Avaya M-ACCF-SF User Manual

Avaya

User’s Guide

M-ACCF/SF MODULE

AVAYA M770 MULTIFUNCTION SWITCH

July 2000

Preface

Introduction

This guide provides the information that you need to install and configure the M-ACCF/SF OC12 ATM Access Modules. These modules fit into the Avaya M770 Modular switch chassis.

This guide is intended for use by network administrators who are responsible for installing and setting up networking equipment. It assumes a basic working knowledge of Local Area Networks.

This guide also explains basic Asynchronous Transfer Mode (ATM) and LAN Emulation (LANE) concepts.

Note: See the accompanying Release Notes for last minute product updates.

User Guide, Embedded Software, Release Notes and CajunView SNMP management updates are available at Avaya Network’s World Wide Web site when they are released: http://www.avayanetwork.com/

ATM Terminology

This user guide uses the term Network-To-Network Interface (NNI). You may know this protocol by its alternative name, Network-to-Node Interface (NNI).

Avaya M770 M-ACCF/SF ATM Access Modules User’s Guide I

Introduction

Finding Information in This Guide

The following Table shows you where to find specific information within this guide.

Table P.1 Finding Information

Use Location

Learning concepts Chapter 1, Overview

Features and Benefits Avaya M770 Frame Switching Domains Network Layer Concepts — LAN Emulation Network Layer Concepts — ATM & ATM Adaptation

Planning your network Chapter 2, Applications

Putting Your ATM Network Together ATM Configuration Rules Extending VLANs Through the ATM Network Network Configuration Examples

Installing the M-ACC ATM Access module

Using TELNET, Accessing screens, Logging on/off, Configuring parameters, Upgrading Software

Network Management and Monitoring (NMS)

Specifications M-ACC Module Module Technical Specifications

Troubleshooting Troubleshooting common problems

Subjects & concepts lookup

Chapter 3, Installation

Installing the M-ACC Module Domain Usage Considerations Configuring the M-ACC Module Setting up the M-ACC Module

Chapter 4, X-Switch CLI and ATM Terminal Interface

X-Switch Command Line Interface (CLI) ATM Access Module Terminal Interface for Configuring ATM Parameters Managing and Monitoring the M-ACC Module

Chapter 5, Network Management and Monitoring

Management of the ATM module using the CajunView M770 Device Manager and LaneMaster applications

Contents, Index

II Avaya M770 M-ACCF/SF ATM Access Modules User’s Guide

Conventions

The following Tables list conventions that are used throughout this guide.

Table P.2 Notice Icons

Icon Notice Type Description

Table P.3 Text Conventions

Convention Description

Introduction

Note Information that describes important features or

instructions

Caution Information that alerts you to potential loss of data or

potential damage to an application, system, or device

Warning Information that alerts you to potential personal injury

Screen displays

Syntax

Commands The word “command” means that you must enter the

The words “enter” and “type”

Keyboard key names

Words in italics Italics are used to:

This typeface represents information as it appears on the screen.

The word “syntax” means that you must evaluate the syntax provided and then supply the appropriate values for the placeholders that appear in angle brackets.

command exactly as shown and then press Return or Enter. Commands appear in bold.

When you see the word “enter” in this guide, you must type something, and then press Return or Enter. Do not press Return or Enter when an instruction simply says “type.”

If you must press two or more keys simultaneously, the key names are linked with a plus sign (+). Example: Press Ctrl+Alt+Del

Emphasize a point. Denote a new term at the place where it is defined in the text. Identify menu names, menu commands, and software button names. Examples: From the Help menu, select Contents. Click OK.

Avaya M770 M-ACCF/SF ATM Access Modules User’s Guide III

Introduction

IV Avaya M770 M-ACCF/SF ATM Access Modules User’s Guide

Introduction ......................................................................................................... I

ATM Terminology ...................................................................................I

Finding Information in This Guide .......................................................... II

Conventions ........................................................................................... III

Contents................................................................................................................ i

List of Figures .................................................................................................. vii

List of Tables...................................................................................................... ix

Chapter 1 Overview............................................................................................................. 1

ATM Access Modules ............................................................................... 1

Features and Benefits............................................................................... 1

ATM Benefits ...........................................................................................1

ATM Access Module Features ..............................................................2

Avaya M770 Frame Switch Domains....................................................... 2

M-ACC Module Architecture ...............................................................2

Network Layer Concepts — LAN Emulation ........................................... 3

LAN Emulation Overview ....................................................................3

Emulated LAN Components ................................................................3

LAN Emulation Client (LEC) ....................................................3

LAN Emulation Server (LES) ....................................................4

Broadcast and Unknown Server (BUS) ....................................4

LAN Emulation Configuration Server (LECS) .......................4

Emulated LAN Connections .................................................................5

Control VCCs ...............................................................................5

Data VCCs .................................................................................... 6

Frame Ordering ...........................................................................7

Operation of the LAN Emulation .........................................................8

Connecting a LEC to an ELAN .................................................8

Registration ..................................................................................9

Address Resolution ................................................................... 10

Connection Management .........................................................10

LAN Emulation Components in Your Network ..................10

Joining the ELAN ...................................................................... 12

Mapping Ethernet and ATM Addresses ................................12

What Happens to Unicast Frames? ........................................14

What Happens to Broadcast and Multicast Frames? ........... 14

Avaya M770 M-ACCF/SF ATM Access Modules User’s Guide i

Contents

Network Layer Concepts — ATM & ATM Adaptation ........................... 15

The Layered Network Architecture ...................................................15

ATM Adaptation Layer (AAL) ...........................................................16

Asynchronous Transfer Mode (ATM) Layer ....................................16

ATM Basics .................................................................................16

ATM is Service Transparent .....................................................17

ATM is Connection-Oriented ..................................................18

ATM Interfaces ...........................................................................21

The ATM Layer and Cell Structure .........................................22

Physical Layer .......................................................................................24

Extending VLANs into the ATM Network .......................................24

Chapter 2 Applications ...................................................................................................... 27

Putting Your ATM Network Together .................................................... 27

Planning Your Network .......................................................................27

ATM Configuration Rules ...................................................................... 28

Extending VLANs Through the ATM Network ...................................... 29

ATM Connections Within Your Network .........................................30

Network Configuration Examples .......................................................... 31

ATM Backbone in the Building ...........................................................31

Avaya M770 Multitechnology Functionality ....................................33

Routing in the X-Switch Domain ........................................................34

Chapter 3 Installation......................................................................................................... 35

Installing the M-ACC Module ................................................................ 35

Safety Information ................................................................................35

Single-mode Module Laser Classification .........................................36

Multi-Mode Module LED Warning ...................................................36

Agency Approval ..................................................................................36

Device Support ......................................................................................36

Pre-installation Procedure ...................................................................36

Domain Usage Considerations................................................................ 37

Budget Calculation Examples .............................................................37

DRU Budget Information Window ....................................................38

Installing the Module ............................................................................. 39

Connecting a Cable to the ATM Port ......................................40

Removing an Existing ATM Access Module ....................................41

Post-Installation Checks .......................................................................42

Configuring the M-ACC Module............................................................ 43

M-ACC Module Default Settings .......................................................43

Connecting to the Serial Port ...................................................43

Establishing a Telnet Session ...............................................................44

ii Avaya M770 M-ACCF/SF ATM Access Modules User’s Guide

Contents

Setting up the M-ACC Module .............................................................. 45

Changing the Default IP Address of the M-ACC Module

Using the CLI ........................................................................................45

To connect to the M-SPX/S Console port .............................. 45

Module Setup Main Menu ..................................................................46

ATM IP Configuration .........................................................................46

Assigning the M-ACC module IP address, Gateway and Net-

mask: ...........................................................................................46

Setting up the ATM Access Module ..................................................47

Chapter 4 X-Switch CLI & ATM Terminal Interface..................................................... 49

Introduction ........................................................................................... 49

M-ACC Module Architecture .............................................................49

Conventions Used .................................................................................. 50

X-Switch Command Line Interface (CLI) .............................................. 51

Commands Summary Table ...............................................................51

To connect to the M-SPX/S Console port .............................. 51

Module Setup Main Menu ..................................................................52

Reset the Module .................................................................................. 52

Software Download to the X-Switch CPU ........................................ 53

Entering Software Download Parameters ............................. 53

Starting the Software Download Process ..............................54

Monitoring the Software Download Process ........................54

Set Primary Version ..............................................................................55

Set Defaults to Factory Settings ..........................................................55

Create Report ........................................................................................55

Clear Mac Address Table ....................................................................56

Configuration Copy .............................................................................56

ATM IP Configuration .........................................................................56

Assigning the M-ACC module IP address, Gateway and

Netmask: .....................................................................................57

ATM Access Module Terminal Interface for Configuring ATM

Parameters.............................................................................................. 58

Commands Tree Chart .........................................................................58

Logging On ............................................................................................58

Logging Off ........................................................................................... 59

Managing the ATM Access Module ....................................................... 59

Submenus .............................................................................................. 59

Main Menu Options .............................................................................61

Configuring System Parameters [1] ...................................................61

System Menu ..............................................................................61

Display Submenu [1,1] .............................................................62

Initialize Submenu [1,2] ............................................................62

Passwords Submenu [1,3] ........................................................62

Reset Submenu[1,4] ...................................................................62

Avaya M770 M-ACCF/SF ATM Access Modules User’s Guide iii

Contents

System Logger Submenu [1,5] .................................................63

Display FLASH Log Messages Submenu [1,5,1] ...................63

Display Memory Log Messages Submenu [1,5,2] .................64

System Software Download Submenu [1,6] ..........................65

Configuring an ATM Port [2] ..............................................................65

ATM access module Configuration ........................................65

Port Submenu [2,1] ....................................................................66

ATM Port Physical Submenu [2,1,6] .......................................67

VCC Submenu [2,2] ...................................................................67

Aging Submenu [2,2,4] .............................................................68

Administering IP and SNMP Management [3] ................................69

IP Submenu [3,1] ........................................................................69

SNMP Configuration Submenu [3,2] ......................................69

Extending VLANs into the ATM Network [4] .................................72

VN Configuration Menu ..........................................................72

Upgrading Software .............................................................................75

Preliminaries ..............................................................................75

Downloading ..............................................................................75

Monitoring the ATM Access Module ..................................................... 76

ATM Port Statistics ...............................................................................76

VCC Statistics ........................................................................................78

Chapter 5 Network Management and Monitoring........................................................ 79

Introduction ........................................................................................... 79

CajunView M770 Device Manager ........................................................ 80

Starting the M770 Manager ................................................................80

M770 Manager as Part of CajunView .....................................80

LANEMaster ........................................................................................... 81

Overview ................................................................................................81

Starting Cajun LANEMaster ...............................................................81

Cajun LANEMaster Views ..................................................................82

Overview .....................................................................................82

Appendix A Specifications .................................................................................................... 85

M-ACC ATM Access Module Technical Specifications........................... 85

Environmental, Safety, and EMC Specifications ..............................85

ATM Cable Specification .....................................................................85

Optical Standard Supported ....................................................86

SDH Standard Supported .........................................................86

Safety Information ................................................................................. 88

Important Safety Information .............................................................88

Appendix B Troubleshooting ............................................................................................... 89

Index ............................................................................................................................................... 91

iv Avaya M770 M-ACCF/SF ATM Access Modules User’s Guide

Contents

How to Contact Us....................................................................................................................... 95

In the United States ..............................................................................95

In the EMEA (Europe, Middle East and Africa) Region .................95

In the AP (Asia Pacific) Region ........................................................... 97

In the CALA (Caribbean and Latin America) Region ..................... 97

Avaya M770 M-ACCF/SF ATM Access Modules User’s Guide v

Contents

vi Avaya M770 M-ACCF/SF ATM Access Modules User’s Guide

List of Figures

Figure 1.1 Basic LAN Emulation Client Connections ...............................5

Figure 1.2 VCCs in LAN Emulation Components.....................................7

Figure 1.3 The Flush Protocol. ......................................................................8

Figure 1.4 Connection Processes of the LEC to LANE Server..................9

Figure 1.5 Address Resolution....................................................................10

Figure 1.6 LAN Emulation Components...................................................11

Figure 1.7 LAN Emulation Clients and Ethernet Hosts..........................13

Figure 1.8 Network Layer Architecture..................................................... 15

Figure 1.9 Service Processing ...................................................................... 17

Figure 1.10 Communication Channels ........................................................ 18

Figure 1.11 Connection Terminology .......................................................... 19

Figure 1.12 Switching Cells Using VPI and VCI Values ...........................20

Figure 1.13 ATM Interfaces ...........................................................................21

Figure 1.14 UNI Management Entities ........................................................ 22

Figure 1.15 ATM Cell Structure....................................................................23

Figure 1.16 VLAN to ELAN Mapping.........................................................25

Figure 1.17 Extending VLANs into the ATM Network. ...........................26

Figure 2.1 ATM Backbone in the Building ................................................ 32

Figure 2.2 Avaya M770 Multitechnology Functionality .........................33

Figure 2.3 Routing in the X-Switch Domain. ............................................34

Figure 3.1 Inserting the Module into the Hub..........................................40

Figure 3.2 LED Indications for the M-ACC ATM Access Module ........ 42

Figure 4.1 Management Submenu Map .................................................... 60

Figure 4.2 Main Menu ..................................................................................61

Figure 4.3 System Menu............................................................................... 61

Figure 4.4 Display Submenu .......................................................................62

Figure 4.5 Passwords Submenu..................................................................62

Figure 4.6 Logger Submenu ........................................................................63

Figure 4.7 Display FLASH Log Messages Submenu ...............................63

Figure 4.8 Display Memory Log Messages Submenu .............................64

Figure 4.9 System Software Download Submenu....................................65

Figure 4.10 ATM Access Module Configuration Submenu......................65

Figure 4.11 Port Submenu .............................................................................66

Figure 4.12 Display Results ........................................................................... 67

Figure 4.13 ATM Port Physical Submenu ................................................... 67

Figure 4.14 VCC Submenu ............................................................................68

Figure 4.15 Aging Submenu..........................................................................68

Figure 4.16 Management Submenu .............................................................69

Avaya M770 M-ACCF/SF ATM Access Modules User’s Guide vii

List of Figures

Figure 4.17 SNMP Submenu..........................................................................69

Figure 4.18 updSysAtt Submenu [3,2,6].......................................................71

Figure 4.19 Community Submenu [3,2,7]....................................................71

Figure 4.20 Virtual net Submenu ..................................................................72

Figure 4.21 ATM Submenu............................................................................76

Figure 4.22 ATM Port Statistics Screen ........................................................77

Figure 4.23 VCC Statistics Display Example...............................................78

Figure 5.1 Cajun LANEMaster Window....................................................83

viii Avaya M770 M-ACCF/SF ATM Access Modules User’s Guide

List of Tables

Table P.1 Finding Information.................................................................... II

Table P.2 Notice Icons................................................................................. III

Table P.3 Text Conventions ....................................................................... III

Table 1.1 Control VCCs................................................................................5

Table 1.2 Data VCCs.....................................................................................6

Table 3.1 Avaya M770 Module DRU Budget..........................................37

Table 3.2 M-ACC LEDs Descriptions.......................................................42

Table 3.3 M-ACC Module Default Settings.............................................43

Table 4.1 Users and their Privileges.........................................................58

Table 4.2 Operational Meanings of Display FLASH Log

Submenu Items...........................................................................63

Table 4.3 Operational Meanings of Display Memory Submenu Items64

Table 4.4 Operational Meanings of Port Submenu Items ..................... 66

Table 4.5 VCC Submenu Items and their Operational Meanings........ 68

Table 4.6 Configure Submenu Items and their Operational

Meanings .....................................................................................70

Table 4.7 Configure Submenu Items and their Operational

Meanings .....................................................................................73

Table 4.8 Port Statistics Display Items and their Meanings..................77

Table 4.9 Statistics Display Items and their Meanings ..........................78

Table A.1 Environmental Specifications...................................................85

Table A.2 Safety and EMC Standards Compliance.................................85

Table A.3 Standard Multi-mode Cable Specifications ............................86

Table A.4 Standard Multi-mode Cable Specifications (continued) ......87

Table A.5 Standard Single-Mode Cable Specifications

(OC-12c/OC-3c Short Reach) ...................................................87

Table B.1 Troubleshooting Tips................................................................. 89

Avaya M770 M-ACCF/SF ATM Access Modules User’s Guide ix

List of Tables

x Avaya M770 M-ACCF/SF ATM Access Modules User’s Guide

Chapter 1

Overview

ATM Access Modules

There are two M-ACC OC-12 ATM Access modules for the Avaya M770 Multifunction switch:

• M-ACCF: 500m, Multimode fiber, can also be OC-3 reduced range

• M-ACCSF: 15 km, Single-mode fiber, can also be OC-3

The M-ACC ATM Access modules need the following S/W Versions:

• M-ACCF/SF ATM Entity S/W Version 1.8

• M-ACCF/SF X-Switch Module S/W Ver. 4.0.7

• M-SPX/M-SPS Embedded S/W 3.2.1 and higher.

Features and Benefits

This Section describes the main features of the M-ACC OC-12 module and the benefits of ATM within your network. The following topics are described:

•ATM Benefits

• ATM Access Module Features

The ATM module provides a high-speed ATM connection between your Avaya M770 X-Switch domain and the ATM network.

Positioned within a workgroup or departmental LAN, the ATM access module provides a fast ATM uplink to the building or ATM campus.

Redundant links protect your Switch from network and equipment failure, while the software upgrade feature future-proofs your Switch by allowing you to add new features as they become available.

ATM Benefits

ATM is the only technology specifically designed to carry voice, video and data traffic simultaneously and to provide the required level of service that these different applications need in order to run effectively across a network. ATM provides the following benefits:

• It is easy and of low cost to add additional services to the ATM network.

• Services can be added as and when they are needed. It is easier to scale ATM networks compared to other network technologies.

• ATM devices interoperate with your existing network. LAN Emulation (LANE) is a standards-based technology specifically designed to provide interoperability between existing Ethernet/Fast Ethernet networks and ATM

Avaya M770 M-ACCF/SF ATM Access Modules User’s Guide 1

Chapter 1 Overview

networks. LANE allows users to interoperate with ATM or traditional LAN based servers over ATM for higher performance and functionality.

ATM Access Module Features

The following list summarizes the ATM access module features. These features are described in more detail in this guide.

• Conforms to ATM Forum Standards

• OC-12c 622Mbps Interface — SONET (STS 3c/STS 12c) compliant (SDH STM-1/STM-4) — Multimode fiber, SC/SM connectors —Single-mode fiber.

• LAN Emulation (LANE) version 1.0 — 16 Emulated LAN Clients — 3,740 Virtual Circuits — 8,000 remote MAC Addresses

• User-To-Network Interface (UNI) version 3.0 and 3.1

• Interim Local Management Interface (ILMI)

• AAL5 ATM Adaptation Layer

• 16 ELAN/VLAN associations (in the range from VLAN 1 to 254)

• Data buffer to store 16,000 ATM cells

• High performance with fast data transfer — Wire Rate Transmission on ATM port

• Redundant Links from two different modules protect your network against cable and equipment failure

• For Management you can use: — Avaya’s CajunView™ SNMP Manager — TELNET

Avaya M770 Frame Switch Domains

The Avaya M770 supports two Frame Switches, named DomainXs: DomainXL (Left DomainX) spans slots 1-7, and DomainXR (Right DomainX) spans slots 8-14. Each DomainX supports up to 6 Gbytes of bandwidth. You can insert the M32-100T into either DomainX, provided you don't exceed the maximum of 100 Domain Resource Units (DRUs) per DomainX. Each module uses a certain number of DRUs; the M32-100T uses 12 DRUs.

M-ACC Module Architecture

The M-ACC module consists of separate X-Switch and ATM entities. The X-switch CPU connects the M-ACC module to the Avaya M770 X-Domain. The ATM CPU performs all ATM signalling. Each entity has it’s own embedded software.

2 Avaya M770 M-ACCF/SF ATM Access Modules User’s Guide

Network Layer Concepts — LAN Emulation

The following Sections describe the LAN emulation and ATM adaptation concepts behind the network layer architecture of a typical ATM network. Chapter 2 describes how to plan your ATM network and provides some examples of where to use the ATM access module within an ATM network.

LAN Emulation Overview

LAN Emulation (LANE) is a method of connecting LAN users over an ATM network which enables them to communicate with each other as if they were operating over traditional LANs. LANE can be configured in an ATM network in several ways:

• To connect legacy end stations directly to other legacy systems, as well as to servers, routers, switches and other networking devices attached to the ATM network.

• To connect bridged-LAN environments to each other over ATM. In this case the Emulated LAN acts as a bridge on the ATM network.

• To connect ATM end stations to each other, enabling communication between them.

More than one emulated LAN can operate on the same ATM network. However, each of the emulated LANs is independent of the others and users cannot communicate directly across emulated LAN boundaries.

Chapter 1 Overview

Emulated LAN Components

LAN Emulation is implemented as a set of connection services collectively called an emulated LAN (ELAN). Each ELAN is composed of a set of LAN Emulation Clients (LEC) and a single LAN Emulation Service. The latter consists of a LAN Emulation

Configuration Server (LECS), a LAN Emulation Server (LES), and a Broadcast and Unknown Server (BUS).

LAN Emulation Client (LEC)

Each LEC is incorporated in an ATM edge device, such as the M-ACC module and represents a set of the device’s LAN users to the ATM network. A LEC has a unique LEC ID as well as an ATM address by which it is known in the emulated LAN. It handles the forwarding of its LAN users’ data frames over the ATM network to their destination, a task which also includes ascertaining the destination LEC address and setting up the connection between them.

Also provided is a MAC-level emulated Ethernet service interface to higher level software which implements the LAN Emulation User to Network Interface (LUNI).

An ELAN is assigned a name (ELAN name). A LEC joining an ELAN may use the ELAN name in the configuration or join phase.

Avaya M770 M-ACCF/SF ATM Access Modules User’s Guide 3

Chapter 1 Overview

LAN Emulation Server (LES)

The LES coordinates and controls an Emulated LAN. It provides the central “directory” service of an emulated LAN to which a LEC can turn to look up the ATM address of another LEC. The LES directory contains a table of LAN destinations (LAN destination refers to either a MAC address or a Route Descriptor) together with the ATM addresses of the LECs that represent them. In order to transmit a data frame to a particular LAN destination, the LEC sends the data frame to the LEC that represents that LAN destination. If the LEC does not already know the destination LEC’s address, it can send the LAN destination to the LES to look it up (resolve). To populate the LES directory, the LECs may register the LAN destination of LAN stations they represent with the LES. Every Route Descriptor must be registered with the LES.

The LANE Service normally resides on a central ATM switch, such as the M770 ATM Switch, but may reside on an ATM end station instead.

Broadcast and Unknown Server (BUS)

The BUS is the LANE connection service which handles ATM traffic other than direct transmissions between LECs. It handles the following:

• Data sent by a LEC to the broadcast MAC address

• All multicast traffic

• Initial unicast frames which are sent by a LEC before the data direct virtual connection to the ATM address has been resolved

• Unknown traffic

• All broadcast, multicast and unknown traffic to and from a LEC passes through a single BUS.

The BUS also handles ATM connections and manages its distribution group.

LAN Emulation Configuration Server (LECS)

The LECS assigns individual LAN Emulation Clients to different emulated LANs. Based on its own programming, configuration database and information provided by clients, it assigns any client which requests configuration information to a particular emulated LAN service by giving the client the LES’s ATM address. This method supports the ability to assign a client to an emulated LAN based on either the physical location (ATM address) or the identity of a LAN destination which it is representing (ELAN name). LECs obtain information from a LECS using the configuration protocol.

4 Avaya M770 M-ACCF/SF ATM Access Modules User’s Guide

Emulated LAN Connections

LECs and LESs communicate with each other by means of ATM virtual channel connections (VCCs). Control signals and data transmissions are handled by separate VCCs: Control VCCs and Data VCCs.

Figure 1.1 Basic LAN Emulation Client Connections

Control VCCs

The control VCCs carry control traffic such as LE_ARP requests and responses. On initialization, control VCCs are established between LEC and LES (bi-directional control-direct VCC and control-distribute VCC) as well as a bi-directional configuration VCC between LEC and LECS. Characteristics of the control VCCs are summarized in Table 1.1.

Chapter 1 Overview

Table 1.1 Control VCCs

VCC Name From/To Information carried

Configuration LEC<==>LECS LEC requests and

receives

Initialized by

Duration

LEC While

needed configuration information from LECS, including LES address

Control-direct LEC<==>LES LEC sends and

receives controls from LES, including

LEC Membership

of LEC in

ELAN LE_ARP information

Avaya M770 M-ACCF/SF ATM Access Modules User’s Guide 5

Chapter 1 Overview

Table 1.1 Control VCCs (Continued)

VCC Name From/To Information carried

Controldistribute

LES==>LEC LES distributes

control traffic to LECs, including

Initialized by

Duration

LES Membership

of LEC in ELAN

LE_ARP information

Data VCCs

Data VCCs carry data frames between LECs and between a LEC and the BUS. Unicast data is normally sent from one LEC to another LEC by data-direct VCCs. Data direct VCCs are set up dynamically in a SVC environment by a transmitting LEC after ascertaining the ATM LEC destination address for the packet to be transmitted. Once established, a data-direct VCC remains in place for transmission of subsequent traffic between the two LECs. However, a data direct VCC that remains unused for VCC-Timeout-period is released by the LEC.

A multicast data VCC pair (multicast-send and multicast-forward) are established between a LEC and the BUS in order to allow the LEC to send and receive multicast data. In addition, initial unicast data (data whose LEC destination has not yet been ascertained by the transmitting LEC) is sent on the multicast-send VCC to the BUS which forwards it to all other LECs in the same ELAN. Characteristics of the data VCCs are summarized in the following table:

Table 1.2 Data VCCs

VCC Name

Datadirect

From/To

LEC<==>LEC Point-to-point

Information carried

Unicast data between LECs

Initialize d by

Duration

LEC Established by

need and released when unused for VCC-Timeoutperiod

Multicastsend

LEC<==>BUS LEC sends

multicast and

LEC Membership of

LEC in ELAN. initial unicast data to BUS

Multicastforward

BUS==>LEC BUS distributes

data traffic to

BUS Membership of

LEC in ELAN. LECs

6 Avaya M770 M-ACCF/SF ATM Access Modules User’s Guide

Chapter 1 Overview

Figure 1.2 illustrates the VCCs active among LAN Emulation Components.

Figure 1.2 VCCs in LAN Emulation Components

Frame Ordering

There are two paths for unicast frames between a sending LAN Emulation Client and a receiving client: one via the BUS and one via a data direct VCC between them. For a given LAN destination, a sending client is expected to use only one path at a time, but the choice of paths may change over time. Switching between those paths introduces the possibility that frames may be delivered to the receiving client out of order. Delivery of out-of-order frames between two LAN endpoints is uncharacteristic of LANs, and undesirable in an ATM emulated LAN. The flush protocol ensures the correct order of delivery of unicast data frames.

Flush Protocol

When switching between paths, the sender first transmits a flush message down the old path and suspends further transmission to that LAN destination. When the flush message is returned by the receiving client (via control VCCs), the sender knows that all previous messages for that LAN destination have been processed and it can start using the new path.

Avaya M770 M-ACCF/SF ATM Access Modules User’s Guide 7

Chapter 1 Overview

Figure 1.3 shows the various stages of the flush protocol:

Figure 1.3 The Flush Protocol.

Switch Data Path from Multicast Send to Data Direct using Flush Protocol

6. Flush_Res

2. Data

7. Data

Operation of the LAN Emulation

The following functions are performed by the LAN Emulation. The LAN Emulation Clients (LEC) and the LAN Emulation Servers interact by way of a well-defined interface (LUNI).

• Connecting a LEC to an ELAN

• Address Registration

• Address Resolution

• Data Transfer

Connecting a LEC to an ELAN

The connection function of the LEC with the LAN Emulation Server (LES) includes the following:

• LECS connect phase in which a LEC establishes a configuration data-direct VCC to the LECS (optional).

• The configuration phase in which the LEC discovers the LES.

• The join phase in which the LEC establishes its control connections to the LES. The LEC may also implicitly register one MAC address with the LES.

• The registering by the LAN Emulation Client of any number of MAC addresses and/or route descriptors.

• The establishment of a connection to the BUS by the LAN Emulation Client.

8 Avaya M770 M-ACCF/SF ATM Access Modules User’s Guide

Chapter 1 Overview

The LECS Connect and Configuration phases may be bypassed for certain applications. The Registration phase may also be bypassed if the LEC performs required address registration during the Join phase.

The Processes connecting the LEC to the ELAN are shown in Figure 1.4.

Figure 1.4 Connection Processes of the LEC to LANE Server

Registration

The address registration function is the mechanism by which LECs provide address information to the LAN Emulation Server. The LAN destinations may also be unregistered as the state of the client changes. A client must either register all LAN destinations for which it is responsible or join as a proxy to other MAC addresses.

Avaya M770 M-ACCF/SF ATM Access Modules User’s Guide 9

Chapter 1 Overview

Address Resolution

Address resolution is the procedure by which a LEC associates a LAN destination with the ATM address of another LEC or the BUS. Address resolution allows clients to set up data direct VCCs to carry frames (refer to Figure 1.5).

Figure 1.5 Address Resolution

Connection Management

In Switched Virtual Connection (SVC) environments, the LAN Emulation entities (LEC, LES and BUS) set up connections between each other using UNI signaling.

LAN Emulation Components in Your Network

Each Emulated LAN consists of a single LANE Service, and a number of LAN Emulation clients.

A LANE Service consists of:

•A LAN Emulation Server (LES)

•A Broadcast and Unknown Server (BUS)

•Optional LAN Emulation Configuration Server (LECS).

Figure 1.6 shows a logical view of a typical ELAN.

10 Avaya M770 M-ACCF/SF ATM Access Modules User’s Guide

Figure 1.6 LAN Emulation Components

Server

(LES)

Chapter 1 Overview

BUS

Router

AT M N e t wo r k

LECS

(optional)

Client (LEC)

Note: The router shown in Figure 1.6 is not a LAN Emulation component, but would be required should a device on one Emulated LAN need to communicate with a device on another Emulated LAN.

LAN Emulation and Avaya Devices

LAN Emulation components are implemented in ATM devices. The LAN Emulation standards do not specify how each vendor implements each of these components.

Avaya provides a wide range of ATM equipment, and the following example is just one way in which you can implement an Emulated LAN using Avaya devices.

An Example:

• The Avaya M770 ATM switch incorporates the BUS, LES and LECS

components. These components are known collectively as LANE Services.

• The M-ACC module has 16 LAN Emulation Clients (LECs); one for each of the

Virtual LANs (VLANs) supported by the module.

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Chapter 1 Overview

Joining the ELAN

Before a LAN Emulation Client (LEC) can transmit any Ethernet frames onto the ATM network it must first join an ELAN. To join the ELAN:

1 The LEC must know the name of the ELAN it is to join.

The ELAN name is specified through the management software on the Switch.

2 The LEC must communicate with the LAN Emulation Server (LES) that is

serving that ELAN.

To communicate with the LES, the LEC must first locate the LES. The LEC can find the ATM address of the LES in one of the following ways:

— If there is a LAN Emulation Configuration Server (LECS) on the network,

— The way in which the LECS determines which LES the LEC needs to

— If the network does not have a LECS, the LEC gets the LES address from the

3 The LEC must have a connection to the Broadcast and Unknown Server

(BUS).

When the LEC has joined the LES, the LES helps the LEC locate the Broadcast and Unknown Server (BUS) associated with that ELAN.

the LEC gets the address of the LES from the LECS.

communicate with, depends on the policy that the LECS is running. Refer to the user guide that accompanies your LECS for more details of the policies your LECS uses.

management software on the ATM device.

Locating the LECS

Before the LEC can ask the LECS for the address of the LES, the LEC must first locate the LECS as follows:

• The LEC can use a well known ATM address that is reserved for the LECS. The well known address is pre-programmed into most LECS devices. The well known address is: 47.00.79.00.00.00.00.00.00.00.00.00.00.00.A0.3E.00.00.01.00

Mapping Ethernet and ATM Addresses

Each device connected to an Ethernet port has one or more MAC addresses.

Each ATM device has a number of LAN Emulation clients, and each LAN Emulation Client (LEC) has an ATM address. An example of this is shown in Figure 1.7.

12 Avaya M770 M-ACCF/SF ATM Access Modules User’s Guide

Chapter 1 Overview

Figure 1.7 LAN Emulation Clients and Ethernet Hosts

Hosts with MAC Addresses

Avaya M770 Multifunction Switch

ATM Port with 16 LAN Emulation Clients (LECs) each with an ATM Address

ATM Access Module

These clients represent (act as a proxy for) devices connected to the Ethernet ports.

Whenever an Ethernet device wants to communicate with another device over the ATM network, the LEC must first discover the ATM address of the LEC that is acting as a proxy for the destination MAC address. The LEC must do this for each unicast Ethernet frame sent. The process is known as Address Resolution.

Address Resolution

The process by which a LEC associates a LAN destination address with the ATM address of another LEC (or the BUS) is known as Address Resolution.

Each LEC keeps a LAN Emulation ARP Table (which should not to be confused with the IP ARP Table). The ARP Table lists the remote destination MAC addresses and the ATM address of the LEC through which each destination MAC address can be reached.

Prior to sending a frame with a known destination, the LEC checks the ARP Table to see if the destination MAC address of the frame is listed in the ARP Table. The action the LEC then takes depends on whether the MAC address is listed in the ARP Table:

• If the destination MAC address is listed in the ARP Table:

— and there is an ATM connection to that LEC, the frame is sent directly to

that LEC.

— and an ATM connection has not already been set up, the LEC sets up an

ATM connection.

• If the destination MAC address is not listed in the ARP Table:

the LEC sends the frame to the BUS. The BUS then sends the frame to all LECs on the Emulated LAN.

Sending a frame to every LEC is an inefficient use of resources, so the LEC also tries to locate the MAC address for future use.

To discover the correct address, the LEC uses a process called LAN Emulation Address Resolution Protocol (LE_ARP).

Avaya M770 M-ACCF/SF ATM Access Modules User’s Guide 13

Chapter 1 Overview

LAN Emulation Address Resolution Protocol (LE_ARP)

An LE_ARP request is sent to the LES to locate the destination MAC address. The LES in turn sends the LE_ARP request to all of the LECs in the Emulated LAN.

LECs represent (act as a proxy for) MAC address devices connected to the Ethernet ports. When a LEC receives an LE_ARP request it checks whether the MAC address is on its Switch. It does this by checking the entries in the Switch database.

If the MAC address belongs to one of the devices connected to an Ethernet port, the LEC sends an LE_ARP response to the LEC that sent the original LE_ARP request.

The LEC that sent the LE_ARP request adds this information to its ARP Table. The LEC then sets up a direct connection through the ATM network to the appropriate LEC, so that subsequent frames are forwarded more efficiently.

What Happens to Unicast Frames?

The path a unicast frame takes through the ATM network depends on whether the location of the destination address is known to the sending LEC.

• If the location of the destination address is known, the LEC sets up a direct connection to the LEC serving the destination address.

• If the location of the destination address is unknown, a unicast frame is sent to the Broadcast and Unknown Server (BUS); where it is treated in the same way as a broadcast or multicast frame.

In addition the sending LEC attempts to locate the LEC serving the destination address. It does this using the LE_ARP process, described in “LAN Emulation Address Resolution Protocol (LE_ARP)”.

What Happens to Broadcast and Multicast Frames?

Each Emulated LAN (ELAN) acts as a broadcast domain. When a broadcast or multicast frame is passed to the LEC for transmission, the frame is sent to the Broadcast and Unknown Server (BUS).

When the LEC receives a broadcast, multicast, or unicast frame it checks to see if it originally sent the frame, and then does the following:

• If the LEC sent the frame, it discards the frame.

• If the LEC did not send the frame, the LEC passes the frame to the Ethernet device so that it can be forwarded to the appropriate port(s)

Note: Unlike broadcast and multicast frames, the number of unicast frames that can be sent to the BUS every second is limited so as not to overload the BUS and LECs with too much traffic.

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