Congestion control by traffic shaping for ground/satellite network

This paper discusses the issues to consider when selecting a congestion control scheme for an integrated ground radio and satellite network engaging primarily in transmitting multimedia traffic, and then it proceeds to discuss effects of smoothing rendered on the input traffic as a congestion control scheme. We chose traffic shaping by smoothing rendered on the input traffic as the congestion control scheme to use for our mixed ground/satellite network due to the considerations of satellite's long propagation delay, high bandwidth of ground network, and the real-time nature of the traffic. Traffic shaping in our case, involves smoothing and policing the traffic by using the "virtual token buckets" and our original "multi-buckets". The simulation results show that in the case of congestion, virtual token bucket and multi-bucket algorithms, improve throughput significantly for the ground/satellite network, with virtual token buckets slightly outperforming multi-buckets. Our experimental multi-buckets algorithm is useful, because it is capable of rendering additional smoothing, and thus affording us more flexibility to examine the impact of smoothing. The fact that virtual token buckets outperform slightly the multi-buckets shows that more smoothing does not always render better throughput, and confirms that factors such as the tradeoffs between smoothing and network utilization, burstiness of the streams, and the number of congested hops traversed need to be considered when examining the usefulness of smoothing.