A practical, service-oriented guide to large-scale ADSL implementation.
From service architecture to applications, standards to business case, Implementing ADSL delivers a complete, up-to-date analysis of what it takes to deploy ADSL. Written by a leading authority in the field, this book will be equally valuable for implementers and decision-makers in both service provider and enterprise IT organizations.
The author begins with a detailed look at the business drivers and financial models associated with ADSL implementation. Learn how to estimate ADSL service demand, revenue, capital, and ongoing expenses over the short and long-term; then review the current status of ADSL, G.Lite, and other xDSL technologies, cable modems, and other alternatives.
Next, Ginsburg introduces the ADSL service architecture, outlining an end-to-end service model from the physical layer to the network layer, and addressing crucial issues such as Quality of Service (QoS), security, and IP multicasting. Understand ADSL's physical infrastructure, including splitters and other premises equipment; DSLAMs and other central office equipment; aggregation, access, and core networks; digital loop carriers; gateways; caching solutions; and other key elements.
The author also reviews a wide range of ADSL services, including end-to-end ATM virtual circuits, PPP connections, bridging, routing, voice, video, and portals. You'll find seven detailed implementation scenarios, complete with diagrams and configuration listings based on actual deployments:
Whether you are a network manager, architect, administrator, or engineer, Implementing ADSL brings together crucial information and insight for making the best possible decisions about today's most important access technology.
(Chapters conclude with a Summary and/or Endnotes.)
1. ADSL History and Requirements.
Growth of the Internet.
Role of Service Providers.
Competition Among Service Providers.
The Business Case for ADSL.
Analysis of an ADSL Business Case.
ADSL History and Standardization.
Universal ADSL Working Group (UAWG).
Internet Engineering Task Force (IETF).
International Telecommunications Union (ITU).
American National Standards Institute (ANSI).
European Telecommunications Standardization Institute (ETSI).
United States ILECs and the JPC.
The ADSL Layer.
ADSL Standardization History.
Performance of CAP and DMT.
Interference within CAP and DMT.
ADSL and ISDN.
ATM and ADSL.
Basic Concepts and Background.
Connection Types and Signaling.
Routing—The Network-Network Interface.
ATM Addressing Plans.
LANE and MPOA.
Point-to-Point Protocol (PPP) over ATM.
Native ATM Services.
The Network and Transport Layers.
The Internet Protocol.
Routing IP Packets.
Quality of Service.
Network Address Translation.
The Dynamic Host Configuration Protocol.
The Domain Name System.
The Transmission Control Protocol and the User Datagram Protocol.
The New Internet Infrastrucure.
The Customer Premises.
Premises Distribution Network.
Central Office Equipment.
MDFs and Splitters.
DSLAM (ATU-C or ATU-LT).
Access and Core Networks.
ATM Access and Core Networks.
Packet-Based Core and Access Networks.
Digital Loop Carrier Systems and the Full Service Access Network.
Content, Caching, and Gateways.
Management and Provisioning.
Telecommunications Management Network.
Element Layer Management—G.997.1 and the ADSL Line MIB.
Network Layer Management.
Authorization and Directory Services.
United States and Telecommunications Deregulation.
European Regulatory Environment.
Pacific Rim and Other Regulatory Environments.
End-to-End ATM Virtual Circuit Connections.
Advantages and Disadvantages to ATM.
SVCs Switched Virtual Circuits.
PPP Point-to-Point Protocol.
L2TP - Layer Two Tunneling Protocol.
Multiprotocol Label Switching (MPLS).
IP Security (IPSec) Tunnels.
Extending PPP to the Desktop.
L2TP to the Desktop.
Subscriber Bridging and Bridge Groups.
Internet Access: Residential and Corporate.
Review of DSL Deployment.
CPE Installation and Configuration.
DSLAM Installation and Configuration.
Service Aggregator Installation and Configuration.
The Last Hundred Meters: PPP over Ethernet (PPPoE).
Combining Policies into Tariffed Services.
Subscriber Service Gateway Configuration.
ISP OSPF Configuration.
Corporate Intranet Access: PPP/L2TP Tunneling.
Corporate Extranet Connectivity: VPRNs.
IP VPN Requirements.
Service Aggregator Configuration.
PSTN Bypass: VoIP.
Entertainment: Video Streaming.
Integrated Digital Subscriber Line (IDSL).
Symmetric Digital Subscriber Line (SDSL).
High-Speed Digital Subscriber Line (HDSL).
Very High Speed Digital Subscriber.
POTS/ISDN Dial-Up Options.
T1, Wireless, and Satellite Services.
Rural Subscriber Issues.
The growth of the Internet has been phenomenal. In just 15 short years, backbone capacity in the United States alone has grown from single T1s (1.544 Mbps) to multiples of OC-48 (2.4 Gbps), a 10,000 percent increase. In the same timeframe, applications have evolved from simple (and sometimes unreliable) email and FTP connectivity to the Web, e-commerce, Internet telephony, and video streaming.
However, until recently, access bandwidth has not kept pace. Except for dedicated corporate access, which has more or less followed the backbone bandwidth curve, bandwidth available to the typical residential user or even telecommuter has grown from 1200 bps to 56 Kbps, or in some cases ISDN at 128 Kbps, a paltry 1000 percent increase. Thus, a disconnect in the Internet's ability to support high-bandwidth content and the average user's ability to take advantage of it.
Only in the last year has this situation changed, with the introduction of the Digital Subscriber Line (DSL) and cable modems. These two technologies deliver, for the first time, megabit connectivity to the masses at an acceptable price point. This last point is critical, since nothing actually precluded running an OC-3 ATM connection to the house down the street: whether they could afford it was another matter.
This book focuses on DSL; specifically, ADSL, the flavor most relevant for casual Internet users and telecommuters. Irrespective of any rhetoric concerning provisioning and reach, ADSL is quickly growing in popularity, as evidenced by the number of users applying to local offerings and the ISPs signing on to support the service. Early difficulties in provisioning have been overcome, and both the ILECs and CLECs are now deploying the technology in quantity.
The availability of megabit connectivity to the average household opens up a wealth of new services, and enables true convergence between Internet content and media. For the first time, high-quality video streaming becomes a reality, and the "world wide wait" experienced when browsing graphic intensive catalogs or auction sites is a thing of the past. For the telecommuter, ADSL delivers on the promise of productivity; access to corporate resources no different than from the corner cubicle.
ADSL is therefore an important technology to understand, both in terms of standardization, and more importantly, how it forms a basis for high-speed Internet services.Who Should Read This Book
This book is for the networking professional who is either involved with ADSL deployment or is interested in how the technology plays a part in Internet service deployments. This is probably the most important point: how the technology finds a role in practical network implementations.
This book covers a broad base of topics, including standardization, the hardware components found within a typical ADSL deployment, and the various higher layer protocols and services riding above this infrastructure. It ties these various components together into a service of implementation examples. However, Implementing ADSL is not intended to be an in-depth treatise on any one of the subjects such as the details of ADSL encoding or ATM traffic management and signaling. For this, the reader is referred to more detailed books on these individual subjects.How This Book is Organized
This book is organized in the following manner:
Craig Sharper, Sayuri Sharper, Enzo Signore, Rene Tio, Guy Fedorkow, and Tim McShane, all of Cisco Systems. Gil Tene, Chin Yuan, and many others at Shasta Networks. And finally, my current employer, Shasta Networks, and former employer, Cisco Systems, who provided me with the opportunity to research and complete this book.