By Kimberly Caisse
Network World, 09/24/01

Once confined to the LAN, Ethernet is storming the metropolitan-area network, promising to save companies money while improving reliability and the speed of provisioning. But a decade of legacy SONET infrastructure must be replaced with newer SONET-like gear before Ethernet service becomes ubiquitous.

Known interchangeably as Optical Ethernet and Gig E, the buzz centers on service provider start-ups such as Yipes Communications, Cogent Communications and Telseon Service ( see related story ).

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Customers say a 10M bit/sec Ethernet MAN link can be more reliable than a tapped-out T-1 line and about half the cost. Last summer, Swarthmore College in Pennsylvania solicited bids from a few national and large regional carriers as well as Yipes. "They offered a similar amount of bandwidth [10M bit/sec], but Yipes' price was literally half of what was offered by the traditional carriers," says Mark Dumic, manager of networking and telecommunications at Swarthmore.

Matt Kesner, CIO of law firm Fenwick & West LLP, is also happy with price and performance of Yipes' Ethernet MAN service. To handle growing volumes of e-mail, the firm needed to upgrade the T-1 between its Palo Alto and San Francisco offices. So it collected bids from national and local carriers. The proposals ranged from 1.5M bit/sec to 45M bit/sec with the lowest bid at $18,000, Kesner says. He then turned to Yipes and is paying less than $6,000 a month for 10M bit/sec. "We have more bandwidth, less latency and the ability to send large attachments," he says (see "Competitive costs").

Optical Ethernet

Users moving from DSL say Ethernet MAN service is a reliability upgrade. "We're definitely getting more bang for the buck with Cogent," says Michael Hollander, president of Slam-Lam, a lamination company in Chicago. "We have enough bandwidth to cover what we need. It's just more consistent."

The flexibility of some Ethernet service providers also lets users increase and decrease bandwidth within hours of notifying their providers, a huge benefit for a company anticipating occasional uploads or downloads of large files. "We very much liked that we could have [our bandwidth] turned up within a few hours," Dumic says. "That's very important to us."

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The SONET stumbling block

But the start-ups operate only in about the top 20 U.S. cities. Ethernet will not become a widespread MAN service validated by incumbent local exchange carriers (ILEC) until legacy SONET equipment is upgraded, and analysts can't say when that will happen. "Service providers own an awful lot of older SONET gear," says David Passmore, research director at The Burton Group.

Competitive costs Price is clearly Optical Ethernet's brightest selling point. Yipes Communications offers its Ethernet metropolitan-area network service for a starting price of $165 per month, per location for 1M bit/sec of bandwidth. Yipes charges $450 per month for 1M bit/sec for Internet service, and WAN service costs $1,300 per month, per location for 1M bit/sec. As customers increase bandwidth, Yipes' prices drop. Yipes' MAN service falls to $32 per megabit, per second when a customer buys 100M bit/sec. Users can scale up to 1,000M bit/sec in 1M bit/sec increments. Click here for more.

By all accounts, traditional SONET cannot efficiently support modern networks. As a pure transport technology, SONET is unaware of whether it's carrying voice or data, and isn't optimized to recognize the different kinds of transport services available today, including ATM, voice over IP, circuit emulation, transparent LAN service and Gigabit Ethernet.

Traditional SONET is also a pain to provision. When a company wants more private line capacity, the carrier usually has to upgrade the entire SONET ring or install an overlay ring. New time division multiplexing (TDM) circuits then have to be provisioned manually. The entire upgrade is expensive, and the process can take months to complete.

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What to ask Ethernet MAN vendors In what cities does your optical Ethernet MAN service operate? How will you provide last-mile access to my office buildings, and who will pay for it? How long will initial provisioning take?

Nevertheless, traditional SONET gear is entrenched in the MAN and so private line services running at speeds of OC-3 to OC-48, and occasionally OC-192, will continue to be the most common services offered by the ILECs.

"Our biggest selling service is still SONET," says Stu Elby, executive director of Verizon's next generation network architecture group. "DS-3s and OC-3s are probably the largest growth areas today."

Service providers defending their legacy SONET infrastructures point out that private lines on SONET have several advantages over an Ethernet service. They can deliver guaranteed performance, important for low-latency applications. And they are inherently more secure because when using your own T-1 line, your traffic isn't mixed with others.

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Setting sights on new SONET gear

Still, ILECs are preparing to offer Optical Ethernet by dabbling with optical edge devices. This equipment natively supports transport services such as Ethernet, storage-area networks, VPNs, transparent LAN and Internet access. Equipment vendors such as Cisco, Nortel, Lucent and Alcatel are taking two approaches to the optical edge.

One set of products, called multiservice equipment, combines the TDM for private line service with other emerging MAN capabilities, including wavelength division multiplexing (WDM). These boxes can have switching or routing capability, and many have Ethernet interfaces to support data transmission.

Compatability check Despite shining promise, Optical Ethernet has its drawbacks If your need for faster, less expensive metropolitan-area network services happens to be in one of the top 20 U.S. cities, Optical Ethernet may be for you. But know the risks. Ethernet service is mainly being offered by start-ups, although a few incumbents, such as Qwest Communications (through its acquisition of US West), offer it selectively. Click here for more.

The other product group, called "super SONET" gear, improves upon the conventional SONET multiplexer. It can scale up to 10G, conserves power and is therefore less expensive to operate. These boxes can cross-connect the metropolitan and enterprise networks. They can be linked to metropolitan WDM boxes, and they may support Ethernet interfaces.

Optical edge devices are drawing the attention of deep-pocket incumbent carriers that can drop them into their existing backbones without a major overhaul, says Anna Reidy, senior analyst at telecom research firm RHK.

Still, don't expect any carriers to start rolling out Ethernet MAN services en masse until they see start-ups peel away customers.

Caisse is a freelance writer living in Massachusetts. She can be reached at kcaisse@gis.net.

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Related links:

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Optical Breaking News page

Network Worldís Optical Networking newsletter ‚

Network Worldís View from the Edge newsletter

Gigabit Ethernet Research page

The standards effort is focusing on three areas:
Network World, 09/17/01

Be your own MAN
Network World, 09/10/01

Report stirs Ethernet vs. SONET debate
Network World Optical Networking Newsletter, 09/05/01

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