TAE-MAGSAGE: Topology Aware Metric Learning for Graph Based Network Intrusion Detection
: The modern network environment, whether enterprise systems or critical infrastructure, is increasingly exposed to sophisticated cyber threats that must be effectively detected. The existing GNN-based approaches construct graphs using feature-similarity heuristics, and connect flows that are statistically similar to one another but not necessarily communicating, hence capturing geometry specific to the dataset. On the other hand, communication topology is a representation of interaction patterns based on real network behaviour. We introduce TAE-MAGSAGE, an edge-centric graph learning model which uses the observed communication structure to construct graphs and applies a line graph transformation to perform flow-level classification without collapsing the interaction relationships. A Mahalanobis-inspired metric warp in message passing re-configures neighborhood similarity with respect to the discriminative feature dimensions, and a Ledoit–Wolf regularized Mahalanobis distance-based classifier learns class-conditional distributions to deal with severe class imbalance. TAE-MAGSAGE achieves an accuracy of 99.31% on the CIC-IDS-2017 dataset, macro F1 of 98.10%, and a false alarm rate of 0.56%, outperforming graph-based baselines. These results show that constructing graphs based on communication structure, combined with metric-conscious embedding and distribution-conscious classification, improves minority attack detection while reducing false alarms.