Congestion Avoidance and Load Balancing in AODV-Multipath Using Queue Length

Congestion, the major reason for a link break is caused due to excessive load on the network, further leads to failure of nodes and topology change in the ad-hoc network. Transferring load of congested route to less congested routes improves overall network performance. Adhoc On-Demand Multipath Distance Vector (AOMDV) selects a path with a lower hop count and discards routes with higher hop count. The proposed protocol (AODV-Multipath) preserves the higher hop count routes in the routing table and utilizes it as alternate path as link failure occurs. AOMDV does not provide any means to avoid congestion and load balancing in the network. Queue Length detects congestion in the network. Queue Length and Hop Count value are together used to select a route from source to destination that avoids congestion and load balancing. If Queue length crosses a certain threshold value then Load balancing via alternate paths is carried out. The broadcast of route request packets is avoided by intermediate nodes if the routes are already congested. The proposed protocol avoids congestion, balance the load and to an extent avoid link failure. The scheme improves packet delivery ratio, throughput reduces number of dropped packets but increases average delay.