End-to-End DSL Architectures
Chapter 6: Cisco IOS configurations
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This chapter presents the configurations of the four basic TCP/IP architectures. These include three architectures based on RFC 2684 (which made obsolete RFC 1483): Integrated Routing and Bridging (IRB), Routed Bridge Encapsulation (RBE), and Point-to-Point Protocol over ATM (PPPoA).
Additionally, this chapter explains Point-to-Point Protocol over Ethernet (PPPoE, RFC 2516). Virtual Private Networks (VPNs) are also described in this chapter, but they are configured beyond the actual DSL network.
In DSL networking, PPPoE is the most popular, although exact market shares of these architectures have not been defined. IRB was the first common architecture in the DSL world and is generally considered obsolescent, although it is still present in legacy networks around the world. RBE is more secure and scalable than IRB while still allowing for the simple, low-cost equipment found in legacy networks. PPPoA is the author's favorite, enabling optimal scalability for provider network expansion and increased end-user sophistication, combined with better security for all parties. All these architectures are encountered in today's DSL networks, and all are covered on the Cisco certification examinations.
This chapter starts with configurations for the Cisco 827 CPE router and then describes the configurations for the Cisco 6000 series of IP/DSL Switches. It finishes with the configurations for the Cisco 6400 Universal Access Concentrator (UAC).
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