VNC in High-Latency Environments and Techniques for Improvement

VNC (Virtual Network Computing), a form of thin client computing, offers many advantages over traditional desktop computing including lower costs, higher security, ubiquitous access to resources, and easier maintenance. In this paper, we focus on the problems of using VNC to display video over a high-latency network, and how to solve them. VNC performance is inherently capped at 1 frame per round-trip time (between the client and server) due to its client-pull communication style. We describe VNC-HL, our extension of VNC, which improves frame rate performance by employing a pre-requesting technique to periodically request updates, even with several previous requests pending. Experimental results demonstrate up to an order of magnitude of improvement. VNC-HL achieved 14 FPS over a network with 500 ms of latency.