Early solutions take over path establishment to provide Quality of Service (QoS). A network that can support QoS is able to provide different levels of services depending on the application requirements. Some applications require real-time delivery of packets and need the assurance that packets will arrive on time. Other applications require packets to arrive correctly. The evolution of path establishment goes from technologies such as Frame Relay to more recent solutions such as Multiprotocol Label Switching (MPLS) and Internet-based Virtual Private Networks (VPNs). This presentation introduces path establishment technologies. Frame Relay and ATM use virtual circuits, and MPLS blends assets from virtual circuits and IP routing to determine paths. A VPN is used to restrict communication only between desired hosts, such as the sites of a company. Finally, IntServ and DiffServ allocate resources to maintain control over the flow of packets. Resource allocation is the process of assigning and distributing resources, such as hardware, software and bandwidth for effective use.