Application traffic management is the process of logically routing client traffic to the best-matching backend resources for their requests. This ensures that data can move optimally across the network, reducing performance bottlenecks while boosting security, reliability, and scalability. Application traffic management is critical to improving application UX and overseeing exactly how traffic is flowing in a given timespan. 

Application traffic management's origins are fuzzy. After all, engineers have attempted to optimize routing performance (for their specific use cases) for as long as scalable applications have existed. The tools organizations use, such as load balancers and management platforms, have steadily evolved over decades. Such advancements have made this process more centralized and approachable.

How does application traffic management work?

Application traffic management relies on tight coupling between the data plane and the control plane. The data plane is responsible for transmitting network data back and forth as packets or datagrams. Meanwhile, the control plane acts as the "brain" or command center, governing traffic routing according to preconfigured rules. A collection of APIs or a centralized GUI enables teams to enforce these conditional routing behaviors globally, or per app. 

Together, the data plane and control plane work together to deliver critical application traffic management features, including the following:

  • Network mapping – Teams can view rich visualizations of how application traffic is flowing, while also seeing where network nodes reside, how they connect to one another, and how packets ultimately travel from Point A to Point B. This topology helps determine which network routes are the most efficient, often using systems of autonomous networks under the Border Gateway Protocol (BGP). 

  • Access control lists (ACLs) – Teams can assert fine-grained control over which clients can access which backend resources or applications. Through measures such as role-based access control (RBAC), ACLs also determine which actions a client can take. They restrict those horizontal, east-west traffic flows by dictating just how "far" clients can move across internal networks. ACLs make these decisions by inspecting source IP addresses, requested paths, requested hosts, and fluctuating request rates. 

  • Stateless client tracking – Stateless HTTP applications can be configured to capture important client behaviors during their sessions, including metrics collection, request rates, request header data, and more. Load balancers can take these bits of information, stored in-memory, and determine how to route clients to services. This process is also helpful for identifying returning clients, spotting malicious behavior (such as abuse), and generally enabling session persistence.

On top of all this, security plays a major role. ACLs and client tracking specifically feed into other security mechanisms that teams can employ, including rate limiting, DDoS protection, bot management, and web application firewalls (WAFs). These features work at the application layer (Layer 7) and make routing decisions based on the specific internet protocol info attached to each request. 

Application traffic management is also enabled through blue-green deployment patterns, flexible rainbow deployments, and canary deployments. This allows app teams to shift traffic between different versions of an application, either gradually or all at once, for easier testing under varying traffic conditions.

What are the benefits of application traffic management?

Application traffic management has many advantages, including the following:

  • Improved security through consistent policy enforcement

  • Improved session persistence and client behavior tracking

  • Better performance and scalability through traffic routing optimization, thus decreasing latency

  • Better reliability through smarter routing and security, thwarting would-be attackers and protecting the application itself 

  • Tighter unification of the data plane and control plane, often via centralization

  • Greater routing flexibility and logical operator support for deeper control over conditional traffic flows

  • Deeper observability and improved application monitoring

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Does HAProxy support application traffic management?

Yes! Application traffic management has become a baseline requirement for any team running modern, distributed applications. The organizations that get it right treat routing, security, and observability as a single discipline rather than three separate problems handled by three separate tools.

A unified application delivery platform makes this all possible. Here are two ways to explore further:

  • Explore the HAProxy One application delivery platform to see how HAProxy Fusion, HAProxy Enterprise, and the Global Profiling Engine work together to manage traffic and enforce security policy across your environments.

  • Request a demo to walk through application traffic management in HAProxy with our team and see how it fits your infrastructure.