Multipath Detection Algorithms (MDAs) are proposed to discover Internet topology in the presence of load balancing (LB). Existing methods assume uniformity in the load-balancing responses (LBR), i.e., responses from the successors of a LB router. However, we reveal that only 20% of the cases exhibit uniformity in the Internet. This finding significantly challenges the completeness of the Internet topology discovered using current MDAs. In this paper, we propose a novel system BayMuDA, that can estimate LBR distributions and calculate the minimum number of probes needed to statistically discover all nodes and links within a given hop. The validation on controlled topologies shows that BayMuDA discovers at least 85%/73% of nodes/links in ~90% of the cases. Our Internet-wide measurement results indicate that BayMuDA can discover millions of Internet nodes and links obscured by the state-of-the-art MDA algorithm, D-Miner, due to uneven responses.

Offloading machine learning models for network classification on high-throughput programmable switches is a promising technology, enabling line-speed in-network classification. Existing solutions are centralized, deploying a complete but heavy model on a single switch with limited hardware resources, causing unsatisfactory accuracy, network-wide resource wastage, and non-generic single-task classification. Therefore, we propose In-Forest-M, a general distributed multi-task in-network classification framework. Firstly, we develop a Lightweight Ensemble Generic Optional Model (LEGO), which can be transformed into base models with full functionality. Each switch only needs to deploy lightweight base models rather than complete ensemble models. The significant reduction in resource consumption allows the deployment of larger models with higher accuracy and more models that support diverse tasks. We employ a fine-grained enhancement mechanism to enhance the classification performance of base models. As traffic traverses different switches, In-Forest-M aggregates the classification results of multiple enhanced base models to improve accuracy further. Secondly, we introduce a two-phase resource-aware model allocation strategy that assigns different task-specific enhanced base models to switches under resource constraints and task requirements. To respond to dynamic traffic changes, we design an optimization-driven reinforcement learning algorithm. Moreover, we propose a lightweight update mechanism for flexible model scaling. Comprehensive experiments reveal that, compared with state-of-the-art in-network classification solutions in three real network topologies, In-Forest-M achieves increased accuracy and reduced switch rules while exhibiting great generality in multi-task classification.

Industrial multimedia recommendation systems extensively utilize cascade architectures to deliver personalized content for users, generally consisting of multiple stages like retrieval and ranking. However, retrieval models have long suffered from Sample Selection Bias (SSB) due to the distribution discrepancy between the exposed items used for model training and the candidates (almost unexposed) during inference, affecting recommendation performance. Traditional methods utilize retrieval candidates as augmented training data, indiscriminately treating unexposed data as negative samples, which leads to inaccuracies and noise. Some efforts rely on unbiased datasets, while they are costly to collect and insufficient for industrial models. In this paper, we propose a debiasing framework named DAMCAR, which introduces Domain Adaptation to mitigate SSB in Multimedia CAscade Recommendation systems. Firstly, we sample hard-to-distinguish samples from unexposed data to serve as the target domain, optimizing data quality and resource utilization. Secondly, adversarial domain adaptation is employed to generate pseudo-labels for each sample. To enhance robustness, we utilize Exponential Moving Average (EMA) to create a teacher model that supervises the generation of pseudo-labels via self-distillation. Finally, we obtain a retrieval model that maintains stable performance during inference through a hybrid training mechanism. We conduct offline experiments on two real-world datasets and deploy our approach in the retrieval model of a multimedia video recommendation system for online A/B testing. Comprehensive experimental results demonstrate the effectiveness of DAMCAR in practical applications.