Organizations: University of Electronic Science and Technology of China Chengdu, Sichuan, China · Renmin University of China Beijing, China · University of Hong Kong Hong Kong, China · Hong Kong Polytechnic University Hong Kong, China
Network traffic classification underpins network security and management but faces growing challenges from pervasive encryption and evolving protocols. Existing representations involve clear trade-offs: hand-crafted flow statistics are efficient but lossy, raw-bit encodings can be accurate but costly, and pre-trained embeddings support transfer but often flatten the protocol stack and entangle cross-layer signals. We observe substantial redundancy both across and within network layers, which existing paradigms do not explicitly address, wasting capacity and encouraging shortcut learning that degrades generalization. To address this, we propose PACC, a redundancy-aware cross-layer representation framework. PACC models protocol layers as multiview inputs and learns faithful, compact projections factorized into shared (cross-layer) and private (layer-specific) components. It incorporates an information-preserving sparse segment representation to reduce structural repetition and supervised intra-layer filtering to suppress task-irrelevant semantic redundancy. A behavior-guided shared/private decomposition aligns cross-layer consensus while retaining layer-specific information, supported by information-theoretic analysis. Across encrypted application classification, IoT device identification, benign/malicious traffic classification, and Tor traffic detection, PACC achieves the best overall performance. On encrypted traffic, it achieves an F1 score of 0.9685, substantially outperforming existing baselines while using approximately 15x fewer computes and less GPU memory than the latest pre-trained traffic model.
Figures & tables
Figure 1: The shared–private principle for cross-layer traffic: capturing cross-layer consensus I(Xi;Xj) and layer-specific, task-relevant evidence such as I(Xi;Y∣Xj) .
Figure 2: Layer-wise analysis on CipherSpectrum. (a) Inter-layer consensus measured by NMI(Xi;Xj) . (b) Task relevance measured by NMI(Xi;Y) , with intra-layer redundancy proxied by the compression ratio. Higher task relevance and lower compression ratio are preferred.
Figure 3: The overall framework of PACC . Compact behavioral features and lossless structural chunks are processed through task-aware semantic denoising, behavior-guided shared–private decomposition, and adaptive fusion. The right panel summarizes the optimization objectives.
Dataset
Metric
Flow Statistics
Raw Packets
Pretrained Embedding
PACC
AppScanner
FlowPrint
TFE-GNN
nPrint
YaTC
NetMamba
Task: Encrypted Application Classification
CipherSpectrum
ACC
0.5356
0.0244
0.2149
0.3037
0.6678
0.5517
0.9685
PRE
0.9278
0.0006
0.2147
0.3933
0.6642
0.5462
0.9694
REC
0.5300
0.0244
0.2149
0.3037
0.6678
0.5517
0.9685
F1
0.6737
0.0012
0.1642
0.2851
0.6633
0.5370
0.9685
Table 1: Classification Results Across Various Domain Traffic Datasets.
Method
Input / flow
Params
MACs / flow
Peak GPU
Latency / flow
Throughput
Prestage + training
YaTC
1600 px
1.866M
971.9M
158 MB
0.1482 ms
6,749/s
— +1420.8s
NetMamba
1600 px
1.867M
683.3M
456 MB
0.0481 ms
20,774/s
— +1169.5s
TFE-GNN
903 nodes / 5768 edges
44.364M
157.4M
1297 MB
6.2624 ms
160/s
1991.7s
PACC
608 elems
1.273M
47.2M
106 MB
0.0168 ms
59,660/s
134.2s+743.0s
Table 2: Efficiency comparison on CipherSpectrum. Input size is reported as model-consumed elements for PACC , pixels for packet-image baselines, and graph size for TFE-GNN. Lower is better for Params, MACs, Peak GPU, and Latency, while higher is better for Throughput. Pipeline time reports preprocessing and training; a dash denotes an unreported prestage cost rather than zero.
Figure 4: Layer-wise analysis of PACC embeddings on CipherSpectrum. (a) Shared consensus measured by NMI(Zis;Zjs) . (b) Shared-component task relevance measured by NMI(Zms;Y) , with redundancy proxied by the compression ratio. (c) Private-component shared-factor leakage measured by I(Zmp;Zg∣Zms) and residual task evidence measured by I(Zmp;Y∣Zg) .
Figure 7
Appendix figures & tables6 assets
Supplementary material from the paper’s appendix.
Appendix
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Extracted statistics
Captured behavior
Length scale
Packet count, total bytes, mean/std/median/90th-percentile/max packet length, and zero-payload ratio
Traffic volume and packet-size variation.
Direction
Forward/backward packet ratios, forward/backward byte ratios, and direction-switching rate
Endpoint dominance and request-response interaction.
Temporal
Summary statistics of log-compressed inter-arrival times
Transmission pace, timing fluctuation, and delayed responses.
Run-level bursts
Number of same-direction runs, average/max run length, and average/max run bytes
Alternating exchanges and directional bursts.
Distribution
Normalized histograms of packet lengths and log-compressed inter-arrival times
Distributional shape beyond low-order moments.
Frequency
Low-frequency Fourier magnitudes of signed packet-length and timing sequences
Deep learning has achieved strong performance in encrypted traffic classification (ETC), yet its computational cost limits deployment on resource-constrained network devices such as routers and middleboxes. Existing compression methods mainly operate on weights, channels, hidden representations, or predictions, but do not explicitly determine which protocol fields and structural contexts should remain. We propose Pruned Traffic Trees (PTT), a three-level protocol-structured model family that treats native protocol structures as compression units. PTT-Full learns protocol-structured representations and field salience from complete Protocol Tree Graphs (PTGs), with flow-level self-supervised learning and protocol-presence-aware sparse execution. The learned salience and TopK+k closure construct Distilled PTGs (PTG-Ds) for PTT-Distilled, while PTT-Lite inherits this topology and reduces width through structure-aligned transfer and flow-level logits distillation. Under flow-disjoint and Strong Information Information (SII)-masked settings, PTT-Full achieves Macro-F1 scores of 0.9519 and 0.9416 on CSTNET-TLS1.3 and CipherSpectrum, while PTT-Lite retains 0.9325 and 0.9136 with 80.3% and 61.3% fewer parameters, 98.85% and 98.78% lower effective GFLOPs, and 8.75× and 8.46× CPU inference speedups. These results demonstrate that treating protocol structure itself as the compression object enables effective performance-efficiency trade-offs for lightweight ETC.
Yuantu Luo, Jun Tao, Xiangyu Xu +2
School of Cyber Science and Engineering, Southeast University, Nanjing, China · School of Computer Science and Engineering, Southeast University, Nanjing, China
We study the problem of learning compact rule-based compressors for structured network traffic. Each packet is a record of header fields that are highly redundant within a flow, and a compressor is a small set of rules matching such records and replacing predictable fields with short codes. We cast rule learning as a two-stage problem: (i) an unsupervised structure-discovery stage that recursively partitions training packets using a normalized entropy-ratio criterion robust to small samples, and (ii) a constrained selection stage that uses dynamic programming to pick the rule subset maximizing expected compression gain under a hard budget on the number of installable rules. We instantiate the framework on Static Context Header Compression (SCHC), the IETF standard for rule-based header compression in constrained networks, and evaluate it on four real-world Internet-of-Things and 5G core-network datasets. Our method, Robust Entropy Clustering for Adaptive comPression (RECAP), surpasses expert-engineered rule sets with a small number of learned rules and removes the need for manual rule design.
Traditional traffic analysis is being fundamentally challenged by the rapid adoption of encryption, tunnelling, and privacy-preserving protocols, which increasingly obscure packet payloads and limit the usefulness of Deep Packet Inspection (DPI). Although machine learning has advanced encrypted traffic analysis, existing approaches often remain tied to protocol-specific header features, depend on large labelled datasets, and degrade when deployed across heterogeneous network environments. We present GETA, a protocol-agnostic framework for encrypted traffic analysis that models network flows as multivariate time series using only traffic metadata, thereby avoiding reliance on packet payloads or header semantics. GETA combines meta-learning, embedding refinement, and self-attention to support few-shot adaptation to previously unseen domains with minimal labelled data. Across nine public datasets spanning application identification, VPN traffic classification, IoT device fingerprinting, and attack detection, GETA consistently outperforms state-of-the-art baselines. These results show that GETA offers a practical and generalisable foundation for robust traffic analysis in modern encrypted networks.