Sun OpenSolaris Crossbow provides the building blocks for network virtualization and resource control by virtualizing the stack and NIC around any service (HTTP, HTTPS, FTP, NFS, etc.), protocol or Virtual machine.
Each virtual stack can be assigned its own priority and bandwidth on a shared NIC without causing any performance degradation. The architecture dynamically manages priority and bandwidth resources, and can provide better defense against denial-of-service attacks directed at a particular service or virtual machine by isolating the impact just to that entity. The virtual stacks are separated by means of H/W classification engine such that traffic for one stack does not impact other virtual stacks.