NFS Protocol Performance Analysis and Improvement for Mobile Transparent Computing

The ubiquitous wireless networks make it become possible for people to access a variety of services anytime and anywhere through mobile devices such as smartphone and tablet. However, due to the diversity and complexity of services, the requirement for storage and computing capacity for mobile devices is becoming higher and higher. Mobile transparent computing is a fit for this scenario. In mobile transparent computing, the client terminal is rather simple and light-weighted, and the operating systems, applications and user data are all regarded as software resources and stored in the server. The resources required in the user services are dynamically scheduled from the server to run on the client terminal in a streaming-block way via wireless network. In mobile transparent computing, we use the NFS (Network File System) protocol to realize the dynamic scheduling of resources. However, the wireless network environment is complex and unstable, and the wireless packet loss rate is high and the retransmission interval of lost packet is long in mobile transparent computing. In order to improve the scheduling efficiency of users´ resources and the NFS performance, we analyze the factors that affect the NFS performance, including NFS read/write block size, wireless bandwidth and so on. We study the effect of bandwidth for the NFS performance when several mobile terminals schedule their resources at the same time. Finally, we improve the NFS performance by setting the optimal block size for read/write, and use TCP as our NFS transmission protocol in mobile transparent computing.