Partially reliable transport service

An analytic model is presented for a partially reliable transport protocol based on retransmissions. The model illustrates tradeoffs between two QoS parameters (delay and throughput), and various levels of reliability. The model predicts that the use of a reliable transport service when an application only needs a partially reliable one causes considerable throughput decreases and delay increases in lossy networks. On the other hand, over lossy networks, an unreliable transport service is unable to respect an application´s loss tolerance. In lossy environments, partially reliable transport service avoids the extra cost of a reliable transport service, and, simultaneously, guarantees the minimal reliability that an application requires. A retransmission-based partially reliable transport service can be provided through either sender-based or receiver-based loss detection and recovery. Results show that both techniques provide almost identical reliability and delay. However, a sender-based approach provides better throughput than a receiver-based approach at high acknowledge loss rates