OFLOPS-SUME and the art of switch characterization

© 2018 IEEE. The philosophy of software-defined networking (SDN) has introduced new challenges in network system management. In contrast to traditional network devices that contained both the control and the data plane functionality in a tightly coupled manner, SDN technologies separate the two network planes and define a remote API for low-level device configuration. Nonetheless, the enhanced flexibility of the SDN paradigm is prone to create novel performance and scalability bottlenecks in the network. To help network managers and application developers better understand the actual behavior of SDN implementations, we present a hardware/software co-design that enables switch characterization at 40 Gbps and beyond. We conduct an evaluation of both software and hardware switches. We expose the unwanted effects of the OpenFlow barrier primitive, potential misbehaviors when adding or modifying a batch of rules, and how simple operations, such as packet modification, can impact the switch forwarding performance. We release the code publicly as open source to promote experiments reproducibility as well as encourage the network community to evolve our solution.This work was supported by the U.K.’s Engineering and Physical Sciences Research Council through the EARL and TOUCAN projects under Grants EP/P025374/1 and EP/L02009/1

PINT: Probabilistic In-band Network Telemetry

© 2020 ACM. Commodity network devices support adding in-band telemetry measurements into data packets, enabling a wide range of applications, including network troubleshooting, congestion control, and path tracing. However, including such information on packets adds significant overhead that impacts both flow completion times and application-level performance. We introduce PINT, an in-band network telemetry framework that bounds the amount of information added to each packet. PINT encodes the requested data on multiple packets, allowing per-packet overhead limits that can be as low as one bit. We analyze PINT and prove performance bounds, including cases when multiple queries are running simultaneously. PINT is implemented in P4 and can be deployed on network devices.Using real topologies and traffic characteristics, we show that PINT concurrently enables applications such as congestion control, path tracing, and computing tail latencies, using only sixteen bits per packet, with performance comparable to the state of the art