Last time, we mentioned how most application acceleration techniques function at Layers 3 through 5 of the OSI model. We also discussed some of the advantages of an emerging approach to application acceleration - one that focuses at the application layer.

Another advantage of a solution that focuses at the application layer is that having an understanding of an application's data objects as well as the application's semantics enables an application optimization solution to recognize application data and anticipate its use from previous requests. This capability allows the solution to make requests of a distant server prior to those requests being made by the client. In this way, the application optimization solution is in a position to respond locally and hence quickly, when the client does make those requests.

It is important to realize that the amount of improvement in the application response time that results from deploying these types of solutions depends on the ability of the solution to accurately identify an application object. As you might guess, identifying an application object is a complex task in part because there are multiple ways that an object can be referenced.

One of the challenges that IT organizations face when evaluating the viability of deploying any application performance enhancement technique, including ones that focus at the application layer, is to quantify in advance the impact that the technique will have on the throughput and response time of their key applications. While third-party tests are helpful, they may not be terribly relevant as it is impossible for a third-party test to be set up in such a way as to reflect the application and network environment found inside every organization. Hence, in order to quantify the impact of an application performance-enhancement technique, IT organizations need to test that technique in their environment. This can be done either by setting up a lab environment that mirrors the company's production environment or by implementing the technique on a segment of the company's network.

On Sept. 13, Network World will be hosting its free IT Roadmap seminar in Dallas. Jim will be moderating a session on network and application optimization and will discuss a variety of network and application optimization techniques, including optimization at the application layer. If you are in the Dallas area, kindly make plans to attend. For more details about the event and how to register, go here.

Steve Taylor is president of Distributed Networking Associates and publisher/editor-in-chief of Webtorials. Jim Metzler is vice president of Ashton, Metzler & Associates.