Avaya OSI User Manual

BayRS Version 14.20

Part No. 308637-14.20 Rev 00 September 2000

600 Technology Park Drive Billerica, MA 01821-4130

Configuring OSI Services

The information in this document is subject to change without notice. The statements, configurations, technical data, and recommendations in this document are believed to be accurate and reliable, but are presented without express or implied warranty. Users must take full responsibility for their applications of any products specified in this document. The information in this document is proprietary to Nortel Networks NA Inc.

The software described in this document is furnished under a license agreement and may only be used in accordance with the terms of that license. The software license agreement is included in this document.

Trademarks

NORTEL NETWORKS and BayRS are trademarks of Nortel Networks.

All other trademarks and registered trademarks are the property of their respective owners.

Restricted Rights Legend

Use, duplication, or disclosure by the United States Government is subject to restrictions as set forth in subparagraph (c)(1)(ii) of the Rights in Technical Data and Computer Software clause at DFARS 252.227-7013.

Notwithstanding any other license agreement that may pertain to, or accompany the delivery of, this computer software, the rights of the United States Government regarding its use, reproduction, and disclosure are as set forth in the Commercial Computer Software-Restricted Rights clause at FAR 52.227-19.

Statement of Conditions

In the interest of improving internal design, operational function, and/or reliability, Nortel Networks NA Inc. reserves the right to make changes to the products described in this document without notice.

Nortel Networks NA Inc. does not assume any liability that may occur due to the use or application of the product(s) or circuit layout(s) described herein.

Portions of the code in this software product may be Copyright © 1988, Regents of the University of California. All rights reserved. Redistribution and use in source and binary forms of such portions are permitted, provided that the above copyright notice and this paragraph are duplicated in all such forms and that any documentation, advertising materials, and other materials related to such distribution and use acknowledge that such portions of the software were developed by the University of California, Berkeley. The name of the University may not be used to endorse or promote products derived from such portions of the software without specific prior written permission.

SUCH PORTIONS OF THE SOFTWARE ARE PROVIDED “AS IS” AND WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.

In addition, the program and information contained herein are licensed only pursuant to a license agreement that contains restrictions on use and disclosure (that may incorporate by reference certain limitations and notices imposed by third parties).

Nortel Networks NA Inc. Software License Agreement

NOTICE: Please carefully read this license agreement before copying or using the accompanying software or installing the hardware unit with pre-enabled software (each of which is referred to as “Software” in this Agreement). BY COPYING OR USING THE SOFTWARE, YOU ACCEPT ALL OF THE TERMS AND CONDITIONS OF THIS LICENSE AGREEMENT. THE TERMS EXPRESSED IN THIS AGREEMENT ARE THE ONLY TERMS UNDER WHICH NORTEL NETWORKS WILL PERMIT YOU TO USE THE SOFTWARE. If you do not accept these terms and conditions, return the product, unused and in the original shipping container, within 30 days of purchase to obtain a credit for the full purchase price.

308637-14.20 Rev 00

1. License grant. Nortel Networks NA Inc. (“Nortel Networks”) grants the end user of the Software (“Licensee”) a personal, nonexclusive, nontransferable license: a) to use the Software either on a single computer or, if applicable, on a single authorized device identified by host ID, for which it was originally acquired; b) to copy the Software solely for backup purposes in support of authorized use of the Software; and c) to use and copy the associated user manual solely in support of authorized use of the Software by Licensee. This license applies to the Software only and does not extend to Nortel Networks Agent software or other Nortel Networks software products. Nortel Networks Agent software or other Nortel Networks software products are licensed for use under the terms of the applicable Nortel Networks NA Inc. Software License Agreement that accompanies such software and upon payment by the end user of the applicable license fees for such software.

2. Restrictions on use; reservation of rights. The Software and user manuals are protected under copyright laws. Nortel Networks and/or its licensors retain all title and ownership in both the Software and user manuals, including any revisions made by Nortel Networks or its licensors. The copyright notice must be reproduced and included with any copy of any portion of the Software or user manuals. Licensee may not modify, translate, decompile, disassemble, use for any competitive analysis, reverse engineer, distribute, or create derivative works from the Software or user manuals or any copy, in whole or in part. Except as expressly provided in this Agreement, Licensee may not copy or transfer the Software or user manuals, in whole or in part. The Software and user manuals embody Nortel Networks’ and its licensors’ confidential and proprietary intellectual property. Licensee shall not sublicense, assign, or otherwise disclose to any third party the Software, or any information about the operation, design, performance, or implementation of the Software and user manuals that is confidential to Nortel Networks and its licensors; however, Licensee may grant permission to its consultants, subcontractors, and agents to use the Software at Licensee’s facility, provided they have agreed to use the Software only in accordance with the terms of this license.

3. Limited warranty. Nortel Networks warrants each item of Software, as delivered by Nortel Networks and properly installed and operated on Nortel Networks hardware or other equipment it is originally licensed for, to function substantially as described in its accompanying user manual during its warranty period, which begins on the date Software is first shipped to Licensee. If any item of Software fails to so function during its warranty period, as the sole remedy Nortel Networks will at its discretion provide a suitable fix, patch, or workaround for the problem that may be included in a future Software release. Nortel Networks further warrants to Licensee that the media on which the Software is provided will be free from defects in materials and workmanship under normal use for a period of 90 days from the date Software is first shipped to Licensee. Nortel Networks will replace defective media at no charge if it is returned to Nortel Networks during the warranty period along with proof of the date of shipment. This warranty does not apply if the media has been damaged as a result of accident, misuse, or abuse. The Licensee assumes all responsibility for selection of the Software to achieve Licensee’s intended results and for the installation, use, and results obtained from the Software. Nortel Networks does not warrant a) that the functions contained in the software will meet the Licensee’s requirements, b) that the Software will operate in the hardware or software combinations that the Licensee may select, c) that the operation of the Software will be uninterrupted or error free, or d) that all defects in the operation of the Software will be corrected. Nortel Networks is not obligated to remedy any Software defect that cannot be reproduced with the latest Software release. These warranties do not apply to the Software if it has been (i) altered, except by Nortel Networks or in accordance with its instructions; (ii) used in conjunction with another vendor’s product, resulting in the defect; or (iii) damaged by improper environment, abuse, misuse, accident, or negligence. THE FOREGOING WARRANTIES AND LIMITATIONS ARE EXCLUSIVE REMEDIES AND ARE IN LIEU OF ALL OTHER WARRANTIES EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION ANY WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Licensee is responsible for the security of its own data and information and for maintaining adequate procedures apart from the Software to reconstruct lost or altered files, data, or programs.

4. Limitation of liability. IN NO EVENT WILL NORTEL NETWORKS OR ITS LICENSORS BE LIABLE FOR ANY COST OF SUBSTITUTE PROCUREMENT; SPECIAL, INDIRECT, INCIDENTAL, OR CONSEQUENTIAL DAMAGES; OR ANY DAMAGES RESULTING FROM INACCURATE OR LOST DATA OR LOSS OF USE OR PROFITS ARISING OUT OF OR IN CONNECTION WITH THE PERFORMANCE OF THE SOFTWARE, EVEN IF NORTEL NETWORKS HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. IN NO EVENT SHALL THE LIABILITY OF NORTEL NETWORKS RELATING TO THE SOFTWARE OR THIS AGREEMENT EXCEED THE PRICE PAID TO NORTEL NETWORKS FOR THE SOFTWARE LICENSE.

308637-14.20 Rev 00

iii

5. Government licensees. This provision applies to all Software and documentation acquired directly or indirectly by or on behalf of the United States Government. The Software and documentation are commercial products, licensed on the open market at market prices, and were developed entirely at private expense and without the use of any U.S. Government funds. The license to the U.S. Government is granted only with restricted rights, and use, duplication, or disclosure by the U.S. Government is subject to the restrictions set forth in subparagraph (c)(1) of the Commercial Computer Software––Restricted Rights clause of FAR 52.227-19 and the limitations set out in this license for civilian agencies, and subparagraph (c)(1)(ii) of the Rights in Technical Data and Computer Software clause of DFARS

252.227-7013, for agencies of the Department of Defense or their successors, whichever is applicable.

6. Use of software in the European Community. This provision applies to all Software acquired for use within the European Community. If Licensee uses the Software within a country in the European Community, the Software Directive enacted by the Council of European Communities Directive dated 14 May, 1991, will apply to the examination of the Software to facilitate interoperability. Licensee agrees to notify Nortel Networks of any such intended examination of the Software and may procure support and assistance from Nortel Networks.

7. Term and termination. This license is effective until terminated; however, all of the restrictions with respect to Nortel Networks’ copyright in the Software and user manuals will cease being effective at the date of expiration of the Nortel Networks copyright; those restrictions relating to use and disclosure of Nortel Networks’ confidential information shall continue in effect. Licensee may terminate this license at any time. The license will automatically terminate if Licensee fails to comply with any of the terms and conditions of the license. Upon termination for any reason, Licensee will immediately destroy or return to Nortel Networks the Software, user manuals, and all copies. Nortel Networks is not liable to Licensee for damages in any form solely by reason of the termination of this license.

8. Export and re-export. Licensee agrees not to export, directly or indirectly, the Software or related technical data or information without first obtaining any required export licenses or other governmental approvals. Without limiting the foregoing, Licensee, on behalf of itself and its subsidiaries and affiliates, agrees that it will not, without first obtaining all export licenses and approvals required by the U.S. Government: (i) export, re-export, transfer, or divert any such Software or technical data, or any direct product thereof, to any country to which such exports or re-exports are restricted or embargoed under United States export control laws and regulations, or to any national or resident of such restricted or embargoed countries; or (ii) provide the Software or related technical data or information to any military end user or for any military end use, including the design, development, or production of any chemical, nuclear, or biological weapons.

9. General. If any provision of this Agreement is held to be invalid or unenforceable by a court of competent jurisdiction, the remainder of the provisions of this Agreement shall remain in full force and effect. This Agreement will be governed by the laws of the state of California.

Should you have any questions concerning this Agreement, contact Nortel Networks, 4401 Great America Parkway, P.O. Box 58185, Santa Clara, California 95054-8185.

LICENSEE ACKNOWLEDGES THAT LICENSEE HAS READ THIS AGREEMENT, UNDERSTANDS IT, AND AGREES TO BE BOUND BY ITS TERMS AND CONDITIONS. LICENSEE FURTHER AGREES THAT THIS AGREEMENT IS THE ENTIRE AND EXCLUSIVE AGREEMENT BETWEEN NORTEL NETWORKS AND LICENSEE, WHICH SUPERSEDES ALL PRIOR ORAL AND WRITTEN AGREEMENTS AND COMMUNICATIONS BETWEEN THE PARTIES PERTAINING TO THE SUBJECT MATTER OF THIS AGREEMENT. NO DIFFERENT OR ADDITIONAL TERMS WILL BE ENFORCEABLE AGAINST NORTEL NETWORKS UNLESS NORTEL NETWORKS GIVES ITS EXPRESS WRITTEN CONSENT, INCLUDING AN EXPRESS WAIVER OF THE TERMS OF THIS AGREEMENT.

308637-14.20 Rev 00

Preface

Before You Begin ............................................................................................................. xiii

Text Conventions .............................................................................................................xiv

Acronyms ......................................................................................................................... xv

Hard-Copy Technical Manuals ........................................................................................xvii

How to Get Help .............................................................................................................xvii

Chapter 1 OSI Overview

OSI Basic Reference Model ...........................................................................................1-2

OSI Network Organization .............................................................................................. 1-4

Level 1 and Level 2 Routing ..................................................................................... 1-5

Level 1 Routing .................................................................................................. 1-6

Level 2 Routing .................................................................................................. 1-7

OSI Network Addressing ..........................................................................................1-7

NSAP Structure .................................................................................................1-8

Allocating NSAP Addresses ............................................................................1-14

OSI Basic Routing Algorithm ........................................................................................1-18

Update Process ......................................................................................................1-19

Decision Process ...................................................................................................1-21

Forwarding Process ............................................................................................... 1-23

OSI Routing Protocols ..................................................................................................1-23

Connectionless Network Service Protocol .............................................................1-24

End System to Intermediate System Routing Exchange Protocol .........................1-25

Configuration Reporting ................................................................................... 1-25

Route Redirecting ............................................................................................1-25

308637-14.20 Rev 00

Intermediate System to Intermediate System Intra-Domain Routing Exchange

Protocol ..................................................................................................................1-27

Intra-Domain Routing ......................................................................................1-27

Inter-Domain Routing ......................................................................................1-29

OSI and TARP ..............................................................................................................1-30

How TARP Works ...................................................................................................1-30

TARP Packet Types ................................................................................................1-31

TARP Packet Fields ................................................................................................1-31

Originating TARP Requests ...................................................................................1-32

Finding an NSAP ............................................................................................. 1-32

Finding a TID ...................................................................................................1-33

Receiving TARP Requests .....................................................................................1-33

Loop Detection .......................................................................................................1-34

Loop Detection Buffer Size ..............................................................................1-34

Loop Detection Timer ......................................................................................1-34

Flush Timer ......................................................................................................1-34

Chapter 2 OSI Implementation Notes

Configuring Manual Area Addresses .............................................................................. 2-2

Correcting Area Partitions ..............................................................................................2-6

Configuring Static External Adjacencies ........................................................................2-9

Configuring OSI over DDN X.25 .....................................................................................2-9

Configuring DECnet IV to V Transition .........................................................................2-10

Configuring OSI over Frame Relay ...............................................................................2-10

Configuration Overview ..........................................................................................2-10

Frame Relay Circuit Modes ....................................................................................2-11

Direct Access ...................................................................................................2-11

Group Access ..................................................................................................2-12

Hybrid ..............................................................................................................2-12

Mixed Access ...................................................................................................2-13

Topology .................................................................................................................2-14

Full Mesh Topology ..........................................................................................2-14

Partial Mesh Topology ..................................................................................... 2-15

308637-14.20 Rev 00

Route Redirecting ..................................................................................................2-15

Designated Router Selection .................................................................................2-16

IS Neighbor Detection ............................................................................................2-16

Circuits per Slot ......................................................................................................2-16

Configuring OSI over ATM ............................................................................................2-16

Configuring OSI over GRE Tunnels ..............................................................................2-18

Advantages ............................................................................................................ 2-19

Chapter 3 Enabling OSI and TARP Services

Chapter 4 Editing OSI and TARP Parameters

Accessing OSI Parameters .............................................................................................4-2

Editing OSI Global Parameters .......................................................................................4-4

Editing OSI Interface Parameters ...................................................................................4-5

Configuring Manual Area Addresses .............................................................................. 4-6

Deleting a Manual Area Address .............................................................................4-7

Configuring Static End System Adjacencies ..................................................................4-8

Adding a Static End System Adjacency ................................................................... 4-8

Copying a Static End System Adjacency .................................................................4-9

Editing a Static End System Adjacency .................................................................4-10

Deleting a Static End System Adjacency ...............................................................4-11

Configuring Static External Address Adjacencies ........................................................4-11

Adding Static External Address Adjacencies .........................................................4-12

Copying Static External Address Adjacencies .......................................................4-12

Editing Static External Address Adjacencies .........................................................4-13

Deleting Static External Address Adjacencies .......................................................4-14

Configuring Static Routes .............................................................................................4-14

Adding Static Routes ..............................................................................................4-15

Copying Static Routes ............................................................................................4-15

Editing Static Routes .............................................................................................. 4-16

Deleting Static Routes ............................................................................................4-17

Configuring TARP .........................................................................................................4-17

Editing TARP Global Parameters ..................................................................................4-18

Editing TARP Circuit Parameters ..................................................................................4-19

308637-14.20 Rev 00

vii

Configuring TARP Static Adjacencies ...........................................................................4-19

Adding TARP Static Adjacencies ...........................................................................4-19

Deleting TARP Static Adjacencies .........................................................................4-20

Configuring TARP to Ignore a Static Adjacency .....................................................4-21

Sending TARP Requests Using the Technician Interface .............................................4-23

Viewing TARP Data Caches Using the Technician Interface ........................................4-23

Deleting OSI from the Router .......................................................................................4-23

Appendix A IP-to-X.121 Address Mapping for DDN

IP-to-X.121 Address Mapping ....................................................................................... A-2

Overview ................................................................................................................. A-2

Background ............................................................................................................. A-3

Standard IP to X.121 Address Mapping ........................................................................ A-7

Class A .................................................................................................................... A-7

Class B .................................................................................................................... A-9

Class C .................................................................................................................. A-10

Appendix B Using the Technician Interface osi lsp Command

Appendix C Enabling the wfOsiFletchRelaxedEnable Attribute Using the Technician Interface

Appendix D Site Manager Parameters

OSI Global Parameters .................................................................................................. D-2

OSI Interface Parameters ............................................................................................ D-10

OSI Manual Area Address Parameter ......................................................................... D-17

OSI Static End System Adjacency Parameters ........................................................... D-18

OSI Static External Address Adjacency Parameters ................................................... D-19

OSI Static Route Parameters ...................................................................................... D-21

TARP Global Parameters ............................................................................................. D-23

TARP Circuit Parameters ............................................................................................. D-27

TARP Static Adjacency Parameters ............................................................................. D-28

TARP Ignore Adjacency Parameters ........................................................................... D-29

Index

viii

308637-14.20 Rev 00

Figures

Figure 1-1. OSI Network Organization ....................................................................... 1-5

Figure 1-2. L1 Routing Within an Area and L2 Routing Between Areas ....................1-6

Figure 1-3. Hierarchical Addressing Authority Structure ............................................ 1-8

Figure 1-4. Basic NSAP Address Structure ...............................................................1-9

Figure 1-5. GOSIP NSAP Address Format ..............................................................1-10

Figure 1-6. ANSI NSAP Address Format .................................................................1-12

Figure 1-7. NSAP Area Address ..............................................................................1-14

Figure 1-8. Campus Routing Domain .......................................................................1-15

Figure 1-9. Assigning NSAP Addresses ...................................................................1-17

Figure 1-10. Router 1 Floods Area A with LSPs About the New End System ...........1-20

Figure 1-11. Lowest-Cost Path (Router A to B to ES) ................................................1-22

Figure 1-12. Route Redirecting ..................................................................................1-26

Figure 1-13. Static Inter-Domain Routing ................................................................... 1-29

Figure 2-1. Original Area Addresses for Area XY ......................................................2-2

Figure 2-2. Manual Area Address 456 Assigned to All Routers in Area XY ...............2-3

Figure 2-3. Manual Area Address 456 Assigned to Specific End Systems ................2-4

Figure 2-4. Area XY Divided into Area X and Area Y .................................................2-5

Figure 2-5. Routers B and C in an Area Partition Due to Improper Network Design .2-6

Figure 2-6. OSI Area Partition Repair ........................................................................2-8

Figure 2-7. Frame Relay Direct Access Mode ..........................................................2-11

Figure 2-8. Frame Relay Group Access Mode .........................................................2-12

Figure 2-9. Frame Relay Mixed Access Modes (Direct and Group) .........................2-13

Figure 2-10. Full Mesh Topology ................................................................................ 2-14

Figure 2-11. Partial Mesh in Hub and Spoke Topology ..............................................2-15

Figure 2-12. Passing OSI Traffic over an IP-Only Network .........................................2-19

Figure 4-1. Configuration Manager Window ...............................................................4-2

Figure A-1. Class A Internet Address ........................................................................ A-4

Figure A-2. Class B Internet Address ........................................................................ A-5

Figure A-3. Class C Internet Address ........................................................................ A-6

308637-14.20 Rev 00

Tables

Table 1-1. OSI Reference Model and Common ISO Standards ...............................1-3

Table 1-2. NSAP Address Structure (Assigned by the ICD 0005 Subdomain) .......1-11

Table 1-3. NSAP Address Structure (Assigned by the DCC 840 Subdomain) .......1-13

Table 1-4. Link State Packet Types .........................................................................1-19

Table 1-5. TARP Packet Types ...............................................................................1-31

Table 1-6. TARP Packet Fields ..............................................................................1-31

Table 2-1. Frame Relay Modes Used for OSI IS-IS Operations ..............................2-11

Table D-1. Suggested OSI Circuit Cost Values ..................................................... D-12

308637-14.20 Rev 00

This guide describes Open Systems Interconnection (OSI) architecture and services and what you do to start and customize OSI services on a Nortel Networks

™

Before You Begin

Before using this guide, you must complete the following procedures. For a new router:

• Install the router (see the installation guide that came with your router).

Preface

router.

• Connect the router to the network and create a pilot configuration file

Make sure that you are running the latest version of Nortel Networks BayRS Site Manager software. For information about upgrading BayRS and Site Manager, see the upgrading guide for your version of BayRS.

308637-14.20 Rev 00

(see Quick-Starting Routers, Configuring BayStack Remote Access, or Connecting ASN Routers to a Network).

™

and

xiii

Configuring OSI Services

Text Conventions

This guide uses the following text conventions:

angle brackets (< >) Indicate that you choose the text to enter based on the

description inside the brackets. Do not type the brackets when entering the command.

Example: If the command syntax is:

ip_address

ping < ping 192.32.10.12

, you enter:

bold text

Indicates command names and options and text that you need to enter.

Example: Enter

Example: Use the

show ip {alerts | routes}.

command.

dinfo

brackets ([ ]) Indicate optional elements in syntax descriptions. Do

not type the brackets when entering the command.

Example: If the command syntax is:

show ip interfaces [-alerts] show ip interfaces

, you can enter either:

show ip interfaces -alerts

italic text Indicates new terms, book titles, and variables in

command syntax descriptions. Where a variable is two or more words, the words are connected by an underscore.

Example: If the command syntax is:

show at <

valid_route

is one variable and you substitute one value

for it.

xiv

308637-14.20 Rev 00

Preface

screen text Indicates system output, for example, prompts and

system messages.

Acronyms

Example:

Set Trap Monitor Filters

separator ( > ) Shows menu paths.

Example: Protocols > IP identifies the IP option on the Protocols menu.

This guide uses the following acronyms:

AAI administrative authority identifier

ACSE association control service element

AFI authority and format identifier

ANSI American National Standards Institute

ARP Address Resolution Protocol

ASN.1 abstract syntax notation

ATM asynchronous transfer mode

B-ISDN Broadband Integrated Services Digital Network

CLNP Connectionless Network Protocol

CLNS connectionless network service

CSNP Complete Sequence Number Packet

DCA Defense Communication Agency

DCC data country code

DCE data circuit-terminating equipment

DDN Defense Data Network

DFI domain format identifier

DLCI data link connection identifier

DSP domain specific part

DTE data terminal equipment

308637-14.20 Rev 00

Configuring OSI Services

ES ID end system identification

ES-IS end system to intermediate system

FDDI Fiber Distributed Data Interface

FTAM File Transfer and Access Management

GOSIP Government OSI Protocol

GRE Generic Routing Encapsulation

GSA General Services Administration

HDLC High-level Data Link Control

ICD International Code Designator

IDI initial domain identifier

IDP initial domain part

IEEE Institute of Electrical and Electronic Engineers

IP Internet Protocol

IS-IS intermediate system to intermediate system

ISO International Organization for Standardization

xvi

ITU-T International Telecommunication Union -

Telecommunication Standardization Sector (formerly CCITT)

L1 Level 1

L2 Level 2

LAN local area network

LDB loop detection buffer

LSP link state packet

MAC media access control

MIB management information base

NSAP network service access point

OSI Open Systems Interconnection

PDN Public Data Network

PDU protocol data unit

PPP Point-to-Point Protocol

308637-14.20 Rev 00

Preface

PSNP partial sequence number packet

PVC permanent virtual circuit

RFC Request for Comments

RIP Routing Information Protocol

SDH Synchronous Digital Hierarchy

SNAP Subnetwork Access Protocol

SNMP Simple Network Management Protocol

SNPA subnetwork point of attachment

SPF shortest path first

TARP TID Address Resolution Protocol

TCP Transmission Control Protocol

TID target identifier

VT virtual terminal

Hard-Copy Technical Manuals

You can print selected technical manuals and release notes free, directly from the Internet. Go to the support.baynetworks.com/library/tpubs/ URL. Find the product for which you need documentation. Then locate the specific category and model or version for your hardware or software product. Use Adobe Acrobat Reader to open the manuals and release notes, search for the sections you need, and print them on most standard printers. Go to Adobe Systems at www.adobe.com to download a free copy of Acrobat Reader.

You can purchase selected documentation sets, CDs, and technical publications through the Internet at the www1.fatbrain.com/documentation/nortel/ URL.

308637-14.20 Rev 00

xvii

Configuring OSI Services

How to Get Help

If you purchased a service contract for your Nortel Networks product from a distributor or authorized reseller, contact the technical support staff for that distributor or reseller for assistance.

If you purchased a Nortel Networks service program, contact one of the following Nortel Networks Technical Solutions Centers:

Technical Solutions Center Telephone

EMEA (33) (4) 92-966-968

North America (800) 2LANWAN or (800) 252-6926

Asia Pacific (61) (2) 9927-8800

China (800) 810-5000

An Express Routing Code (ERC) is available for many Nortel Networks products and services. When you use an ERC, your call is routed to a technical support person who specializes in supporting that product or service. To locate an ERC for your product or service, go to the www12.nortelnetworks.com/ URL and click ERC at the bottom of the page.

xviii

308637-14.20 Rev 00

Chapter 1

OSI Overview

This chapter provides a general overview of OSI networking and describes how OSI routing services for Nortel Networks routers work. It includes information about the following topics:

Topic Page

OSI Basic Reference Model

OSI Network Organization 1-4

OSI Basic Routing Algorithm 1-18

OSI Routing Protocols 1-23

OSI and TARP 1-30

1-2

308637-14.20 Rev 00

1-1

Configuring OSI Services

OSI Basic Reference Model

OSI is a nonproprietary distributed processing architecture. The International Organization for Standardization (ISO) developed OSI to provide communication standards. These standards allow computer systems from different vendors to communicate.

The OSI basic reference model combines a structured computer system architecture with a set of common communication protocols. It comprises seven layers. Each layer provides specific functions or services and follows the corresponding OSI communication protocols to perform those services.

OSI is an “open system” architecture. Peer-to-peer common layers between systems abolish the vendor-specific restrictions imposed by other architectures. The principles of the OSI layering scheme include the following:

• Similar services are on the same layer.

• Services provided by lower layers are transparent to the layers above it.

• The lower the layer, the more basic the services it provides.

• The higher layers build upon the services offered by the layers below them.

1-2

OSI services for BayRS Version 7.60 and later software are United States Government OSI Protocol (GOSIP) Version 2.0 compliant. In addition, Nortel Networks router software provides support for the first three layers of the ISO/ CCITT (now ITU-T) recommended set of standards for international open systems support and vendor interoperability. These layers are physical, data link, and network.

Tabl e 1-1

lists some of the most common ISO standards implemented by OSI.

308637-14.20 Rev 00

Table 1-1. OSI Reference Model and Common ISO Standards

8571 File Transfer and Access Management (FTAM)

Application Layer

Presentation Layer

Session Layer

Transport Layer

Network Layer

8649 OSI Association Control Service Element (ACSE) 9040 Virtual Terminal (VT) Protocol

8822 OSI connection-oriented and connectionless presentation services 8824 Abstract Syntax Notation One (ASN.1) 9576 OSI connectionless protocol to provide connectionless service

8326 Session service definitions 8327 Session layer protocols

8072 Transport service definition, both connection and connectionless 8073 Transport connection-oriented protocol definition 8602 Transport definition for connectionless-mode protocol

8473 Connectionless-mode network service 9542 End System to Intermediate System routing exchange protocol 10589 Intermediate System to Intermediate System routing exchange protocol

OSI Overview

Data Link Layer

Physical Layer

308637-14.20 Rev 00

8802 Local area network standards (mostly derived from IEEE standards) 8471 HDLC balanced, link address information 8886 Data link service definition for OSI

9314 Fiber Distributed Data Interface (FDDI) 9543 Synchronous transmission quality at DTE/DCE interface 9578 Communications connectors used in LANs

OSI0001A

1-3

Configuring OSI Services

OSI Network Organization

An OSI network is made up of end systems and intermediate systems (routers) that are organized hierarchically.

• End systems originate and receive data. They do not perform any routing services. Examples of end systems on a network include workstations, file servers, and printers.

• Intermediate systems originate and receive data, as well as forward (route) data. The Nortel Networks OSI router is an intermediate system.

Note:

This guide uses the terms intermediate system and router

interchangeably.

End systems and intermediate systems are divided administratively into separate routing areas. A collection of areas that are under the control of a single administration and operate common routing protocols is a routing domain.

1-4

308637-14.20 Rev 00

OSI Overview

A network manager defines the boundaries of routing domains. An entire group of routing domains that are under one administrative authority (for example, a company or a university) is an administrative domain (Figure 1-1).

Administrative Domain

Routing Domain

Area

End Systems

and

Routers

Figure 1-1. OSI Network Organization

Level 1 and Level 2 Routing

In an OSI network, the router runs Connectionless Network Service (CLNS) and transfers data in a connectionless (packet) format using the Connectionless Network Protocol (CLNP). The router routes data through the network, using:

• Level 1 (L1) routing for routing data within an area

• Level 2 (L2) routing for routing data between areas

308637-14.20 Rev 00

OSI0002A

1-5

Configuring OSI Services

You can configure a Nortel Networks router running OSI to function as an L1 router, an L2 router, or an L1/L2 router (Figure 1-2)

Area A

Routing Domain

Area B

Key

L1 Routing

L2 Routing

End System

L1 Router

L1/L2 Router

Figure 1-2. L1 Routing Within an Area and L2 Routing Between Areas

OSI0003A

1-6

Level 1 Routing

An L1 router exchanges data with systems located within its area and forwards packets destined for a different area or domain to the nearest L1/L2 router for processing.

308637-14.20 Rev 00

Level 2 Routing

Level 2 routing exchanges data with systems located in a different area. In addition, L2 routing forwards data externally between routing domains, as long as you statically define an external link.

To support routing between areas, every area must contain at least one router configured to support L2 routing services.

OSI Network Addressing

The OSI addressing scheme is based on the hierarchical structure of the OSI global network. A unique network service access point (NSAP) address identifies each system within an OSI network. The NSAP address specifies the point at which the end system or intermediate system performs OSI network-layer services.

The complete set of NSAP addresses contained within the OSI network is the

global network addressing domain. This domain is divided into subsets called network addressing domains (which can be further divided into various subdomains). A network addressing domain is a set of NSAP addresses regulated

by the same addressing authority. The addressing authority is the administration responsible for allocating unique NSAP addresses to OSI networks.

OSI Overview

Each addressing authority operates independently of other authorities at the same level. An addressing authority for a higher domain can authorize the addressing authorities for its subdomains to assign NSAP addresses (Figure 1-3). The subdomain specifies the format of the NSAP addresses allocated to the network.

Two of the addressing authorities that administer NSAP addresses for OSI networks in the United States are the United States General Services Administration (GSA), which allocates NSAPs that are intended primarily for government use, and the American National Standards Institute (ANSI).

308637-14.20 Rev 00

1-7

Configuring OSI Services

Global Network Addressing Domain

Domain Addressing Authority BDomain Addressing Authority A

Subdomain Addressing

Authority A.1

NSAP NSAP

Subdomain Addressing

Authority A.2

Subdomain Addressing

Authority B.1

NSAP NSAP

Figure 1-3. Hierarchical Addressing Authority Structure

NSAP Structure

The basic NSAP address structure reflects the hierarchical assignment of NSAPs throughout the global network addressing domain. NSAP addresses must be globally unique. They can be up to 20 bytes long and contain two basic parts: the initial domain part (IDP) and the domain specific part (DSP) (Figure 1-4).

Subdomain Addressing

Authority B.2

OSI0004A

1-8

308637-14.20 Rev 00

OSI Overview

IDP

IDIAFI

Key

IDP Initial Domain Part AFI Authority and Format Identifier IDI Initial Domain Identifier DSP Domain Specific Part

DSP

Figure 1-4. Basic NSAP Address Structure

The IDP consists of an authority and format identifier (AFI) and an initial domain identifier (IDI). The AFI is 1 octet in length and specifies the format of the IDI,

the network addressing authority responsible for allocating values to the IDI, and the abstract syntax of the DSP.

The IDI is variable in length. It specifies the addressing authority responsible for allocating values to the DSP and the subdomain from which they come. The authority identified by the IDI determines the structure and semantics of the DSP.

For example, if you register your OSI network with the GSA, it will probably assign your network to the ISO International Code Designator (ICD) 0005 subdomain. The DSP portion of the NSAP addresses allocated from this subdomain follows the GOSIP Version 2 structure illustrated in Figure 1-5

OSI0005A

308637-14.20 Rev 00

1-9

Configuring OSI Services

IDP DSP

DFIIDIAFI

Octets 1 2 1 3 2 2 2 6 1

AAI

Rsvd RDI Area ID S

Key

IDP Initial Domain Part DSP Domain Specific Part

AFI Authority and Format Identifier IDI Initial Domain Identifier DFI Domain Format Identifier AAI Administrative Authority Identifier

Rsvd Reserved RDI Routing Domain Identifier Area Area Identifier ID System Identifier S NSAP Selector

Figure 1-5. GOSIP NSAP Address Format

The AFI for these NSAP addresses is 47, which shows that the network belongs to an ICD subdomain. The IDI is 0005, specifying the ICD 0005 subdomain, which is reserved for use by the U.S. government. The domain format identifier (DFI) is 80, specifying that the DSP portion of NSAP is in GOSIP format. (Currently, the only DSP format defined by the ICD 0005 subdomain is that defined by GOSIP.)

The administrative authority identifier (AAI) portion of these NSAP addresses is a globally unique number assigned by the ICD 0005 subdomain. It identifies the network within the ICD 0005 subdomain, where the NSAP resides, and the authority responsible for organizing the network into routing domains and areas. Note that the authority specified by the AAI assigns values to the routing domain ID, area ID, system ID, and NSAP selector portions of the NSAP address.

Tabl e 1-2

describes the contents of each field for this type of NSAP address.

OSI0006A

1-10

308637-14.20 Rev 00

OSI Overview

Table 1-2. NSAP Address Structure (Assigned by the ICD 0005

Subdomain)

Field Value Meaning

AFI 47 Identifies the subdomain as ICD. Specifies the syntax of the

DSP as binary octets.

IDI 0005 Indicates that the subdomain is ICD 0005.

DFI 80 Specifies that the format of the DSP is GOSIP.

AAI variable Identifies the network within the ICD 0005 subdomain where

the NSAP resides, and the authority responsible for organizing the network into routing domains and areas.

RSVD 0000 Indicates that this field is reserved.

RDI variable Specifies the routing domain where the NSAP resides

(assigned by the authority identified in the AAI field).

Area variable Identifies the local area where the NSAP resides (assigned by

either the authority identified in the AAI field or the local administrative authority that the AAI authority has delegated to this routing domain).

ID variable Specifies the system where the NSAP resides (assigned by

the local area administrator that a higher authority has delegated to this area).

S 0 or 1 Selects the transport layer entity the system uses. This entity

is specified in the ID field.

Similarly, if you register your OSI network with ANSI, it is assigned to the ISO data country code (DCC) 840 subdomain. Currently, the structure of the DSP portion of NSAP addresses allocated by the DCC 840 subdomain is not standardized. However, the most recent proposal suggests a structure identical to that specified by GOSIP, with the administrative authority identifier field replaced by an organization identifier field (Figure 1-6)

308637-14.20 Rev 00

1-11

Configuring OSI Services

IDP

DFIIDIAFI ORG Rsvd RDI Area ID S

octets 1 2 1 3 2 2 2 6 1

Key

IDP Initial Domain Part DSP Domain Specific Part AFI Authority and Format Identifier IDI Initial Domain Identifier

DFI Domain Format Identifier

DSP

ORG Organization Identifier

Rsvd Reserved RDI Routing Domain Identifier Area Area Identifier ID System Identifier S NSAP Selector

Figure 1-6. ANSI NSAP Address Format

The AFI for these NSAP addresses is 39, which shows that the network is registered with ANSI and belongs to a DCC subdomain. The IDI is 840, specifying the DCC 840 subdomain, which is reserved for use by networks located in the United States. The DFI is not standardized and is assigned by the DCC 840 subdomain.

OSI0007A

1-12

The organization (ORG) identifier portion of the NSAP address is a globally unique number that is assigned by the DCC 840 subdomain. It identifies the network within the DCC 840 subdomain where the NSAP resides and the authority responsible for organizing the network into routing domains and areas. (The organization identifier serves the same purpose as the administrative authority portion of an NSAP address assigned by the ICD 0005 subdomain; refer

to Table 1-2.) Tabl e 1- 3 describes the contents of each field for this type of NSAP

address.

308637-14.20 Rev 00

+ 122 hidden pages

Avaya OSI User Manual

Configuring OSI Services

Contents

Figures

Tables

Before You Begin

Preface

Text Conventions

Acronyms

Hard-Copy Technical Manuals

How to Get Help

OSI Basic Reference Model

OSI Network Organization

Level 1 and Level 2 Routing

Level 1 Routing

Level 2 Routing

OSI Network Addressing

NSAP Structure