FANT: Flexible active in-band network telemetry

Abstract

With the ever-increasing complexity of networks, the need for fine-grained and comprehensive network monitoring has become crucial. In order to provide higher precision and multidimensional network status, In-band Network Telemetry (INT) has been incorporated into certain modern merchant silicon devices. INT, specifically active INT (ANT), in conjunction with SDN, enables network-wide visibility by capturing device-internal status along probe traces. However, as network management applications require more measurements from different perspectives to identify potential network issues, switch vendors are continuously expanding the scope of telemetry measurements available on their devices. The proliferation of telemetry items results in increased overhead for the network and places a heavier processing load on the INT analyzer. In this paper, we introduce a novel approach called Flexible Active in-band Network Telemetry (FANT) that enhances the measurement capabilities of the system by decoupling it into a mechanism and a probe-switching policy. FANT divides the measurement space into basic and detailed parts based on the relationship between INT metadata. The mechanism of FANT leverages a combination of ANT and Software-Defined Networking (SDN) to perform network-wide basic measurements. By centrally analyzing these measurements, FANT dynamically adjusts certain port measurements from basic to detailed. Additionally, we propose two probe-switching policies to generate low-redundant Detail Probes that cover all abnormal ports. In the first policy, we present an optimized Iterative deepening $A^{\ast }$ algorithm that provides near-optimal solutions in low measurement frequency scenarios. The second policy achieves improved performance and reduced overcontrol using the random cover algorithm in high measurement frequency scenarios. To validate the effectiveness of the proposed mechanism, we implement a FANT prototype system. Furthermore, we extensively evaluate FANT’s performance in various topologies, including wide area networks and data center networks of different scales.