High-speed optical networks latency measurements in the microsecond timescale with software-based traffic injection

摘要

In many optical network scenarios, such as Storage Array Network (SAN) replication, keeping latency under control is cornerstone to provide a proper Quality of Service (QoS). Hence, measuring latencies in such optical networks becomes fundamental. However, for low distances, microseconds resolution is required, which, in turn, demands ad-hoc hardware implementation for the measurement device. Alternatively, a more cost-effective solution is that of software-based methods, but up to date they were not precise enough at 10 Gbit/s or above. In this paper, we analyze current high-performance packet engines, such as DPDK, and pinpoint the issues involved when it comes to measure latencies in high-speed optical networks. Based on these findings, we propose the use of a software-based solution to measure latency. Furthermore, we also propose an extension that serves to measure bandwidth as well, with the novel concept of convoy of packet trains.