TCP Optimal Performance in Wireless Networks Applications

Abstract

Mobile Ad Hoc Network (MANET) consists of dynamic topology as nodes in the network are mobile, and connected via wireless links. The nodes are grouped in clusters for the purpose of routing. Nodes within the cluster communicate directly. However, nodes communicate outside the cluster through a centralized node that is called a clusterhead. An elected clusterhead is assigned for communication with all other clusters. The centralized clusterhead can become a bottleneck and possibly cause a lower throughput for the clustering system. We propose a mechanism in which communication outside the cluster is distributed through separate clusterheads. We prove that the overall averaged throughput for the clustering system increases considerably, about doubles for our distributed number of clusterheads. We also show that the increase in overall averaged throughput is reduced by the increase in the overall averaged error rate ratio resulting from the added clusterheads. Additionally, the routing reliability to outside the cluster is increased since routes to different clusters use distinct clusterhead.

TCP Karak: A New TCP AIMD Algorithm Based on Duplicated Acknowledgements for MANET

“…Wireless networks, such as MANET and wireless sensor networks (WSN), are also characterized by high bit error rate (BER) channels [8]. TCP faces some challenges over these networks since it is not inherently designed to adapt for such environments properties.…”

“…TCP faces some challenges over these networks since it is not inherently designed to adapt for such environments properties. The performance of TCP degrades with high mobility and bit error rate since it reduces the transmission rate when a segment is lost due to link breakages or bit errors and cannot distinguish between these two cases and severely congested routers buffers [7] [8].…”

TTAF: TCP Timeout Adaptivity Based on Fast Retransmit over MANET

“…Packet loss is considered as a sign of congestion and is detected by timeout expiration. Should the destination receive an out of order packet, then it sends a duplicated ACK of the last packet that has been received in order [2][3][4][5].…”

“…This provides a kind of assurance that the packet is really lost and should be retransmitted immediately without the need to wait until the RTO expiration in order to retransmit that lost packet. Fast retransmission allows higher channel utilization and throughput [4].…”

“…TCP faces some challenges over wireless networks since it was not originally designed to work in such an environment which is characterized by very dynamic topology and high bit error rate [4]. The performance of TCP degrades with high mobility since it reduces the transmission rate due to link breakages and consequently packet dropping.…”