A Programmable Hardware Calendar for High Resolution Pacing

The challenge addressed in this paper consists in offloading packet-based pacing to a hardware Network Interface Card, while retaining the flexibility of software timers. In this direction, we propose, design, implement, and evaluate a hardware calendar, which can be programmed via a simple yet very flexible programming interface leveraging stateful (adaptive) per-packet timers. We show, for both specific examples (exponential, linearly increasing, etc) as well as for the general case, how to derive such a per-packet timer setting from a high-level desired rate envelope. Further, we describe and evaluate an FPGA implementation which relies on a novel insertion strategy for solving collisions in the calendar's hash table.