Cloud service providers use replication across geographically distributed data centers to improve end-to-end performance as well as to offer high reliability under failures. Content replication often involves the transfer of huge data sets over the wide area network and demands high backbone transport capacity. In this paper, we discuss how a Globally Reconfigurable Intelligent Photonic Network (GRIPhoN) between data centers could improve operational flexibility for cloud service providers. The proposed GRIPhoN architecture is an extension of earlier work [34] and can provide a bandwidth-on-demand service ranging from low data rates (e.g., 1 Gbps) to high data rates (e.g., 10-40 Gbps). The inter-data center communication network which is currently statically provisioned could be dynamically configured based on demand. Today's backbone optical networks can take several weeks to provision a customer's private line connection. GRIPhoN would enable cloud operators to dynamically set up and tear down their connections (sub-wavelength or wavelength rates) within a few minutes. GRIPhoN also offers cost-effective restoration capabilities at wavelength rates and automated bridge-and-roll of private line connections to minimize the impact of planned maintenance activities.

Traditional backbone optical networks can take months to provision a wavelength connection. Future optical networking aims at reducing the provisioning time to a few minutes. In conjunction, new services that allow the customers to dynamically set up and take down their connections is emerging. In this paper, we introduce the problem of optimizing network resources on a reconfigurable optical backbone network that provides such dynamic optical services. The problem grows exponentially in network scale and customer's demands, thus solving the entire problem for a realistic network is impractical. We address this problem by developing a heuristic optimization procedure, combined with problem-size reduction techniques. We show that good results can be achieved using small amounts of computing power and that our solutions are within 11% of a lower bound.

In a network with Reconfigurable Optical Add/drop Multiplexers (ROADMs), transient effects from network failures trigger sudden power changes to channels, even on spans (ROADM-to-ROADM links) upstream/downstream from the failure. Some ROADMs rely on restrictive wavelength assignment rules, calledfield-of-use(FOU), to insure surviving channels meet performance objectives.Dropdepth(DD) (ratio of surviving channels) andspanoverlapcount(SOC) (length of spans of overlapping lightpaths) are two parameters defined for FOU guidelines. For a given DD, FOU guidelines specify a corresponding maximum SOC for each wavelength. Generally, a wavelength can support a longer span overlap count under a smaller drop depth restriction. However, the measured drop-depth changes as wavelengths are assigned. We propose methods to optimize transient-constrained wavelength assignment in commercial ROADM networks. Our solutions have been shown to provide 40% more channels than with typical FOU guidelines.

The purpose of this paper is to understand the relationship between utilization, fairness and access delay in high speed slotted bus networks. We illustrate this relationship by means of a protocol called FUFA (fully utilized and fair). We define full utilization, and fairness precisely, and show that both are achieved together in the FUFA protocol. In addition, the protocol provides bounded access delay that is linear in the round trip propagation delay, and at most a constant away from its minimum possible value for any bus protocol that is both fully utilized and fair. The main idea is that each station takes account of the idle slots propagated previously to interpret the information from downstream (i.e., estimated aggregate number of data segments in the queue downstream and estimated number of active downstream stations). This allows the active downstream stations to be served in a round robin fashion according to the updated information.