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Internet Routing Architectures, Second Edition

Sam Halabi

Danny McPherson

Publisher: Cisco Press

Second Edition August 23, 2000

ISBN: 1-57870-233-X, 528 pages

Internet Routing Architectures, Second Edition expands on the highly successful first edition, with new updates on BGP4 and current perspectives on internetworking routing architectures. This book is intended for any organization needing to build an efficient, reliable, enterprise network accessing the Internet. Its purpose is to make you an expert on integrating your network into the global Internet. It is written to address real routing issues, using real scenarios, in a comprehensive and accessible manner. Internet Routing Architectures, Second Edition uses a practical, example-oriented approach to provide solutions for ISP connectivity issues.

Table of Contents

 

About the Technical Reviewers ..........................................

1

Acknowledgments ...................................................

2

Introduction .......................................................

3

Objectives ........................................................

3

Audience ........................................................

3

Organization ......................................................

3

Approach ........................................................

4

Features and Text Conventions ..........................................

5

Command Syntax Conventions ..........................................

5

Icons Used in This Book ..............................................

6

I: The Contemporary Internet ..........................................

8

1. Evolution of the Internet .............................................

9

Origins and Recent History of the Internet ..................................

10

Network Access Points ..............................................

14

Routing Arbiter Project ..............................................

18

The Very High-Speed Backbone Network Service ............................

22

Transitioning the Regional Networks from the NSFNET ........................

24

NSF Solicits NIS Managers ...........................................

25

Other Internet Registries .............................................

28

Internet Routing Registries ............................................

29

The Once and Future Internet ..........................................

30

Looking Ahead ...................................................

33

Frequently Asked Questions ...........................................

34

References ......................................................

35

2. ISP Services and Characteristics ......................................

36

ISP Services .....................................................

36

ISP Service Pricing, Service-Level Agreements, and Technical Characteristics .........

40

Looking Ahead ...................................................

50

Frequently Asked Questions ...........................................

51

3. IP Addressing and Allocation Techniques ................................

53

History of Internet Addressing .........................................

53

IP Address Space Depletion ...........................................

60

Looking Ahead ...................................................

79

Frequently Asked Questions ...........................................

79

References ......................................................

81

II: Routing Protocol Basics ............................................

83

4. Interdomain Routing Basics .........................................

84

Overview of Routers and Routing .......................................

84

Routing Protocol Concepts ............................................

87

Segregating the World into Autonomous Systems .............................

91

Looking Ahead ...................................................

98

Frequently Asked Questions ...........................................

98

References ......................................................

99

5. Border Gateway Protocol Version 4 ...................................

101

How BGP Works .................................................

102

BGP Capabilities Negotiation .........................................

117

Multiprotocol Extensions for BGP ......................................

118

TCP MD5 Signature Option ..........................................

119

Looking Ahead ..................................................

120

Frequently Asked Questions ..........................................

121

References .....................................................

122

III: Effective Internet Routing Designs ..................................

123

6. Tuning BGP Capabilities ..........................................

124

Building Peer Sessions .............................................

125

Sources of Routing Updates ..........................................

131

Overlapping Protocols: Backdoors ......................................

137

The Routing Process Simplified .......................................

139

Controlling BGP Routes ............................................

145

Route Filtering and Attribute Manipulation ................................

165

BGP-4 Aggregation ...............................................

174

Looking Ahead ..................................................

179

Frequently Asked Questions ..........................................

180

References .....................................................

183

7. Redundancy, Symmetry, and Load Balancing ............................

184

Redundancy ....................................................

185

Symmetry ......................................................

191

Load Balancing ..................................................

191

Specific Scenarios: Designing Redundancy, Symmetry, and Load Balancing ..........

192

Looking Ahead ..................................................

214

Frequently Asked Questions ..........................................

214

References .....................................................

215

8. Controlling Routing Inside the Autonomous System ........................

216

Interaction of Non-BGP Routers with BGP Routers ..........................

216

BGP Policies Conflicting with Internal Defaults .............................

218

Policy Routing ...................................................

225

Looking Ahead ..................................................

229

Frequently Asked Questions ..........................................

230

9. Controlling Large-Scale Autonomous Systems ...........................

232

Route Reflectors .................................................

232

Confederations ...................................................

242

Controlling IGP Expansion ..........................................

246

Looking Ahead ..................................................

252

Frequently Asked Questions ..........................................

252

References .....................................................

254

10. Designing Stable Internets .........................................

255

Route Instabilities on the Internet ......................................

255

BGP Stability Features .............................................

258

Looking Ahead ..................................................

263

Frequently Asked Questions ..........................................

263

IV: Internet Routing Device Configuration ................................

265

11. Configuring Basic BGP Functions and Attributes ........................

266

Building Peering Sessions ...........................................

267

Route Filtering and Attribute Manipulation ................................

271

Peer Groups ....................................................

280

Sources of Routing Updates ..........................................

282

Overlapping Protocols: Backdoors ......................................

289

BGP Attributes ..................................................

290

BGP-4 Aggregation ...............................................

302

Looking Ahead ..................................................

319

12. Configuring Effective Internet Routing Policies ..........................

320

Redundancy, Symmetry, and Load Balancing ..............................

321

Following Defaults Inside an AS .......................................

347

Policy Routing ...................................................

361

Route Reflectors .................................................

364

Confederations ...................................................

367

Controlling Route and Cache Invalidation .................................

372

BGP Outbound Request Filter Capability .................................

378

Route Dampening .................................................

379

Looking Ahead ..................................................

383

V: Appendixes ...................................................

384

A. BGP Command Reference .........................................

385

B. References for Further Study .......................................

390

Interesting Organizations ............................................

390

Research and Education .............................................

390

Miscellaneous ...................................................

390

Books ........................................................

391

Internet Request For Comments .......................................

391

C. BGP Outbound Route Filter (ORF) ...................................

394

When to Use BGP ORF .............................................

394

Configuration ...................................................

394

EXEC Commands ................................................

396

Closing Remarks .................................................

397

D. Multiprotocol BGP (MBGP) ........................................

398

The Motivation Behind the New Command-Line Interface ......................

398

Organizing Command Groups in the New Configuration .......................

399

Peer Groups ....................................................

403

Route Maps .....................................................

404

Redistribution ...................................................

405

Route Reflector ..................................................

407

Aggregation ....................................................

407

List of BGP Commands .............................................

408

Upgrading to the AF Style ...........................................

409

Internet Routing Architectures, Second Edition

About the Technical Reviewers

Alexei Roudnev is currently a Software System Engineer for Genesys Labs/Alcatel group in, San Francisco, California. He worked for 10 years as a Network Engineer at Relcom Network, one of the creators of the Russian Internet, in Moscow, Russia. Alexei was also a UNIX based systems Software Developer in Moscow for 9 years.

Abha Ahuja is currently a Senior Network Engineer at Internap Network Services. She works on network design, architecture and operational issues. Previous to Internap, she worked at Merit Network, a leading network research institution where she worked on the Route Server Next Generation project, a nationwide deployment of routing servers at exchange points, and the Internet Performance Measurement and Analysis (IPMA) project. She continues to play an active role in the Internet community and pursues research interests including inter-domain routing behavior and protocols, network operations and performance statistics, and network security. She is a skilled network engineer, certified troublemaker and a classic Scorpio.

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