Interleaved Sketch: Toward Consistent Network Telemetry for Commodity Programmable Switches

Abstract

Network telemetry is vital to various network applications, including network anomaly detection, capacity planning, and congestion alleviation. State-of-the-art network telemetry systems are claimed to be scalable, flexible, all-purpose, and accurate. They adopt interval approaches that track network traffic in each interval and collect statistics for analysis at a specific epoch. However, interval methods are impaired by collecting inconsistency and clearing inconsistency, which pollute statistics. Moreover, The state-of-the-art centralized controllers have long latency, which aggravates the discrepancy. Accordingly, we propose the interleaved sketch, a consistent and decentralized network telemetry system across all switches. Each switch has two asymmetric sketches that work in an interleaved fashion, and is self-supervised to improve consistency. The distributed control plane extracts the flow characteristics and provides network-wide telemetry with low latency. We build a P4 prototype of our proposed interleaved sketch and test it on a Barefoot Tofino switch. Experimental results demonstrate that our interleaved sketch achieves ideal accuracy at line speed, with 6% resource overhead.