Efficient Design of Survivable and Protected Flexi-Grid Inter-Datacenter Networks

Project: Research

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Cloud service providers (CSP), such as Google and Facebook, replicate and transport their content between geographically distributed datacenters using inter-datacenter wide area networks. Total inter-datacenter traffic volume is over 0.6 Exabyte per day, and is growing at a rate of over 25% per annum. Therefore, its transport consumes a significant amount of energy and represents a substantial cost burden on CSPs. This project will develop a new network design methodology to achieve cost effective and energy conserving operations that meet the performance and reliability requirements of future inter-datacenter networks. For the first time, network design methodologies based on integrating flexi-grid communications, protection, disaster survivability, and light-tree assignment will be provided. Flexi-grid communications technology has the potential to increase efficiency and flexibility. Protection guarantees sufficient capacity on alternative routes when links fail; disaster survivability guarantees high probability of connectivity in case of major disasters, and light-trees provide cost effective all-optical data transport especially for multicasting traffic. The project will provide an assessment of the extent to which energy and cost savings are achieved using flexi-grid communications and light-trees in inter-datacenter networks. Inter-datacenter networks have the following unique features: (1) inter-datacenter traffic involves replications that require significant multicasting - this justifies the use of light-trees; (2) datacenters may have advance information on the volume of data per connection - this enables efficient utilization of the flexible network resources considered in this project (i.e. flexi-grid based light-trees and lightpaths) and justifies their applicability, and (3) the number of nodes of an inter-datacenter network is not large. The proposed solution methods exploit these features; they are based on Integer Linear Programming (ILP), and on accurate and efficient heuristics. An ILP formulation provides a rigorous description of the engineering and economic considerations of the relevant optimization problem. ILP can also provide an optimal solution for small CSPs, and serves as a benchmark for other suboptimal solutions. Although the proposed methodologies are well adapted to inter-datacenter networks, the results and conclusions of the project can also apply to some extent to other optical networks. The project will address both legacy and greenfield scenarios. Under the legacy scenario, we will optimize the traffic routing and wavelength/spectrum assignment of lightpaths and light-trees for a given topology. In the greenfield scenario, the topology is optimally designed by minimizing cost subject to meeting disaster survivability requirements with special attention given to cable shapes that may not be in straight lines.


Project number9042070
Grant typeGRF
Effective start/end date1/01/1511/06/18

    Research areas

  • inter-datacenter networks ,multicasting,disaster survivability,flexi-grid ,