Implementing Transport Coding in OMNeT++ for Message Delay Reduction

Transport coding reduces message delay in packet-switched networks by introducing controlled redundancy at the transport layer: $k$ original packets are encoded into $n\ge k$ coded packets, and the message is reconstructed after the first $k$ successful deliveries, effectively shifting latency from the maximum packet delay to the $k$-th order statistic. We present a concise, reproducible discrete-event implementation of transport coding in OMNeT++, including a multi-hop Kleinrock-type network, FIFO queues, exponential service and link delays, and explicit receiver-side reconstruction that records message delay and deadline violations. Using paired uncoded ($n=k$) and coded ($n>k$) configurations at the same message generation rate, we compare delay, reliability, and saturation effects across code rates and input loads. Simulation results show consistent reductions of average delay and late-delivery probability for moderate redundancy, while keeping the saturation throughput close to the uncoded baseline. The proposed model provides a transparent bridge between analytical transport-coding formulas and executable simulation for tuning redundancy in low-latency services.