Introduction

The motivation behind this book is the continued interest in the implementation of quality of service(QoS) in IP/MPLS networks. QoS arises as a key requirement for these networks, which have become the preferred technology platform for building converged networks that support multiple services. The topic can be one of the most complex aspects of the network design, implementation, and operation. Despite the importance of and interest in this topic, no other Cisco Press title provides a detailed discussion of this subject. A significant amount of the content of this book also applies to pure IP networks that do not have immediate plans to migrate to a full IP/MPLS network.

This material covers both QoS and Multiprotocol Label Switching Traffic Engineering (MPLS TE). In particular, it covers MPLS TE as a technology that complements traditional QoS technologies. MPLS TE can be an instrumental tool to improve the QoS guarantees that an IP/MPLS network offers. As such, it can contribute to improving both network performance and availability. However, this book provides a concise discussion of MPLS TE. Those readers interested in further information should consult the Cisco Press title Traffic Engineering with MPLS

The book takes the point of view of those individuals responsible for the IP/MPLS network. Other Cisco Press titles describe the details of the QoS implementation for those devices receiving the services that the network offers.

You should have a basic understanding of both IP and MPLS to obtain the most benefit from this book. That understanding should include basic IP addressing and routing, along with the basics of MPLS forwarding. However, the book provides a technology overview of QoS and MPLS TE to help those with less exposure to these technologies or to serve as a review/reference to those more familiar with those topics.

This book touches a broad topic and does not pretend to address all QoS aspects of interest. You can expect future Cisco Press books to cover important areas, including the following:

• Implementation of QoS for specific services (for instance, IP, Ethernet, ATM)

• QoS management (including monitoring and provisioning)

• Interprovider QoS

Visit this book's website, http://www.ciscopress.com/title/1587052334, for further information.

Who Should Read This Book?

This book's primary audience is the technical staff of those organizations building IP/MPLS networks as an infrastructure to provide multiple services. The material includes technology, configuration, and operational details to help in the design, implementation, and operation of QoS in IP/MPLS networks. Service providers are a prime example of the organizations that this book targets. However, government agencies, educational institutions, and large enterprises pursuing IP/MPLS will find the material equally useful.

A secondary audience for this book is those individuals in charge of service definition or those individuals subscribing to network services. Both types can benefit from a better understanding of the differentiation capabilities that IP/MPLS networks can offer.

How This Book Is Organized

Although this book could be read cover to cover, it is designed to be flexible and allow you to easily move between chapters and sections of chapters to cover just the material that you need more work with. The content is roughly divided into three parts:

• Chapters 1 and 2 provide a technology overview.

• Chapters 3 and 4 discuss Cisco implemenation.

• Chapter 5 covers different backbone design options.

Here is a brief synopsis of each chapter:

Chapter 1, "QoS Technology Overview"This chapter provides a review of QoS technology for IP and IP/MPLS networks. The chapter initially discusses the IP QoS architectures and how they apply to MPLS. Multiple sections elaborate on MPLS support for Differentiated Services (DiffServ), including a detailed discussion on EXP-inferred-class link switched path (E-LSP), Label-inferred-class LSP (LLSP), and DiffServ tunneling models (pipe, short pipe, and uniform). This dicussion leads into a summary of traffic-management mechanisms with a detailed look at traffic policing, traffic shaping, traffic scheduling, active queue manangemt, and so on. The chapter also discusses QoS signaling with a focus on the Resource Reservation Protocol (RSVP).

Chapter 2, "MPLS TE Technology Overview"This chapter reviews the basic operation of this technology with its DiffServ extensions and applicability as a traffic-protection alternative. This review elaborates on the concepts of contraint-based routing, DiffServ-aware Traffic Engineering (DS-TE) and fast reroute (FRR) (including link, shared-risk link group, and node protection).

Chapter 3, "Cisco QoS"This chapter covers the Cisco QoS behavioral model and the modular QoS command-line interface (MCQ). The chapter abstracts the platform specifics to facilitate the understanding of Cisco QoS and provides a complete reference of the configuration commands. In addition, the chapter includes numerous examples to illustrate the configuration and verification of different traffic-management mechanisms in Cisco IOS and Cisco IOS XR. This material is equially relevant to IP and IP/MPLS networks.

Chapter 4, "Cisco MPLS Traffic Engineering"This chapter presents Cisco implementation of MPLS Traffic Engineering in both Cisco IOS and Cisco IOS XR. It includes multiple configuration and verification examples illustrating the implementation of basic MPLS TE, DS-TE, and FRR.

Chapter 5, "Backbone Infrastructure"This chapter discusses the backbone performance requirements and the different design options. The chapter reviews different designs, ranging from a best-effort backbone to the most elaborate scenarios combining DiffServ, DS-TE, and FRR. Numerous configuration examples illustrate their implementation using Cisco IOS and Cisco IOS XR.