#126 TECHNOLOGY WHITE PAPER HowEthernet, RPR, andMPLSWorkTogether: The Unified Future of Metro Area Networking Page: 1 of 19 ABSTRACT Over the last year, three new and particularly promising technologies have emerged at the forefront of Metro networking. The three are Multi-protocol Label Switching (MPLS), 10-Gigabit Ethernet, and Resilient Packet Ring (RPR). Today, as the standards slowly settle into hardware, each is finally reaching the stage beyond speculation, and into network deployment. Pundits and vendors have pinned exceptional hopes on each of these technologies, particularly for effecting a long-awaited transformation of Metro Area Networking. The Metro remains the last geographical section of the network still largely dependent on late 1980s and early 1990s technology (low to mid-capacity SONET rings), and is clearly in need of data-focused improvements. Each of the three discussed technologies, on their own, add features to Metro Area Networks that are currently lacking. Yet little attention has been focused on the question of how these technologies are meant to work together. There is no question that they will occupy the same geographical space and need to interoperate with each other as well as legacy technologies. But there exists an unfortunate tendency to describe each as the one "magic bullet" that will relieve all service provider concerns. The goal of this paper is to present a unified, if tentative, vision of how MPLS, RPR, andEthernet should be deployed together in the Metro Networks of the near-future. To counter any existing misunderstandings, we want to make as clear as possible where these technologies are appropriately deployed (and where not), and for what. The goal is to isolate the particular strengths of that technology, and its appropriate role in a Metro deployment. We have also made every effort to portray reasonable migration from existing deployments; the suggested network improves upon and co-exists with current networking equipment, rather than fully replacing it. In short, the goal is to suggest "best practices" for the Metro technology deployments of the future. To this end, we begin by presenting the overview of the network, and then provide a brief description of each technology, with a focus on the particular strengths and weaknesses of each technology for Metro networking.