Ronald A. Skoog

Architectures and Protocols for Capacity Efficient, Highly Dynamic and Highly Resilient Core Networks [Invited]

The Core Optical Networks (CORONET) program addresses the development of architectures, protocols, and network control and management to support the future advanced requirements of both commercial and government networks, with a focus on highly dynamic and highly resilient multi-terabit core networks. CORONET encompasses a global network supporting a combination of IP and wavelength services. Satisfying the aggressive requirements of the program required a comprehensive approach addressing connection setup, restoration, quality of service, network design, and nodal architecture. This paper addresses the major innovations developed in Phase 1 of the program by the team led by Telcordia and AT&T. The ultimate goal is to transfer the technology to commercial and government networks for deployment in the next few years.

Automatic Identification of Impairments Using Support Vector Machine Pattern Classification on Eye Diagrams

We have demonstrated powerful new techniques for identifying the optical impairments causing the degradation of an optical channel. We use machine learning and pattern classification techniques on eye diagrams to identify the optical impairments. These capabilities can enable the development of low-cost optical performance monitors having significant diagnostic capabilities

Applications of Artificial Neural Networks in Optical Performance Monitoring

Applications using artificial neural networks (ANNs) for optical performance monitoring (OPM) are proposed and demonstrated. Simultaneous identification of optical signal-to-noise-ratio (OSNR), chromatic dispersion (CD), and polarization-mode-dispersion (PMD) from eye-diagram parameters is shown via simulation in both 40 Gb/s on-off keying (OOK) and differential phase-shift-keying (DPSK) systems. Experimental verification is performed to simultaneously identify OSNR and CD. We then extend this technique to simultaneously identify accumulated fiber nonlinearity, OSNR, CD, and PMD from eye-diagram and eye-histogram parameters in a 3-channel 40 Gb/s DPSK wavelength-division multiplexing (WDM) system. Furthermore, we propose using this ANN approach to monitor impairment causing changes from a baseline. Simultaneous identification of accumulated fiber nonlinearity, OSNR, CD, and PMD causing changes from a baseline by use of the eye-diagram and eye-histogram parameters is obtained and high correlation coefficients are achieved with various baselines. Finally, the ANNs are also shown for simultaneous identification of in-phase/quadrature (I/Q) data misalignment and data/carver misalignment in return-to-zero differential quadrature phase shift keying (RZ-DQPSK) transmitters.

Management of switched systems at 100 Tbps: The DARPA CORONET program

The DARPA CORONET program is laying the foundations for a next generation IP-over-Optical network that supports 100 Tbps of traffic and provides rapid, on-demand, switched wavelength services. The wavelength services are very dynamic, with setup times of 100 ms and holding times as short as a few seconds to a minute. A major management challenge is designing a provisioning protocol for the dynamic services. We describe in this paper a 3-Way Handshake (3WHS) protocol that meets the service requirements, and we provide simulation results of the performance of the 3WHS.

Lessons learned from CORONET

The DARPA CORONET Program is focused on multi-terabit core optical networks supporting highly dynamic IP and wavelength services. We describe key methodologies for achieving CORONET objectives and insight into important elements for future commercial applicability.

Metro network design methodologies that build a next-generation network infrastructure based on this generation's services and demands

This paper describes two key network architecture design concepts that relate to evolving existing transport networks into economically viable next-generation optical networks. Todays metropolitan transport networks largely consist of synchronous optical network/synchronous digital hierarchy rings or switch-to-switch fiber connections for some form of optical Ethernet. The result is an optical-electrical-optical infrastructure that has limited use in providing wavelength services. Wavelength-division multiplexing (WDM) is the enabling technology for wavelength services, but it has limited penetration in the metropolitan area due to its cost justification being dependent primarily on fiber relief. The first part of this paper shows how existing services, primarily using time-division-multiplexing (TDM) transport, can be used to economically justify a WDM infrastructure while achieving significantly lower costs than legacy design techniques would produce. Dynamic bandwidth-on-demand (BoD) service is another elusive goal envisioned for next-generation metropolitan networks. This paper addresses how an economically viable BoD infrastructure can be built based on revenues from existing enterprise services rather than relying on revenues from new and unproven services. Quantitative analyses, presented in the paper, show the key parameters that determine when BoD services will be used, how bandwidth granularity affects BoD decisions, and how the customers use of BoD drives service provider network design considerations.

Performance of IP over optical networks with dynamic bandwidth allocation

IP over optical network performance can be improved with dynamic bandwidth allocation, depending on the reallocation paradigm and the network topology. Under high connectivity, dynamic bandwidth allocation provides a notable boost to the networks traffic-carrying capacity.

Architectures and protocols for highly dynamic IP-over-Optical networks

The DARPA CORONET program is laying the foundations for a next generation IP-over-Optical network that supports 100 Tbps of traffic and provides rapid, on-demand, switched wavelength services. The wavelength services are very dynamic, with setup times of 100 ms and holding times as short as a few seconds to a minute. A major management challenge is designing a provisioning protocol for the dynamic services. We describe in this paper a 3-Way Handshake (3WHS) protocol that meets the service requirements, and we provide simulation results of the performance of the 3WHS.

Designing fault tolerant networks to prevent poison message failure

Summary Poison message failure is a mechanism that has been responsible for large-scale failures in both telecommunications and IP networks. We design a fault management framework that integrates passive diagnosis and active diagnosis to identify the poison message and prevent network instability. Passive diagnosis uses real-time inference and reasoning techniques to analyze network information and generates a probability distribution of the poison message, and the probability distribution is used in active diagnosis for further failure identification. In active diagnosis, message filtering is used to block suspect message types. Blocking messages affects network performance and service. The tradeoff of message filtering is formulated as a Markov Decision Process (MDP). The large size of the state space makes it impractical to use traditional techniques to solve the MDP. Consequently, we use a combination of reinforcement learning and feature-based function approximation to obtain a suboptimal policy. Extensive simulations demonstrate the effectiveness of passive diagnosis, and show that the suboptimal policy performs significantly better than a well-known heuristic policy. Copyright # 2008 John Wiley & Sons, Ltd.

Data in the optical domain technology: A network-level perspective

This study focuses on network-level issues that fall into three broad categories: 1) network performance, 2) network requirements and 3) drivers and applications for the DOD-N. The goal of this work is to investigate the value, viability, and fit of this new networking technology across a broad spectrum of network scenarios. A network simulation environment is constructed, which allows the investigation of the performance of DOD-networks as a function of node design and technologies, network architecture, network scale, traffic characteristics, physical layer constraints, and other parameters. The intent of Telcordias project is to bring network-level issues to bear to optimize both the performance and the utility of the DOD-N technologies.