Study on Congestion Avoidance in MANET

Congestion is a main challenge in modern network environment. Unawareness of the network topology the network devices are demand to provide sufficient and structured connection establishment to the network. Nowadays Mobile Adhoc Network (MANET) plays a vital role in the modern networks. Because MANET can constructs its network a nd its paths based upon the current circumstances. Due to this instant network organization, the congestion is very essential and tough task in MANET. The congestion control mechanism has two basic classifications one is the congestion avoidance and next is slow start. Slow-start is used in conjunction to avoid transmitting huge amount of data in a single path in a network. It is used to control the congestion inside the network and works by increasing the TCP congestion window each time the acknowledgment is received. This is not the fair because any traffic occurs in the network the congestion window size is reduced by half. The window size is calculated by estimating the congestion between the nodes. TCP provides this information to the sender and the sender maintains the congestion window. All segments are received and the acknowledgments reach the sender on time, the window grows exponentially until a timeout occurs or the receiver reaches its limit. This paper focuses on congestion avoidance in the terms of widow size and data rate .The simulation results were obtained from Network Simulator2 (NS2) version 2.3.9.