Chapter 9: OSPF 355
Chapter 10: BGP 393
Chapter 11: MPLS and VPN Services 427
Appendix A: Chapter Assessment Questions and Answers 469
Appendix B: Lab Exercises and Solutions 525
Glossary 649
Index . . . 675
Contents at a Glance
Foreword . . . .xix
Introduction . . . .xxi
Chapter 1: Introduction To Networking 1 Pre-Assessment . . . .2
1 .1: Before the Internet . . . .4
ARPAnet: Genesis of the Internet . . . .4
ARPAnet Challenges and the origin of tCP/IP . . . .6
From War Room to Boardroom: the Internet Comes of Age . . . .8
1 .2: service Providers and Content Providers . . . .9
1 .3: Modern Internet service Providers . . . . 13
1 .4: overview of tCP/IP . . . . 15
Understanding the tCP/IP Layers . . . . 18
Forwarding Data . . . . 21
the osI Reference Model . . . . 27
Chapter Review . . . . 31
Post-Assessment . . . . 32
Chapter 2: The Alcatel-Lucent 7750 SR and 7450 ESS Components and the Command-Line Interface 37 Pre-Assessment . . . . 38
2 .1 the Alcatel-Lucent 7750 service Router Family . . . .40
the Alcatel-Lucent 7450 ethernet service switch Group . . . . 42
Control Plane versus Data Plane . . . .44
Physical Components of the Alcatel-Lucent 7750 sR and 7450 ess series . . . . 45
How Packets Are Processed by the IoM . . . . 47
Basic Bootup Components . . . . 48
system Initialization Process . . . . 50
the Boot options . . . . 51
2 .2 Command-Line Interface . . . . 54
Provisioning the Alcatel-Lucent sR/ess systems . . . . 58
Using Logs and Alarms . . . . 62
Contents
Practice Lab: Alcatel-Lucent 7750/7450 Hardware and the CLI . . . .66
Lab section 2 .1: First Contact . . . .66
Lab section 2 .2: What Is the Router Doing? Getting Help and Information . . . . 69
Lab section 2 .3: saving Configuration Changes . . . . 75
Chapter Review . . . . 78
Post-Assessment . . . . 79
Chapter 3: Data Link Overview 83 Pre-Assessment . . . .84
3 .1 osI Layer 2 overview . . . . 86
types of Data Link Layer Protocols . . . . 87
scope of the Data Link Layer . . . .88
3 .2 Layer 2 Protocols: PPP, AtM, and time Division Multiplexing . . . .90
PPP: the Point-to-Point Protocol . . . .90
Circuit-switching and AtM . . . . 93
time Division Multiplexing . . . . 97
Broadcast and shared Access Data Links . . . . 98
3 .3 ethernet overview . . . . 100
ethernet Addressing and operations . . . . 106
ethernet transmission—CsMA/CD . . . . 109
ethernet Physical standards . . . . 114
Practice Lab: Configuring IoMs, MDAs, and Ports . . . . 116
Lab section 3 .1: A Full Deck of Cards . . . . 117
Lab section 3 .2: An MDA for every need . . . . 120
Lab section 3 .3: All Ports Up . . .to L2 ethernet . . . . 123
Chapter Review . . . . 126
Post-Assessment . . . . 127
Chapter 4: Switched Networks, Spanning Tree, and VLANs 131 Pre-Assessment . . . . 132
4 .1 ethernet Devices: Hubs and switches . . . . 134
4 .2 ethernet switching operations . . . . 136
4 .3 ethernet Link Redundancy: LAG . . . . 139
LAG Configuration . . . . 140
4 .4 ethernet Path Redundancy: stP . . . . 143
Using stP to Prevent Loops . . . . 146
4 .5 Virtual LAns . . . . 154
Chapter Review . . . . 163
Post-Assessment . . . . 165
Chapter 5: IP Addressing 169 Pre-Assessment . . . . 170
5 .1 Interconnecting networks . . . . 172
the need for Layer 3 . . . . 172
How Layer 3 Functions . . . . 173
5 .2 the IP Header . . . . 177
IP Header Fields . . . . 178
5 .3 IP Addressing . . . . 180
Class-Based IP Addressing . . . . 184
Private IP Addressing . . . . 189
types of IP Addresses . . . . 189
5 .4 IP subnetting . . . . 192
Identifying an IP subnet . . . . 193
IP subnet Address Planning . . . . 197
IP subnets and VLsM examples . . . . 202
subnet Creation exercises . . . . 207
Answers to subnet Questions . . . . 209
5 .5 CIDR and Route Aggregation—the end of Classful IP Addressing . . . . 211
CIDR versus VLsM . . . . 215
Practice Lab: IP Addressing and Routing . . . . 218
Lab section 5 .1: IP Addressing with enterprise Customers . . . . 219
Lab section 5 .2: IP Addressing with P, Pe, and Ce Routers . . . . 221
Lab section 5 .3: Layer 3 Interfaces . . . . 224
Chapter Review . . . . 231
Post-Assessment . . . . 232
Chapter 6: IP Forwarding and Services 237 Pre-Assessment . . . . 238
6 .1 the IP Forwarding Process . . . . 240
6 .2 typical IP Configurations . . . . 243
nAt and PAt . . . . 246
DHCP . . . . 249
6 .3 Additional IP-Related services . . . . 252
ICMP . . . . 252
ARP . . . . 254
6 .4 IP Filtering . . . . 260
Practice Lab: ICMP and ARP . . . . 267
Lab section 6 .1: testing for ICMP and ARP . . . . 268
Chapter Review . . . . 273
Post-Assessment . . . . 274
Chapter 7: Transport Layer Services—TCP and UDP 279 Pre-Assessment . . . . 280
7 .1 Understanding the transport Layer . . . . 282
7 .2 transport Control Protocol (tCP) . . . . 284
the tCP Header . . . . 286
establishing a tCP Connection—the three-Way Handshake . . . . 289
tCP Reliable Data transfer . . . . 290
tCP Flow Control . . . . 293
tCP operation . . . . 295
Congestion Control in tCP . . . . 297
7 .3 User Datagram Protocol (UDP) . . . .300
Capabilities of UDP . . . . 301
the UDP Header . . . . 302
UDP similarities with tCP . . . . 303
7 .4 Port numbers and sockets . . . . 304
Chapter Review . . . . 306
Post-Assessment . . . . 308
Chapter 8: Introduction to IP Routing 313 Pre-Assessment . . . . 314
8 .1 IP Routing Concepts and Purposes . . . . 316
IGPs and eGPs . . . . 317
IP Forwarding Using the Routing table . . . . 318
Building a Routing table . . . . 322
IP Forwarding Details . . . . 325
selecting Routes from Multiple Routing Protocols . . . . 328
8 .2 static and Default Routes . . . . 331
8 .3 Dynamic Routing Protocols . . . . 334
Practice Lab: Introduction to IP Routing . . . . 340
Lab section 8 .1: static Routes . . . . 341
Lab section 8 .2: Default Routes and Router Logic . . . . 345
Chapter Review . . . . 350
Post-Assessment . . . . 351
Chapter 9: OSPF 355 Pre-Assessment . . . . 356
9 .1 Introduction to osPF . . . . 358
the shortest Path First Algorithm . . . . 359
Additional osPF Features . . . . 360
9 .2 Router IDs and their Function . . . . 361
osPF Point-to-Point Adjacencies . . . . 362
Forming an osPF Adjacency . . . . 364
osPF Commands . . . . 367
9 .3 Link state Updates and Flooding . . . . 375
osPF Metrics and sPF Calculation . . . . 379
Practice Lab: open shortest Path First (osPF) . . . . 381
Lab section 9 .1: single Area osPF . . . . 382
Chapter Review . . . . 387
Post-Assessment . . . . 388
Chapter 10: BGP 393 Pre-Assessment . . . . 394
10 .1 Interior and exterior Gateway Protocols . . . . 396
10 .2 Autonomous systems . . . . 398
10 .3 History and Features of BGP . . . .400
10 .4 BGP Metrics . . . . 403
10 .5 When to Use BGP . . . . 405
10 .6 Packet Details and operation . . . .406
BGP Update Processing . . . . 407
10 .7 BGP Case studies . . . .408
Use Case I . . . .408
Use Case II . . . . 410
Use Case III . . . . 411
Practice Lab: BGP Routing . . . . 412
Lab section 10 .1: external BGP Routing . . . . 413
Chapter Review . . . . 421
Post-Assessment . . . . 423
Chapter 11: MPLS and VPN Services 427 Pre-Assessment . . . . 428
11 .1 services overview . . . . 430
the Building Blocks of MPLs and VPn services . . . . 431
Understanding VPn services . . . . 433
Understanding MPLs . . . . 435
Understanding LDP . . . . 437
11 .2 MPLs in Detail . . . .440
11 .3 VPn services in Detail . . . . 443
VPWs . . . .444
VPLs . . . . 445
VPRn . . . . 447
Practice Lab: services . . . . 449
Lab section 11 .1: services Framework . . . . 450
Lab section 11 .2: VPLs example . . . . 457
Chapter Review . . . .464
Post-Assessment . . . . 465
Appendix A: Chapter Assessment Questions and Answers 469 Assessment Questions . . . . 470
Chapter 1 . . . . 470
Chapter 2 . . . . 473
Chapter 3 . . . . 476
Chapter 4 . . . . 479
Chapter 5 . . . . 483
Chapter 6 . . . . 487
Chapter 7 . . . . 490
Chapter 8 . . . . 493
Chapter 9 . . . . 497
Chapter 10 . . . .500
Chapter 11 . . . . 503
Answers to Assessment Questions . . . . 506
Chapter 1 . . . . 506
Chapter 2 . . . . 507
Chapter 4 . . . . 510
Chapter 5 . . . . 512
Chapter 6 . . . . 514
Chapter 7 . . . . 516
Chapter 8 . . . . 517
Chapter 9 . . . . 519
Chapter 10 . . . . 520
Chapter 11 . . . . 522
Appendix B: Lab Exercises and Solutions 525 Chapter 2: Alcatel-Lucent 7750/7450 Hardware and the Command Line Interface . . . . 526
Lab section 2 .1: First Contact . . . . 526
Lab section 2 .2: What Is the Router Doing? Getting Help and Information . . . . 529
Lab section 2 .3: saving Configuration Changes . . . . 534
Chapter 3: Configuring IoMs, MDAs, and Ports . . . . 538
Lab section 3 .1: A Full Deck of Cards . . . . 539
Lab section 3 .2: An MDA for every need . . . . 542
Lab section 3 .3: All Ports Up . . .to L2 ethernet . . . . 545
Chapter 5: IP Addressing and Routing . . . . 548
Lab section 5 .1: IP Addressing with enterprise Customers . . . . 548
Lab section 5 .2: IP Addressing with P, Pe, and Ce Routers . . . . 550
Lab section 5 .3: Layer 3 Interfaces . . . . 554
Chapter 6: ICMP and ARP . . . . 560
Lab section 6 .1: testing for ICMP and ARP . . . . 560
Chapter 8: Introduction to IP Routing . . . . 565
Lab section 8 .1: static Routes . . . . 566
Lab section 8 .2: Default Routes and Router Logic . . . . 569
Chapter 9: open shortest Path First (osPF) . . . . 574
Lab section 9 .1: single Area osPF . . . . 574
Chapter 10: BGP Routing . . . . 580
Lab section 10 .1: external BGP Routing . . . . 581
Lab section 10 .2: Internal BGP Routing . . . . 585
Chapter 11: services . . . . 590
Lab section 11 .1: services Framework . . . . 591
Lab section 11 .2: VPLs example . . . . 599
solutions . . . .606
Lab section 2 .1 exercises . . . .606
Lab section 2 .2 exercises . . . .606
Lab section 2 .3 exercises . . . .608
Lab section 3 .1 exercises . . . .609
Lab section 3 .2 exercises . . . . 610
Lab section 3 .3 exercises . . . . 611
Lab section 5 .1 exercises . . . . 613
Lab section 5 .2 exercises . . . . 613
Lab section 5 .3 exercises . . . . 615
Lab section 6 .1 exercises . . . . 618
Lab section 8 .1 exercises . . . . 620
Lab section 8 .2 exercises . . . . 623
Lab section 9 .1 exercises . . . . 625
Lab section 10 .1 exercises . . . . 628
Lab section 10 .2 exercises . . . . 629
Lab section 11 .1 exercises . . . . 638
Lab section 11 .2 exercises . . . . 639
Glossary 649 Index . . . . 675
Foreword
T
he Internet continues to change the way the world communicates. New appli-cations steadily emerge, facilitating meaningful links between information, content, and people. Video is increasingly a part of the web experience, and social networks have formed around all conceivable communities of interest. We have every reason to believe that highly collaborative multimedia applications will continue to flourish and that the Web 2.0 user experience will draw on innovative content distri-bution mechanisms.Service providers need to build, operate, and maintain their IP networks to meet the demands of these new applications, and do so in a profitable manner. Your invest-ment in this introductory certification from the SRC program will be critical to understanding how to balance the growth in transport costs associated with massive amounts of Internet traffic with the need to extract greater value from more sophisti-cated services.
Scaling routing performance while also scaling service sophistication requires meaningful changes to basic router and network design: an evolution from Internet routing to Service Routing. Five years after we introduced the world’s first Service Router, the Alcatel-Lucent 7750 SR, this new approach has been widely embraced.
From a standing start the 7750 SR family of routers has grown quickly to over 260 deployments around the world.
The need for Service Routing arises as providers attempt to implement more than basic Internet service on an IP/MPLS network. Any application that requires more than best-effort handling including VPNs, voice, and video requires a host of impor-tant new features to operate effectively. In addition to scaling in multiple dimensions, operational and resiliency considerations are central to making IP/MPLS platforms the common bearer of multi-service traffic.
In summary, a new era in building networks is upon us. With this certification you will be well positioned to help your employer or customer in this all-important transi-tion, maximizing their opportunity and the value of their capital investments.
Basil Alwan
President, IP Division Alcatel-Lucent
Introduction
T
his book is based on the Alcatel-Lucent’s Scalable IP Networks course. It is designed to teach you the same material that is in the course and prepare you for the Alcatel-Lucent Network Routing Specialist I Certification exam (4A0-100). Like the course, this book teaches IP professionals the fundamentals of IP Service Routing, and so it is designed for network professionals with a limited knowledge of IP and Eth-ernet networking technologies.While the primary focus of the book is to prepare you for the Alcatel-Lucent NRS I exam, bear in mind that the technologies discussed are also relevant to everyday networking activities and so the book can be useful as a reference even for those not intending to take the exam. However, the primary goal of this work is to prepare the reader to take the 4A0-100 exam, and thus not all topics are covered at the same level of detail that they might be for a general-purpose work on networking. Every effort has been made to cover the topics at a sufficient level of detail to prepare someone to take and pass the exam without giving too much information to overwhelm a network newcomer. The level of information for each topic has been carefully chosen to match the level of the exam.
Like the Alcatel-Lucent Scalable IP Networks course, the book has many objec-tives. Upon completing study of the topics contained in this work, the reader should be able to perform the following tasks:
Describe the use of the Lucent 7750 Service Router (SR) and the
Alcatel-•
Lucent 7450 Ethernet Service Switch (ESS) in the Internet.
Execute basic commands with the Alcatel-Lucent SR command-line interface (CLI).
•
Describe the purpose and operations of common Layer 2 technologies.
•
Describe the IP forwarding process.
•
Analyze an IP address with subnet mask and calculate subnet boundaries.
•
Develop an IP address plan using IP subnetting and address summarization.
•
Explain the differences between static routes and dynamic routing protocols.
•
Configure static routes and dynamic routing in a single area OSPF network.
•
Explain the purpose and basic features of BGP.
•
Explain the purpose of MPLS and how it can be used to create tunnels across an
•
IP network.
Describe the MPLS-based VPN services supported on the Alcatel-Lucent 7750 SR:
•
VPWS, VPLS, and VPRN.
Your success at understanding these objectives will determine your success on the exam. Each of these topics is covered in sufficient detail in this book to enable you to succeed when you take the Alcatel-Lucent NRS I exam if you apply yourself diligently to studying the materials. Some of the materials covered, such as IP subnetting, may be challenging and daunting to a network newcomer. However, we have strived to clearly explain the more difficult information and to provide guidance and examples that will help you understand the explanations. The Lab Exercises attached to the chapters will give you the opportunity to practice your new knowledge.
How This Book Is Organized
This book follows the outline of the Alcatel-Lucent Scalable IP Networks course. In the first chapter, we will give an introduction to the Internet and its history and a brief overview of the TCP/IP protocol suite. Chapter 2 examines the Alcatel-Lucent 7750 Services Router and the Alcatel-Lucent 7450 Ethernet Services Switch and provides an overview of the command-line interface used on both systems. Chapter 3 covers data link technologies, paying particular emphasis to the Ethernet protocol. Chapter 4 continues the discussion of Ethernet by looking at Ethernet switching and virtual LAN technology.
Chapter 5 looks at the IP protocol, including its addressing structure, and covers the concept of subnetting, complete with some sample exercises for creating subnets.
Chapter 6 looks at the IP packet forwarding process and also some value-added ser-vices such as IP packet filtering. Chapter 7 concentrates on examining the upper transport layers of the IP stack and discusses both Transmission Control Protocol (TCP) and User Datagram Protocol (UDP). Chapter 8 begins a discussion of IP rout-ing protocols and how they function in an IP network. Chapter 9 continues the dis-cussion of IP routing by examining the Open Shortest Path First (OSPF) protocol.
Chapter 10 concludes the discussion of IP routing with a discussion of the Border Gateway Protocol (BGP). We conclude in Chapter 11 with a discussion of Multi Pro-tocol Label Switching (MPLS) and Virtual Private Networks (VPNs).
Each chapter begins with a few pre-assessment questions to give you a flavor of the chapter content, and a post-assessment quiz to test your understanding of the mate-rial. You can find all the assessment questions and their answers in Appendix A. Most chapters include a Lab Exercises section to give you practical experience to reinforce what you are learning. The Lab Exercises from all chapters are collected in Appen-dix B, along with the exercise solutions.
In topics related to networking, it is not possible to avoid TLAs (Three-Letter Acro-nyms) or acronyms in general. The acronyms are so heavily used in the networking industry that some of the terms are more readily recognized by their acronyms, rather than through the expanded term. For easy reference, most of the commonly used terms and acronyms in the book are listed along with their definitions in the Glossary at the end of the book.
Conventions Used in the Book
Alcatel-Lucent provides a modular approach for configuring the Alcatel-Lucent 7750 SR and Alcatel-Lucent 7450 ESS products. In this approach, most of the IP addressing and IP protocol features are configured in a modular fashion. The modular approach makes IP network designs simple and elegant. This makes node configurations easier to understand and maintain.
CLI commands are entered at the command-line prompt. Entering a command makes navigation possible from one command context (or level) to another. When you initially enter a CLI session, you are in the root context. At the root context, the prompt indicates the active Central Processor Module (CPM) slot and the name of the node. (For more information on CPM, see Chapter 2.) Navigate to another level by entering the name of successively lower contexts. As you change through the levels, the prompt also changes to indicate the context you are in. Listing 1 shows an example CLI navigation and prompt change according to the context.
Listing 1: Navigation and prompt change A:AIRP_R01#
A:AIRP_R01# show A:AIRP_R01>show#
The root prompt of Listing 1 indicates that the active CPM slot of the node is A and the name of the node is configured as AIRP_R01. In the listing, upon entering the com-mand show, the prompt changes to indicate the show context. As you can see in this paragraph, when CLI codes are used inline along with the main text, they are indi-cated by the use of monofont text.
A standard set of icons are used throughout this book. A representation of these icons and their meanings are listed under the section, “Standard Icons.”
Audience
This book is targeted for network professionals who have some experience with IP and Ethernet networks and who need to prepare for the Alcatel-Lucent NRS I exam (4A0-100). While the topics covered are of general use and information for any networking professional, the level of detail and the particular aspects of the technologies covered match explicitly what is needed to prepare for the exam.
This book assumes that the reader has a basic knowledge of networking, the Inter-net or IP protocol, and experience with binary numbers. Familiarity with configur-ing the Alcatel-Lucent 7750 Service Router or Alcatel-Lucent 7450 Ethernet Service Switch platforms will be helpful, but it is not required. In order to perform the labs in the book, you will need access to Alcatel-Lucent 7750 SR platforms. However, even if you do not have this access, you can still glean valuable information by reading through the labs to see the types of configuration tasks that are relevant to the topics under discussion.
Visit www.alcatel-lucent.com/src for additional information on the Alcatel-Lucent SRC Program.
Feedback Is Welcome
It would be our pleasure to hear back from you. Please forward your comments and suggestions for improvements to the following email address:
sr.publications@alcatel-lucent.com
Welcome to your preparation guide for the Alcatel-Lucent NRS I exam, and good luck with your studies and your career.
Kent Hundley
Alcatel-Lucent NRS I No.1558
The Alcatel-Lucent Service Routing Certification Program Overview
First in its class, the Alcatel-Lucent Service Routing Certification (SRC) Program offers extensive training to arm students with the skills, confidence, and credibility necessary to work in complex network environments. Through its rich focus on solu-tions and services, the SRC program meets the critical requirements for the third wave of IP innovation to meet service provider expectations. The Alcatel-Lucent SRC pro-gram is specifically designed to equip networking engineers, as well as operations and strategic planning staff, with the skills necessary to meet new operational challenges and to align network changes with their companies’ business goals. Adding video and VoIP to the service mix creates an entirely new set of networking architectural chal-lenges. The SRC program is unique in its ability to prepare service provider support staff to address these challenges, both now and in the future.
The SRC program offers four certifications:
Alcatel-Lucent Network Routing Specialist I
•
Alcatel-Lucent Network Routing Specialist II
•
Alcatel-Lucent Triple Play Routing Professional
•
Alcatel-Lucent Service Routing Architect
•
Based on their experience, expertise, and goals, students can choose which certifi-cation to follow. Certificertifi-cations are awarded based on the successful completion of the relevant mandatory exams.
Courses from the SRC Program are delivered at Alcatel-Lucent sites globally. Visit
www.alcatel-lucent.com/src for the latest class schedules.
Alcatel-Lucent provides credit for some Cisco and Juniper IP certifications. Visit
www.alcatel-lucent.com/src/exemptions for a detailed overview of certification exemptions.
The Scalable IP Networks Self-Study Guide is published by the Alcatel-Lucent Service Routing Certification (SRC) Program (www.alcatel-lucent.com/src).
Alcatel-Lucent Scalable IP Networks Exam (4A0-100)
The Alcatel-Lucent Scalable IP Networks Exam is delivered by Prometric, a leading global provider of testing and assessment services. Prometric offers exam registration online, by telephone, or by walk-in (in selected locations). The exam is delivered in English in a secure and supervised environment at Prometric’s global test sites. Partici-pants have 75 minutes to answer 60 randomly generated questions. There are no exam prerequisites. Once Alcatel-Lucent has received the result for your exam (typically within 5 business days), an acknowledgment of your result will be sent to you.
Upon successful completion of the exam (4A0-100), participants will receive the Alcatel-Lucent Network Routing Specialist I Certification. The Alcatel-Lucent
Upon successful completion of the exam (4A0-100), participants will receive the Alcatel-Lucent Network Routing Specialist I Certification. The Alcatel-Lucent