How load balancing works in proxy systems

Load balancing is a mechanism for distributing incoming requests across multiple servers or devices so that none of them becomes overloaded, and the overall service operates faster and more reliably.

Why is it needed?

A single server rarely handles peak traffic on its own. Clients experience longer wait times, and delays quickly turn into negative impressions and loss of trust. A load balancer transforms chaotic traffic spikes into a controlled flow. It can distribute requests evenly, select nodes with the lowest load, or take client-specific characteristics into account. The “health” of the target system is also monitored — if one server fails, others take over its workload, and the user hardly notices any disruption.

Why load balancing is especially important for proxy servers

Proxy servers handle incoming client requests, process them, sometimes cache popular content, and forward them further. Without a load balancer, a single proxy may become overloaded, and users will start noticing slow responses. Load balancing distributes traffic across multiple proxy nodes so that each client receives a fast response, while the system remains resilient even if one of the nodes goes offline.

The role of proxies in network architecture

A proxy can be viewed as an intelligent intermediary between clients and target services. Depending on the task, a proxy can:

• hide the client’s real location;
• filter content;
• cache popular requests;
• help manage access;
• distribute incoming requests;
• protect internal services;
• accelerate content delivery.

Internal proxies represent deeper layers of architecture that can distribute tasks between microservices, provide caching within a cluster, accelerate data access, and centrally manage access policies. In modern infrastructure, these roles are complemented by solutions such as API gateways and service meshes (the former is a type of reverse proxy tailored for API requests; the latter is a collection of proxies within a cluster that manage service-to-service communication, provide observability, and enforce security at the level of microservice calls).

Proxies often occupy a central place in architecture because they enable centralized control: unified security policies, a single point of traffic visibility, the ability to quickly deploy updates, and flexible resource access management.

• Through caching, filtering, and content acceleration, proxies improve performance.
• Through routing and TLS termination, they reduce backend load and enhance security.
• Through flexible scaling scenarios, they simplify adding new nodes and data centers.

Proxies transform a complex network of multiple services into a manageable and predictable architecture where each component performs its clearly defined role and works seamlessly with the others.

In proxy systems, the load balancer acts as an intermediary layer responsible for distributing incoming traffic across multiple nodes or services.

Core load balancing algorithms

Even request distribution (Round-robin)

• Each new request is sent to the next available node in sequence, without considering the current load of the nodes.
• Works well when nodes are approximately equal in capacity and workload.
• Keep in mind: it may send many requests to an overloaded node if its state changes rapidly.

Selecting the server with the lowest load (Least connections, or Least load)

• Directs new requests to the node currently handling the fewest active connections.
• Works well when load distribution is uneven and connections vary in duration.
• Keep in mind: requires up-to-date real-time metrics.

Considering the performance or capacity of each node (Weighted / Capacity-aware)

• Each node is assigned a weight reflecting its actual capacity (CPU, memory, I/O) or current throughput.
• Works well when nodes differ in power or when cluster configuration changes.
• Keep in mind: weights must be dynamically adjusted; otherwise, a weaker node may become a bottleneck.

Load balancing at the protocol level

L4 load balancing (transport layer: TCP/UDP)

• Focuses on packet transmission at the IP and TCP/UDP level. The load balancer makes decisions based on network-layer headers and certain connection properties.
• Advantages: very fast processing, minimal latency, transparent to the client.
• Limitations: does not see application-level content and cannot make decisions based on URL, headers, or request body.

L7 load balancing (application layer, HTTP/HTTPS)

• Load balancing with deep integration into the HTTP/HTTPS protocol. L7 balancers analyze headers, request paths, methods, cookies, parameters, and even the request body.
• Advantages: maximum flexibility, the ability to optimize specific usage scenarios, improved responsiveness through content-based routing.
• Limitations: slightly higher latency due to protocol inspection, requires careful certificate and security management, and may present scaling challenges in highly dynamic traffic patterns.

Advantages and possible challenges

Advantages

High availability ensures that even if one node temporarily fails, others continue processing requests. As a result, users do not experience noticeable downtime, and the service maintains uninterrupted operation even during traffic surges. Optimal load distribution turns peak demand into a manageable flow, with the balancer considering node load, client geography, and traffic characteristics so that all parts of the infrastructure operate harmoniously while latency remains minimal. Performance becomes predictable and controllable: clients receive consistent response times and avoid sudden latency spikes, even when demand changes unexpectedly.

Potential challenges

Configuring load balancers requires understanding which algorithms to apply, how to balance speed and routing precision, and which metrics must be continuously monitored. In real-world environments, routing may introduce slight latency, especially when deep protocol inspection (L7) or TLS termination is involved. Global configurations add further complexity, including inter-regional latency, security policy management, and cache consistency across distributed locations.

Conclusion

Load balancing is a key component of a clear and resilient proxy architecture, and in this context, the proxy service Belurk serves as a tool that combines the strengths of load balancing and network management. Belurk offers flexible balancing mechanisms that allow traffic distribution not only to be fast but also content-aware — taking into account request paths, headers, and TLS sessions. It provides efficient TLS termination, reducing computational load on backend systems, and supports dynamic traffic redistribution in case of failures or changes in node composition. With broad geographic coverage, node health checks, and adaptive routing strategies, Belurk enables organizations to quickly adapt to demand growth, regional conditions, and architectural changes without sacrificing responsiveness or stability.