DDoS Attack Tracking Using Multi-Round Iterative Viterbi Algorithm in Satellite Internet

Satellite Internet (SI) provides broadband access as a critical information infrastructure in 6G. However, with the integration of the terrestrial Internet, the influx of massive terrestrial traffic will bring significant threats to SI, among which DDoS attack will intensify the erosion of limited bandwidth resources. Therefore, this paper proposes a DDoS attack tracking scheme using a multi-round iterative Viterbi algorithm to achieve high-accuracy attack path reconstruction and fast internal source locking, protecting SI from the source. Firstly, to reduce communication overhead, the logarithmic representation of the traffic volume is added to the digests after modeling SI, generating the lightweight deviation degree to construct the observation probability matrix for the Viterbi algorithm. Secondly, the path node matrix is expanded to multi-index matrices in the Viterbi algorithm to store index information for all probability values, deriving the path with non-repeatability and maximum probability. Finally, multiple rounds of iterative Viterbi tracking are performed locally to track DDoS attack based on trimming tracking results. Simulation and experimental results show that the scheme can achieve 96.8% tracking accuracy of external and internal DDoS attack at 2.5 seconds, with the communication overhead at 268KB/s, effectively protecting the limited bandwidth resources of SI.