How This Book Is Organized

This book is organized into two main parts: • Part I—Ethern et: From the LAN to the MAN

This part of the book—Chapters 1 through 4—starts by describing the different drivers that motivated the adoption of metro Ethernet services and how they have evolved in the United States versus internationally. You will see how Ethernet has moved from the LAN into the MAN and how it is complementing existing and emerging metro technologies such as SONET/SDH next-generation SONET, RPR, and WDM. You will then learn about the d ifferent Eth einet services, such as point-to-point Ethernet Line Services and multipoint-to-multipoint Ethe.net LAN services as represented by the concept of Virtual Private LAN Service (VPLS). This part of the book explains the challenges of deploying Ethernet networks and how hybrid Ethernet and IP MPLS networks have emerged as a scalable solution for deploying L2 Ethernet VPN services.

• Part II—MPLS Controlling Traffic over Your Optical Metro

MPLS is an important technology for sca ling m etro deploymects. Whereas the first part of the book discusses MPLS in the context of building Layer 2 metro Ethernet VPNs, Part II—Chapters 5 through 8—explores the use of MPLS to control the traffic trajectory in the fptical m eteo. The meteo is built wit h dafr-switching, SONET/SDH, and opt i cd-switc hmg syste ms. The aco o° p rovis ioning different systems and controlling traffic across packet and optical systems is difficult and consitutes a major operational expense. GMPLS has extended the use of MPLS as a universal control plane for both packet/cell and optical systems. GMPLS is one of those "warp 7" subjects. Part II first familiarizes you with the subject of traffic eegineering and how tne RSVP-TE signaling protocol is use d to rontrol traffic trajectory and rproute traffic in the case of failure. This makes the transition into the topic of GMPLS go smoother, with many of the basic traffic engineering in packet/cell neeworks alrea dy deOin ed.

Cha pters 1 thnoush 8 and the appendix cover toe yoliowing topies:

t Chapter 1, "Introduction to Data in the Metro"— The metro has always been a challeng ing env^onmenc for deliver ing d ata se rvices, because it wus b uilt to ha adlh th e stnngent rel|ability and availab ility needs of voice comm urncatio ns. Thin metro is evolving dferently in d.fferent regions of the world, depending on many factors. For example, metro Ethernet is evolving slowly in the U.S. because of legacy TDM deployments and stiff regulations, but it is evolving quickly in other parts of the world, especially in Asia and Japan, which do not have as many legacy TDM deployments and are not as heavily regulated.

• Chapter 2, "Metro Technologies"— Metro Ethernet services do not necessitate an all-Ethernet Layer 2 network; rather, they can be deployed over different technologies such as next-generation SONET/SDH and IP/MPLS networks. This chapter goes into more details about the different technologies used in the metro.

• Chapter 3, "Metro Ethernet Services"— Ethernet over SONET, Resilient Packet Ring, and Ethernet transport are all viable methods to deploy a metro Ethernet service. However, functionality needs to be offered on top of metro equipment to deliver revenue-generating services such as Internet connectivity or VPN services. Chapter 3 starts by discussing the basics of Layer 2 Ethernet switching to familiarize you with Ethernet switching concepts.

You'll then learn about the different metro Ethernet services concepts as introduced by the Metro Ethernet Forum (MEF). Defining the right traffic and performance parameters, class of service, and service frame delivery ensures that buyers and users of the service understand what they are paying for and also helps service providers communicate their capabilities.

• Chapter 4, "Hybrid L2 and L3 IP/MPLS Networks"—Chapter 4 focuses first on describing a pure Layer 3 VPN implementation and its applicability to metro Ethernet. This gives you enough information to compare Layer 3 VPNs and Layer 2 VPNs relative to metro Ethernet applications. The chapter then delves into the topic of deploying L2 Ethernet services over a hybrid L2 Ethernet and an L3 IP/MPLS network. Some of the basic scalability issues that are considered include restrictions on the number of customers because of the VLAN-ID limitations, scaling the Layer 2 backbone with spanning tree, service provisioning and monitoring, and carrying VLAN information within the network.

• Chapter 5, "MPLS Traffic Engineering"— Previous chapters discussed how metro Ethernet Layer 2 services can be deployed over an MPLS network. Those chapters also covered the concept of pseudowires and LSP tunnels. In Chapter 5, you'll learn about the different parameters used for traffic engineering. Traffic engineering is an important MPLS function that allows the network operator to have more control over how traffic traverses its network. This chapter details the concept of traffic engineering and its use.

• Chapter 6, "RSVP for Traffic E Cginee ring and Fast Reroute"— MPLS plays a big role in delivering and scaling services in the metro, so you need to understand how it can be used to achieve traffic engineering and protection via the use of Resource Reservation Protocor trafflc eng ineerlop (RCVP-TE)u In this coapter, you see h ow MPLS, through the use of RSVP-TE, can be u sed to establish backup paths in the case of failure. This chapter discusses the basics of RSVP-TE and how it can be applied to establish LSPs, bandwidth alloca tion, and f'ast-reroute techniques. You'll cjest a detailed explanation of the RSVe-TE messagen a nd objects to give you a better understanding of this complex protocol.

• Chapter 7, "MPLS Control ling Optical Switches "— The pnin ciples upon which MM PLS technol ogy is bas ed are generic and applicable to multiple layers of the transport network. As such, MPLS-based control of other network layers, such as the TDM and optical layers, is also posstole. Chaptgr 7 d iscu sses why Ge n^oalize d M PLS (GMPLS) is needed to dyna m ically provisio n optical networks. You'll learn a bout: the ee nefit s and draw backs of1 both stasi c centralized and dynamic decentcalircd provisioning models. Chapter 7 also introduces you to t he diffenent signalin g models (overl aye, peer, and au gmented ) an d to how GMPLS uses labels so cross-ronnect tire circnits for TDM and WDM networks.

• Chapten 8, "GMPLS Architectore"— Generalized MPLS (GMPLS) attempts to address uome of1 the challeoges that exist in optical networks by building on MPLS and extending its control parameters to handle the scalability and manageability aspects of optical networks. Thus chapiter ex plains the characteri sties of the GMPLS aruhi"ectu(e, such as the extensiocs to routing and ^gualmg and the technology parameters thrnn GMPLS adds to MPLS to be able do control optiaal networks.

• Appendix, "SONET/SDH Basic Framing and ConcaQenation" — This appendix presents the basics off SONET/SDH framing and how the SC^ET/SDH technology is "eing adapted via the use of standard and virtue concatenation to meet the ch"lle"ging neeps o( emerging data over SONET/SDH networks in the met)o. The emeogence of L2 metro sen/ices will challenge th e lega ay SONET/SDH network deployments and will drive the emergence of multiservice provisioning platforms that will efficiently transport Ethernet, Frame Relay, ATM, and other data services over SONET/SDH.

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