Zeng Qingji

Joint operation in multi-hop WDM networks under dynamic data traffic

In view of the present dynamic data traffic, we raise and analyze critical issues in joint operation under IP over WDM architecture. Wavelength division multiplexing technology has been introduced into todays optical network infrastructure to accommodate the rapid growth of Internet data traffic. To minimize total network cost and maximize network resource efficiency, two main approaches have been proposed: (1) reducing the protocol stack; and (2) bypassing or eliminating electronic processing. A simplified protocol stack is proposed herein which integrates an interlayer manager with the IP adaptation layer between the IP and WDM layers. The focus of this paper is on the operation of this interlayer manager, namely joint operation of IP and WDM layers. This paper highlights the grooming issue, further formulates it into an integer linear program (ILP), and finally proposes heuristic algorithms.

Wavelength requirements in wavelength-routed ring networks

In this paper, we discuss the wavelength requirements for wavelength-routed ring networks. A new integer linear programming (ILP) formulation is proposed for routing and wavelength assignment of wavelength path (WP) and virtual wavelength path (VWP) routing schemes. Because the ILP formulation is computationally expensive, an effective heuristic algorithm is also proposed. By using these algorithms, we analyze various network examples with uniform and non-uniform traffic loads. These results will contribute to the optimal usage of wavelength resources in optical networks.

Wavelength reusability in wavelength-routed optical networks

Wavelength reusability is proposed as an efficient criterion to evaluate the network performance in wavelength-routed optical networks. The maximum wavelength reusability is limited for a given network. The maximum wavelength reusability mainly depends on the average nodal degree.

Design of logical topologies for wavelength-routed ring network

We formulate the logical topology design of wavelength-routed ring network as a mixed integer linear programming (MILP) problem. For a given traffic demand matrix, the objective function of the optimal problem is to minimize the average packet hop distance. We take the bidirectional ring network as an example. For different network architecture parameters, the numerical results and analyses were provided. In addition, we also compare the case of a unidirectional ring network with bidirectional ring network. The optimal results can be used to maximize the utilization of network resource in the ring network design.

Reference configuration for performance management in multiwavelength optical transport networks

A set of reference points for performance management is proposed, which is based on the general functional architecture of the multiwavelength optical transport networks. These reference points can be mapped into the physical interfaces of optical networks to guide the execution of performance monitoring and controlling.

Self-healing mechanism in the WDM all optical metropolitan network: SHONET

SHAONET (Shanghai All Optical Network Testbed), the first WDM all optical network testbed in China, is a metropolitan self-healing ring. This paper compares the self-healing mechanisms and presents the realization of the fast self-healing mechanism used in SHAONET.

Self-stimulated effect in WDM all-optical network

A novel phenomena called self-stimulated effect was found in the Shanghai all-optical network (SHAONET). We first research in detail its cause, evolution and influence on communication performance. According to simulation and experimental results, we found that the effect has no relationship with the actual topology of optical network and is very harmful to the communication performance of signal channels.