What is Load Balancing? What Load Balancing Solutions Are There? – Citrix

An employee’s day-to-day experience in a digital workspace can be highly variable. Their productivity may fluctuate in response to everything from the security measures on their accounts to the varying performance of the many applications they use—an issue that can be worsened by poor responsiveness due to inadequate load balancing.

In other words, digital workspaces are heavily application-driven. As concurrent demand for software-as-a-service (SaaS) applications in particular continues to ramp up, reliably delivering them to end users can become a challenge if proper load balancing isn’t in place. Employees who already struggle to navigate multiple systems, interfaces, and security requirements will bear the additional burden of performance slowdowns and outages.

To promote greater consistency and keep up with ever-evolving user demand, server resources must be readily available and load balanced at Layers 4 and/or 7 of the Open Systems Interconnection (OSI) model:

• Layer 4 (L4) load balancers work at the transport level. That means they can make routing decisions based on the TCP or UDP ports that packets use along with their source and destination IP addresses. L4 load balancers perform network address translation (NAT) but do not inspect the actual contents of each packet.
• Layer 7 (L7) load balancers act at the application level, the highest in the OSI model. They can evaluate a wider range of data than L4 counterparts, including HTTP headers and SSL session IDs, when deciding how to distribute requests across the server farm.

Load balancing is more computationally intensive at L7 than L4, but it can also be more efficient at L7, due to the added context in understanding and processing client requests to servers. In addition to basic L4 and L7 load balancing, global server load balancing (GSLB) can extend the capabilities of either type across multiple datacenters so large volumes of traffic can be efficiently distributed without degradation of service for the end user.

As applications are increasingly hosted in cloud datacenters located in multiple geographies, GSLB enables IT organizations to deliver applications with greater reliability and lower latency to any device or location. Doing so ensures a more consistent experience for end users when they are navigating multiple applications and services in a digital workspace.