IP Traffic Load Distribution in NGEO Broadband Satellite Networks - (Invited Paper)

Given the fact that more than half of the world lacks a wired network infrastructure, satellite networks are seen as an important alternative to achieve global coverage. Since most of the world population lives around the equator or in middle-latitude regions, satellite constellations have to deal with different communication requirements from different regions. The traffic requirements become further unbalanced as the population density varies among urban and rural areas. This results in the congestion of some satellites while others remain underused. The issue of traffic engineering over satellite networks can be resolved by distributing the traffic in a balanced way over underutilized links. This paper proposes an Explicit Load Balancing (ELB) routing protocol which is based on information of traffic load at the next hop on the remainder of the path to the destination. A satellite with high traffic load sends signals to its neighboring satellites requesting them to decrease their sending rates before it gets congested and packets are ultimately dropped. Neighboring satellites should accordingly respond and search for other alternate paths that do not include the satellite in question. The performance of the proposed scheme is evaluated through simulations. From the simulation results, the proposed scheme achieves a more balanced distribution of traffic load, and reduces the number of packet drops and queuing delays. The resulting satellite constellation is a better-utilized and traffic-balanced network.