Medium access control protocol and resource allocation for passive optical interconnects

Passive optical interconnects (POIs) have recently been considered as a promising solution to offer high bandwidth and low power consumption for data center networks. This paper proposes a medium access control protocol for a POI based on arrayed waveguide gratings (AWGs) to facilitate efficient collision-free communications. In order to efficiently accommodate bursty traffic generated by the servers in the data center, we develop a tailored dynamic bandwidth allocation (DBA) algorithm, which is able to schedule resources in both time and spectrum. In the simulation, not only the impact of DBA algorithm parameters but also the system configurations, such as wavelength tuning time, line rate, and the size of the interconnect, have been investigated. For a typical link utilization on an optical interconnect at the top of the rack, the proposed resource allocation scheme ensures both low latency (<0.1 ms) and a low frame drop ratio (almost zero).