Application delivery controller
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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 accelerators 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.
There are many type of ADC vendors. Software-only ADC vendors such as Avi Networks, Buoyant, NGINX, Snapt Inc & Pulse Secure. Traditional ADC vendors such as A10 Networks, F5 Networks, Citrix Systems & Kemp Technologies. As the market evolves there will be an increasing amount of vendors offering cloud-integrated and software-centric versus hardware based.
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.
Application acceleration products were available from many companies by 2007, for example F5 Networks, Juniper Networks, Microsoft, KEMP Technologies, AVANU WebMux, Snapt Inc, and aiScaler. Cisco Systems offered application delivery controllers, until leaving the market in 2012. Market leaders like F5 Networks, Radware and Citrix had been gaining market share from Cisco in previous years.
The ADC market segment became 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 more aware of optimization strategies that work best with a particular application framework, focusing on ASP.NET or AJAX applications, for example.
In 2005, a market research firm estimated the ADC market at US$ 727 million, with major vendors including F5 Networks and Cisco Systems. In 2012, Cisco Systems lost market share to companies like F5, Citrix, Radware, aiScaler and A10 Networks . F5 has since gone on to become the market leader within the ADC space.
In 2015, Brocade Communications Systems acquired the SteelApp business unit of Riverbed Technologies, Inc. to expand on its ADC offerings and consolidate its position in the Software Defined Data Center/Software Defined Network arena. Brocade renamed SteelApp to Brocade Virtual Traffic Manager (aka VTM).
In 2016, Webscale launched their Cloud-based Application Delivery Platform, with the included software-defined ADC to integrate seamlessly with the application and utilize cloud infrastructure to improve performance, availability and security 
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- "Brocade acquires Riverbed ADC to bolster virtual delivery services".
- "APPLICATION DELIVERY CONTROLLERS".
- "CLOUD ADC".