Understanding Load Balancing and Load Balancers

This article explains the basics of load balancing and describes different types of load balancers.

Load balancing is the method used to distribute workload evenly across multiple resources. Load balancers are the tools used to achieve this.

A load balancer can be a dedicated piece of hardware, a software application, or a combination of both.

The “load” being balanced can be various things such as tasks, web traffic, or application requests.

Why is Load Balancing Needed?

Load balancing is essential for several key reasons:

• To Scale Up Applications and Services: Load balancing allows you to distribute traffic across multiple servers, enabling your application to handle a greater volume of requests.
• To Facilitate Easy Maintenance and Administration: With multiple backup servers ready to take over, you can perform maintenance on individual servers without interrupting service.
• Resource Sharing: Load balancing can offload heavy traffic from a single server and distribute it across multiple servers connected on different ports. This is particularly useful for websites experiencing high traffic. Multiple servers host identical copies of.jpgages, allowing the load balancer to distribute requests efficiently.
• Pipelining: The concept of pipelining, commonly used in processors (CPUs), can also act as a form of load balancing. Instead of executing tasks sequentially, pipelining enables tasks to be performed in parallel, thereby speeding up the overall operation of the computing device.
• Complex Wireless Receivers: Load balancing principles are also applied in complex wireless receivers. Algorithms are often split between Digital Signal Processors (DSPs) and Field-Programmable Gate Arrays (FPGAs). Time-critical tasks are handled by the FPGA, while less critical tasks are managed by the DSP. For instance, Layer 1 (Physical Layer) algorithms might run on the FPGA, while Layer 2 and higher-layer functionalities are handled by the DSP.

Load Balancer Types

Load balancers come in various types, each designed to handle different types of workloads and employ different load balancing algorithms. Here are a few common algorithms:

• Round Robin: The load balancer distributes incoming requests evenly across a group of connected servers in a cyclical fashion.
• Least Connections: The load balancer monitors the number of active client connections on each server. New client requests are then routed to the server with the fewest current connections.
• Based on IP Address: The load balancer examines the incoming IP packet and port number to determine the appropriate server to which the packet should be routed.

The image above illustrates a typical setup for balancing traffic load across servers. A Server Load Balancer is used to distribute the load evenly.

To accomplish this, the load balancer performs the following functions:

• It maintains information about the servers, including their IP addresses and port numbers.
• It utilizes protocols like TCP/IP, UDP/IP, FTP, and SIP to perform its function.
• It performs Network Address Translation (NAT), rewriting packets with new IP addresses and port numbers as they pass through the load balancer.