There may be more real competition in virtualization than ever, but the rivals are still working in the wake of the industry's first mover. As bread-and-butter virtualization features that were once solely within VMware's domain have become available in other solutions, VMware has consistently pushed forward with new innovations.
With vSphere 5.1, VMware takes the first coherent, integrated step toward a completely virtualized environment, from servers through storage and network. Significant enhancements to VXLAN, VMware's network overlay technology, move the network segmentation, security, and load-balancing tasks to the hypervisor, rather than external switches, firewalls, and load balancers. Thus, VMware is bringing the configuration for the entire infrastructure within a single package, easing administration, automation, and disaster recovery.
-- Paul Venezia