NCL, Computer Science Department, Columbia University

Virtual Network Address Translation (VNAT) is a novel architecture that allows transparent migration of end-to-end live network connections associated with various computation units. Such computation units can be either a single process, or a group of processes, or an entire host. VNAT virtualizes network connections perceived by transport protocols so that identification of network connections is decoupled from stationary hosts. Such virtual connections are then remapped into physical connections to be carried on the physical network using network address translation.

VNAT requires no modification to existing applications, operating systems, or protocol stacks. Furthermore, it is fully compatible with the existing communication infrastructure; virtual and normal connections can coexist without interfering each other. VNAT functions entirely within end systems and requires no third party services.

We have implemented a VNAT prototype with the Linux 2.4 kernel and demonstrated its functionality on a wide range of popular real-world network applications. Our performance results show that VNAT has essentially no network performance overhead except when connections are migrated, in which case the overhead of our Linux prototype is less than 7 percent over a stock RedHat Linux system.