What Is Load Balancing? How Do Load Balancers Work?

Today, as online services and applications have become integral to our daily lives, the network’s availability, performance, and reliability take center stage. In this setting, load balancing emerges as a foundational concept in modern web architectures, acting as an essential tool to accomplish these objectives.

Understanding Load Balancing

Load balancers distribute incoming network traffic across several servers or resources to prevent any one server from becoming overloaded. When a load balancer receives a request, it directs the request to the server it determines is best equipped to handle it. This technique optimises resource utilisation, prevents bottlenecks, and enhances the overall responsiveness and fault tolerance of a system.

Types Of Load Balancers

The load balancer can be classified based on the supported technologies or based on geographical support. The technological types are,

• Server Load Balancer: Server Load Balancers distribute traffic among multiple servers to optimise resource utilisation. They can operate at different layers of the network stack, offering flexibility and diverse functionalities. They are further classified as,
• Application-aware load balancers, also known as Layer 7 load balancers, make routing decisions based on application-level data. They can inspect HTTP headers, cookies, or other application-specific attributes to intelligently route traffic to appropriate backend servers based on the application’s requirements.
• Network-level load balancers, also known as Layer 4 load balancers, focus on routing traffic based on IP addresses and ports. They distribute incoming requests evenly across backend servers without considering application-level details.
• Link Load Balancers: Link Load Balancers specialise in distributing internet or network traffic across multiple connections, optimising outbound traffic from data centers to various external destinations. By aggregating multiple links into a logical bundle, these load balancers intelligently route data packets. Link load balancers offer enhanced failover capabilities, automatically redirecting traffic to alternative links in the logical bundle if one or more links experience issues.

The load banker classifications based on geographical support are,

• Local Load Balancers: They are deployed within a single data center or location and distribute traffic among servers within that data center. They ensure efficient resource utilisation, high availability, and low-latency connections for users accessing services or applications hosted locally.
• Global Load Balancers: They distribute traffic across multiple data centers or geographically dispersed locations. Global load balancers enable efficient load distribution and redundancy across multiple regions, ensuring high availability and disaster recovery capabilities.

How Load Balancers Work

• Traffic Distribution: Load balancers act as the entry point for incoming traffic, intelligently assessing the state of backend servers or links before deciding where to route each request. Factors such as server or link health, current load, and response times are considered to ensure optimal distribution of the workload.
• Health Monitoring: Load balancers continuously monitor the health of all the servers in the backend pool. They regularly send health check requests to each server or the status of the links in a link load balancer setup to assess their availability and responsiveness. If a server or link fails to respond or experiences issues, the load balancer detects this and automatically takes the problematic server or link out of rotation. This helps prevent directing traffic to unhealthy servers or links and contributes to maintaining high availability.
• Load Balancing Algorithms: Both server load balancers and link load balancers employ various load balancing algorithms to determine how to distribute traffic among backend servers or links. These algorithms consider factors such as round-robin, least connections, weighted round-robin, least response time, and more. The choice of algorithm depends on the specific load balancing needs and characteristics of the applications running in the data center.
• Session Persistence: Maintaining session persistence is essential for certain applications. Load balancers can ensure this continuity by implementing session persistence techniques. For example, using sticky sessions, the load balancer maps a user’s initial request to a specific backend server, and subsequent requests from the same user are directed to the same server throughout the session. This ensures that session-related data remains consistent during the user’s interaction with the application.

Get High Performance with Yotta Load Balancer as a Service

Load balancing is an indispensable tool in the world of modern web architecture. By effectively distributing incoming traffic across multiple servers, load balancers optimise resource utilisation, enhance performance, and ensure high availability.

Yotta Load Balancer as a Service offers a virtual load balancer that efficiently manages online traffic, automatically distributing workloads across multiple servers and resources. By doing so, it optimises workload performance, prevents overload, and ensures a seamless user experience. This load balancer supports heterogeneous OS, physical, and virtual servers, and it can handle various HTTPS and TCP applications, including TCP/IP, UDP/IP, HTTP, FTP, DNS, Mail, Telnet, and more.

Users can choose from a range of flexible algorithms or policies to suit their specific needs, benefiting from dynamic load steering, active origin monitoring, and configurable origin weights. Additionally, the load balancer provides session affinity, SSL offloading to enhance performance, and the advantage of the fastest managed DNS with no DNS propagation delays for proxied traffic.