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Load Balancing

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Load balancing helps keep networks running smoothly and prevents servers from getting overwhelmed by requests.

What Is Load Balancing?

Load balancing spreads incoming network traffic across a group of backend servers to ensure satisfactory speed and optimized functioning. The group of backend servers is commonly called a server farm or server pool. The larger the server farm and the more optimized the load balancing, the less clients experience slowdown when one of the servers is down or overloaded.

High‑traffic websites serve thousands or even millions of people each day. Part of the service is displaying content, such as text, image, and video. Servers need to identify the data needed and deliver it reliably every single time.

Load balancing prevents a website from becoming crippled when there’s an overflow of requests. A load balancer sends requests to servers that can efficiently handle them to maximize speed and performance.

Videos on Load Balancing

What Is Load Balancing?
Scaling Web Applications with Load Balancing
TCP/UDP Load Balancing

How Is Load Balancing Done at the IP Layer?

Also known as Layer 4 load balancing, load balancing at the IP layer refers to a deployment where the load balancer’s IP address is the one advertised to clients for a website, and therefore recorded as the destination address. When the load balancer gets the request, it changes the recorded destination IP address to that of the content server it has chosen. Read more about Layer 4 load balancing here.

Session Persistence

In some cases, it is essential that all requests from a client are sent to the same server for the duration of a session, for example when a client is putting items in a shopping cart and then completing the purchase. Maintaining the connection between client and server is known as session persistence. Without session persistence, information has to be synchronized across servers and potentially fetched multiple times, creating performance inefficiencies.


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