A Network Layer Approach to Enable TCP over Multiple Interfaces
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The mobile Internet is set to become ubiquitous with the deployment of various wireless technologies. When heterogeneous wireless networks overlap in coverage, a mobile terminal can potentially use multiple wireless interfaces simultaneously. In this paper, we motivate the advantages of simultaneous use of multiple interfaces and present a network layer architecture that supports diverse multi-access services. Our main focus is on one such service provided by the architecture: Bandwidth Aggregation (BAG), specifically for TCP applications.
While aggregating bandwidth across multiple interfaces can improve raw throughput, it introduces challenges in the form of packet reordering for TCP applications. When packets are reordered, TCP misinterprets the duplicate ACKS received as indicative of packet loss and invokes congestion control. This can significantly lower TCP throughput and counter any gains that can be had through bandwidth aggregation. To improve overall performance of TCP, we take a two-pronged approach: (1) We propose a scheduling algorithm that partitions traffic onto the different paths (corresponding to each interface) such that reordering is minimized. The algorithm estimates available bandwidth and thereby minimizes reordering by sending packet pairs on the path that introduces the least amount of delay. (2) A buffer management policy is introduced at the client to hide any residual reordering from TCP. We show through simulations that our network-layer approach can achieve good bandwidth aggregation under a variety of network conditions.
Keywordsnetwork architecture TCP scheduling algorithm simulation
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- Network Simulator. ns2. Available: http://www.isi.edu/snam/s.
- Web Traffic Generator. Available: http://www.isi.edu/snam/s/s-contributed.html.
- Inverse multiplexing for ATM IMA specification, version 1.1, ATM forum doc. AF-PHY-0086.001, 1999.Google Scholar
- A. Acharya and J. Saltz, A study of internet round-trip delay, Technical Report CS-TR 3736, Univ. of Maryland, College Park, 1996.Google Scholar
- D. Brudnicki, Third Generation Wireless Technology. Available: http://www.seasim.org/rchive/sim102001.pdf.
- K. Chebrolu, Multi-access services in heterogeneous wireless networks, PhD thesis, ECE Department, U.C. San Diego, May 2004.Google Scholar
- bag-video K. Chebrolu and R.R. Rao, Bandwidth aggregation for real-time applications in heterogeneous wireless networks, IEEE Transactions on Mobile Computing, accepted.Google Scholar
- K. Chebrolu and R.R. Rao, Communication using multiple wireless interfaces, in: Proc. IEEE WCNC′02 (Orlando, March 2002).Google Scholar
- A. Demers, S. Keshav and S. Shenker, Analysis and simulation of a fair queuing algorithm, in: Proc. ACM SIGCOMM′89 (Austin, Texas, September 1989) pp. 1–12.Google Scholar
- H. Hsieh and R. Sivakumar, A transport layer approach for achieving aggregate bandwidths on multi-homed mobile hosts, in: Proc. ACM MOBICOM′02 (Atlanta, Sep. 2002).Google Scholar
- V. Jacobson, Modified TCP Congestion Avoidance Algorithm, end2end-interest mailing list (April 1990). Available: ftp://ftp.ee.lbl.gov/mail/anj.90apr30.txt.
- L. Kleinrock, (ed.), Queueing Theory (Wiley, New York, 1975).Google Scholar
- L. Magalhaes and R. Kravets, Transport level mechanisms for bandwidth aggregation on mobile hosts, in: Proc. IEEE ICNP′01 (Riverside, Nov 2001).Google Scholar
- A. Mahler and C. Steinfield, The Evolving Hot-Spot Market for Broadband Access, in ITU Telecom World 2003 Forum panel on Technologies for Broadband (Oct 2003).Google Scholar
- S. Ostermann, M. Allman and H. Kruse, An application-level solution to TCP’s satellite inefficiencies, in: Proc. WOSBIS′96 (Rye, Nov 1996).Google Scholar
- D.S. Phatak and T. Goff, A novel mechanism for data streaming across multiple IP links for improving throughput and reliability in mobile environments, in: Proc. IEEE INFOCOM′02 (New York, June 2002) pp. 773–781.Google Scholar
- B. Raman, An Architecture for Performance and Availability Constrained Service Composition in the Wide-Area Internet, PhD thesis, University of California at Berkeley (Dec. 2002).Google Scholar
- H. Sivakumar, S. Bailey and R.L. Grossman, Psockets: The case for application-level network striping for data intensive applications using high Speed wide area networks, in: Proc. IEEE Supercomputing′00 (Dallas, Nov. 2000).Google Scholar
- K. Sklower, B. Lloyd, G. McGregor, D. Carr and T. Coradetti, The PPP multilink protocol MP, in: RFC 1990 (Aug. 1996).Google Scholar
- R. Stewart et al, Stream control transmission protocol, in: RFC 2960 (October 2000).Google Scholar
- M. Zhang, B. Karp, S. Floyd and L. Peterson, Improving TCP’s performance under reordering with DSACK, Technical Report TR-02-006, International Computer Science Institute, Berkeley (July 2002).Google Scholar