TCP Extensions for Wireless Networks

Abstract

Traditional transport protocols (like TCP) are tuned to perform well in wired networks where the packet losses are mainly due to congestion. Wireless networks are characterized by losses due to transmission errors and handoffs. TCP interprets these losses as congestion and invokes congestion control mechanisms resulting in degradation of performance. In this paper, I discuss proposed schemes to improve performance of TCP in wireless networks. Proposed schemes for satellite networks are also discussed.

Table of Contents:

1. Introduction
2. Issues with wireless networks

    2.1 Link Error Rate
    2.2 Bandwidth
    2.3 Mobility
3. TCP extensions for wireless networks

    3.1 Wireless unaware TCP at the fixed host
        3.1.1 I-TCP (Indirect TCP)
        3.1.2 Berkeley Snoop Module
        3.1.3 M-TCP
        3.1.4 Delayed duplicate acknowledgements
    3.2 Wireless aware TCP at the fixed host
        3.2.1 Fast Retransmit
        3.2.2 Mobile TCP
        3.2.3 Multiple Acknowledgements
        3.2.4 Discriminating congestion losses from wireless losses
        3.2.5 Distinguish losses by making two connections
4. TCP extensions for satellite networks

    4.1 Issues
    4.2 Proposed Solutions
        4.2.1 Slow Start and congestion avoidance
        4.2.2 Fast Retransmit
        4.2.3 Large Window Sizes
        4.2.4 Delayed Acknowledgements
        4.2.5 Selective Acknowledgements
        4.2.6 TCP for transaction
        4.2.7 Explicit Congestion Notification
5. Conclusion
6. References

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