The Critical Role of an Application Delivery Controller

In any economic environment a company's senior management expects that their IT organization will continually look for ways to cut cost, get better control over the company's data assets, and show a high rate of return on the investments that they make.  The current economic environment has significantly increased those pressures.  One of the initiatives that many IT organizations have taken in order to respond to senior management's expectations is to consolidate resources, such as applications, servers and storage into centralized data centers.  Due to the economy of scale that occurs upon consolidating resources, this initiative reduces cost.  This initiative also enables an IT organization to have better control over who has access to a company's data and to be better able to enforce security policies.

However, before these resources were consolidated, most data traffic transited a high-speed, low latency LAN.  After resource consolidation, most data traffic transits a relatively low-speed, high latency WAN.  In addition, in many cases a chatty protocol such as Common Internet File System (CIFS), which was designed to run over a LAN, now runs over a WAN.  A chatty protocol requires tens, if not hundreds of round trips, to complete a single transaction.  The combination of factors such as these often results in unacceptable application performance.

Another initiative that many IT organizations have taken in order to respond to senior management's expectations is to deploy new Web-based applications and to implement Web-based interfaces on existing applications.  The resulting applications are accessed via a Web browser over a network such as the Internet or an intranet.  Among the advantages of Web-based applications is the fact that it eliminates the need to install and manage clients on each access device.  Web-based applications utilize protocols such as HTTP.  The good news is that HTTP is not as chatty as is CIFS.  The bad news is that is common for a Web application to use fifty or more objects to create a single page.  It is also common to have each object require ten or more packets be transmitted.  The result of having to transmit hundreds of packets in order to down load a single Web page is unacceptable delay and user frustration.

Resource consolidation and the deployment of Web-based applications are just two examples of IT initiatives that provide significant value, but which often result in unacceptable performance.  As will be shown in this brief, in order to overcome these performance challenges, IT organizations need to implement an Application Delivery Controller (ADC).  This brief will also discuss criteria that IT organizations should use in order to choose an appropriate ADC.

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