Evolution of the virtual interface architecture

To provide a faster path between applications and the network, researchers have advocated removing the operating system kernel and its centralized networking stack from the critical path and creating a user level network interface. With these interfaces, designers can tailor the communication layers each process uses to the demands of that process. Consequently, applications can send and receive network packets without operating system intervention, which greatly decreases communication latency and increases network throughput. Unfortunately, the diversity of approaches and lack of consensus has stalled progress in refining research results into products-a prerequisite to the widespread adoption of these interfaces. Recently, however, Intel, Microsoft, and Compaq have introduced the Virtual Interface Architecture, an emerging standard for cluster or system area networks. Products based on the VIA have already surfaced, notably GigaNet's GNN1000 network interface. As more products appear, research into application level issues can proceed and the technology of user level network interfaces should mature. Several prototypes-among them Cornell University's U-Net2-have heavily influenced the VIA. We describe the architectural issues and design trade-offs at the core of these prototype designs.