arXiv subjects
Publications and source records attributed to Joshua L. Benjamin.
We propose a new algorithm for generating custom network traffic matrices which achieves 13x, 38x, and 70x faster generation times than prior work on networks with 64, 256, and 1024 nodes respectively.
Benchmarking is commonly used in research fields, such as computer architecture design and machine learning, as a powerful paradigm for rigorously assessing, comparing, and developing novel technologies. However, the data centre networking community lacks a standard open-access benchmark. This is curtailing the community's understanding of existing systems and hindering the ability with which novel technologies can be developed, compared, and tested. We present TrafPy; an open-access framework for generating both realistic and custom data centre network traffic traces. TrafPy is compatible with any simulation, emulation, or experimentation environment, and can be used for standardised benchmarking and for investigating the properties and limitations of network systems such as schedulers, switches, routers, and resource managers. To demonstrate the efficacy of TrafPy, we use it to conduct a thorough investigation into the sensitivity of 4 canonical scheduling algorithms (shortest remaining processing time, fair share, first fit, and random) to varying traffic trace characteristics. We show how the fundamental scheduler performance insights revealed by these tests translate to 4 realistic data centre network types; University, Private Enterprise, Commercial Cloud, and Social Media Cloud. We then draw conclusions as to which types of scheduling policies are most suited to which types of network load conditions and traffic characteristics, leading to the possibility of application-informed decision making at the design stage and new dynamically adaptable scheduling policies. TrafPy is open-sourced via GitHub and all data associated with this manuscript via RDR.
We introduce PULSE, a sub-microsecond optical circuit-switched data centre network architecture controlled by distributed hardware schedulers. PULSE is a flat architecture that uses parallel passive coupler-based broadcast and select networks. We employ a novel transceiver architecture, for dynamic wavelength-timeslot selection, to achieve a reconfiguration time down to O(100ps), establishing timeslots of O(10ns). A novel scheduling algorithm that has a clock period of 2.3ns performs multiple iterations to maximize throughput, wavelength usage and reduce latency, enhancing the overall performance. In order to scale, the single-hop PULSE architecture uses sub-networks that are disjoint by using multiple transceivers for each node in 64 node racks. At the reconfiguration circuit duration (epoch = 120 ns), the scheduling algorithm is shown to achieve up to 93% throughput and 100% wavelength usage of 64 wavelengths, incurring an average latency that ranges from 0.7-1.2 microseconds with best-case 0.4 microsecond median and 5 microsecond tail latency, limited by the timeslot (20 ns) and epoch size (120 ns). We show how the 4096-node PULSE architecture allows up to 260k optical channels to be re-used across sub-networks achieving a capacity of 25.6 Pbps with an energy consumption of 85 pJ/bit.