Applications are core to how most users use their endpoint devices. Even when using a web browser, the websites are usually web applications running on backend servers or in the cloud. Application use is widespread and application proliferation shows no signs of slowing down any time soon. Indeed, many mobile apps are web applications wrapped in a mobile interface.
Organizations now rely on many applications to serve customers, empower employees and keep operations running smoothly. They need these applications to be fast, secure and highly available. To achieve this, organizations use Application Delivery Controllers (ADCs) to optimize network traffic, improve application protection and deliver consistent performance.
In this blog, we’ll explore what ADCs are, why they matter and how you can get started with the 100% free edition of the Progress Kemp LoadMaster solution. This free edition is a core part of the broader LoadMaster family. It runs on the same code base as the commercial editions of the LoadMaster solution, which means you can upgrade to a paid license at any time without reinstalling or reconfiguring a deployment that’s working the way you want.
LoadMaster free load balancer is a 20Mbps load balancer that is a free forever solution that includes core load balancing features, including layer 4 and layer 7 load balancing, advanced health checking, session persistence, intelligent traffic management and more.
The free edition does have a few restrictions compared to the commercial versions. See the compare page for more details:
Organizations can’t use it for commercial purposes
Layer 7 throughput gets capped at 20Mbps
TPS License (2K Keys) for TLS (SSL) sessions get capped at 50 per second
Active/Hot-standby Redundant Operation and Multi-Node Clustering are not available
Web Application Firewall (WAF) Commercial Rules are not available
What is Application Delivery?
Application delivery is the process of managing, optimizing and securing how applications get delivered across networks to users. It provides the infrastructure that enables applications to be fast, reliable and accessible wherever and whenever they are needed.
Application delivery involves balancing workloads, protecting data and fine-tuning performance to meet the fluctuating demands of businesses and other organizations.
Delivering an application that is highly available and high-performance requires a comprehensive set of supporting services. This is where the idea of an application delivery platform comes into focus.
Application delivery includes the services, technologies and processes that enable the reliable, secure and optimized delivery of applications to end-users. It involves using various technologies such as application delivery controllers (ADC), application performance monitoring (APM), application security solutions, load balancing and traffic management technologies to accelerate, monitor, manage and enhance the security of a software application.Ultimately, the goal is to provide a positive user experience for end-users whenever they use an application.
Organizations often struggle to provide IT teams with the tools they need to deliver the resilience of their application delivery infrastructure. And when outages occur, the costs can be significant. According to recent research from Uptime Institute, over 60% of outages result in at least $100,000 in total losses, underscoring the importance of application delivery as a key enabler of application performance and uptime.
What is an Application Delivery Controller (ADC)?
An ADC is a hardware network device or software solution that manages, optimizes and secures application traffic flowing between user devices and servers. ADCs act as an intelligent traffic agent, directing user requests to the best server while adding layers of security and performance optimization.
Gartner defines an ADC as follows, ”The application delivery controller is a key component within enterprise and Cloud data centers to improve availability, security and performance of applications. Application delivery controllers (ADCs) provide functions that optimize delivery of enterprise applications across the network.”
We’d add that ADCs take processor-intensive tasks off the web servers so they can focus on application tasks. An ADC is a core component of an Application Delivery Network, which is made up of a suite of technologies deployed in concert to deliver applications efficiently over the network.
Examples of ADCs include the Kemp Free Load Balancer and the Kemp LoadMaster family. These solutions deliver enterprise-grade features in both free and commercial editions, enabling businesses of any size to improve their application delivery.
Key Features of ADCs
Load Balancing (Layer 4 and Layer 7) - ADCs distribute incoming traffic across multiple servers to prevent any one server from becoming overwhelmed. Layer 4 load balancing works at the transport layer, making routing decisions based on IP addresses and TCP/UDP ports. Layer 7 load balancing functions at the application layer, enabling more advanced routing based on application content, URLs, HTTP headers and other application-specific criteria.
Security Features - Modern ADCs act as the primary defense for applications. WAFs monitor and filter application traffic to block attacks like SQL injection and cross-site scripting. SSL offloading capabilities enable ADCs to manage the resource-intensive process of SSL encryption and decryption, easing the load on application servers while keeping security intact. Other security features include intrusion prevention systems, Direct Denial of Service (DDoS) protection and data loss prevention tools.
Performance Optimization - ADCs use various techniques to boost application performance. Caching temporarily stores frequently requested content locally, which reduces response times and lowers server load. Data compression decreases the size of data transmitted over networks, enhancing bandwidth use and response times. Connection pooling and multiplexing improve network resource efficiency by managing server connections effectively.
Health Monitoring and Failover - ADCs continuously check the health of application servers and services. When they detect failures or performance issues, they automatically reroute traffic to healthy servers, maintaining application availability even during outages.
Global Server Load Balancing (GSLB) - Advanced ADCs offer global traffic management features, directing users to the most suitable data center or cloud region based on factors like geographic location, server load and network conditions.
API Management and Integration - Modern ADCs provide RESTful APIs, PowerShell integration and other management interfaces that facilitate seamless integration with DevSecOps workflows, automation tools and existing infrastructure management systems.
Benefits of Using ADCs
Deploying an ADC as part of your infrastructure delivers significant advantages for application delivery and overall business operations.
Enhanced Application Performance and Reliability - ADCs significantly boost application efficiency through smart traffic routing, caching, compression and connection management. By spreading workloads across multiple servers and automatically managing failover processes, ADCs keep applications accessible even during hardware failures or traffic surges. Users benefit from quicker response times and more dependable access to essential business applications.
Enhanced Security and Compliance - An ADC acts as a security gateway for applications, offering multiple layers of protection against modern threats. ADCs have integrated WAFs that analyze application traffic for malicious content, while SSL offloading provides secure communications without overloading application servers. DDoS protection features help keep applications available during attacks. These security capabilities assist organizations in meeting compliance standards for industries such as healthcare, finance and e-commerce.
Simplified Management and Scalability - ADCs centralize traffic management and offer unified visibility into application performance across the entire infrastructure. Administrators can oversee multiple applications and servers through a single interface, reducing operational complexity. As business demands increase, organizations can easily add new servers to existing ADC configurations without interrupting service. The scalable architecture means ADCs support everything from small departmental applications to large enterprise deployments.
Cost Optimization - By enhancing server utilization and lowering the computational load on application servers, ADCs assist organizations in maximizing the value of their current infrastructure investments. Efficient resource use means fewer servers are required to handle the same workload, which lowers hardware, power and maintenance expenses.
Seamless Cloud Integration - Modern Application Delivery Controllers support hybrid and multi-cloud deployments, allowing organizations to distribute applications across on-premises data centers and public cloud platforms while maintaining consistent performance and security policies via a single ADC management interface across all platforms.
How Do Application Delivery Controllers Work?
Application Delivery Controllers function by positioning themselves strategically within the network between users and application servers. They serve as intelligent intermediaries that make real-time decisions on how to route, process and optimize application traffic.
When a user starts a connection to an application, their request first reaches the ADC. The ADC assesses the request based on its configured policies and rules, taking into account factors such as the type of application, current server loads, health status of available servers and any applicable security policies.
For Layer 4 load balancing, the ADC looks at basic network details such as source and destination IP addresses and port numbers. It then chooses an appropriate backend server using algorithms like round-robin, least connections or weighted distribution. The ADC sends the request to the selected server and then manages the ongoing connection between the client and server.
Layer 7 load balancing adds application-aware intelligence to this process. The ADC inspects application-layer content such as HTTP headers, URLs, cookies and payload data. This deeper inspection allows for more advanced routing decisions. For example, an ADC might direct requests for static images to a specific group of servers optimized for image delivery, while sending database queries to servers specially configured as database servers.
Your load balancer ADC choice can have a significant impact on application traffic security processing. An ADC’s WAF checks incoming requests for malicious content by comparing them against known attack signatures and behavioral patterns. ADC TLS/SSL processing involves handling encrypted connections from clients, decrypting the traffic for inspection and analysis, then passing requests on to backend servers.
Performance optimization occurs via several mechanisms. Content caching systems store frequently requested data locally within the ADC, enabling subsequent requests for the same content to be served immediately without asking backend servers. Compression algorithms decrease the size of data transmitted between the ADC and clients, enhancing response times and reducing bandwidth use.
Health monitoring systems constantly check backend servers to confirm their operational status. The ADC removes any failed servers from the pool of available options and automatically redirects traffic to healthy ones. When failed servers recover, the ADC detects their return to service and resumes including them in load balancing decisions.
GSLB applies these principles across multiple data centers or cloud regions. DNS-based GSLB systems direct initial client connections to the most suitable location based on geographic proximity, current load levels and site availability.
Use Cases for Application Delivery Controllers
ADCs are valuable across many industries and deployment scenarios where performance, availability and security are critical business needs.
Online retailers rely on ADCs to manage traffic spikes during busy shopping seasons, enhance secure payment processing and provide fast page load times that directly influence conversion rates. During events like Black Friday or Cyber Monday, ADCs automatically scale to distribute large traffic loads across server farms while maintaining the security standards needed for payment card processing. Note: As mentioned previously, one of the few restrictions on the Free Load Balancer is that organizations cannot use it for commercial applications.
Software-as-a-Service (SaaS) applications rely on ADCs to provide consistent performance for users worldwide. Multi-tenant architectures benefit from smart traffic routing that maintains resource separation between customers while maximizing system efficiency. Global Server Load Balancing (GSLB) directs users to the closest data center, reducing latency and enhancing the user experience.
Healthcare organizations rely on ADCs to publish electronic health record systems, medical imaging applications and telemedicine platforms that stay operational 24/7. Delivering HIPAA compliance is supported through advanced security features like TLS/SSL termination, data loss prevention and audit logging capabilities.
Financial services such as banks, investment firms and insurance companies use ADCs to secure online banking platforms, trading systems and customer portals. High-frequency trading environments require ultra-low latency, which optimized ADC setups can help deliver. At the same time, regulatory compliance gets boosted via extensive security and monitoring features.
Critical infrastructure and utilities, including power companies, telecommunications providers and government agencies, rely on ADCs to keep essential systems operational. Redundant ADC deployments mean that control systems, billing platforms and customer service applications continue running smoothly even during infrastructure failures.
Enterprise application teams deploy ADCs to boost the performance of critical business applications like Microsoft Exchange, SharePoint, SAP and Oracle systems. Pre-configured templates help simplify the deployment of ADCs with optimal settings for these specific enterprise applications, reducing implementation time and maintaining best practice deployments.
Educational institutions, including universities and school systems, use ADCs to support learning management systems, student information systems and research applications. Traffic patterns in educational environments often show significant fluctuations between peak usage during class hours and low activity during breaks, making the scaling features of ADCs especially valuable, especially during exam times.
How to Choose the Right ADC for Your Needs
Selecting the appropriate Application Delivery Controller requires careful evaluation of your organization’s specific requirements, technical environment, and growth plans. We have discussed this topic at length, and we also have a freely downloadable buyers’ guide PDF to help you make the right choice for your needs (registration required). Here’s a summary of the main points to consider:
Performance Requirements - Begin by evaluating your current and expected traffic volumes, connection counts, and throughput needs. Consider peak usage times and plan for growth over the next 2-3 years. Determine whether your applications need Layer 4 load balancing, Layer 7 application-aware routing, or both. Take into account TLS/SSL processing requirements, since TLS/SSL termination can substantially impact performance specifications.
Feature Requirements - Identify the specific ADC capabilities your environment needs. Basic deployments might only require simple load balancing and health monitoring, while complex setups may need advanced features such as GSLB, robust WAF protection, advanced caching capabilities and detailed analytics. Also, consider how the ADC should integrate with existing network management tools, monitoring systems and automation platforms.
Deployment Environment - Decide whether you need physical hardware appliances, virtual appliances, or cloud-based solutions. Virtual appliances provide flexibility and cost advantages for many deployments, while hardware appliances deliver maximum performance for high-throughput environments. Cloud-native implementations can benefit from solutions specifically designed for public cloud platforms like AWS and Azure. You can also deploy in Google Cloud via hosted virtual machines.
Budget Considerations - Assess both initial acquisition costs and ongoing operational expenses, including support, maintenance and potential licensing fees. Consider the total cost of ownership over several years, taking into account the value of avoided downtime, improved performance and reduced administrative overhead.
Support and Expertise - Assess your team’s expertise with ADC technologies and evaluate the level of support you’ll need from the vendor. Some organizations prefer solutions with extensive built-in templates and automated configuration options, while others want maximum flexibility for custom configurations.
Comparison of ADC Solutions - The market provides various established ADC platforms, each with unique strengths and positioning. For a detailed comparison of leading solutions, including Progress Kemp LoadMaster, F5 BIG-IP and Citrix NetScaler, visit our comprehensive comparison page. While this comparison focuses on the commercial versions of these three solutions, it’s important to highlight that the free Kemp Load Balancer runs the same tested LoadMaster code base as the commercial LoadMaster family.
Starting with Free Solutions - The Free Load Balancer offers a great way to evaluate ADC capabilities without an initial investment. Organizations can use the free version to gain hands-on experience with ADC functions, verify performance in their specific environment and develop operational procedures before deciding on a commercial solution.
Conclusion: Enhance Your Network with ADCs
ADC have evolved from simple load balancers into comprehensive platforms that address the challenges of modern application delivery. The benefits they provide – improved performance, enhanced security, simplified management and seamless scalability – make them essential components of a robust IT infrastructure.
The key features of modern ADCs work together to create a powerful application delivery platform. Layer 4 and Layer 7 load balancing provide optimal traffic distribution, while advanced security capabilities, including WAFs and TLS/SSL offloading protect applications from evolving threats. Performance optimization features like caching and compression deliver the fast response times users expect and comprehensive monitoring means administrators have visibility into application behavior.
Organizations across multiple industries have discovered that ADCs deliver measurable business value through improved application availability, better user experiences and reduced operational complexity. From e-commerce sites handling traffic spikes to healthcare systems ensuring 24/7 availability of critical applications, ADCs provide the foundation for reliable application delivery.
Ready to experience the benefits of Application Delivery Controllers for yourself? The Progress Kemp LoadMaster family exemplifies the power and flexibility of modern ADC solutions. The free Load Balancer edition offers a risk-free way to experience enterprise-grade ADC capabilities, with the confidence that you can seamlessly upgrade to commercial licensing as your needs grow, with no reinstallation or reconfiguration required.
Remember, the free LoadMaster solution can be upgraded to a commercial version through a simple license upgrade, maintaining your initial investment in deployment and configuration carries forward as your organization grows.
Download a free, forever copy of Free LoadMaster today.