Arrayed Waveguide Grating Router and server-based Passive Optical Network data centres

The continuous growth in Internet-connected devices results in significant increase in data centres’ traffic which in turn necessitates the development of scalable, high bandwidth, low power consumption data centre architectures. Passive Optical Networks (PONs) with their proven performance in access networks can provide efficient solutions to support connectivity inside modern data centres. Recently, different novel PON architectures were proposed to manage the inter-rack and intra-rack communication in a data centre.
In this thesis, we further studied one of the PON designs proposed earlier by our group where routing is performed by Arrayed Waveguide Grating Routers (AWGRs) and servers. This work is the first to analyse the AWGR and server-based PON data centre architecture. A Mixed Integer Linear Programming (MILP) model was developed, where the routing and wavelength assignment involving the AWGRs of the PON cell is optimised to support inter group interconnections. Also, the power consumption of this design was compared to a traditional server-based data centre architecture, BCube. Our study showed that the AWGR and server-based data centre architecture reduced the power consumption by 83% as compared to the standard BCube architecture. In addition, we further investigated this AWGR and server-based PON data centre architecture in cloud applications. We developed a MILP model along with a heuristic that minimise power consumption by optimising the embedding of virtual machine requests which is achieved by optimising the servers selected to host VMs. Our study showed that the AWGR and server-based PON data centre architecture reduced the power consumption by up to 34%, compared to the non-optimised embedding model of VMs which tries to fulfil all the requests by maximising the number of VM requests served. Furthermore, a third MILP model was developed to evaluate the resilience of the AWGR and server-based PON data centre architecture modified designs. We also studied the impact of failure of the main components in the proposed PON data centre architecture. In particular, we evaluated the impact of different failure modes on the power consumption and delay of the proposed AWGR and server-based PON data centre architecture. Our study showed that duplicating the special servers reduces power consumption and delay compared to the option where the servers in each rack share a star coupler / backplane. However, choosing between these two resilient designs is a compromise between cost and performance.