An Axiomatic Analysis of Path Selection Strategies for Multipath Transport in Path-Aware Networks

Abstract

Path-aware networking architectures like SCION provide end-hosts with explicit control over inter-domain routing, while multipath transport protocols like MPTCP and MPQUIC enable the concurrent use of multiple paths. This combination promises significant gains in performance and policy enforcement, but it also creates a stark trade-off between individual performance optimization and overall network stability. This paper quantifies this trade-off through a rigorous axiomatic analysis. We evaluate a spectrum of algorithms, from greedy (Min-RTT) and cooperative (Round-Robin) to hybrid approaches (Epsilon-Greedy), against axioms of Efficiency, Loss Avoidance, Stability, and Fairness in a simulated path-aware environment. Our simulations reveal that purely greedy strategies, while efficient under low contention, induce catastrophic packet loss, increasing by over >18,000% as the number of competing agents grow, due to herd effects that cause severe network instability. Conversely, cooperative strategies ensure fairness and stability but at the cost of underutilizing high-capacity paths. Crucially, we demonstrate that hybrid strategies resolve this conflict. The Epsilon-Greedy algorithm, for instance, achieves the highest efficiency of all tested strategies in high-contention scenarios while mitigating the instability inherent to the greedy approach. Our axiomatic analysis suggests that tunable, hybrid algorithms are essential for designing robust and high-performance path selection mechanisms for next-generation networks.