIM-A6DP

The ATM Bridge/Router Interface Modules feature high
speed ATM connectivity (at rates up to 155 Mbps). They
are fully compatible with the 9A000 ATM Switch Module
for the SmartSwitch
They support the IETF AToM MIB, Multi-Protocol
Encapsulation over AAL5, and many other protocols,
and meet ATM Forum UNI speciÞcations. The BRIM-A6
supports a single ATM interface, and the BRIM-A6DP
supports two redundant ATM interfaces.

¨

Element Manager

¨

9000, and Fore SystemsÕ ASX-200.

BRIM-E6

The Ethernet BRIM has a user-conÞgurable Ethernet Port
Interface Module (EPIM) port that provides media
ßexibility for AUI, UTP, STP, Þber or coax cable.

1-1

Introduction

NOTE

BRIM-E100

BRIM-F6

BRIM-W6

Cabletron Systems has discontinued manufacturing several BRIMs, including the
BRIM-WT1, the Cisco BRIM-W/E, the BRIM-A100, the BRIM-T6, the BRIM-FO, the
BRIM-FD1, the BRIM-FD2, and the BRIM-F5.

The Fast Ethernet BRIM has a user-conÞgurable Fast
Ethernet Port Interface Module (FEPIM) port that
provides either 100BASE-TX connectivity (via an RJ-45
interface) or 100BASE-FX connectivity (via an MMF
interface with an SC connector).

The FDDI Bridge/Router Interface Module is a
translational FDDI to Ethernet bridge, via media
conÞgurable Fiber Port Interface Module (FPIM)
connectors using MMF or SMF Þber, or UTP or STP
copper. The BRIM-F6 supports the IETF FDDI MIB and
dual homing. Its DAS attachment is ANSI-compliant.

The WAN Bridge/Router Interface Module supports
Synchronous, T1 and E1 connections. It carries PPP,
Frame Relay and X.25 protocols through its WAN Port
Interface Modules.

Using the BRIM User’s Guide

Each chapter in this guide describes one major functionality or a collection of
several smaller functionalities that the BRIM adds to the device. This guide
contains information about software functions which are accessed directly from
the device icon; for information about management functions which are accessed
via the SPECTRUM Element Manager platform, consult the SPECTRUM Element

Manager UserÕs Guide , and SPECTRUM Element Manager Tools Guide , and the
Remote Administration Tools UserÕs Guide .

Chapter 1, Introduction , provides a list of related documentation, describes
certain software conventions, and shows you how to contact Cabletron SystemsÕ
Global Call Center.

Chapter 2, Bridging , provides a comprehensive look at all management options
associated with the bridge portion of the device, including Bridge Performance
Graphs, Spanning Tree, and the Filtering and Special Filtering Databases.

Chapter 3, FDDI Applications , describes the FDDI management windows,
including ConÞguration, Connection Policy, Station List, and Performance.

Chapter 4, WAN Applications , describes the windows available for WAN Port
conÞguration, and the Synchronous Port Statistics window.

Chapter 5, ATM ConÞguration , describes how to conÞgure Permanent Virtual
Circuits (PVCs) for the ATM interface(s) available on the ATM BRIM.

1-2 Using the BRIM User’s Guide

We assume that you have a general working knowledge of Ethernet IEEE 802.3,
FDDI, WAN, and ATM type data communications networks and their physical
layer components, and that you are familiar with general bridging concepts.

Related Manuals

The BRIM UserÕs Guide is only part of a complete document set designed to
provide comprehensive information about the features available to you through
SPECTRUM Element Manager. Other guides which include important
information related to managing the BRIM include:

Cabletron SystemsÕ SPECTRUM Element Manager UserÕs Guide

Cabletron SystemsÕ SPECTRUM Element Manager Tools Guide

Cabletron SystemsÕ SPECTRUM Element Manager Remote Administration Tools

UserÕs Guide

Introduction

Cabletron SystemsÕ SPECTRUM Element Manager Remote Monitoring (RMON)

UserÕs Guide

Cabletron SystemsÕ SPECTRUM Element Manager Alarm and Event Handling

UserÕs Guide

Cabletron SystemsÕ Network Troubleshooting Guide

Microsoft CorporationÕs Microsoft Windows UserÕs Guide

For more information about the capabilities of the BRIM and the host device in
which it is installed, consult the appropriate hardware documentation.

For more information about the capabilities of SPECTRUM Element Manager for
the host device, consult its UserÕs Guide.

BRIM Management Applications

When a device (e.g., MicroMMAC, NBR-620, EMM-E6, or ESXMIM) has a BRIM
installed and enabled, additional applications will be available from the Chassis
View window. These applications will depend on the type of BRIM installed in
your device.

¥ Bridge Status will be available from the Device menu for all devices with

BRIMs installed. The Bridging options that are available from the Bridge Status
window will vary depending on the device and the type of BRIM you have
installed; see Chapter 2, Bridging, for details on the bridge applications.

¥ Router Utilities ( Basic Router ConÞguration and Advanced Router

ConÞguration ) will be available from the Tools menu when a BRIM is

installed and enabled on your device. For more information, see the Routing
Services ConÞguration Guide.

Related Manuals 1-3

Introduction

¥ FDDI menu will be available on devices that have an FDDI BRIM installed and

enabled; see Chapter 3, FDDI Applications, for details.

¥ WAN Status will be available from the Device menu for devices that have a

WAN BRIM installed and enabled; see Chapter 4, WAN Applications, for
details.

¥ ATM Connections will be available from the Device menu for devices that

have an ATM BRIM installed and enabled; see Chapter 5, ATM ConÞguration,
for details.

If you cannot determine if you have a BRIM installed in your device or are unsure of the

TIP

type of installed BRIM, the I/F Summary window can help you Þnd the answer. To access
this window, select DeviceÐ>I/F Summary from your deviceÕs Chassis View window.
This windowÕs Description Þeld lists the interface descriptions for the device, including
the type of BRIM installed in the device (e.g., Ctron FDDI BRIM port). The BRIM port(s)
will always be listed at the end of the interface list, after all the non-BRIM interfaces.

Software Conventions

SPECTRUM Element ManagerÕs device user interface contains a number of
elements which are common to most windows and which operate the same
regardless of which window they appear in. A brief description of some of the
most common elements appears below; note that the information provided here is
not repeated in the descriptions of speciÞc windows and/or functions.

In accordance with Year 2000 compliance requirements, SPECTRUM Element Manager

NOTE

displays and allows you to set all dates with four-digit year values.

Using the Mouse

This document assumes you are using a Windows-compatible mouse with two
buttons; if you are using a three button mouse, you should ignore the operation of
the middle button when following procedures in this document. Procedures
within the SPECTRUM Element Manager document set refer to these buttons as
follows:

1-4 Software Conventions

Introduction

Left Mouse Button

Right Mouse Button

Figure 1-1. Mouse Buttons

For many mouse operations, this document assumes that the left (primary) mouse
button is to be used, and references to activating a menu or button will not
include instructions about which mouse button to use.

However, in instances in which right (secondary) mouse button functionality is
available, instructions will explicitly refer to right mouse button usage. Also, in
situations where you may be switching between mouse buttons in the same area
or window, instructions may also explicitly refer to both left and right mouse
buttons.

Instructions to perform a mouse operation include the following terms:

¥ Pointing means to position the mouse cursor over an area without pressing

either mouse button.

¥ Clicking means to position the mouse pointer over the indicated target, then

press and release the appropriate mouse button. This is most commonly used
to select or activate objects, such as menus or buttons.

¥ Double-clicking means to position the mouse pointer over the indicated

target, then press and release the mouse button two times in rapid succession.
This is commonly used to activate an objectÕs default operation, such as
opening a window from an icon. Note that there is a distinction made between
Òclick twiceÓ and Òdouble-click,Ó since Òclick twiceÓ implies a slower motion.

¥ Pressing means to position the mouse pointer over the indicated target, then

press and hold the mouse button until the described action is completed. It is
often a pre-cursor to Drag operations.

¥ Dragging means to move the mouse pointer across the screen while holding

the mouse button down. It is often used for drag-and-drop operations to copy
information from one window of the screen into another, and to highlight
editable text.

Software Conventions 1-5

Introduction

Common Device Window Fields

Similar descriptive information is displayed in boxes at the top of most
device-speciÞc windows in SPECTRUM Element Manager, as shown in

Figure 1-2.

IP Address

Figure 1-2. Sample Window Showing Group Boxes

Device
Name

Location

MAC
Address

Device Name

Displays the user-deÞned name of the device. The device name can be changed
via the System Group window; see the Generic SNMP UserÕs Guide for details.

IP Address

Displays the deviceÕs IP (Internet Protocol) address; this will be the IP address
used to deÞne the device icon. IP addresses are assigned via Local Management
for the device; they cannot be changed via SPECTRUM Element Manager.

Location

Displays the user-deÞned location of the device. The location is entered through
the System Group window; see the Generic SNMP UserÕs Guide for details.

1-6 Software Conventions

Introduction

MAC Address

The physical layer address assigned to the interface associated with the IP address
used to deÞne the device icon when it was added to SPECTRUM Element
Manager. MAC addresses are hard-coded in the device, and are not conÞgurable.

Informational Þelds describing the boards and/or ports being modeled are also
displayed in most windows:

Board Number

Displays the number indicating the position of the monitored board in the chassis.

Port Number

Displays the number of the monitored port.

Active Users

Indicates the number of users processing information through the deviceÕs
repeater channel, board, or port, as determined by MAC addresses.

Uptime

Displays the amount of time, in a days hh:mm:ss format, that the device has been
running since the last start-up.

Using Window Buttons

The Cancel button that appears at the bottom of most windows allows you to exit
a window and terminate any unsaved changes you have made. You may also
have to use this button to close a window after you have made any necessary
changes and set them by clicking on the OK, Set, or Apply button.

An OK, Set, or Apply button appears in windows that have conÞgurable values;
it allows you to conÞrm and SET changes you have made to those values. In some
windows, you may have to use this button to conÞrm each individual set; in other
windows, you can set several values at once and conÞrm the sets with one click
on the button.

The Help button brings up a Help text box with information speciÞc to the
current window. For more information on the Help button, see Using On-line

Help, page 1-8.

The command buttons, for example Bridge, call up a menu listing the windows,
screens, or commands available for that topic.

Any menu topic followed by ... (three dots) Ñ for example Statistics... Ñ calls up
a window or screen associated with that topic.

Software Conventions 1-7

Introduction

Getting Help

This section describes different methods of getting help for questions or concerns
you may have while using SPECTRUM Element Manager.

Using On-line Help

You can use the BRIM window Help buttons to obtain information speciÞc to the
device. When you click on a Help button, a window will appear which contains
context-sensitive on-screen documentation that will assist you in the use of the
window and its associated command and menu options. Note that if a Help
button is grayed out, on-line help has not yet been implemented for the associated
window.

From the Help menu accessed from the host deviceÕs Chassis View window menu
bar, you can access on-line Help speciÞc to the Chassis View window, as well as
bring up the Chassis Manager window for reference. Refer to the deviceÕs userÕs
guide for information on the Chassis View and Chassis Manager windows.

All of the online help windows use the standard Microsoft Windows help facility. If you

NOTE

are unfamiliar with this feature of Windows, you can select Help from the Windows
Start menu, or Help Ñ>How to Use Help from the primary SPECTRUM Element

Manager window, or consult your Microsoft Windows product UserÕs Guide.

Accessing On-line Documentation

The complete suite of documents available for SPECTRUM Element Manager
can be accessed via a menu option from the primary window menu bar:
Help Ñ> Online Documents. If you chose to install the documentation when you
installed SPECTRUM Element Manager, selecting this option will launch AdobeÕs
Acrobat Reader and a menu Þle which provides links to all other available
documents.

If you have not yet installed the documentation, the Online Documents option will not

TIP

be able to access the menu Þle. In order to activate this option, you must run the
setup.exe again to install the documentation component. See your Installation Guide
for details.

1-8 Getting Help

Getting Help from the Cabletron Systems Global Call Center

If you need technical support related to SPECTRUM Element Manager, or if you
have any questions, comments, or suggestions related to this manual or any of
our products, please feel free to contact the Cabletron Systems Global Call Center
via one of the following methods:

By phone: [phone]

24 hours a day, 365 days a year

By mail: Cabletron Systems, Inc.

PO Box 5005
Rochester, NH 03866-5005

By Internet mail: [e-mail]

FTP: ftp.ctron.com (134.141.197.25)

Login anonymous
Password your email address

By BBS: [phone]

Introduction

Modem Setting 8N1: 8 data bits, 1 stop bit, No parity

For additional information about Cabletron Systems products, visit our
World Wide Web site: http://www.cabletron.com/. For technical support,
select Service and Support.

Getting Help 1-9

Introduction

1-10 Getting Help

Chapter 2

Bridging

About bridging methods; viewing and managing bridging interfaces; using the Bridge Status window;
viewing bridge statistics; using Spanning Tree; using the Filtering Database; configuring duplex
modes; using the Interface Configuration window; and setting Bridge Translation

Bridging Basics

Bridges are used in local area networks to connect two or more network segments
and to control the ßow of packets between the segments. Ideally, bridges forward
packets to another network segment only when necessary.

Bridges are also used to increase the fault tolerance in a local area network by
creating redundant bridge paths between network segments. In the event of a
bridge or bridge segment failure, an alternate bridge path will be available to
network trafÞc, without signiÞcant interruption to its ßow.

The method a bridge uses to forward packets, choose a bridge path, and ensure
that a sending stationÕs messages take only one bridge path depends on the
bridgeÕs type: Transparent (generally used in Ethernet or FDDI environments) or
Source Routing (generally used in Token Ring environments), source
routing-transparent, or source route-transparentÑthe two latter being
combinations that are found in a mixed network environment.

About T ransparent Bridging

Transparent bridges are most common in Ethernet networks. Individual
Transparent bridges monitor packet trafÞc on attached network segments to learn
where end stations reside in relation to each segment by mapping the Source
Address of each received frame to the port (and segment) it was detected on. This
information gets stored in the bridgeÕs Filtering Database.

When in the Forwarding state, the bridge compares a packetÕs destination address
to the information in the Filtering Database to determine if the packet should be
forwarded to another network segment or Þltered (i.e., not forwarded). A bridge

2-1

Bridging

Þlters a packet if it determines that the packetÕs destination address exists on the
same side of the bridge as the source address.

If two or more bridges are connected to the same Ethernet LAN segmentÑplaced
in parallelÑonly a single bridge must be allowed to forward data frames onto
that segment. If two or more bridges were forwarding data frames onto the same
Ethernet segment, the network would soon be ßooded.

With a data loop in the topology, bridges would erroneously associate a single
source address with multiple bridge ports, and keep proliferating data by
forwarding packets in response to the ever-changing (but incorrect) information
stored in their Filtering Database.

To avoid such data storms, Transparent bridges communicate with one another
on the network by exchanging Bridge Protocol Data Units (BPDUs) to determine
the network topology and collectively implement a Spanning Tree Algorithm
(STA) that selects a controlling bridge for each LAN segment. This ensures that
only a single data route exists between any two end stations and that topology
information remains current.

About Source Route Bridging

Source Routing is typically used to connect two or more Token Ring network
segments. Source Route bridges differ from Transparent bridges in that they do
not build and then use a physical address database to make forwarding decisions.
Instead, the source end station transmits packets with a header that contains
routing information (added by bridges in the network topology during a route
discovery process between end stations); once a route has been determined, a
Source Route bridge simply reads the header of a source routed packet to
determine whether it is a participant in routing the packet.

In Source Routing, sending and receiving devices employ broadcast
packetsÑknown as explorer packetsÑto determine the most efÞcient route for a
message to travel. Generally, before a station sends a message, it will Þrst send a
test packet to all stations on the same ring; if the sending station receives a
response to this packet, it assumes that the destination station is on the same ring
and therefore it will not include routing information in frames sent to that station
in the future. Any further packets issued between stations will appear to be
transparent-style frames without embedded routing information.

If the sending station does not receive a response to the test packet, it will send
explorer packets to the destination; the explorer packets will be propagated by the
networkÕs bridges as either All Paths Explorer (APE) packets or as Spanning Tree
Explorer (STE) packets. The task of both packet types is to get the destination
station to return speciÞc route information to the sending station. They achieve
this by including an identiÞer for each ring the explorer packet traversed and for
each bridge between any rings).

Since the data ßow on a Source Routed network is determined by end stations
(unlike a Transparently bridged network), a looped bridge topology is not an
issue for data ßow. APE packets are sent from the source station over every

2-2 Bridging Basics

Bridging

possible bridge path to the end station. The original APE frame contains no
routing information (e.g., bridge numbers and ring numbers). As the frame is
propagated along all available paths to the destination station, each bridge along
the way adds its own bridge and ring numbers to the packetÕs RIF before
forwarding it, thereby providing route information.

In response to each received APE packet, the destination station directs a reply to
the sending station. On receiving the replies, the sending station ideally assumes
that the Þrst returned reply contains the most efÞcient route. The sending station
then stores the route information and uses it to send subsequent transmissions to
the same station.

Because APE frames do increase network trafÞc, some sites may use STE explorer
frames as an alternate method of route discovery. With STE exploration, a
Spanning Tree Algorithm (either conÞgured automatically via BPDUs or
manually via management) is maintained for the sole purpose of determining
how to direct an explorer frame during route discovery.

During the discovery process, a source station will send out STE explorer frames
into a bridged topology. If a bridge is in a forwarding state according to Spanning
Tree, it will forward an explorer frame onto its attached LAN segment (appending
the Bridge and LAN Segment IdentiÞers in the appropriate area of the RIF); if the
bridge is Þltering, it will discard the explorer frames. In this fashion, only a single
explorer frame will reach each individual LAN segment.

Ultimately, the destination station will receive only a single STE packet, and will
respond with APE packets (that return to the sending station on all possible
bridge paths) or an STE packet (that returns to the sending station via in the
reverse route of the STE explorer packet).

Although the Spanning Tree Algorithm determines the bridge path an STE takes
to the destination station, during future communication between the stations,
bridges along the route will use Source Routing to forward the packet (i.e., the
bridges will read the Routing Information Field in the header of speciÞcally
routed frames to decide whether to forward them).

About Source Route-Transparent Bridges

Because network topologies have developed in which bridges must be able to
handle network trafÞc from end stations which support source routing and others
which do not, a hybrid type of bridgeÑSource Route-Transparent (SRT) Ñ
combines elements of both bridging methods.

An end stationÕs network drivers can be conÞgured in software to use a bit setting
in the source address portion of a data frame to indicate whether the station is to
operate in a Source Route or Transparently bridged network environment. The
Routing Information Indicator (RII) bit of the source address is set to 1 if the
station is to use Source Routing; if the station is to operate in a Transparently
bridged environment, the RII bit is left unchanged (i.e., at 0).

Bridging Basics 2-3

Bridging

Not all end stations in a Token Ring environment have network drivers which
support Source RoutingÑwhether the drivers are improperly conÞgured via
management or they simply are not source-route capable.

In a network with a mix of Source Route and Transparent end stations, data
frames from both station types must be bridged correctly. An SRT bridge inspects
the RII bit setting of incoming frames to determine whether they should be
Transparently bridged (if the RII bit was at 0) or Source Routed (if the RII bit was
set to 1) to their destination and will use the appropriate bridge method to
forward the frame.

Cabletron has extended the functionality of Ethernet ports on translational bridges, so the

NOTE

ports can be set to Source Route mode. When an Ethernet port is in Source Route mode
and receives an SR packet from a Token Ring port, it will save the Source Routing
information and send out the packet transparently. When the response comes back, the
source routing information will be restored and then sent to the Token Ring port.

About Source Route-Translational Bridges

Because SmartSwitch 2000, 6000, and 9000 modules have the ability to combine
mixed network topologies, yet another hybrid bridge methodÑcalled a Source
Route Translational bridge (SR-TB)Ñis used by a number of these SmartSwitch
modules.

An SR-TB bridge supports both Source Routing and Transparent bridging
capabilities, with the added requirement of maintaining Source Route
information across an FDDI interfaceÑeither the SmartSwitch 9000 FNB
backplane, or an installed FDDI High Speed Interface Module (HSIM).

An SR-TB bridge does this by ÒtranslatingÓ the Token Ring physical frame format
(by stripping out routing information, if necessary) so that the frameÕs source
address can be recognized on an FDDI, Ethernet, or ATM segment; then, when
data is returned to the source, the bridge restores the necessary route information
to forward it along a bridged Token Ring environment.

For data that is restricted to the Token Ring networks available from the SR-TB
bridgeÕs front panel, the bridging method is user-conÞgurable via local
management to be Source Route-only (bridged packets must include RIF
information and will be source routed; no transparent bridging is enabled),
Source Route-Transparent (bridging method will be determined by whether the
RII bit is set), or Transparent only (no source routed packets will be bridged).
Remote management of these interfaces is based upon their current mode (as set
through local management).

For data that will ultimately be sent across an FDDI interface to an ATM, Ethernet,
FDDI, or another Token Ring segment, the Routing Information Field will be
stripped from the packet so the packet can be transparently bridged onto Ethernet
or FDDI media; however, the RIF information as well as the source address of the
packet is stored in a RIF cache of the SR-TB bridge. When data is returned to that
source address, the SR-TB bridge can look up the address information in its RIF

2-4 Bridging Basics

Bridging

cache, append the proper Routing Information onto the packet, and then forward
the data to the Token Ring segment.

The RIF cache is a software table that can store up to 8192 entries. An SR-TB
bridge updates its RIF cache much like a Transparent bridge dynamically updates
its Filtering Database: it learns new address information by listening to incoming
packets on each port, saves that information to an Address Database, andÑif the
address was learned to be Source-Route capableÑupdates routing information
for that source address in the RIF cache. Every time a packet arrives from an FDDI
interface for a MAC address that is communicating through the SR-TB bridgeÕs
front panel, the RIF cache table is searched for an address/RIF match.

There are conÞguration issues when a Token Ring module receives a packet from
an FDDI interface for a destination address that is unknown, and not in its
Address Database or RIF cache. You must conÞgure your SR-TB bridge to treat
incoming packets with an unknown destination address as either a Source Route
or Transparently bridged packet (since Token Ring end stations attached to the
module may or may not support Source Routing).

If the bridge is conÞgured to treat an incoming packet with unknown addresses as
a Source Routed frame, it will forward it using either STE or ARE frames. If the
bridge is conÞgured to treat an incoming packet with an unknown destination as
a Transparently bridged frame, it simply forwards the frame.

After a packet with a previously unknown destination has been bridged
successfully, and communication begins between the two end nodes, the RIF
cache will be updated and packets will be translated as described previously.

Viewing and Managing Bridging Interfaces

With SPECTRUM Element Manager, you can view and manage each bridging
interface supported by your device, including any installed interface modules,
such as BRIMs (Bridge/Router Interface Modules) and HSIMs (High Speed
Interface Modules).

You can manage your bridge by using the following windows:

¥ The Bridge Status window provides you with basic information about the

current status of the deviceÕs bridging interfaces, and allow you to enable or
disable bridging at each of those interfaces. The Bridge Status window also lets
you access further windows to conÞgure bridging at the device. See The

Bridge Status Window, page 2-7, for details.

¥ Bridge statisticsÑincluding the Performance Graph, Interface Statistics,

CSMACD Statistics, PPP Link Statistics, Dot5 Error Statistics, and Source
Route Statistics windowsÑgraphically display the trafÞc passing between

your bridged networks, and let you compare and contrast trafÞc and errors
processed by each interface. See Bridge Statistics, page 2-15 for details.

Viewing and Managing Bridging Interfaces 2-5

Bridging

¥ The Spanning Tree window shows bridge port information and protocol

parameters relating to the Spanning Tree AlgorithmÑthe method of
determining the controlling bridge when a series of bridges are placed in
parallel; see Spanning Tree, page 2-34, for details.

¥ With the Filtering Database window, you can see the contents of the Static and

Learned databasesÑthe two address databases which construct the IEEE 802.1
Source Address Table. The bridge uses the contents of these databases to make
its packet Þltering and forwarding decisions. You can conÞgure entries in these
databases to increase bridging efÞciency across your network. See Filtering

Database, page 2-41, for details.

¥ The Ethernet Special Filter Database and Token Ring Special Filter Database

windows let you conÞgure special Þltering schemes. With these schemes, you
can enter Þlter parameters for a frame based on the contents of its source or
destination address Þeld, type Þeld, or data Þeld (with offset)Ñthen specify
the bridging action to take place at each port when a frame matching your
speciÞcations is encountered (see Special Filter Databases, page 2-47).

¥ The I/F ConÞguration port-level menu option invokes the Interface

ConÞguration window, which allows you to select a bridging method for a
Token Ring bridging interface. This window also allows you to select one of
three transmission methods that should be used when unknown addresses are
received from end stations attached to the selected bridge port. See Using the

Novell Translation Window, page 2-97, for details.

¥ The Source Route ConÞguration option enables you to conÞgure source

routed trafÞc passing between bridge ports; see Source Route ConÞguration,

page 2-57, for details.

¥ The Bridge ConÞguration option allows you to set address and routing

information for all interfaces on a Token Ring bridging device, including the
Bridge Number and the Virtual Ring Number. It also allows you to set source
route bridging parameters at the device level. See Using the Token Ring

Bridge and Port ConÞguration Windows, page 2-65, for details.

¥ The Port ConÞguration option allows you to view the address and routing

information for an individual Token Ring bridging interface. This window
displays information that is set at the device level via the Bridge ConÞguration
window, such as the Bridge Number and the Virtual Ring Number. It also
allows you to set source route bridging parameters for that port. See Using the

Token Ring Bridge and Port ConÞguration Windows, page 2-65, for details.

¥ The Duplex Modes window lists each interface on your device and whether

or not it is operating in Full Duplex mode. The window allows you to switch
full duplex mode on and off for each interface on the device. Full Duplex
Switched Ethernet (FDSE) mode allows the interface to transmit and receive
information simultaneously, effectively doubling the available bandwidth. See

Using the Token Ring Bridge and Port ConÞguration Windows, page 2-65,

for details.

2-6 Viewing and Managing Bridging Interfaces

Bridging

¥ The SmartTrunk option invokes the SmartTrunk ConÞguration and Status

window, which enables you to group interfaces logically to achieve greater
bandwidth between devices that support this feature. There is no limit to the
number of ports that can be included in a single trunk, nor is there a limit to
the number of trunked instances that can be supported. See ConÞguring

SmartTrunking, page 2-85, for details.

¥ The Broadcast Suppression window enables you to monitor the number of

broadcast packets received by each interface of a selected device, and
conÞgure the maximum number of broadcast packets that will be forwarded
to other interfaces; see ConÞguring SmartTrunking, page 2-85, for details.

¥ The Token Ring Bridge Mode window lets you select which type of bridging

will be used by the Token Ring bridging deviceÑTransparent, Source Routing,
or Source Route Transparent; see Token Ring Bridge Mode, page 2-89, for
details.

¥ The Bridge Translation window allows you to control the necessary

translation of frames that must occur for Token Ring frames to be bridged to
Ethernet. This window offers Auto and Dual modes for translation and
includes the IBM and SNAP Translation tables. See Setting Bridge

Translation, page 2-91, for details.

¥ The Novell Translation window enables you to conÞgure each module port

for translation of Novell packets that are received and transmitted across a
Token Ring bridge; see Using the Novell Translation Window, page 2-97, for
details.

The menu options that are available will vary depending on the type of device you are

NOTE

monitoring, and on the type of bridge interfaces supported by the device.

The following sections detail how to use each of the bridge management
windows.

The Bridge Status Window

The Bridge Status window provides you with basic information about the current
status of bridging across your device. Color-coding of each port display allows
you to quickly ascertain the status of each interface. The Bridge Status window
also lets you access further windows to control bridging at your device.

To access the Bridge Status window from the Chassis View window:

1. Click on the Device selection in the menu bar. A menu will appear.

2. Click on Bridge Status. The Bridge Status window, Figure 2-1, will appear.

The Bridge Status Window 2-7

Bridging

NOTE

Figure 2-1. The Bridge Status Window

When you Þrst open the Bridge Status window the Prev and Next buttons will be grayed
out, and a message will appear stating that the application is initializing and processing
each interface. You will not be able to scroll the display until after all the bridging
interfaces have been processed. The Prev and Next buttons are activated when a device
supports over four bridge interfaces, so that you can scroll the display to show all
interfaces.

The following information is provided by the Bridge Status window for the
monitored device as a whole and for each individual bridging interface.

Up Time

At the top of the Bridge Status window, you can see the time period (in a days,
hours, minutes, seconds format) that has elapsed since the device was last reset or
initialized.

2-8 The Bridge Status Window

Bridging

Bridge State on Interface

Indicates the state of bridging over the port interface. Possible bridge states and
their corresponding colors are:

¥ Forwarding (green)ÑThe port is on-line and forwarding packets across the

bridge from one network segment to another.

¥ Disabled (blue)ÑBridging at the port has been disabled by management; no

trafÞc can be received or forwarded on this port, including conÞguration
information for the bridged topology.

¥ Listening (magenta)ÑThe port is not adding information to the Þltering

database. It is monitoring Bridge Protocol Data Unit (BPDU) trafÞc while
preparing to move to the forwarding state.

¥ Learning (magenta)ÑThe Forwarding database is being created, or the

Spanning Tree Algorithm is being executed because of a network topology
change. The port is monitoring network trafÞc, and learning network
addresses.

¥ Blocking (orange)ÑThe port is on-line, but Þltering trafÞc from going across

the bridge from one network segment to another. Bridge topology information
will be forwarded by the port.

Interface Type

Indicates the interface type which applies to each device bridging port interface
(e.g., ethernet). The interface type (ifType) is a mandatory object type from the
SNMP MIB II Interface (if) Group.

Bridge Address

Indicates the physical address of the bridge interface.

Speed

Indicates the speed of the interface in Mbps or Gbps.

Accessing Bridge Status Window Options

At the top of the Bridge Status window, you can click Bridge to access a menu
that provides other bridge management options. Depending on which device you
are monitoring via SPECTRUM Element Manager, the following bridge
management options will be available:

¥ The Module Type window displays a description of the device that is

currently being monitored.

¥ The Find Source Address window allows you to discover the bridge interface

through which a particular MAC address is communicating; see Using the

Find Source Address Feature, page 2-62, for details.

¥ The Performance Graph window displays statistics for trafÞc across the entire

bridge; see Performance Graphs, page 2-15, for details.

The Bridge Status Window 2-9

Bridging

¥ The Spanning Tree window allows you to set the Spanning Tree Algorithm

parameters for bridging on your device; see Spanning Tree, page 2-34, for
details.

¥ The SmartTrunk option invokes the SmartTrunk ConÞguration and Status

window, which enables you to group interfaces logically to achieve greater
bandwidth between devices, if both devices support the SmartTrunk feature.
There is no limit to the number of ports that can be included in a single
Òtrunk,Ó nor is there a limit to the number of trunked ÒinstancesÓ that can be
supported. See ConÞguring SmartTrunking, page 2-85, for details.

¥ The Filtering Database window lets you see the contents of the Static and

Learned databasesÑthe two address databases which construct the IEEE 802.1
Source Address Table. The bridge uses the contents of these databases to make
its packet Þltering and forwarding decisions. You can conÞgure the bridgeÕs
acquired and permanent Þltering databases to Þlter or forward trafÞc across
the device. See Filtering Database, page 2-41, for details.

¥ The Ethernet Special Filter Database window lets you conÞgure a special

Þltering scheme at your bridge. With this scheme, you can enter Þlter
parameters for a frame based on the contents of its source or destination
address Þeld, type Þeld, or data Þeld (with offset); you can then specify the
bridging action to take place at each port when a frame matching your
speciÞcations is encountered. See Special Filter Databases, page 2-47, for
details.

¥ The Token Ring Special Filter Database window enables you to deÞne

complex Þlters for transparently-bridged Token Ring frames based upon
receive port, source or destination MAC address, Token Ring data type, or data
Þeld information (up to 64 bytes); see Special Filter Databases, page 2-47, for
details.

¥ The Token Ring Bridge Mode window lets you select which type of bridging

will be used by the Token Ring bridging deviceÑTransparent, Source Routing,
or Source Route Transparent; see Token Ring Bridge Mode, page 2-89, for
details.

¥ The Bridge Translation window allows you to control the necessary

translation of frames that must occur for Token Ring frames to be bridged to
Ethernet. This window offers Auto and Dual modes for translation and
includes the IBM and SNAP Translation tables. See Setting Bridge

Translation, page 2-91, for details.

¥ The Novell Translation window enables you to conÞgure each module port

for translation of Novell packets that are received and transmitted across a
Token Ring bridge; see Using the Novell Translation Window, page 2-97, for
details.

¥ The Duplex Modes window allows you to conÞgure duplex mode (on or off)

for supporting interfaces on the device; see Using the Token Ring Bridge and

Port ConÞguration Windows, page 2-65, for details.

2-10 The Bridge Status Window

Bridging

¥ Enable Bridge and Disable Bridge options allow you to administratively

activate or deactivate bridging at the device level; see (Enabling and

Disabling Bridging, page 2-14, for details.

¥ The Bridge ConÞguration option opens a window that allows you to set

address and routing information for all interfaces on a Token Ring bridging
device, including the Bridge Number and the Virtual Ring Number. It also
allows you to set source route bridging parameters at the device level. See

Using the Token Ring Bridge and Port ConÞguration Windows, page 2-65,

for details.

The individual bridge port index ( ) menu that you can access from the Bridge
Status window will provide the following options, depending on which device
you are monitoring through SPECTRUM Element Manager:

¥ The Connection Type window displays a text description of the connection

type of the selected bridge interface.

¥ The Description option displays a text description of a bridge interface from

the ifDescr value of the ifIndex related to the selected port.

¥ The Performance Graph window graphically displays the trafÞc passing

between your bridged networks, and lets you compare and contrast trafÞc
processed by each interface; see Performance Graphs, page 2-15, for details.

¥ The Source Addressing window displays the contents of the deviceÕs Filtering

Database with respect to a selected port. This will display the source MAC
addresses that have been detected by the port as it forwards data across the
network. The window also lets you set the aging timer that controls how long
an inactive MAC address will continue to be stored in the Source Address
Database before being aged out. See Source Route ConÞguration, page 2-62,
for details.

¥ The PPP Link Status option invokes the PPP Link Statistics Window, which

enables you to view color-coded statistics related to the PPP (Point-to-Point
Protocol) link at the selected interface; see PPP Link Statistics, page 2-25, for
details.

¥ The Source Route Statistics option opens a window that allows you to view

statistics for source routed trafÞc passing between bridging ports. The window
enables you to view the frames that were received, transmitted, and discarded
by the bridge. See Source Route Statistics, page 2-31, for details.

¥ The I/F ConÞguration port-level menu option invokes the Interface

ConÞguration window, which allows you to select a bridging method for a
Token Ring bridging interface. This window also allows you to select one of
three transmission methods that should be used when unknown addresses are
received from end stations attached to the selected bridge port. See Using the

Novell Translation Window, page 2-97, for details.

¥ The Source Route ConÞguration option opens a window that enables you to

conÞgure source routed trafÞc passing between bridging ports; see Source

Route ConÞguration, page 2-57, for details.

The Bridge Status Window 2-11

Bridging

¥ The Port ConÞguration option opens a window that allows you to view the

address and routing information for an individual Token Ring bridging
interface. This window displays information that is set at the device level via
the Bridge ConÞguration window, such as the Bridge Number and the Virtual
Ring Number. It also allows you to set source route bridging parameters for
that port. See Using the Token Ring Bridge and Port ConÞguration

Windows, page 2-65, for details.

¥ The Dot5 Errors invokes a window that allows you to view 802.5 statistics for

the selected bridging interface on a Token Ring bridging device; see Dot5

Errors, page 2-28, for details.

¥ The RMON MAC Layer option opens the Token Ring Statistics window for

Token Ring devices that support RMON, which enables you to view a
statistical breakdown of trafÞc on the monitored Token Ring interface
(network segment). Note that if the RMON Default MIB component is
disabled, the RMON MAC Layer menu option will launch the Interface
Statistics window. Refer to the RMON UserÕs Guide for more information on
how to enable and disable RMON MIB components. For more information
about this menu option, refer to the Statistics chapter in the Remote

Monitoring (RMON) UserÕs Guide, and/or the appropriate device-speciÞc
UserÕs Guide.

¥ The RMON Promiscuous Stats option opens the Token Ring Promiscuous

Statistics window, which allows you to view statistical information about
those packets that carry the normal data ßow across a bridging interface
(network segment). Note that if the RMON Default MIB component is
disabled, the RMON Promiscuous Stats menu option will launch the Interface
Statistics window. Refer to the Remote Monitoring (RMON) UserÕs Guide for
more information on how to enable and disable RMON MIB components. For
more information about this menu option, refer to the Statistics chapter in the
RMON UserÕs Guide, and/or the appropriate device-speciÞc UserÕs Guide.

¥ The I/F Statistics option activates the Interface Statistics Port window, which

allows you to view color-coded statistical information about each individual
bridge port on the currently monitored device; see Interface Statistics,

page 2-20, for details.

¥ The ConÞguration option opens a window that enables you to conÞgure the

selected bridge interface for either full duplex or standard mode; see Ethernet

Port ConÞguration, page 2-72, for details.

¥ The Alarm ConÞguration option appears as a menu choice for Ethernet

devices which support RMON, and invokes the RMON Basic Alarm
ConÞguration window that enables you to create alarms or actions at a speciÞc
bridge interface based on rising and falling thresholds for Broadcast/Multicast
packets, Kilobits, or Total Errors. Note that if the RMON Default MIB
component is disabled, the Alarm ConÞguration menu option will still appear
and the window will still display; however, you will not have the ability to set
anything. Refer to the Remote Monitoring (RMON) UserÕs Guide for more
information on how to enable and disable RMON MIB components. For more

2-12 The Bridge Status Window