Dynamic and Distributed Load Balancing Scheme in Multi-gateway Based 6LoWPAN

In 6LoWPAN, all the nodes access the Internet through the gateways, which are on the border to legacy IP networks and handle ingress and egress data traffic. A gateway as the traffic center may easily become the congestion-concentrated point so that causes reliability problems and performance degradation. Gateway bottleneck is the dominant reason for network capacity and throughput constriction, since all traffic should pass through the GW. Even though we apply multiple gateways, the network capacity and network throughput cannot increase linearly with the number of gateways because of the imbalance of traffic load among gateways. The load balancing between gateways is a key technology to reduce the traffic congestion thereby enlarging the network capacity, satisfying the capacity fairness among nodes, and removing network reliability issue. In this paper, we propose a dynamic and distributed load balancing scheme to achieve a global load fairness, motivated by water flow behavior, named MLEq (Multi-gateway Load Balancing Scheme for Equilibrium). We implement our load balancing scheme in ns-2 simulator and it is verified by extensive simulations. As a result, we show that throughput can be improved by the proposed scheme and the load can be fairly distributed over LoWPAN. More importantly, the results show that network capacity and throughput can increase linearly with the number of gateways.