Network Policy Enforcement with Commodity Multiqueue NICs for Multitenant Data Centers

Data centers are the fundamental component in the Internet of Things (IoT) system architecture. Data center servers where IoT services are co-located require hierarchical network policy enforcement to ensure fair bandwidth sharing among tenants and to prioritize latency-sensitive traffic within a tenant simultaneously. Meanwhile, emerging network interface cards (NICs) in servers make use of multiple hardware queues to drive increasing line rates. Unfortunately, multiqueue NICs make it hard to enforce hierarchical policies because the NIC packet scheduler dequeues packets in a static round-robin (RR) fashion for per-flow fairness. In this article, we enable hierarchical network policy enforcement with existing commodity multiqueue NICs. We design TONIC, a multiqueue NIC packet scheduling solution that approximates hierarchical packet scheduling by manipulating the packet dequeueing sequence of the NIC scheduler through dynamic packet enqueueing decisions. Specifically, TONIC leverages multiple hardware queues and the double-ended queue structure of qdiscs to express different tenant weights and application priorities without hardware modifications. We implement a TONIC prototype as a Linux kernel module and evaluate it on a testbed with commodity multiqueue NICs. Our experiment results show that TONIC can enforce hierarchical policies consisting of weighted fair sharing and traffic prioritization while maintaining robustness to various network conditions.