Applying multi-controller collaboration in fine-grained all-optical intra-datacenter networks

The exponential growth in emerging applications in datacenters leads to significant increases in traffic and bandwidth consumption in datacenter networks. Finegrained optical switching technology can provide lowlatency end-to-end connection with flexible granularity in intra-datacenter networks. In such a scheme, the centralized network controller will compute an end-to-end path and provide switch state commands for each connection request. However, as network scale and traffic requirements continually increase, the centralized controller will face a significant challenge in low-latency end-to-end connection provisioning under a heavy traffic load. Limited by the controller’s computation and processing performance, the continuously arriving connection requests may block the server's message queue and slow down the controller’s processing rate. In this paper, we propose a multi-controller control scheme for fine-grained all-optical datacenter networks. We take optical time slice switching as an example of fine-grained all-optical switching to illustrate our detailed control scheme. Partitioning rules for the network and controllers’ responsibilities, the routing algorithm, and the signaling process are also discussed. The proposed multi-controller control scheme can greatly reduce each controller’s computation and processing burden and improve network performance. Dynamic datacenter network emulations are launched to verify our proposed scheme. The emulation results indicate that the multi-controller scheme can reduce connection setup delays and request and data failure rates, while the single controller fails to handle all the requests.