Dahai Han

Convergence of sensor networks/internet of things and Power Grid Information Network at aggregation layer

The Sensor Networks and “Internet of Things” (IOT for short) have been regarded as the trend of information technology. At the same time, Intelligent Power Grid is also becoming the key part of national energy program. As the collection of power engineering and ICT, the key technologies of IOT and ICT applied in Power Grid System are being highly concerned with manufacturers and government. In this paper, the natural bottleneck between mass sensor information and Electric Power Communication Transmission Network is proposed and put forward the concept of information aggregation layer under the background of heterogeneous network convergence. Power Grid Information Network and Sensor information processing and data fusion in Aggregation Layer will be taken on the embedded smart gateway and provide front-end processing and analysis of sensor information, which can be used to implement in varied Intelligent Power Grids scenario with a unified data-aware, access, transmission and data fusion. At the end, the article describes a number of Intelligent Power Grids application of innovation based on the aggregation layer embedded smart gateway device and looking forward to a vision of fully perception and integrated next-generation Power Grids.

QoS sensitive routing in DiffServ MPLS-TP networks

QoS sensitive routing is a very important component of traffic engineering in DiffServ MPLS-TP networks. This study investigated the characteristics of packet scheduling algorithms and the problem of unfairness when QoS routing does not consider the mix of traffic classes. A new routing scheme STE-QOSPF-Mix, which takes the reserved bandwidth supported WFQ algorithm into account, is proposed. To determine the QoS route for a flow request, STE-QOSPF-Mix considers the effective available bandwidth instead of residual bandwidth of the path, which is more suitable in DiffServ MPLS-TP networks. The simulation results show that our proposed STE-QOSPF-Mix scheme outperforms the TE-QOSPF-Mix scheme in terms of packet loss ratio and end to end delay.

Research of novel complex optical network routing architecture

Abstract This article puts forward a novel routing architecture for complex optical network, which core component is path calculation element (PCE). As is well known, the PCE-based distributed path computation structure is making the routing control and computation loosely coupled from traditional control plane. In the study, the resource allocation and routing algorithm are the critical part of PCE hierarchy. To compare the performance of new architecture and the traditional one, the user uses the flooding suppression, routing delay, resource utilization and traffic blocking probability as performance simulation parameters and taking the verification simulation on objective modular network testbed (OMNeT) platform against to source-node routing architecture. The numerical analysis, computer simulation and experiment work indicate that the operation of PCE-based routing architecture can reduce the flooding information of path calculation request as well as the routing hops significantly and improve the quality of service (QoS) by decreasing the blocking probability when failure happened.

Group-failure based cross-layer survivability research in intelligent optical networks

Different from general multi-failure, group-failure in cross-layer intelligent optical networks has the characteristic of cluster. Because multi-failure may occur due to single failure, it is more harmful for multi-failure than single failure. The original survivability with regards to multiple single failures is not suitable for group-failure based cross-layer survivability research. Group-failure based cross-layer survivability is eager to be solved in intelligent optical networks, and the corresponding key theory and technology are anxious to be proposed. This paper mainly focuses on the performance of cross-layer survivability based on group-failure in intelligent optical networks. Three topics are mainly paid attentions to, including the generation mechanism and model of group-failure in multi-layer optical networks, fast location mechanism for group-failure, and protection and recovery strategies applied to group-failure. At last, a PCE-based fast reroute algorithm (PFRR) is proposed and analyzed in the paper.

The EXC management in the OTN over WDM network

The OTN over WDM network is one of the best solutions of the optical transmission network. As a traditional multi-layer network, multi-layer traffic grooming algorithms in the OTN over WDM network have been fully studied. However, the cross-connects capacity management problem of the OTN node in the OTN over WDM network is still under study. In our previous work, an OTN over WDM numeric model is proposed to analyze the cross-connects capacity management problem of the OTN node, and numeric results show that the best LIU placement ratio is 60%–70% in the backbone network. In this paper, we pushed our previous work, and proposed a heuristic algorithm called minimum blocking probability optimization (MBPO) for solving the cross-connects capacity management problem. All simulations have been done on a simulation platform implemented using disperse event simulation tool OMNeT++, and the proposed algorithm has been implemented using Perl language. Numeric results showed that the MBPO algorithm has better performance than the linear algorithm, and the resultant scheme enables the operators to decrease the CapEx and the OpEx.

PCE-based Service Level Agreement constraint routing strategy in multi-domain optical network

We developed a framework for constraint routing in multi-domain optical network which combines PCE with service plane. With the distributed routing computation characteristic of PCE and the adaptability of service plane for service attributes, the framework provides an optimal SLA-based constraint routing strategy. Experiment results verify our framework and strategy.

Routing on pre-configured topology for dynamic optical networks

Dynamic optical networks are the physical basis of the development and evolution of the next generation network (NGN). By pre-configuring the resources of dynamic optical networks, we can reconstruct the topology, increase the number of direct routes, and then optimize the performance of routing and forwarding. This article analyzes the characteristics of the pre-configuration process, and gives the corresponding mathematical description. A planning scheme of resource pre-configuration that forms a pre-configured topology different from physical topology and virtual topology has been introduced for dynamic optical networks. Two dynamic routing algorithms have been run on the pre-configured topology. Simulations results show that the connection establishing time of the control plane could be significantly reduced by using the resource pre-configuration strategy.

The Research of Invulnerability in Complex Optical Networks

The complexity of optical networks has been researched and some complexity laws are described here. Then some metrics from complex networks, such as mean path length, nodes degree distribution and nodes clustering coefficient have been introduced into optical networks. The invulnerability in complex optical networks is mainly researched in this paper.

Implementation of bandwidth on-demand service on adaptive service provisioning platform of transport networks

A novel framework named Service Plane is put forward in transport networks on the basis of the principle of adaptive multi-services provisioning platform. The flexible implementation of service and the expansibility of framework is what we concern most in this kind of Service Plane. Here we raise the core algorithms of bandwidth on demand service on this platform, simulation testbed and the implementation result are also presented in this paper.

The analysis of LIU placement in the OTN over WDM network

The OTN over WDM network is one of the best solutions of the transmission network. How to manage the cross-connects capacity of the OTN node is a key problem in the OTN over WDM network. In this paper, an OTN over WDM numeric model is proposed to solve the OTN LIU placement problem. Based on the numeric model above, three multi-layer traffic grooming algorithms (OC-DKI, OC-DIK and OC-DIKP) are also proposed, in which the OTN capacity constraint is taken into account. LIU placement problem is simulated and analyzed using OC-DKI, OC-DIK and OC-DIKP algorithms on the NSFNET network topology and ARPA network topology. Numeric results show that the best LIU placement ratio is 60%-70% in backbone networks.