Load Distribution and Balancing

This chapter reviews the architectural, operational and service quality considerations of both proxy and nonproxy load balancing technologies. Load distribution algorithms implemented by proxy load balancers include simple methods such as static configuration, Round Robin, random choices, performance based, status based, and orchestration enabled. DNS is probably the most common nonproxy load distribution strategy used by applications. Unlike proxy load balancers, nonproxy load distribution is not generally in the critical delivery path particularly in the case of static configuration. Complex applications are generally architected with several tiers of service and functionality, and load distribution mechanisms and policies are generally implemented at each tier. The load balancer should provide metrics to an operational support system (OSS) or a virtual machine server controller (VMSC). The chapter also talks about cloud-based load balancing challenges, the role of load balancing in support of redundancy, and load balancing and application service quality.