JUNOS Enterprise Switching

Preface

It wasn’t but a day or so after we finished JUNOS Enterprise Routing, the companion book to this one, that our editor started pressuring us to start writing again. Writing a book may seem easy on the surface; how hard could it have been to write some words on these pages? But in reality, writing a book is a time-consuming and collaborative effort that affects everyone close to you. Also, at the time of the request, the EX Series was a new product line, and although we had extensive experience in the switching space, we did not have many customer deployments of the EX Series switches.

We were really impressed when the first EX units arrived for us to put in the rack that we reserved for this book. As JUNOS “experts,” we expected a lot, and we were impressed at the ease of configuration and stability that the JUNOS software provided to the EX. Although the performance and configuration of the EX switches are slightly different from those of a JUNOS router, the EX platform fit our needs, and hopefully it will fit yours, too.

The world of Ethernet switching changed when Juniper Networks got involved. At the time of this writing, the EX Series switches are already making significant inroads into the enterprise marketplace.

In this book, we have extended the same approach and writing style we used in JUNOS Enterprise Routing so that you, the reader, can have a set of books that work together. We did not write these books with the idea that you’d read one before the other, so some content overlap may exist. Most people will want to work up the OSI stack and read this book before the routing book; still, for many reasons, the routing book came out first, and we kept this in mind as we organized this book.

This book does double duty. It is both a field guide and a certification study guide. Readers who are interested in attaining a Juniper Networks certification level are wise to note that we discuss and cover topics that are relevant to the official exams (hint, hint), and at the end of each chapter we provide a list of examination topics covered, as well as a series of review questions that allow you to test your comprehension. Since the EX does both switching and routing, you should be able to answer a majority of enterprise certification questions by reading and understanding the content of all of the chapters in both books.

We wrote this book to serve as a field guide for any time you work on your EX. We present a lot of tutorials and samples, with lots of actual command output. We like to think that the detailed theoretical coverage we provide goes well beyond any certification exam, to give you something that can’t be tested: the ability to get things to work the right way the first time. When plan A fails, this material provides the steps needed to monitor network operation and quickly identify and resolve the root cause of malfunctions. We believe this level of coverage extends the life of both this book and its predecessor, far beyond any short-term certification goals.

Some of our chapters tend to be on the longer side; we’re sorry about that. Or maybe we should say “You’re welcome” in keeping with the “more is better” philosophy. Just dog-ear the pages, write notes in the margins, and perhaps even update the topology illustrations with something more akin to your own fiefdom. We hope you’ll make this copy your own.

What Is JUNOS Enterprise Switching?

The idea of switched networks is definitely not a new concept. LANs and Ethernet networks have been around since the 1970s, and some of you reading this book may actually remember the days of vampire taps and Thicknet cabling! Like the Atari 2600, those stories are great to relate and are actually quite amazing in their own technology light, but thankfully, technology advances. Now a LAN is synonymous with Ethernet; people know that if they plug their laptop’s network port into the wall, they will wind up on an Ethernet network.

Switching had historically been a fairly simple process, which allowed bridges to outperform routers of the same era. After the MAC address table was built, a simple filtering and forwarding process was all that was needed. Intelligence and switches were never used in the same sentence. If forwarding intelligence was needed, it was slow, and it was often reserved for higher OSI layers.

However, as technology improved, intelligence was no longer a compromise for speed. That was the premise of Juniper Networks’ “speed without compromise” routers that brought Juniper into the networking space against the big giant, Cisco—a dangerous place littered with the remnants of all the other companies that had failed before. Some may argue about how successful Juniper has been, but nobody can argue that Juniper will remain a player for many years to come, as evidenced by the large deployed base of its products and the much-loved JUNOS software that is its foundation.

As technology evolved, so did Juniper, as did its historic focus on routing within service provider networks. Juniper set its sights squarely on the enterprise, a market that was still being dominated by Cisco, and it saw a place where it could leverage the experience and reliability of JUNOS. The first “Layer-2-aware” device that Juniper Networks released was the MX Series. Although it was well received, the MX platforms were targeted at service providers and were really seen as routers with dense Ethernet connectivity but that also happened to offer some Layer 2 services. The first true Ethernet LAN switch is the EX Series, the basis of this book.

Will Juniper displace Cisco in the enterprise switching market? Only time will tell. So far, the EX platforms have been well received in the industry (and don’t forget, they have JUNOS going for them). The purpose of this book is to provide details on the product’s capabilities, and to show examples of its deployment and operation in support of those features. This book is not designed to sell boxes, or to convince you to use one vendor over another. We believe that after reading the material you will be able to make an informed decision as to what products work best for your needs. In all probability, the Juniper EX was not even an option the last time you shopped for LAN switching gear. We think you will want to keep the EX in mind the next time.

So, come join us in the exciting new world of enterprise switching and JUNOS on the new EX Series of high-performance LAN switches. With all the excitement in the air it seems like 1998 and the release of Juniper’s first router, the M40, all over again.