Double the DSL With Half the Trouble

Rainfinity bonded digital subscriber lines enhance reliability by promoting always-on Web access

With all the troubles the typical DSL customer endures on the road to Internet connectivity, why would anybody want to deal with two digital subscriber line providers at the same time?

For Brian Hauer, systems architect and IT manager at TechEmpower Inc., the answer is twofold: First, two DSL connections together are less expensive for him than one T-1 line; second, if the two DSL lines can be bonded and used simultaneously, they can provide a level of comfort regarding reliability that even higher-end connections cant provide.

"Its a curious conundrum that small businesses are in because ... DSL—even before it became almost an exercise in futility [following service provider bankruptcies]—would have outages," Hauer said. "The ability to get two of any type of connections and bond them together has been tragically lacking."

This week, Rainfinity, which makes high-availability software for e-businesses, is unveiling RainConnect, a tool to give small enterprises always-on Internet access. Built on the San Jose, Calif., companys patented Reliable Array of Independent Nodes technology, the product makes Internet "multihoming"—connecting via two or more ISPs (Internet service providers) at the same time—available and affordable to small and midsize enterprises. The software automatically moves traffic from a failed connection to a functioning link.

Last week, the DSL Forum trumpeted nearly 10 million DSL subscribers worldwide, with more than 3.5 million in North America.

Consolidation in the telecommunications service provider market is pointing toward decreasing choices just as dependency on the Internet is rising among small and midsize businesses. Although service providers are increasingly eager to boast SLAs (service-level agreements) that compensate for downtime, enterprises are looking for ways to avoid the impact of outages altogether. "SLAs are not that useful to you because they reimburse you for downtime but not at all for the business you may have lost," Hauer said. "Really, what were looking for is truly 100 percent uptime."

TechEmpower, a Web-enabled applications developer in El Segundo, Calif., regularly posts works in progress online for clients to test and review. A daylong network outage could cost the company as much as $20,000 in lost business, but compensation per an SLA would reimburse only the cost of the days connection—less than $100, according to Hauer, who will be testing RainConnect.

Without bonding, using two separate Internet links is inefficient because one is left idle most of the time. In addition, when an outage on one network occurs, it takes time to manually migrate to the other. At TechEmpower, Hauer has to readdress all the servers in the office and reassign IP addresses when an ISP goes down. "It takes an hour or two when theres an outage [to manually switch service providers]," he said. "Each time, we have to go through a process where we evaluate when the service is likely to come back on before deciding to make the switch."

Most data networks have multiple points of failure, and only a small number may be controlled by the provider offering an SLA. Large enterprises have been able to use Border Gateway Protocol to multihome and achieve seamless failover, but its a complex technology to configure and requires expensive, high-memory routers and a cooperative ISP.