Five years ago, the Pend Oreille County Public Utility District (Newport, Washington, U.S.) had a great idea. It leveraged an underutilized fiber-optic network and turned it into a high-capacity communications backbone, becoming not only a provider of water and electricity, but also wholesale telecommunications services. The problem was, it was a network somewhat ahead of its time. It is Ethernet-based, with vast bandwidth, but its service- provider customers, and their customers in turn, were all still quite content with their traditional services, such as T1 circuits. The utility serves a sparsely populated 1400-sq-mile (3626-sq-km) county in northeastern Washington, where there is not a lot of large corporate demand to drive big bandwidth needs.
“Our original vision that folks would break down the doors to access Ethernet was tempered by the reality that many don't understand or fully trust Ethernet,” says Joe Onley, community network system manager for the Pend Oreille PUD.
Delivering traditional communications services such as T1s is a challenge for Ethernet networks, since T1s are TDM-based (time division multiplexed), while Ethernet networks are designed to move traffic via packets. The two are essentially incompatible, but the Pend Oreille PUD found a perfect solution through a technology called Pseudowire, or TDM over IP.
The utility installed IPmux gateways from RAD Data Communications (Mahwah, New Jersey, U.S.), which use Pseudowire to carry traditional TDM traffic through the Ethernet network, in a seamless solution that is completely transparent to customers.
“It turned out that we needed to use our ultramodern, state-of-the art fiber-optic network to transport signals that worked just fine over legacy copper wiring,” Onley says. “But there really wasn't any equipment that could transport those signals until we found the IPmux.”
In addition to selling wholesale services to Internet service providers and telephone companies, the Pend Oreille PUD uses the network for its own internal communications and for a SCADA network that monitors its substations. The network is also part of the Northwest Open Access Network (NoaNet), a consortium of utility districts that links their fiber networks.
Over time, Onley expects that bandwidth demands will increase and more customers will want the high-capacity services that the Ethernet network enables. Until then, he says, the network is a “building block” for the future, one that gives the utility complete control over its own communications for now.