Vertical and horizontal flow controls for TCP optimization in the mobile ad hoc networks

In mobile ad hoc network (MANET), each end-node operates as an end-host and as a router simultaneously. Thus differently from wired-network, the occurrence of network congestion in end-host leaves much room for consideration. In the case of MANET, we can improve TCP throughput by using flow control algorithm that operates between layers because that algorithm reduces packet drops which caused by network congestion in end-hosts (source or destination). In MANET, usually IEEE 802.11 MAC protocol is used in a link layer transmission of two neighbored nodes for reliability and hidden terminal problem. But this protocol does not offer flow control mechanism in link layer. Link layer flow control can prevent packet drops caused by buffer overflow that can occur just after packet transmission. And in result, this prevention of packet drop can reduce the waste of bandwidth and energy which are limited in wireless environment. In this paper, we propose two flow control algorithms called, respectively, vertical flow control and horizon flow control. We show improved TCP throughput and reduced power consumption in end-nodes through the use of proposed two flow control algorithms in performance evaluation.