vSphere is a server virtualization software that optimizes performance, efficiency and innovation for traditional and next gen apps. It consists of two core components: ESXi and vCenter Server. ESXi is a hypervisor that runs on physical servers and allows you to create and manage virtual machines. vCenter Server is a management platform that provides a centralized interface for controlling your vSphere environment. vSphere also supports various features and functions for network management, security, reliability, and performance optimization.