This Article 
 Bibliographic References 
 Add to: 
Improving NFS Performance Over Wireless Links
March 1997 (vol. 46 no. 3)
pp. 290-298

Abstract—NFS is a widely used remote file access protocol that has been tuned to perform well on traditional LANs which exhibit low error rates. Users migrating to mobile hosts would like continued remote file access via NFS. However, low bandwidth and high error rates degrade performance on mobile hosts using wireless links, hindering the use of NFS. We conducted experiments to study the behavior of NFS in a wireless testbed. Based on these experiments, we incorporated modifications into the mobile NFS client. This paper presents two mechanisms which improve NFS performance over wireless links: an aggressive NFS client and link-level retransmissions. Our experiments show that these mechanisms improve response time by up to 62%, which brings the performance to within 5% of that obtained in zero error conditions.

[1] R. Sandberg, D. Goldberg, S. Kleinman, D. Walsh, and B. Lyon, "Design and Implementation of the Sun Network File System," Proc. USENIX Summer Conf., pp. 119-130, 1985.
[2] B. Pawlowski, C. Juszczak, P. Staubach, C. Smith, D. Lebel, and D. Hitz, "NFS Version 3 Design and Implementation," Proc. USENIX Summer Conf., pp. 137-152, 1994.
[3] P. Bhagwat, P. Bhattacharya, A. Krishna, and S. Tripathi, "Enhancing Throughput Over Wireless LANs Using Channel State Dependent Packet Scheduling," Proc. IEEE INFOCOM, pp. 1,133-1,140, Mar. 1996.
[4] C. Juszczak, "Improving the Performance and Correctness of an NFS Server," USENIX Conf. Proc., pp. 53-63, Jan. 1989.
[5] C. Juszczak, "Improving the Write Performance of an NFS Server," USENIX Conf. Proc., pp. 247-260, Jan. 1994.
[6] M. Satyanarayanan, “Scalable, Secure, and Highly Available Distributed File Access,” Computer, vol. 23, no. 5, pp. 9-21, May 1990.
[7] J.J. Kistler and M. Satyanarayanan, "Disconnected Operation in the Coda File System," ACM Trans. Computer Systems, vol. 10, no. 1, Feb. 1992, pp. 3-25.
[8] M. Satyanarayanan et al., "Application-Aware Adaptation for Mobile Computing," Operating Systems Review, Vol. 29, No. 1, Jan. 1995.
[9] P. Honeyman, L. Huston, J. Rees, and D. Bachmann, "The Little Work Project," Proc. Third IEEE Workshop on Workstation Operating Systems, 1992.
[10] D. Bachmann, P. Honeyman, and L.B. Huston, "The Rx Hex," Proc. First Int'l Workshop Services in Distributed and Networked Environments, pp. 66-74, June 1994.
[11] L. Brakmo, S. O'Malley, and L. Peterson, "TCP Vegas: New Techniques for Congestion Detection and Avoidance," Proc. SIGComm 94, ACM Press, New York, 1994, pp. 24-35.
[12] R. Caceres and L. Iftode, "The Effects of Mobility on Reliable Transport Protocols," Proc. 14th Int'l Conf. Distributed Computing Systems, pp. 12-20, June 1994.
[13] R. Yavatkar and N. Bhagwat, "Improving End-to-End Performance of TCP Over Mobile Internetworks," Proc. Mobile 94 Workshop Mobile Computing Systems and Applications, pp. 146-152, Dec. 1994.
[14] A. Bakre and B. Badrinath, "I-TCP: Indirect TCP for Mobile Hosts," 15th Int'l Conf. Distributed Computing Systems (ICDCS), May 1995.
[15] A. Bakre and B.R. Badrinath, "M-RPC: A Remote Procedure Call Service for Mobile Clients," Proc. First ACM Conf. Mobile Computing and Networking, pp. 97-110, Nov. 1995.
[16] Network Working Group, "RPC: Remote Procedure Call Protocol Specification," RFC 1057, 1988.
[17] H. Balakrishnan et al., "Improving TCP/IP Performance over Wireless Networks," Proc. 1st ACM Int'l Conf. Mobile Computing and Networking, ACM Press, New York, Nov. 1995.
[18] A. DeSimone, M.C. Chuah, and O.C. Yue, "Throughput Performance of Transport-Layer Protocols Over Wireless LANs," Proc. IEEE GLOBECOM, pp. 542-549, 1993.
[19] S. Paul, E. Ayanoglu, T.F. LaPorta, K.H. Chen, K.K. Sabnani, and R.D. Gitlin, "An Asymmetric Link-Layer Protocol for Digital Cellular Communications," Proc. IEEE INFOCOM, pp. 1,053-1,062, 1995.
[20] V. Bhargavan, A Demers, S. Shenkar, and L. Zhang, MACAW: Media Access Protocol for Wireless LANs, Proc. ACM SIGCOMM '94, pp. 212–225, 1994.
[21] V. Jacobson, "Congestion Avoidance and Control," Proc. ACM SIGCOMM '88, pp. 314-329, Aug. 1988.
[22] H. Balakrishnan et al., "A Comparison of Mechanisms for Improving TCP Performance over Wireless Links," Proc. ACM SIGCOMM Conf., ACM Press, New York, 1996.
[23] S. McCanne and V. Jacobson, "The BSD Packet Filter: A New Architecture for User-Level Packet Capture," Proc. USENIX Winter Conf., pp. 259-269, Jan. 1993.
[24] G. Nguyen, R. Katz, B. Noble, and M. Satyanarayanan, "A Trace-Based Approach for Modeling Wireless Channel Behavior," Proc. Winter Simulation Conf., Dec. 1996.
[25] T. Sato, M. Kawabe, T. Kato, and A. Fukasawa, "Throughput Analysis Method for Hybrid ARG Schemes Over Burst Error Channels," IEEE Trans. Vehicular Technology, vol. 42, no. 1, pp. 110-118, Feb. 1993.
[26] H.S. Wang and N. Moayeri, "Finite State Markov Channel—A Useful Model for Radio Communication Channels," IEEE Trans. Vehicular Technology, vol. 44, no. 1, pp. 163-171, Feb. 1995.
[27] H. Hashemi, M. McGuire, T. Vlasschaert, and D. Tholl, "Measurements and Modeling of Temporal Variations of the Indoor Radio Propagation Channel," IEEE Trans. Vehicular Technology, vol. 43, no. 3, pp. 733-737, Aug. 1994.
[28] C. Kent and J. Mogul, "Fragmentation Considered Harmful," Proc. ACM SIGCOMM, pp. 390-401, Aug. 1987.
[29] A. Romanow and S. Floyd, "Dynamics of TCP Traffic Over ATM Networks," ACM SIGCOMM, vol. 24, no. 4, pp. 79-88, Oct. 1994.
[30] C. Tait, H. Lei, S. Acharya, and H. Chang, "Intelligent File Hoarding for Mobile Computers," Proc. First ACM Int'l Conf. Mobile Computing and Networking, pp. 119-126, Nov. 1995.
[31] T.M. Kroeger and D.D.E. Long, "Predicting Future File-System Actions from Prior Events," Proc. USENIX Winter Technical Conf., pp. 319-328, Jan. 1996.

Index Terms:
Performance evaluation, NFS, wireless LAN, mobile computing, link-level retransmission, file systems.
Rohit Dube, Cynthia D. Rais, Satish K. Tripathi, "Improving NFS Performance Over Wireless Links," IEEE Transactions on Computers, vol. 46, no. 3, pp. 290-298, March 1997, doi:10.1109/12.580425
Usage of this product signifies your acceptance of the Terms of Use.