An application delivery network (ADN) is a network that helps ensure high performance, high availability, and security for web applications. The overall goal of an ADN is to provide improved user experiences on the client side while optimizing resource utilization and infrastructure health on the backend. 

An ADN leverages multiple geographical infrastructure locations to help serve applications to nearby users—much like a content delivery network (CDN) aims to bring users and data closer together. However, application delivery networks stand apart by serving dynamic content and data (plus the entire application stack) versus static (cacheable) content such as videos, images, client-side scripts, and other files. 

For example, a dynamic web application will often display differently for each user while a static equivalent would appear identical for everyone. This often requires multiple database queries that wouldn't be necessary for static web applications.

What makes an application delivery network (ADN) useful?

For the reasons we've mentioned, dynamic applications are generally more resource intensive and require heavier optimization to perform as expected. Delivering a good end-user experience is still the goal, but the application acceleration and high availability features baked into ADNs can lighten the backend load. 

ADNs don't exist merely to make dynamic web applications perform similarly to static web applications, but as a reflection of these unique (and numerous) challenges. 

ADNs can optimize performance in multiple ways by doing the following: 

  • Reducing latency

  • Increasing throughput

  • Reducing resource utilization (CPU, memory, disk space)

  • Optimizing data I/O (indicators of payload management and compression effectiveness)

  • Managing thread counts

  • Reducing network bandwidth consumption

A system that's healthy and performant will respond faster, handle a greater number of requests per second (average or peak), induce less server load, and avoid gumming up networks. Another way to realize sweeping performance gains is to deploy an ADN and CDN together—as many organizations do—to better serve all content and plug any geographical gaps.

Does HAProxy provide application delivery network (ADN) functionality?

Yes! HAProxy Edge is a globally distributed application delivery network, or ADN, that provides a wide range of turnkey application delivery services at massive scale and with first-class observability. These services include advanced security, application and content acceleration, and load balancing. 

HAProxy Edge bolsters this support with optional CDN functionality to help serve more users more quickly with static content. This is ideal for boosting performance for those who don't need the extra security measures offered by our ADN. 

To learn more about HAProxy Edge and related ADN functions within HAProxy, check out our HAProxy Edge datasheet.