In-band Network Telemetry (INT) technology enables fine-grained network monitoring by encapsulating intra-switch network status into INT probes, which is essential in data center networks for ensuring Quality of Service (QoS). Existing INT-based telemetry systems leverage centralized controllers to compute non-overlapping probe paths, thereby facilitating lightweight and network-wide measurements. However, these systems fail to adapt effectively to network topology changes caused by link or device failures, primarily due to inflexible path planning under dynamic conditions. To address this problem, we propose INT-Source, a unified policy-based network-wide telemetry system for probing and forwarding. First, we design a data plane forwarding mechanism for INT probes to ensure telemetry coverage during topology changes and reduce telemetry overhead. Second, we design a probe packet structure and introduce a switch-based probe verification and discard mechanism to prevent redundant link probing. Third, we introduce two algorithms for INT-Source: a Single-Source algorithm to facilitate deployment and a Multi-Source algorithm to enable lightweight and scalable telemetry. Our evaluation shows that INT-Source reduces bandwidth overhead to 12.5% compared to existing methods across three network topologies. Even with a 10% link failure rate, INT-Source is able to monitor 93.1% of network ports, demonstrating strong robustness.

With the expansion of production networks, new challenges arise in scaling telemetry systems to accommodate the massive number of network devices. In-band Network Telemetry (INT) is widely adopted for its fine-grained and accurate measurements. However, system robustness and performance scalability remain key challenges for INT-based network-wide telemetry systems. Existing INT-based measurements manage the network as a whole and rely on a centralized controller for path planning and telemetry data collection. As networks scale and the probability of failures increases, frequent re-planning leads to prolonged telemetry interruptions. In this work, we propose INT-Partition, a hierarchical and fault-tolerant in-band network telemetry system with a divide-and-conquer paradigm. INT-Partition conducts telemetry in two stages: network partitioning and telemetry within each partition, enabling scalability for mega-scale networks. Our evaluations, including mega-scale simulations using BMv2 software switches and small-scale validations on Tofino hardware switches, demonstrate the effectiveness of our approach. With 1% of network equipment out of order, INT-Partition covers over 89.67% of the area and accurately locates faults. As the network scales, telemetry planning and deployment time is reduced by 75.62% to 96.02%, and hot reloading enables seamless switching of telemetry deployment.

In-band network telemetry (INT) enables hop-by-hop fine-grained network monitoring without interacting with the controller at every hop. Existing INT-based network-wide telemetry systems achieve low-overhead monitoring with the non-overlapped path planning algorithms. However, they do not bound the length of the generated probing paths, which may lead to packet loss when the collected telemetry data exceeds the MTU limit. In this paper, we propose an MTU-adaptive path segmentation algorithm to solve this problem. First, we provide two single-path planning algorithms: the INT-optimize algorithm produces a single path that covers the entire network with the lowest southbound communication overhead, and the INT-low-cost algorithm further improves the path planning efficiency of the INT-optimize. By taking the MTU limit into account, we further propose INT-Segment, a novel path segmentation algorithm to split the single long path produced from the previous step into multiple path segments. Extensive evaluations show that the proposed INT-Segment can realize sub-second network-wide telemetry for large-scale networks. It takes less than 2.9ms to calculate the probing paths for an 18-pod FatTree. Compared with the state-of-the-art INT-path, our solution makes the probing path well adapted to the network MTU limit and improves the telemetry efficiency by 10%-94%.