Multi-layer Energy Savings in Optical Core Networks

We propose a multi-layer energy saving technique for optical core networks that aims at reducing energy consumption by powering off components in different layers of the network. After obtaining satisfactory results in saving energy by powering off ports in the IP layer in our previous work, in this paper we target more savings by considering additional layers in the network. The model proposed in this paper is a heuristic that bases the capacity prediction for a future time slot on the number of 40G links needed in the current time slot. It also revolves around four parameters for which the values are empirically set. We set two thresholds, low and high, as well as the number of links to power off or power on each time the utilization is below or above a threshold. We assess our model through experiments featuring an Internet2-like topology and a real one-day worth of traffic split into five-minute time slots. The results offer a comparison between different parameters settings and how they affect energy savings and the number of overflows in the network that result from mis-prediction. That said, we demonstrate that our model can achieve up to 90% reduction in energy consumption in the best case when the future traffic is known; otherwise, the savings can range between 82% and 88%, with the occurrence of a small amount of traffic overflow events

Balancing Cost and Reliability in the Design of Internet Protocol Backbone Using Agile Optical Networking

To address reliability challenges due to failures and planned outages, Internet Service Providers (ISPs) typically use two backbone routers (BRs) at each central office. Access routers (ARs) are connected to these BRs in a dual-homed configuration. To provide reliability through node and path diversity, redundant backbone routers and redundant transport equipment to interconnect them are deployed. However, deploying such redundant resources increases the overall cost of the network. Hence, to avoid such redundant resources, a fundamental redesign of the backbone network leveraging the capabilities of an agile optical transport network is highly desired. In this paper, we propose a fundamental redesign of IP backbones. Our alternative design uses only a single router at each office. To survive failures or outages of a single local BR, we leverage the agile optical transport layer to carry traffic to remote BRs. Optimal mapping of local ARs to remote BRs is determined by solving an Integer Linear Program (ILP).We describe how our proposed design can be realized using current optical transport technology.We evaluate network designs for cost and performability, the latter being ametric combining performance and availability. We show significant reduction in cost for approximately the same level of reliability as current designs