Application Delivery Controller

An application delivery controller (ADC) is a computer network device in a datacenter, often part of an application delivery network (ADN), that helps perform common tasks, such as those done by web sites to remove load from the web servers themselves. Many also provide load balancing. ADCs are often placed in the DMZ, between the outer firewall or router and a web farm.

A common misconception is that an ADC is an advanced load-balancer. This is not an adequate description. In fact, an ADC includes many OSI layer 3-7 services including load-balancing. Other features commonly found in most ADCs include SSL offload, Web Application Firewall, NAT64, DNS64, and proxy/reverse proxy to name a few. ADC & ADN are marketing terms invented by F5 Networks and other vendors to imply that business applications require front-end intelligence to supplement and enhance application flows from client to server back to client.

First generation ADCs, starting around 2004, offered simple application acceleration and load balancing. In 2006, ADCs began to mature when they began featuring advanced applications services such as compression, caching, connection multiplexing, traffic shaping, application layer security, SSL offload and content switching combined with services like server load balancing in an integrated services framework that optimized and secured business critical application flows.

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