How Server Load Balancing Technology Works

How Server Load Balancing Technology Works

Redundancy. It’s a critical factor for many industries. Whether your company follows a business-to-business or business-to-consumer approach, it’s essential your online services and company resources are accessible to both your customers and your team. That’s where server load balancing technology comes in to help.

What Is Server Load Balancing?

So what is server load balancing? It’s a type of load maintenance, which is a concept that focuses on performance, scalability and redundancy. Instead of relying on a single computer, you divvy up your company’s workload across multiple machines.

In server load balancing, you divide that workload among a cluster of two or more servers, also known as a server farm or server pool. Network cables and clustering software connect servers to share data, monitor machine status and initiate recovery procedures in case of a server failure.

What Is Network Load Balancing?

Another offshoot of load balancing is network load balancing. For many, server load balancing and network load balancing are one in the same. The truth is that the two are different, however. So what is network load balancing?

It’s also a method for managing machine workloads, but focuses on network demands. Sessions for accessing websites and email servers, for example, can use network load balancing to ensure these internet resources remain accessible even in the event of an outage.

How Does Server Load Balancing Work?

Even though network and server load balancing differ from a technical perspective, they’ve become linked with the evolution of the global marketplace. Hence the introduction of global server load balancing, which is when servers exist in multiple geo-locations to deliver faster service to users across the globe.

The goal of server load balancing is simple: provide high availability (HA) and limited downtime. How does server load balancing work, though? It’s thanks to load balancing technology. Via a hardware- or software-based load balancer, such as Microsoft’s Network Load Balancing (NLB) program, you have the necessary management tools for your cluster. With network load balancing, you’re overseeing a few features, including:


As you establish your global server load balancing systems, it’s essential you configure the following:

  • Cluster parameters
  • Port rules
  • Host parameters

Factors like port rules will influence your load balancing algorithm.

NLB Modes

Microsoft’s NLB includes two modes: unicast and multicast. In either method, it’s critical to limit switch flooding.

Unicast is Microsoft’s default mode, which alters the Media Access Control (MAC) address of your network adapters. Instead of your server clusters using their original MAC addresses, they use the virtual MAC and IP address of your host.

Multicast delivers a similar result as the unicast mode. Instead of changing the MAC address of your network adapters, however, it creates a two-layer multicast address. What’s convenient about this approach is that your clusters keep their original MAC address.

Load Balancing Algorithm

How your server farm operates also depends on its load balancing algorithm, which the following factors influence:

  • NLB mode
  • Affinity
  • Port rules
  • Host priorities
  • Client port number
  • Client IP address
  • Internal load information

Based on these factors, several load balancing algorithms are available, including:

  • Round robin
  • Least connections
  • Least latency
  • Least traffic
  • URL hash
  • IP hash

Now that we’ve built a backstory for load balancing, let’s look at how global server load balancing works in action:

  1. A user in the U.S. visits your company website.
  2. A request is sent to your server farm’s host, which is based in Europe.
  3. A query is delivered to the user for their IP address.
  4. A receipt of the user’s information is provided to the server pool’s host.
  5. A status check of the server farm is conducted by the host.
  6. A server in the cluster is directed to handle the user request, likely one based in the U.S.

Once that server processes the request, your company’s site loads. It’s a quick, seamless process.

Why Global Server Load Balancing Is Important

Companies with an international presence agree: global server load balancing is critical in today’s market. With a cluster of servers in multiple geo-locations, your business enhances its redundancy and business continuity plans by ensuring your website and services stay accessible.

Another benefit of this type of load balancing is its performance. If your servers are based in the U.K., yet your U.S. consumer base is growing, you can expect they’re experiencing increased latency when viewing and loading your web pages. With servers in multiple geo-locations, you can ensure they receive immediate access to your site.

Power Your Global Server Load Balancing With Worldwide Supply

At Worldwide Supply, we carry the load balancing technology your company needs to succeed. In addition to stocking load balancers from Coyote, Barracuda and other trusted manufacturers — which include a standard lifetime warranty — we also provide repair services.

Learn more about our ISO- and TL 9000-certified company and services by contacting us today!

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