Research Cell: An International Journal of Engineering Sciences

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TCP In Conflict-Based Wireless Links


Affiliations
1 Department of Computer Science, D.A.V. Colege, Sector 10, Chandigarh, Punjab, India
2 Department of Computer Science, SD College, Lalgaon, Rewa (MP),, India
3 Department of Computer Science, Kurukshetra University, Regional Centre, Jind (Haryana), India
 

TCP's bidirectional traffic causes self-interference in contention-based wireless links as in IEEE 802.11 wireless LANs and results in the loss of TCP data segments and ACKs. The fast-recovery algorithm is the basis for congestion control in most TCP enhancements proposed to address wireless network characteristics. However we show in this paper, that fast-recovery worsens performance during self-interference by causing deadlock situations that only terminate with a timeout. Both Reno and New Reno are evaluated in comparison to the lesser-optimized TCP-Tahoe to demonstrate the degradation in performance during fast-recovery. The less-optimized TCP-Tahoe that forgets all outstanding packets soon after fast-retransmit, outperforms TCP-Reno with an 80% gain in throughput. For the minrto_ parameter set to 1 second, Tahoe outperforms New Reno by a significant margin. A key contribution in this paper is the visualization of TCP dynamics that capture MAC layer collisions due to self-interference, and the protocols' behavior during congestion control. The paper demonstrates the disadvantages of combined error and flow control and makes a sound case for cross-layer awareness in transport protocols over wireless networks.
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  • TCP In Conflict-Based Wireless Links

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Authors

Gagandeep Singh Brar
Department of Computer Science, D.A.V. Colege, Sector 10, Chandigarh, Punjab, India
G. N. Singh
Department of Computer Science, SD College, Lalgaon, Rewa (MP),, India
Anupam Bhatia
Department of Computer Science, Kurukshetra University, Regional Centre, Jind (Haryana), India

Abstract


TCP's bidirectional traffic causes self-interference in contention-based wireless links as in IEEE 802.11 wireless LANs and results in the loss of TCP data segments and ACKs. The fast-recovery algorithm is the basis for congestion control in most TCP enhancements proposed to address wireless network characteristics. However we show in this paper, that fast-recovery worsens performance during self-interference by causing deadlock situations that only terminate with a timeout. Both Reno and New Reno are evaluated in comparison to the lesser-optimized TCP-Tahoe to demonstrate the degradation in performance during fast-recovery. The less-optimized TCP-Tahoe that forgets all outstanding packets soon after fast-retransmit, outperforms TCP-Reno with an 80% gain in throughput. For the minrto_ parameter set to 1 second, Tahoe outperforms New Reno by a significant margin. A key contribution in this paper is the visualization of TCP dynamics that capture MAC layer collisions due to self-interference, and the protocols' behavior during congestion control. The paper demonstrates the disadvantages of combined error and flow control and makes a sound case for cross-layer awareness in transport protocols over wireless networks.