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One of the high-stakes arenas in the WAN technology crapshoot is last-mile access. Technologies such as analog, 56 Kbps, ISDN and even T1--the traditional high rollers in the game of "last mile" connectivity for branch/remote office communication--are reaching their cost or performance limits and are ripe for replacement by brash new players and technologies like the cable companies

with Hybrid Fiber-Coaxial (HFC) networks and the telephone companies with Asymmetric Digital Subscriber Line (ADSL) networks. These new technologies--which boast deeper bandwidth pockets and greater reliability at a better price--have been carefully planned, tested and fermented over the past decade.

Roll The Dice
What will these technologies mean for you and your business? Nothing--until we start seeing deployment over the next one to three years. Then these services will have at least limited availability except in the largest and most lucrative metropolitan areas.

Despite the proclamations from the cable industry, cable isn't going to be a business solution for some time because of its history and network structure. Enterprise networks need a broad portfolio of services, such as dial-up, private networks, frame relay and management. At the same time, many customers want simplified billing, consolidated contracts, service-level guarantees and performance monitoring. The cable companies cannot provide any of this. They do, however, have the potential to win the war for residential access beating out analog, ISDN and ADSL services, while driving exchange carriers to compete with one another and with the cable industry for customers.

ADSL will prevail as a temporary solution fo r business access between small-office/home-office (SOHO) sites and the corporate office. Telephone companies understand the need for Internet access and telecommuting and can use what they've learned from ISDN to help them prepare for the corporate rush. However, it won't be easy for the telcos either: Most of them still are stumbling over ISDN deployment and billing and how to handle the load 128-Kbps ISDN brings on their equipment.

The competition between these industries will drive down the price of both HFC- and ADSL-based networking. From the high end, it will also drive down the price of T1 access, possibly making it cheap enough to consider for branch-office and small-office connectivity. When the dust settles and services are installed, applications that demand high bandwidth, voice over IP and other services will be a reality at corporate sites and SOHO locations.

Hitting The ADSL Jackpot
To compete against local cable companies, competitive acces s providers and, in many instances, themselves, the local telephone companies have been testing ADSL technology, which is based on their existing copper infrastructure. Although its topology differs, ADSL resembles the cable companies' HFC network in that it uses frequency demodulation to carry services, such as video and data, to plain old telephone service (POTS) customers. Like cable, the service is dedicated and nonswitched, and it requires a modem to demodulate the signals and tie the data and other services to the appropriate equipment at the customer site.

To download an Adobe Acrobat .pdf format version of the "WAN Access Technologies At A Glance" chart, click here.

To download an Adobe Acrobat .pdf format vers ion of the ADSL Network Access diagram, click here.

To download an Adobe Acrobat .pdf format version of the Hybrid Fiber-Coaxial Network Access diagram, click here.