RESUMO
The existing path consistency verification solutions in software-defined networking (SDN) were implemented by proactive injecting large number of probing packets or by embedding linear-scale tags as the path lengthens, which incurred significant bandwidth and communication overhead. A lightweight path consistency validation mechanism based on in-band network telemetry (INT) in SDN is proposed. Based on INT, in the scheme, the ingress switch inserts a telemetry instruction header with probability, each subsequent switch updates the telemetry data using a uniform sampling algorithm and only carries partial path information in INT packet to keep the head space size constant, the egress switch reports the final sampled telemetry data to the controller to verify the path compliance according to aggregated telemetry data. A heuristic flow selection algorithm is proposed to implement network-level path consistency validation. The proposed scheme was implemented and evaluated. The analyses and experiments demonstrate the proposed mechanism effectively limits the packet head overhead and introduces less than 7% of additional forwarding delays and 6% of throughput degradation at most.