Tom Connors, manager of enabling technologies at Sensata, cites the Dominican Republic, where the company has a newly acquired plant, as one trouble spot. "The cost of a T1 there is extremely high compared to our other manufacturing sites. A WAN compression box was cost- and functionally effective, but [after a company transition] we went with a managed network and managed WAN-optimization was a natural fit."

Sensata uses a managed WAN-optimization service from Virtela Communications. Although Connors reports no problems integrating the service, he has one lesson to share: IT had to configure such applications as Microsoft Exchange to use consistent switch-ports rather than what Connors calls "pseudo-random" ports -- those configured as virtual ports that can change based on the network configuration and potentially conflict with applications. This is one of the precautions companies doing WAN optimization should take: Often, compression algorithms and caching work best when the network configuration stays stable.

When it works -- or doesn't

Other rules of thumb apply, too. For example, a managed WAN-optimization service is great for companies that have Web applications where access is unpredictable and the nature of those transactions -- many small bits of data -- is easy to optimize, Skorupa says. Likewise, a company with a fast network -- established for video and media distribution, for example -- would not benefit greatly from a managed WAN-optimization service. The greater the physical-network speed, the more a managed service will charge for optimization: a fact that often distinguishes entry-level vendors from the top tier.

Optimization is much more effective when data is not encrypted or compressed, adds Peter Sevcik, president of NetForecast. Oftentimes, that has companies in the financial, health and legal sectors avoiding managed services, because trusting optimization to an outside vendor might mean a potential breach of unencrypted data, Skorupa says.

For the most part, managed WAN-optimization services work independently of the application framework -- meaning a service can compress Adobe Flex data just as easily as Microsoft .Net data, Sevcik says. In addition, performance gains from a managed WAN-optimization service essentially are the same as those a company would achieve using an appliance. The reason? Enterprises and carriers are using the same WAN optimization gear, he says.

Carriers, however, are more apt to update their equipment more quickly than an enterprise will, says Charles King, an analyst with Pund-IT. "This results in customers enjoying optimized network performance without any of the headaches and hassles of purchasing, managing or maintaining that equipment themselves. For smaller companies, managed services offer levels of performance that would be nearly impossible for them to afford themselves. The benefits to enterprises mainly reside in being able to eliminate upfront costs and long-term management expenses, and reduce overall IT-staff head count. That can lead to significant financial savings."

Costs for managed WAN-optimization services vary by provider. In general, a carrier will price its service based on the types of applications, the number of users accessing them, the speed and quality of the physical line being optimized for them, and the number of remote sites being optimized.

As with any managed service, in the end the benefits match the costs: With faster physical networks, optimization becomes more complex and cost prohibitive. Sevcik advises companies to do the hard work of determining how optimization fits their changing needs and processes, then weighing the benefits of outsourcing bandwidth optimization.

Brandon, a freelance technology writer, can be reached at jbrandonbb@gmail.com.