Quality of Service and Message Aggregation in Delay-Tolerant Sensor Internetworks

We present traffic-shaping and message-aggregation algorithms that provide reservation-based quality-of-service mechanisms for delay-tolerant internetworks utilizing graph-based routing protocols. We define a Traffic Shaping with Contacts (TSC) method that alters the edge weights in a graph structure to represent service level specifications, rather than physical capacity. This adjustment allows existing routing mechanisms to implement bandwidth reservations without additional processing at the node. We define a Payload Aggregation and Fragmentation (PAF) algorithm that calculates preferred payload sizes over traffic-shaping contacts. PAF aggregates too-small payloads together and fragments too-large payloads to optimize contact capacities. Unlike other mechanisms, TSC/PAF are unaffected by heterogeneous physical, data-link, and transport layer protocols across an internetwork and require only minor modifications to internetwork-layer graph-routing frameworks. Simulation results show that together TSC/PAF reduce the number of messages in a sensor internetwork by 43 % while increasing the goodput of the network by 63 % over standard graph-routing techniques.