Application Delivery Controllers (ADC)

What are Application Delivery Controllers?

An application delivery controller (ADC) is a network component that manages and optimizes client connections to web and application servers. Its capabilities are implemented through either a hardware device or software. ADCs are housed in a data center between network firewalls and application servers and are a part of application delivery networks (ADNs) along with WAN (wide area network) optimization controllers (WOCs).

Application delivery controllers are used to accelerate application delivery, maintain website performance, and promote application availability, visibility, security, and scalability.

ADCs speed up application delivery through load balancing, SSL offloading, smart caching, and intelligent compression. ADCs can include firewalls and intrusion detection, fend off DDoS (distributed denial-of-service) attacks and provide analytics regarding application performance.

ADCs help support outward-facing applications such as eCommerce sites and internal applications such as CRM, ERP, BI, MS Exchange, and SharePoint. Software-defined networking trends have pushed ADCs to function more like SaaS (software-as-a-service).

Organizations that use large-scale delivery content networks (CDNs), employ application delivery controllers to ensure responsive and secure web application services for their high-volume sites. IT, network, and DevOps teams manage and analyze application delivery controller performance.

Application Delivery Controllers Features

Application delivery controllers will have many of these features

• Application acceleration
• Load balancing / global load balancing
• Caching
• Compression
• SSL offloading
• Proxy and reverse proxy
• Bandwidth management
• Traffic shaping
• TCP multiplexing
• Multi-tenancy architecture support
• Security, SSO (single sign-on), application authorization
• Application and server health monitoring
• Web application firewall
• DNS firewall
• Intrusion detection
• DDoS protection

Application Delivery Controllers Comparison

Consider the following when purchasing application delivery controllers.

Application delivery controller physical device vs ADC software: A physical device supports more features, has better performance due to customized computer chips and specialized network interfaces, and comes at a higher cost than its software counterpart. The software implementation is more flexible, offers a simplified infrastructure, runs on any infrastructure including a public cloud, can be provisioned on-demand, and is priced lower than an ADC physical device.

Scope of Features: ADC’s offer a broad range of features, however, if your needs are limited to Load Balancing Software, for example, no need to countenance the higher costs that ADCs with extensive features will incur.

ADC Capacity: Determine your requirements for incoming connections per minute, and the amount of bandwidth that will need to be managed along with any scaling up requirements that may occur in the future. ADCs offer different capacity levels, with their costs increasing as their capacities expand.

Pricing Information

Pricing is dependent upon the features and capacity of the application delivery controller, and whether it is a physical device or a virtual software appliance. Pricing models can be for a perpetual license or a monthly fee. Basic physical devices can be found starting at around $1,000 dollars while full-featured, high-capacity, enterprise-level physical devices can cost up to and over $200,000. Software versions pricing is based on the number of connections, bandwidth, and rules to be applied. Vendor price quotes are usually required. Free trials are usually available.