Brian J. Wilson

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.

Comparison of capacity efficiency of DCS network restoration routing techniques

A crucial issue in the management of telecommunications networks is restoration after a network failure. We compare the capacity efficiency (the amount of traffic restored over fixed capacity) of several types of restoration methods for Digital Crossconnect Systems (DCSs) under both node or link failures in metropolitan networks. These restoration methods can be broadly categorized based on the type of control of the restoration process and the type of procedure for rerouting traffic around the failure. It is easily shown that point-to-point methods (where traffic is rerouted end-to-end) restore a higher percent of traffic than patch methods (where traffic is rerouted only around the failed segment). However, quantification of the difference in efficiency among the methods is important to fully evaluate other trade-offs, such as cost and speed of restoration. To evaluate the efficiency difference, we generated random network traffic distributions by simulation and then failed links and nodes for each simulation sample. Statistics were generated on the expected amount of restored traffic for each restoration method. In particular, we found that the efficiency advantage of point-to-point methods over patch methods is greater for link failure than for node failure. Also, the difference was not statistically significant in low levels of network congestion (i.e., networks with large amounts of excess capacity) and became more significant as network congestion increased.

The MONET New Jersey network demonstration

The multiwavelength optical networking (MONET) consortium has demonstrated national-scale optical networking in a multilocation testbed in New Jersey. The demonstration involves transparent optical connections over path lengths as long as 2290 km, through several network elements (NEs) controlled by two interoperating network control and management (NC&M) systems. This paper describes in detail the three constituent testbeds and the experiments.

Multiwavelength optical networking management and control

This paper describes the network management research done by the Network Control and Management (NC&M) Task under the Multi-wavelength Optical Networking (MONET) Program. MONET is sponsored by the Defense Advanced Research Project Agency (DARPA) of the U.S. Government Department of Defense, with participation from Telcordia Technologies, AT&T, Lucent Technologies, several government agencies and regional Bell Operating Companies. MONETs vision is to develop technologies needed for a flexible, reliable, high-capacity, high-performance, cost-effective national scale optical network based on the multi-wavelength fiber-optic technology. As an important component in realizing this vision, the MONET program includes the architecture and design of a prototype network control and management system that will manage MONETs reconfigurable wavelength-division-multiplexing (WDM) all-optical network. The primary objectives of the prototype research work are to develop the architecture and framework for managing national-scale. Transparent reconfigurable WDM optical networks, and to demonstrate the feasibility of the NC&M prototype system in a field experiment network in Washington, DC. This prototype system will allow the program participants to conduct experiments and gain experience in the management and operations of reconfigurable optical networks. This paper describes the features and capabilities of the prototype system, addressing issues such as management architecture, information model, interoperability and algorithms of the prototype management system. We also relate some of our experience in testing, installing and using the prototype system in the MONET network.

Connection management for multiwavelength optical networking

This paper describes the connection management research done by the Network Control and Management (NC&M) task force under the multiwavelength optical networking (MONET) program. MONET is sponsored by the Defense Advanced Research Project Agency (DARPA) the US Government Department of Defense, with participation from Bellcore, AT&T, Lucent Technologies, several government agencies, and regional Bell operating companies. MONETs vision is to develop a flexible reliable high-capacity high-performance cost-effective national optical network based on multiwavelength fiber optic technology. As an important component in realizing this vision, the MONET program includes the architecture and design of a prototype network control and management system for MONETs reconfigurable wavelength-division multiplexing (WDM) all-optical network. The primary objectives of the prototype research work are to develop the architecture and framework for managing national-scale transparent reconfigurable WDM optical networks and to demonstrate the feasibility of the NC&M prototype system in a field experiment network in Washington, DC. This prototype system allows the program participants to conduct experiments and gain experience in the management and operations of reconfigurable optical networks. This paper describes the connection management aspects of the prototype system, addressing issues such as the management architecture, information model, and provisioning algorithms of the prototype management system.

A management and visualization framework for reconfigurable WDM optical networks

As the phenomenal advance in optical WDM networking technologies continues, optical WDM network equipment has been deployed not only in backbone networks, but also in regional, metropolitan, and access networks. It is widely believed that a major component of the next-generation Internet will be an IP-based optical network employing WDM. WDM wavelength routing and signaling have become an active research field, and dynamic and adaptive wavelength routing and assignment algorithms have been proposed. However, there is less work on reporting network control and management system implementation efforts over testbed WDM networks. This article presents a network management and visualization framework aimed at guiding the development of management applications for reconfigurable WDM optical networks. A layered framework architecture including element and network management and visualization is provided, and an object-based information model representing the WDM network is introduced. Functional components on reconfiguration, software agent, and network visualization services are presented, and important issues related to optical lightpath generation are discussed. A network visualization service also provides WDM control and management APIs to applications and access networks such as an IP network management system. To illustrate the usage of the framework, we share our experience in implementing the MONET network control and management system, and present network visualization views obtained from the MONET WDM network to highlight the framework features.

Network control and management of reconfigurable WDM all-optical network

To meet the demand for huge bandwidth created by the multimedia communications revolution, there is an urgent need to dramatically upgrade the existing telecommunications infrastructure. In todays infrastructure, fiber-optics is used in point-to-point transmission links, with all networking and services functions done electronically. To upgrade such an infrastructure in a cost-effective way, Wavelength Division Multiplexing (WDM) technology may be used to transmit multiple optical channels per fiber. This way, network capacity may grow in response to increased demand. In addition, with the reconfigurability of WDM networks, network configuration may adapt in response to changing traffic patterns. To ensure successful deployment and operations of WDM networks, it becomes essential to have a comprehensive network control and management system which is versatile, robust, and scaleable. In this paper, we describe a network control and management system prototype developed under the Multiwavelength Optical Networking (MONET) project funded by the US governments Defense Advanced Research Project Agency. The prototype system provides configuration, connection, fault, and performance management functionalities for reconfigurable WDM all-optical networks. The design of the prototype system follows the TMN logical layered architecture, and it is implemented on a fault-tolerant, CORBA-compliant distributed object computing platform which facilitates robust and scaleable operations.

Network management research in ATDNet

The Advanced Technology Demonstration Network (ATDNet) is a major testbed facility established by DARPA and other U.S. government agencies to conduct network and applications research on the next generation of high speed ATM/SONET networks. This article presents the approaches and results of our work in network management on ATDNet. The research addresses different aspects of next-generation systems design, including integrated network management of different technology layers, multitier and multiprotocol architectures, robust distributed computing platforms, and object-oriented technologies. To address these challenges in a practical manner, the authors describe their implementation of a prototype software system developed on a distributed computing platform, discuss how this research addresses the current and evolving needs of ATDNet, and present possible future research directions.

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.

A scheduling application for WDM optical networks

Optical networking using WDM technology has matured considerably, and commercial WDM network equipment and WDM network control and management prototypes have appeared. To use such a network efficiently, a scheduling facility and its enabling mechanisms have to be provided. This scheduling facility should be integrated to interoperate with the rest of the network control and management software such as connection manager or signaling daemon. We present a scheduling application to address this need. The architecture for the application and its key components are presented. Agent-related enabling mechanisms are introduced to monitor the optical signal quality and collect performance measurements. A resource broker is used to manage the communication and interoperability between agents and the application. An event service is developed to decouple the communication between the agents and the scheduling application, and to enable the communication among the agents themselves. The scheduling application consists of the quality of signal information and threshold objects, current network usage, history data module, scheduling module, and access to a performance database. To provide traffic control and high network resource utilization, the application is equipped with wavelength scheduling algorithms. An experimental study for the basic scheduling algorithms has been conducted over the MONET DC network.