Building 10-Gig/DWDM MANs

The need to expand metropolitan network capacity to accommodate high-speed wide area networks is well recognized but finding innovative, cost-effective solutions has not been easy. Many metropolitan network service providers have been deploying SONET and Wave Division Multiplexing across existing fiber despite the difficulties in supporting existing customer networks, particularly Ethernet. A new solution is emerging - 10 Gb/s Ethernet over DWDM fiber - that offers the advantages of speed, flexibility, scalability, and technical simplicity. Extensions to existing Ethernet standards have proven to be both feasible to develop and practical to implement. The 10 Gb/s Ethernet standard, currently being developed by the IEEE with the assistance of the 10GEA Committee, will be completed in early 2002 and then used for open systems deployment. In the meantime, proprietary pre-standard products can provide interim support for Ethernet networks in campus and metro environments. Interfaces are being provided for a variety of transmission media, including both single mode and WDM fiber. As Riverstone Networks and the Industry begin supplying 10 Gb/s Ethernet products, certain questions still remain. For example, how will 10 Gb/s Ethernet compare to the existing versions of Ethernet? What functions, features and frame structure will apply? What services can be expected from service providers? This white paper examines the driving forces for 10 Gb/s Ethernet standardization, looks at the specific opportunities for metropolitan network service providers, and shows how 10 Gb/s Ethernet can fit into a broadband network infrastructure. The ongoing efforts in the standardization of 10 Gb/s Ethernet will be highlighted.

Table of Contents

• Abstract
• Introduction
• Broadband Network Applications
• The Metro Area Network Infrastructure
• Elements of a 10GbE Solution
• Differences Between 1GbE and 10GbE
• Building 10GbE/DWDM Metro Networks
• The Advantages of 10 Gigabit Ethernet over DWDM
• Summary
• Glossary of Terms

Introduction

Network service providers face a variety of challenges as they seek to capitalize on the opportunities resulting from emerging technologies, from advances in network standards and from ever more demanding user requirements. Telecommunications industry de-regulation has resulted in increased competition, has certainly stimulated innovation and has helped to reduce service prices. At the Metro Area Network (MAN) level, there is now tremendous pressure for expanded capacity to support broadband local access and high-speed wide area networks, especially the Internet. All of these factors suggest that a flexible, proven MAN architecture combined with multi-vendor compatible implementations is urgently needed so that new provider services can be introduced. Standards-based 10 Gb/s Ethernet (10GbE), especially combined with metro area optical fiber networks based on Wave Division Multiplexing (WDM), promises to be a viable solution - it offers a hierarchy of speeds, end-to-end protocol consistency, and technical features that are needed by both providers and users.

Fundamentally, Riverstone Networks is developing 10GbE to interconnect Ethernet LANs that may now be operating at 10, 100, or 1,000 Megabits/second. New types of applications for Ethernet include application and content hosting, Internet-based data centers, server co-location and others that go beyond the traditional enterprise. This white paper first examines these new application and infrastructure requirements to see why 10GbE has become an attractive option for LAN and WAN packet transport. Next, the potential for 10GbE deployment in both the MAN and the WAN is investigated.

Standards for 10GbE are being developed by the IEEE (the 802.3ae committee) and will be promoted in the marketplace by the 10 Gigabit Ethernet Alliance (10GEA). Completion of the formal standardization process is expected by early 2002, with conforming products and deployments arriving shortly thereafter. In the meantime, pre-standard products are becoming available to support existing Ethernet networks in a campus or metro environment. This white paper examines the progress of standards development and compares 10GbE to earlier Ethernet standards. It also discusses the advantages of using DWDM to provide physical connectivity for Ethernet.

Ethernet as an end-to-end network solution is a new concept, one that may come as a surprise to many network architects and designers. Ethernet, originally conceived only for use in local networks, is gradually being accepted at the MAN and WAN levels. This white paper reviews the benefits of having Ethernet compatibility across local and metro networks and indeed from end-to-end.