John Y. Wei

Just-in-time signaling for WDM optical burst switching networks

We describe the architecture, design, and implementation of a novel just-in-time (JIT) signaling protocol for optical burst switching (OBS) in wavelength division multiplexed (WDM) optical networks. The JIT-OBS paradigm is designed for ultra-low-latency unidirectional transport of data-bursts across an optical network. It combines the desirable features of circuit-switching and packet-switching. It features out-of-band control signal processing that eliminates buffering of data-burst at intermediate nodes, while minimizing the setup time, and maximizing the cross-connect bandwidth efficiency. We motivate and describe the architecture of JIT signaling, and analyze its basic performance. We present the detailed signaling message design and discuss the rationale and considerations that went into this design. We describe and examine various scenarios that illustrate the operations of the JIT signaling protocol (JIT-SP) in connection establishment and teardown. Finally, we describe and summarize the JIT signaling software prototype in the Washington, DC Testbed network implemented under the MONET project.

Advances in the management and control of optical Internet

Given the ever increasing demand for network bandwidth, and the phenomenal advances in optical wavelength division multiplexing (WDM) networking technologies, a major component of the next generation Internet will be an Internet protocol (IP)-based optical WDM network. As IP over WDM networking technologies mature, a number of important architectural, management and control issues have surfaced. These issues need to be addressed before a true next generation optical Internet can emerge. We enumerate some of the key architectural, management and control issues and discuss corresponding approaches and advances made toward addressing these issues. We first review the different IP/WDM networking architectural models and their tradeoffs. We outline and discuss several management and control issues and corresponding approaches related to the configuration, fault, and performance management of IP over dynamic WDM networks. We present an analysis and supporting simulation results demonstrating the potential benefits of dynamic IP over WDM networks. We then discuss the issues related to IP/WDM traffic engineering in more detail, and present the approach taken in the NGI SuperNet Network Control and Management Project funded by DARPA. In particular, we motivate and present an innovative integrated traffic-engineering framework for reconfigurable IP/WDM networks. It builds on the strength of multiprotocol label switching for fine-grain IP load balancing, and on the strength of reconfigurable WDM networking for reducing the IP networks weighted-hop-distance, and for expanding the bottleneck bandwidth.

Towards hitless reconfiguration in WDM optical networks for ATM transport

This paper proposes a methodology for reconfiguring a wavelength division multiplexed (WDM) optical network to adapt to changing traffic requirements at the ATM layer. The ATM network layer is reconfigured to adapt to changes in traffic patterns. These changing ATM network topologies or connectivities are known and are used to design the network. The proposed method sizes the ATM switches and then assigns wavelengths between pairs of ports so as to support the required ATM network topologies and their reconfiguration in a hitless manner.

Just-in-time optical burst switching for multiwavelength networks

We describe the architecture, performance analysis and simulation result of a novel switching paradigm for optical WDM networks called Just-In-Time Optical Burst Switching (JIT-OBS) designed for ultra-low-latency transport of data-bursts across an optical WDM network. It combines the desirable features of circuit-switching and packet-switching, and features an out-of-band signaling scheme on a separate control channel with explicit feedback on delivery of data-bursts. We provide a performance analysis and simulation of the JITOBS approach, and compare its performance with those of circuit-switching and packet-switching approaches. We find that it has the best latency performance among the different switching mechanisms, and it has a better throughput performance than circuit-switching, and its performance is insensitive to network propagation delays.

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.

The manager/agency paradigm for distributed network management

The manager/agent model has been the de facto paradigm used for designing network management systems. However, as the network size grows and new network and computing technology emerges, consistency, flexibility, reliability, and scalability issues of distributed network management systems might not be fully addressed within the model. This paper proposes an extension to the manager/agent model, called the manager/agency paradigm, to address these issues. In the manager/agency paradigm, a manager performs management functions through an agency of cooperating management entities, (lower-level) managers and/of agents, which are collaboratively working together to achieve consistent management goals. Agencies may recursively constitute other agencies, based on the layering and partitioning principles, to scale with ever growing network size. They may be organized flexibly according to different management functionalities, goals and policies, and may present a single management view to their (upper-level) managers by hiding management complexity. Inside an agency, various fault tolerant schemes, such as active replication or primary-backup approach, may be used to implement reliable management functionality transparently to its manager. The paper begins by describing the anatomy and semantics of an agency and comparing the manager/agency model against the manager/agent model. It then demonstrates its applications to address the consistency and reliability issues of network management problems. Finally, applications of the manager/agency model to the broader, distributed enterprise management is discussed.

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.

The role of DCN in optical WDM networks

With the recent advances in WDM networking technology, and the growing deployment of WDM networking equipment, we are now witnessing the establishment of the next generation networking infrastructure. This paper briefly reviews the role of the data communication network (DCN) in transport networks, and describes MONETs DCN architecture. We then describe a new signalling application of the DCN for WDM-based networks.

IP over WDM network traffic engineering demonstration and experimentation

Traffic-engineering solutions that effectively exploit WDM reconfigurability are urgently needed for IP/WDM networks. This paper describes the testbed and software developed and demonstrated under the DARPA NGI SuperNet NC&M Project, and reports traffic-engineering experiments conducted over the testbed.