By IT Brew Staff
less than 3 min read
Definition:
In life’s high-traffic situations—like a busy intersection, airport, or Trader Joe’s—it helps to have a director who can send you down the right lane and get everyone moving to their destinations as quickly as possible.
Site traffic has its own version of rush hour, too—and its own version of traffic controllers to help with the crowd. Hardware, software, and cloud-based technologies known as load balancers send network traffic efficiently to a company’s various server options.
Like the host at a restaurant, the load balancer sits in front of a group of servers. The tool parcels out incoming client requests. For example:
- A client sends a request to the load balancer’s address.
- The load balancer uses its scheduling algorithm to pick the right server, factoring in connections and a server’s health. (The traffic manager here can also monitor the health of individual servers and remove unresponsive or ineffective ones.)
- The selected server processes the request.
In addition to hardware load balancers (which run on dedicated hardware devices) and software load balancers, there are also open systems interconnection (OSI) load balancers, including layer 4 balancers (which make routing choices based on network-level details like IP addresses and TCP ports), and layer 7 balancers (which review application-related details such as URLs, cookies, and user location). Configurations, for example, could send URLs for a checkout page to one dedicated server pool.
Static algorithms make decisions based on fixed rules like specific IP addresses. A “round-robin” method handles servers in a sequential order; a weighted round-robin version also allows tech pros to configure servers to handle more traffic than others if needed.
Dynamic algorithms make decisions measuring factors like fewest connections, least response time, and availability of compute and memory.
Benefits. A balancer lets companies scale their IT operations. The technology allows admins to add (or subtract) servers in line with traffic fluctuations—without changing a user’s experience.
Ultimately, the tool divvies out resources to prevent a poor server from taking on all network traffic, and crashing or responding sluggishly. The intelligent distribution helps a site stay up and running as it experiences a sudden surge in visitors.
