Introduction

Since the first Cisco Press book on the fundamentals of 802.11 networks, much has changed. Wireless local-area networks (WLAN) have grown dramatically in size and scope, creating changes for traditional wireless deployment architectures. Many of the challenges with prior generations of wireless networking designs have been greatly reduced with development of the Cisco Wireless Unified Network (CUWN) architecture. The Cisco Unified approach has allowed wireless networks to efficiently scale to meet new requirements and business needs. WLAN controllers rapidly became the dominant wireless architecture and have been standardized through the IETF Control and Provisioning of Wireless Access Points (CAPWAP) protocol. CAPWAP defines an industry-standard protocol for how controllers manage wireless access points. The other foundational change to wireless has been the increased performance supported by the 802.11n amendment to the IEEE 802.11 wireless LAN standard. While the controller removed the management and scaling constraints, 802.11n is removing many of the performance constraints with wireless networking. The results have been a shift from wireless networks being a convenience to becoming mission-critical for most organizations.

This book focuses on introducing the concepts and reasoning behind controller-based wireless and higher-performance wireless networks. The elements of wireless LAN controller (WLC)–based WLANs are introduced, and the goal is to provide an update on many of the fundamentals that have been introduced since the publication of the Cisco Press 802.11 fundamentals book. This book is targeted toward IT engineers who are new to wireless controllers, 802.11n, Wireless Control System (WCS), wireless multicast, and mission-critical wireless networks. This book should be viewed as an introduction to wireless controllers and the knowledge needed to support life cycle design and support of controller-based architectures. Organizations new to wireless controllers and those migrating from legacy wireless networks to controller-based and 802.11n wireless networks will find this book to be a valuable guide.

This book also has a wealth of knowledge gleaned from the authors’ experiences in terms of guidelines, deployments, and configuration of wireless LAN architectures.

Goals and Methods

The goal of this book is to introduce you to the concepts and principles of mission-critical, high-performance, controller-based wireless LAN deployments. To accomplish this, the book includes the following elements:

• Drivers for the migration to controller architecture: The book covers the evolution, challenges, and reasoning about why WLAN controllers have become essential in modern WLAN deployments.

• Elements of the controller-based wireless architecture: The book introduces each of the elements in the end-to-end controller-based wireless architecture.

• Wireless controller WLAN design and implementation: The book includes details on how to design and implement WLANs with wireless controllers.

• Wireless security with a wireless LAN controller: This book covers the key principles of security WLANs with a wireless LAN controller.

• Wireless multicast design and implementation: This book covers the key principles of both wired and wireless multicast implementations within the wireless LAN controller.

Who Should Read This Book

This book is planned and written for network engineers who design, configure, implement, and maintain wireless networks, with an emphasis on WLAN controller basics, 802.11n principles, wireless architecture designs, and wireless network management. This book also focuses on the “newbie” to wireless networking in the hopes of clarifying the alphabet soup commonly known as IEEE 802.11 and introducing the key principles to designing and managing a wireless architecture.

How This Book Is Organized

Although this book can be read from cover to cover, it is designed to be flexible and allow you to easily move between chapters and sections of chapters to learn just the information that you need.

The book covers the following topics:

• Chapter 1, “The Need for Controller-Based Wireless Networks”: This chapter describes the evolution of WLANs and the principles that drove the development of the wireless LAN controller.

• Chapter 2, “Wireless LAN Protocols”: This chapter explains radio wave fundamentals so that you have the basis for understanding the complexities of deploying wireless LANs.

• Chapter 3, “802.11n”: This chapter describes the key features provided by 802.11n. 802.11n increases the performance and reliability of WLAN through protocol improvements and the support for multiple input, multiple output (MIMO) radio systems. The concepts on how MIMO improves performance are presented.

• Chapter 4, “Cisco Unified Wireless LAN Security Fundamentals”: This chapter explains the key elements of wireless security in the unified wireless networks.

• Chapter 5, “Design Considerations”: This chapter provides a background and consideration for designing unified wireless networks.

• Chapter 6, “Cisco Unified Wireless LAN Architectures”: This chapter explains the details of the unified wireless LAN architecture.

• Chapter 7, “Troubleshooting”: This chapter focuses on how to troubleshoot client issues using the unified wireless networks.

• Chapter 8, “Introduction to WCS”: This chapter provides an overview of the key features and principles and configuration steps that you should complete when deploying a wireless LAN management solution. This chapter also navigates you through the key menus within the WCS management platform, highlighting the key elements in planning, designing, and configuring the Cisco Unified Wireless Network architecture.

• Chapter 9, “Next-Generation Advanced Topics: Multicast”: This chapter focuses on both the wired and wireless design and implementation phases of multicast. This chapter takes a deep approach to multicast, with a detailed emphasis of controller-based multicast design best practices and principles.