An application delivery controller (ADC) is a network device in the datacenter that helps perform common tasks done by web sites in an effort to remove load from the web servers themselves. Many also provide load balancing

Load balancing (computing)

Load balancing is a computer networking methodology to distribute workload across multiple computers or a computer cluster, network links, central processing units, disk drives, or other resources, to achieve optimal resource utilization, maximize throughput, minimize response time, and avoid...

. They usually sit between the firewall

Firewall (computing)

A firewall is a device or set of devices designed to permit or deny network transmissions based upon a set of rules and is frequently used to protect networks from unauthorized access while permitting legitimate communications to pass....

/router and the web farm. The ADC is in many cases described as the next generation load balancer. They tend to offer more advanced features such as content manipulation, advanced routing

Routing

Routing is the process of selecting paths in a network along which to send network traffic. Routing is performed for many kinds of networks, including the telephone network , electronic data networks , and transportation networks...

 strategies as well as highly configurable server health monitoring. ADCs tend to offer features like compression, cache, connection multiplexing

Multiplexing

The multiplexed signal is transmitted over a communication channel, which may be a physical transmission medium. The multiplexing divides the capacity of the low-level communication channel into several higher-level logical channels, one for each message signal or data stream to be transferred...

, application layer security, SSL offload

SSL acceleration

SSL acceleration is a method of offloading the processor-intensive public key encryption algorithms involved in SSL transactions to a hardware accelerator....

, content switching combined with basic server load balancing.

Application acceleration products are available from many companies. This market segment is now becoming fragmented into two general areas: 1) general network optimization and 2) application/framework specific optimization. Both types of devices improve performance, but the latter is usually much more aware of optimization strategies that work best with a particular application framework, focusing on ASP.NET

ASP.NET

ASP.NET is a Web application framework developed and marketed by Microsoft to allow programmers to build dynamic Web sites, Web applications and Web services. It was first released in January 2002 with version 1.0 of the .NET Framework, and is the successor to Microsoft's Active Server Pages ...

 application performance tuning, or AJAX

Ajax

- Mythology :* Ajax , son of Telamon, ruler of Salamis and a hero in the Trojan War, also known as "Ajax the Great"* Ajax the Lesser, son of Oileus, ruler of Locris and the leader of the Locrian contingent during the Trojan War.- People :...

application performance tuning, for example.

There is growing consensus that the application acceleration market is moving towards more convergence between the network and the application layers

External links

• Application Acceleration Market Hits $1.2B eWeek. Retrieved 10/27/2007.