August 26, 2013, 5:05 PM — This vendor-written tech primer has been edited by Network World to eliminate product promotion, but readers should note it will likely favor the submitter's approach.
It was a decade ago, in 2003, when Gartner first defined the application delivery controller (ADC). At that time, ADC was little more than the marriage of load balancing and offload technology.
Fast forward to 2013 and the definition of an ADC bears very little resemblance to its original form. ADC now comprises a robust set of capabilities such as SSL VPN, IPv6 gateway, web application firewall, WAN optimization and programmability, among other things.
This evolution in the definition of ADC was not arbitrary; rather, it reflected the inclusion of new, adjacent capabilities. As related trends such as Web 2.0, social networking and cloud impacted application and data center architectures, functions such as identity and access management were offloaded and consolidated on ADC systems capable of rapidly providing these services.
The natural topological deployment of an ADC as the entry point or gatekeeper to applications made the inclusion of a variety of related features a logical step forward. As the primary point of control, services like security and access, filtering and steering were a natural fit for ADC, despite definitions of the ADC that notably excluded identity management or HTTP message steering.
Throughout this migration of services onto ADC systems, the ADC market has continued to grow. Every time a new capability is integrated into the ADC -- such as WAN optimization, web application firewalling or application acceleration -- the market expands. The upper limit on the ADC market is constrained only by current definitions -- definitions that have historically evolved and expanded. Definitions that will no doubt expand and evolve again.
The pressure from technologies like cloud, software-defined networking (SDN), and even mobile computing, is forcing organizations -- and the vendors that support them -- to react rapidly to the need for more and varied services. The traditional quick, pain-point solution purchase is no longer acceptable because it introduces operational overhead that results in higher short- and long-term costs and complicates architectures. An extensible, service-oriented model is now desired, as evidenced by the interest in SDN and adoption of cloud computing.
The ADC is based on such a model. It is a platform, not a product, and as such can extend its capabilities rapidly in response to changing business and architectural needs.
Platforms and Ecosystems