From the last 100 meters to the first mile

Users can find the familiar and reliable Ethernet protocol outside their premises.

Users can find the familiar and reliable Ethernet protocol outside their premises.

Thanks to a set of specifications that has been available for about half a decade, coupled with the efforts of an industry group with membership that now approaches 150, the Ethernet protocol that has traversed campus backbones and reached user desktops can now also provide enterprises with a high-speed connection to the outside world.

Ethernet in the First Mile is a commonly used name for the Institute of Electrical and Electronics Engineers (IEEE; www.ieee.org) Standard 802.3ah-2004 specifying “Media Access Control Parameters, Physical Layers, and Management Parameters for Subscriber Access Networks.” Approved in June 2004 and published that September, the standard allows users to run the Ethernet protocol over previously unsupported media, such as single pairs of telephone wiring and single strands of singlemode fiber. That is according to a “frequently asked questions” page at ethernetinthefirstmile.com. That site also notes: “The ‘Last Mile' is the name traditionally given to the part of a public communication network that links the last provider-owned node (the central office, the street cabinet or pole) with the customer premises equipment. The ‘First Mile' is the exact same thing, viewed from the customer's perspective.” So, Ethernet in the First Mile is the same thing as Ethernet in the Last Mile.

Enterprise-customer needs

The semantics are noteworthy, particularly the final four words from the previous quote—from the customer's perspective. A significant result of the IEEE 802.3ah specifications is that it allows enterprise customers, the majority of whom have relied on Ethernet as a transmission protocol for several generations of network evolution, to also use Ethernet as a connection protocol to the public network.

Allowing such access is one thing; causing it to flourish may be quite another. A group called the Metro Ethernet Forum (MEF; www.metroethernetforum.org) is seeing to it that first-mile Ethernet does indeed flourish, and began doing so years before the 802.3ah standard became official. The MEF was founded in 2001, and its members include telecommunications service providers, cable operators, multiple system operators (MSOs), as well as manufacturers of network equipment, test equipment, software, and semiconductors. Of that group, about 30% are service-provider organizations and the remainder vendors.

Arie Goldberg, founder and chief executive officer of Omnitron Systems (www.omnitron-systems.com), is also a director and secretary of the MEF. “The main driving force for the MEF was the huge demand for bandwidth that has been growing over more than 10 years,” he explains. “All kinds of new technologies, from remote medicine and online commerce to mobile backhaul, are demanding more bandwidth.” Many enterprise users and, in fact, industry as a whole, were being held back by the physical limitations and costs associated with T-1 and T-3 lines.

On the formation of the MEF, Goldberg describes, “Industry vendors got together and asked, ‘how do we turn Ethernet technology, popular in the enterprise, into carrier-grade technology? How can we create something we can all use to compete, yet at the same time, cooperate in order to create it?'”

Enterprise users could benefit from a turnkey service, Goldberg continues, that allows them to create a circuit from one office to another, geographically distant office. The need has existed for some time, but as Goldberg stated, options such as T-1, T-3, and Frame Relay have been unable to meet needs for both connectivity and speed.

A recent research report from Vertical Systems Group (www.verticalsystems.com) indicates that service providers have made significant leaps in offering precisely that kind of high-speed, reliable connectivity. Vertical Systems reports that even in the midst of the economic downturn, U.S. demand for business Ethernet service ports expanded at an annual rate of 43% in 2008. The researcher cited lower bandwidth costs and higher service availability as drivers of the jump in demand.

“Despite a near paralysis of new telecom spending at the end of the year, there were tens of thousands of new business Ethernet service installs during 2008,” says Rick Malone, principal with Vertical Systems. “Deployments were most active in the third quarter before many enterprises implemented spending freezes or staff reductions. Customer installations in the fourth quarter consisted primarily of follow-through on in-process network conversions.”

The researcher lists eight providers that each have at least 5% market share as of the end of 2008. While Vertical Systems did not provide granular market-share data, it listed the eight providers in order of market-share. From top to bottom, they are: AT&T, Verizon, tw Telecom, Cox, Qwest, Cogent, Time Warner Cable, and Level3.

Progressive evolution

The report that this many providers have achieved at least a 5% foothold in the marketplace supports Goldberg's description of where the Metro Ethernet Forum, now nearly eight years into its existence, is in its evolution. “We are into our third phase,” he says. “Phase one was: What are we trying to do? Phase two was implementation and deployment. Phase three, which we're going into now, is global interconnection implementation.”

Goldberg continues, “We're moving from providing services within a metro and crossing state boundaries, now to crossing national boundaries. For example, if Verizon has a presence in a city on the East Coast, it may not have a presence in a certain West Coast city. It needs to interconnect with AT&T or Cox perhaps.” The scenario may sound familiar, he explains, because it's how T-1 connections were constructed.

One element of the MEF's global interconnection implementation initiative is to ensure there is a common template upon which service providers can do wholesale business with one another, particularly in situations like the one described above. Again recalling the T-1 scenario as an example, it was relatively straightforward for one provider to create a business deal with another provider in order to offer a T-1 to an end user.

“In the Ethernet world, it can get more complicated,” Goldberg says. “The conversation might go like this: ‘I want Gigabit, with the rate ratcheted down to 200 Megabits.' In a way, Ethernet is simpler, but the many options available can make it complicated as well.” Hence, the benefit of a common data-rate template.

Technical specifications

Also on the MEF's agenda are physical specifications for a user network interface (UNI), which is also frequently referred to as a network interface device (NID). The NID resides on the customer premises, often converting incoming fiber from the service provider to copper media used by the enterprise.

“The NID is thought about tradi- tionally as a media converter,” Goldberg says. “But the device has grown dramatically to include many sophisticated features, including OAM—operation, administration, and maintenance of equipment in the field.” In the example of East Coast-West Coast connected offices, the NIDs on each site will talk to each other constantly, sending frames to one another and monitoring for anomalies such as frame delay or frame loss.

“NIDs go way beyond the typical media converter,” according to Goldberg. “They are capable of troubleshooting and can find which segment of the network loses connectivity by conducting a trace. It pings boxes along the way and recognizes which box it does not reach.”

The Metro Ethernet Forum has produced several technical specifications covering UNIs, and as the devices make capability gains, the MEF specifications keep pace.

No small part of the MEF's mission is to educate enterprise end users about their Metro Ethernet options. In February, Bangalore, India was the site of an MEF Enterprise Workshop, at which attendees heard about the latest advances in carrier Ethernet services, learned statistics about the technology's global growth trends, and heard real-life case studies.

“Enterprise customers have adopted and are increasing leveraging our certified Ethernet services to simplify their network infrastructure and achieve the flexible and scalable environment they need to support their business objectives,” said Deepak Verma of Indian service provider Reliance Communications (www.rcom.co.in), a participant in the Bangalore workshop. “Our experience strengthens our belief and commitment toward Ethernet being the key technology for ever-growing telecom networks, now and in the future.”

PATRICK McLAUGHLIN is chief editor of Cabling Installation & Maintenance.

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