* Centralized Application Delivery Systems and Distributed ADS
Last time, I started a discussion about application performance over WANs, which was prompted by a paper sent to me by an industry watcher. While the last focused more on the problem, this newsletter will focus more on the solutions available today.
Recently, Peter Sevcik, president of research firm NetForecast and his colleague Rebecca Wetzel released an extensive report, dubbed “Field Guide to Application Delivery Systems.” The report is available here, after registration. (It is worth noting the report was sponsored by vendors in the market, Citrix, Juniper, Packeteer, Radware and Riverbed.)
Centralized Application Delivery Systems (ADS), or those that require technology on one side of the WAN link; and Distributed ADS, which use appliances or software installed in the data center and remote locations, perform many similar functions.
For example, both offer techniques to control (such as QoS) and accelerate traffic, using various techniques. Sevcik and Wetzel offer tips on how to choose an ADS system based on application performance and business needs; sometimes products that help control traffic are better suited to customer needs, and sometimes products that accelerate are. (The full report includes extensive charts detailing the techniques and technologies and what they are best suited to address.)
“When you need to protect your users’ application performance experience from insufficient bandwidth and/or server resources, you need to look at control solutions,” the report states. “The subset of control techniques that will help in your situation depends on the particular performance problem you face, and the particular protocols that you need to protect.”
For instance, ADS control techniques, the report states, can help protect business continuity, manage application traffic and enable more predictable performance. The report authors recommend using control technologies to enhance user productivity with certain applications, to enable remote users access to centralized resources and to facilitate remote collaboration.
