Ethernet: the next standard in WANs: optical choice offers enterprise LANs flexibility and affordability between metropolitan sites - Network Services

Communications News, June, 2003 by Ron Young

Enterprises continue to hunger for more bandwidth as they put more applications on the Web, exploit the cost advantages of distance learning and streaming media, and take advantage of the security and flexibility of storage-area networks. Many enterprises, however, are frustrated by the expense and complexity of provisioning and maintaining high-bandwidth circuits that use traditional technologies, such as synchronous optical network (SONET)-based TDM, frame relay and asynchronous transfer mode (ATM). The result is a disconnect between gigabit office LANs at the edge and the giant data pipelines that now criss-cross the globe.

Traditional service approaches have several notable shortcomings: including rigid bandwidth increments for T-1, DS-3, OC-3, OC-12 and OC-48 that typically require thousands of dollars in up-front customer investments in customer-premise equipment (CPE); long lead times in provisioning services; and the need to hire or train staff to design, procure, test, install, manage and maintain specialized WAN technologies, CPE platforms and management systems.

Optical Ethernet offers remedies for each of these ailments. Utilizing relatively low-cost Gigabit Ethernet switches and routers, with optical interfaces that transmit signals 70 kilometers or more without regeneration, metro Ethernet networks can handle the various and changing needs of enterprises for transparent LAN services between metro sites or to the Internet with greater flexibility, simplicity and affordability.

Modern Ethernet switches offer finely granular scalability from 1 Mbps to 1 Gbps. Some Ethernet carriers offer services only at typical LAN speeds (10 Mbps, 100 Mbps, 1,000 Mbps), while others offer committed information rates in 1 Mbps increments, with low (and guaranteed) round-trip latency and packet loss.

Service providers can typically change bandwidth levels on a network link with simple software commands to their switches. This flexibility allows enterprise customers to buy only the service level they need. They can also order more bandwidth on short notice for temporary applications, such as videoconferencing or storage back-ups, if overall network capacity is available.

Because these services are delivered over a simple Ethernet interface, customers require only an Ethernet port on a low-cost Layer 2/3 LAN switch instead of expensive and complex WAN interfaces. Unlike WAN interfaces, the Ethernet switch need not be replaced as service levels change. Ethernet interfaces are typically 25% to 40% less expensive per Mbps of bandwidth than TDM, frame relay and ATM ports, and up to 10 times less expensive than high-speed SONET interfaces.

With ethernet services, enterprise IT departments can save time and money by focusing on their core competency--Ethernet-based LANs--instead of mastering the arcana of WAN interfaces. Communication between multiple sites over metro Ethernet networks with standard 802.1Q tagging is as simple to administer as one large LAN.

Many enterprises have discovered that optical Ethernet services deliver on their promises in the real world. Fenwick & West, a large technology law firm based in Silicon Valley, upgraded its maxed-out T-1 Internet service to a 10 Mbps optical Ethernet connection in 2000, avoiding the cost and complexity of multiplexing T-1 lines or installing DS-3 gear.

Fenwick's Ethernet service cost one-third as much as a DS-3, not counting the up-front savings of tens of thousands of dollars in CPE. When the firm needed to download gigabytes of data from a client, it dialed up the bandwidth to 50 Mbps for a day and got the job done at minimal expense. Whereas the CPE for a DS-3 would consume an entire rack in Fenwick's IT department, its Ethernet CPE occupies only as much space as a few pizza boxes.

"Another determining factor in selecting the Ethernet service was its use of standards-based hardware and software," says Matt Kesner, CIO of Fenwick & West. "With a straight Ethernet hand-off, our IT department doesn't have to learn a new technology or buy new equipment."

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For more information from the Metro Ethernet Forum: www.rsleads.com/306cn-264

Young is chairman of the Metro Ethernet Forum, Newport Beach, Calif., and CEO of MetNet Communications.