Turn to Ethernet for Small and Medium Business Needs

By David M. Piscitello
Core Competence, Inc.

Business customers have two issues with "residential broadband," in the form of ADSL. The first is one shared in common with residential and home office users: it's difficult to get. The second is more problematic: once they get ADSL, they soon find they can't live with the sub-megabit upstream delivery.

In many cases, a megabit "plus" downstream is enough to satisfy bandwidth needs for ten or so active users in small and medium business. But it's often not enough for offices of say, twenty-five to fifty employees actively engaged in e-whatever. ADSL is commonly configured for 384 Kbps upstream. This quickly proves to be an inhibitor to businesses looking to put intranet, extranet, and eBusiness services on line over their not-so-broadband local access connection.

Businesses need symmetric bandwidth. Or perhaps more accurately, bandwidth symmetry based on user traffic. ADSL can provide an increase in upstream bandwidth, but only at the sacrifice of bandwidth delivered downstream. This is in part because ADSL is a constant bit rate (CBR) service, and requires continuous power to deliver signals bi-directionally between customer premises and central office equipment, and partly because it's a full-duplex service.

Ethernet over the Local Loop
Ethernet over the local loop-EtherLoop-is a compelling technology because it challenges the wisdom of utilizing continuous power to support a constant bit rate, full-duplex service: residential broadband is primarily about packet (IP) data, and packet data delivery is bursty, so tell me again why I really need CBR and full-duplex? The answer is, "you don't".

EtherLoop, developed by Elastic Networks, an independent unit of Nortel Networks, works over existing loop pairs. Texas Instruments provides programmable DSPs for EtherLoop. Spectrally compatible with ISDN, POTS, T1 and ADSL, it's a clever blend of DSL signaling and modulation combined with Ethernet framing and a rate adaptation technique. EtherLoop transmitters only send when there's something to send, they only generate signal and consume power during the transmission or "burst", reducing overall power consumption. EtherLoop measures interference and cross talk and adjusts frequencies when it senses trouble to achieve the best transmission rate "at this time, for this bundle".

EtherLoop is deployed over the local loop in a point-to-point topology, much like a single station is connected to an Ethernet switch, so it has the same privacy properties as other DSL variants. However, EtherLoop is a half-duplex service. It allows one transmitter the full bandwidth available over the copper pair when it transmits. Yes, turnaround time reduces overall bandwidth, but, hey, there's no ATM cell tax. And the achievable transmission rates are impressive.

Benefits
The real bang for the buck comes at distances where ADSL can only offer a megabit or better downstream: EtherLoop operates at 2 Mbps over 12,000 feet, 2.5 at 9000 feet, 4 Mbps at 6000 feet, and 10 Mbps at 3000 feet. Sub-megabit service can be deployed up to 21,000 feet (4 miles). Tim Sharrard, COO of CLEC-ISP Oregon Trail Internet, a 2-year veteran EtherLoop provider, explains, "With our customer base and geography, we really needed to be out at that 4 mile mark. That extra 4000 feet really makes a difference".

Another huge bonus with EtherLoop is that it can be deployed over phone lines with bridge taps. "Since EtherLoop accepts bridged lines, we can order a regular voice grade line from the telco", explains John Coutts, system administrator at Edsonet in Edson, Alberta CA. "This is a big savings for us". Edsonet operates EtherLoop over Telus-provisioned dry copper from business and residential customers to its operations network. It offers 1.5 Mbps service at rates comparable to what I'm paying for 384Kbps/1.1 Mbps ADSL on Hilton Head Island. Oregon TrailInternet's Sharrard agrees. "We chose EtherLoop because ADSL won't work on dirty copper," said Sharrard. "With ADSL, it's always a question of 'How many pairs of copper do you have to go through to find one that's going to work?' but with EtherLoop, our orders for dry copper go 'installed' in as few as 3 days."

Etherloop can be deployed at competitive (and in some deployment scenarios, significantly lower) recurring rates than T1 and multiple T1/TDM arrangements. Commodity priced Ethernet chipsets make for less expensive CPE, and service providers can base intra-office data switching on inexpensive Ethernet rather than costly ATM. Voice and Video over IP are realizable additional services with the bandwidths achieved over EtherLoop.

Not a pure data CLEC play
EtherLoop isn't a pure data CLEC play. Some of the providers actively deploying EtherLoop include Northwest Internet, Oregon Trail Internet, and Hargray Communications. BellSouth and Sprint are among the major players who now offer or are trialing EtherLoop. EtherLoop is also suitable for MTU/MDU deployment: CAIS Internet plans to use EtherLoop technology to provide high speed Internet access over existing phone wiring to guest rooms and business centers in participating hotels.

Attractive Pricing
Pricing of course varies, but 1 Mbps service ranges from $150-300 per month, and 500 Kbps available in the $60-120 range, with remarkably low monthly modem rentals. These certainly are more attractive prices than fractional-T1 and T1 rates anywhere I've inquired. Oregon Trail's Sharrard compared a recent order for a 512 Kbps fractional T1 against an equivalent EtherLoop solution. "A one-time LATA line install in our serving area is $95, compared to $700 for a T1 line. T1 CPE runs about $3200, compared to a $9.95/month Etherloop modem rental. The combined T1-Internet charges are around $650; business EtherLoop at 512 Kbps runs $119.95.

Just do it
EtherLoop provides a megabit or better solution business customers can't get from ADSL, over practically any copper, at greater distances. Do you want to spend time qualifying copper or offering service? And rate symmetry is especially important for the small-to-medium business customer who can't step up to the expense of multiple T1's or who can't deal with the operational complexity and costly footprint of TDM-based access equipment. If you're about to sell broadband to a company devoid of network competencies, do you want to explain what multiplexing is, or do you want to show them a plug-and-play EtherLoop modem?

David Piscitello is president of Core Competence, Inc., a network consulting firm and founder of The Internet Security Conference.