SPT: sketch-based polling in-band network telemetry

Network traffic measurement is central to successful network operations, especially for today's large-scale networks. Although existing researches have made great contributions, they fail to achieve the following three criteria simultaneously: 1) low total overhead, which refers to the ability to acquire information in low bandwidth cost; 2) constant overhead of on-path measurement; and 3) easy to organize, meaning that the system is able to satisfy most of the user's measurement requests. We propose SPT to meet these three criteria simultaneously. To realize flexible control, SPT supports various measurements in INTs passport mode. To save the bandwidth, SPT adopts sketch-guided elephant flow selection, extension filed reuse, and compression of control instructions. To achieve flexed-length extension fields, SPT decomposes multiple measurement tasks carried by one packet of a flow into separate measurement tasks carried by multiple sequential packets of the flow. We also need to consider the deployment of the framework so we optimize the pipeline to save the SRAM resources. We implemented a SPT prototype on a testbed with P4 software switches in a linear topology. We conduct comparative experiments with a classical measurement framework SINT and a state-of-the-art measurement framework PINT. Experimental results show that SPT can obtain per-hop flow-level information with the highest accuacy when the overhead is the same.