The paper presents the architecture and experimentation of a 10-Gb/s QoS-enabled almost-all-optical packet switching system (QOPS) for metro WDM networks. By applying cluster-based wavelength sharing and downsized single-staged optical buffers, QOPS is featured by its highly scalable and cost-effective design. In this paper, we first introduce the switch architecture, system operation, and the key techniques. We describe the in-band header/payload modulation and optical label swapping that is suitable for high-speed optical packet switching. We also present the design of the highly efficient Four-Wave Mixing wavelength converters for packet preemption. We then present an adaptive bifurcated routing (ABR) that directs same-connection packets to different switch clusters according to optimal bifurcation probabilities. Experimental and simulation results demonstrate that QOPS can achieve superior packet-loss performance, QoS differentiation, and minimize traffic blocking probability.

An optical header extraction and recognition structure was presented in the paper. The optical header is extracted by the improved iTOAD structure with DPSK modulation, while the header recognition is realized by discrete time stretch technology with super-continuum pulse to slow down the optical header speed for the high-speed asynchronous optical packet switch. Analysis and Experimental results shows that the iTOAD with time stretch technique can enlarge the output header 20dB and improve the switching ratio to 15dB when the input pulse is only 0.1pJ. By adjusting the tunable FDL length, the two pulses after the coupler switching have the π phase shift in the iTOAD SOA. The structure can slow down the high-speed optical header speed. Furthermore, the low speed header has the low latency time decreases (latency time less than 100μs) and overcomes the drawbacks of time bandwidth limitation associated with dispersion in long lengths of fiber. The system is highly scalable, lower power consumption and photonic integration.

A scheme using ahead-label to record packets' reaching time is proposed. The Principle of ahead-label and scheduling strategy for FDL is explained. With this scheme, the performance of slotted optical packet switching networks is significantly improved.

The suitability and efficiency of network architectures strongly depend on the service requirements and the mixture of services at different network levels. A case study has been performed in which five different service scenarios have been defined considering the characteristics of network operators. Starting with a service scenario which assumes only Layer 3 IP services, the amount of Layer 2 (Ethernet) and Layer 2 services (leased line) have been increased subsequently in the remaining four scenarios. Moreover, Layer 1 services have been differentiated with respect to broadband leased lines and narrowband services. The service scenarios have been applied to assess network architectures based on IP/MPLS, Ethernet and flexible and static optical systems, respectively. The impact of control plane implementations, i.e GMPLS and ASON, have been analyzed. Ethernet is making its way into metro and core networks. The development of Ethernet services and technology and their integration into MPLS/GMPLS based networks is still hampered by open issues. Evolutions in this area will be a key differentiator for network architecture evolutions.

A distributed flexible architecture of adaptive control and service provisioning founded on automatic switched optical network is proposed in this paper. The testbed named Adaptive Multi-Service Optical Network (AMSON) has been developed for proof of the fundamental of adaptive control for intelligentized service realization and lightpath transmission.

GMPLS-based Bandwidth on Demand (BoD) service experiment using the GMPLS network testbed of JGN II was conducted, and GMPLS connections with GbE bandwidth were successfully established by our developed user-friendly web-based GUI on the demand basis. The combination of the GMPLS-based network and the user-supporting system was verified to enable the BoD service in the actually operational environment. The setup time of the GMPLS-based lambda-path in this BoD service was very immediate and became available within only one minute from the time when the users want to use it.

Grid technology which provide a uniform interface to geographically distributed resources has been extensively developed in recently years. It is imperative to support QoS for Grid application, the main problems providing QoS in OBS network is exact understanding different Grid application's requirements and selecting the right policy to quantitatively offer them. In this paper we combine the Class Based Weight Fair Queuing and Preemption Latest Available Unused Channel with Void Filling (PLAUC-VF) and propose a absolute QoS architecture in OBS network for Grid application.

To reduce burst drop probability is a key issue in optical burst switching networks for it was connected strongly with the network's overall performance. In this paper, we propose a novel O/E/O conversion and electronic storage based strategy to resolve burst contention. Unlike traditional FDLs based contention resolution which is only able to provide discrete buffering time, O/E/O storage based strategy can offer unlimited buffering time. We propose an intermediate node architecture and corresponding scheduling algorithm called Nearest Available Void (NAV). Simulations show that our novel burst contention resolution enjoys high contention resolution capability and only introduce extremely low extra delay time compared to FDLs based mechanism. The maximum electronic RAM demand is also studied, and the result shows that the demand is comparatively small, which implies the cost of this strategy can be economic.

A main issue for the realization of Optical Packet Switched (OPS) networks is the resolution of packet contention due to the lack of RAM-like optical buffer. Although an optical buffer using Fiber Delay Line (FDL) has been proposed as alternative, its capacity is extremely limited. For this reason, several studies have been challenged on this problem. One approach is a deflection routing. It is widely used in electronic packet switched networks or optical burst switched (OBS) networks. However, in the OPS networks, packet length is short, thus, speed limitation for route look-up is significantly stringent. If the network topology is geometric such as a Manhattan Street Network (MSN), a hop-by-hop routing can be implemented by simple optical logic devices without an electronic routing table, but if the topology is non-geometric, it is hard to implement the deflection routing electronically or optically. Another approach is a reflection routing. It is easy to implement, but its packet loss probability is inferior to that of the deflection routing. In this paper, we propose a packet contention resolution scheme that is based on the reflection routing and furthermore enables to detour the reflected packet to alternate path if its primary path is under congestion. Our method enables to alleviate the time limitation for alternate path setting by using the packet reflection latency and to improve the performance of packet loss probability. We evaluate the performance of the proposed method to confirm its effectiveness.

This paper describes photonic network technologies from the viewpoint of optical switching functionality and photonic network transparency, and presents an analysis of the various types of current photonic nodes. The analysis results show that the most important choice is whether or not the photonic network node system is constructed in an optically transparent manner. This paper also describes various types of photonic node architecture. Regarding the optical add drop multiplexing (OADM) system, the merits of the reconfigurable OADM (ROADM) are precisely analyzed.

IP based traffic is seen as the convergence protocol for all future services and is already dominating today's networks. From the current situation with circuit switched SDH/SONET and packet switched IP backbones, an evolution is described towards long term optical transport network architectures featuring multi-layer transport with a novel Layer 2 transport service based on optical and opto-electronic burst/packet techniques as convergence layer providing the flexibility, scalability, reliability and Quality-of-Service to support all future higher layer services optimizing both CAPEX and OPEX. The operation of such a network will be mostly automatic supported by an integrated Control Plane on the basis of GMPLS protocols covering Layer 1, Layer 2 and Layer 3 (vertical integration of WDM, SDH, Ethernet, Bursts, IP etc.) and providing end-to-end control over various administrative and vendor domains (horizontal integration). The introduction of a new L2 transport service and its integration into a multi-layer Control Plane will be a long term evolutionary process also involving the necessary steps in the evolution of current standards. A few examples of network architectures and solutions are described together with dimensioning and control aspects and their relation to a roadmap for the introduction of optical burst/packet networks.

Recently, IP over WDM has been envisioned as dominant network architecture to meet the ever-increasing bandwidth requirement in the IP networks and to eliminate the intermediate layers and able to make better use of advanced optical technologies. Among existing several optical switching paradigms for IP over WDM, optical burst switching (OBS) is the more promising one, which combines the advantages of optical circuit switching (OCS) and optical packet switching (OPS), and can also loose the implementation complexity even though the optical random-access buffer is unavailable, and optical logic processing is not mature up to now. Therefore, OBS will play a very important role in next generation IP networks. However as much more trends shown, OBS-based IP optical network requires an appropriate control plane able to control and manage resource/service between IP and WDM. Currently, Generalized Multi-Protocol Label Switching (GMPLS) has been regarded as one of excellent candidate control planes for most of network scenarios because it enhances some issues of MPLS (including routing and signaling, link management, and fault protection and restoration), and also supports various granularity switching (such as packet, TDM timeslot, wavelength, waveband, and fibre-switched). Moreover, some practical deployments have shown GMPLS able to achieve automatic path provisioning and online network management. Therefore naturally, the integration and cooperation between GMPLS and OBS attracts more attentions from many research institutes and organizations. Of course, the similar concepts are originally given in the labeled OBS (LOBS) framework proposed by Dr. Qiao. Most of importance, LOBS provides the basic ideas for the collaboration of MPLS and OBS. However, how to efficiently integrate GMPLS and OBS to make the best of their advantages requires much more detailed discussions. To our knowledge, there are very few literatures and material to expatiate on the related issues. Here, the paper will present our some research results and viewpoints related to the integration and extension of GMPLS into OBS. Firstly, the paper proposes a GMPLS-based OBS network model for the integration of IP and WDM. Secondly, it defines the packets format for control and data information. Third, it also gives the node's functional architecture and the collaborative control operations between GMPLS and OBS. Finally, it proposes a unified software system to integrate the functions of GMPLS and OBS. Besides, the paper also presents some GMPLS enhancements to support OBS, such as traffic engineering, fault recovery, and link management, etc.

Many recent studies have convincingly demonstrated that network traffic exhibits a noticeable self-similar nature, and most studies of optical burst switching (OBS) networks are under a fundamental assumption that full wavelength conversion is available throughout the network. In practice, however, economic and technical considerations are likely to dictate a more limited and sparse deployment of wavelength converters in the optical network. Therefore, we present a novel scheme for OBS Networks, called logical cascaded private subnet with start wavelength assignment policy. We define the concept of canoe relative to cluster in self-similar traffic, and introduce a new device named payload segregator at the edge node as a gateway to the OBS core node. According to the changes in the edge node framework, we put forward the concept of cluster private subnet and canoe private subnet in OBS core node correspondingly. Due to the absence of wavelength conversion capabilities, we assign start wavelengths to both private subnets before network start operation. A new start wavelength assignment policy is proposed for the absence of wavelength conversion capabilities in the core node of OBS Networks. The analytical results clearly show that logical cascaded private subnet scheme can yield better performance in terms of block probability than traditional OBS Networks, and logical cascaded private subnet with start wavelength assignment policy has the potential to improve the block probability by more than one order of magnitude compared with traditional OBS Networks, helping reduce the performance gap with respect to full wavelength conversion.

In this paper, we study access protocol for multicasting in an optical burst switched (OBS) WDM ring environment. Ring nodes are equipped with a single fixed transmitter and tunable receiver (FTTR). Signaling is done via a dedicated control wavelength. The performance of the multicast access protocol is analyzed by simulation.

With fiber being cheaper and cheaper, the core fiber bandwidth utilization is not the key factor of the network, how to use the huge bandwidth flexibly and efficiently is one of the hot topics of optical networks. Optical burst switching (OBS) is the best choice to statistically use the optical resources, OBS based transparent optical network attracting attentions. We proposed an integrated policy by using dual fiber links server model along with traffic spacing mechanism (TSM) by address differentiating and transmitting those traffics between adjacent nodes by IP directly, the others by OBS mechanism. The theoretical results show that this method can improve network performance and be practically used in fields.

All-optical label switching (AOLS) is a potential technique which is introduced to fully use the bandwidth capacity in future optical networks and the packet operations are mostly carried out in the optical layer. The key issue in the AOLS approach is the method of coding the optical label onto the packet as it directly determines the structure and the performance of the optical core router as well as the channel bandwidth efficiency and the transmission quality of the packet and its label. With the bit rate increasing above 40Gb/s, new labeling scheme is needed to enhance the spectral efficiency. In this paper, recent advanced labeling schemes for future high speed AOLS network are reviewed, especially the new schemes demonstrated in Tsinghua University, China. Two novel labeling scheme based on vestigial sideband (VSB) modulation are mainly introduced both in principle and experiment. One is compact wavelength labeling scheme which achieves high spectral efficiency since the wasteful double sideband of 40Gb/s has been reduced to vestigial sideband. This scheme can be easily carried out by using optical filters. Another is polarization shift keying scheme with VSB payload which has high spectral efficiency near to 0.8bit/s/Hz. This scheme utilizes two polarization orientations to carry the label signal and causes little distortions between the label and payload. And this scheme is also independent of the payload bit rate which is a good character for future networks. Both the two schemes have little power penalties after long distance SMF transmission and are promising to be used in beyond 40Gb/s optical networks.

With the fast development of optical network technologies, for dealing with the shortcoming of the traditional grid based on the Internet, it is considered to introduce the optical network resource as one of grid resources in the control and management of grid. So the idea of optical grid was proposed. This paper analyzes the characteristics of optical grid differing from traditional grid. And then we propose a new transmission scheme applied in optical grid---multi-path transport scheme. We compare and analyze its performance in the optical grid. Eventually we draw the conclusions.

We propose a more practical resource model for optical grid applications by extending the classic list scheduling algorithm to achieve communication contention aware scheduling of optical grid applications. An effective adaptive routing scheme is also proposed to improve the performance of the extended list scheduling. The impacts of different routing schemes on the extended list scheduling are comparatively investigated by simulations.

Recently, some solutions (such as UCLP, GARA and GridJIT, etc.) have been proposed to manage optical network resources as other grid resources. However, most of them are focused on using grid technologies to encapsulate the management and control functions of optical control plane. And actually, they do not perform schedule optical network resources as grid resources. This paper proposes an economic-based scheme for lightpath resources scheduling and leveraging in grid-enabled optical networks. We also present the scheduling model and algorithm, and finally demonstrate their effectiveness by experiments on GridSim.

Optical Grid that provides a way to integrate the geographical distributed resources for large-scale grid applications. This paper mainly focuses on the task scheduling issue in Optical Grid and proposes two task scheduling algorithms to minimize the total time or scheduling length required for a given task. A simulated optical grid has been addressed to demonstrate the effectiveness of the scheduling approach. The performance tests and analysis of the two algorithms are investigated to show the effect of the routing policy on the scheduling length. A more flexible policy is able to further improve scheduling length.

Optical grid provides scheduled optical network resource to grid application. For supporting intensive data in optical grid, LPoD service architecture is presented to implement multiple light paths scheduling on demand under the driven of applications. In the proposed architecture, we introduce load division for intensive data or huge size file to cut bulk data into fractions, which will be transferred by different light paths only if the original sending node owns multiple communication interfaces or using multi-wavelength paths. About the type of the applications that runs on optical grid with LPoD on load division, we illustrate the parallel and distributed computing, and compare the total expensing time under different processing ability and transmitting distances. The result shows that for remote collaborating job in optical grid, LPoD as communication resource providing method can satisfy grid demand. When there are many available nodes, selecting the nodes with nearer distance and strong processing will obtain good transmitting quality from executing time.

In this paper, we propose OBS ring network structure and OBS access protocol for burst collision resolution. Our collision free scheme can save wavelengths for transmission and effectively transport bursty and asymmetric traffic. It shows better throughput performance than OBS ODD RR-R, RR-P, and RR-NP protocols.

An efficient fault detection method, employing cycle cover theory, is proposed. Three classic cycle finding algorithms are compared in terms of cost-saving and feasibility. We through computation and statistic find that our proposed method is economical and practical.

Optical Burst Switching (OBS) is supposed to be a promising switching technology in the future WDM networks, which is suitable to support burst traffic. A problem with OBS network is that bursts with longer routing lengths are more likely to be dropped before arriving at the destination router. In this paper, we propose two approaches using offset time differentiation (OTD) and burst length differentiation (BLD) to solve the burst loss differentiation (BLP) unfairness problem in OBS networks. Simulations show that BLP fairness in OBS is greatly enhanced with our approaches, especially with the OTD approach. Besides, we also investigate the BLP unfairness problem in offset time based QoS scheme.

In this paper, different kinds of optical performance monitoring (OPM) techniques, in particular the optical signal-to-noise ratio (OSNR) monitoring and chromatic dispersion (CD) monitoring, are reviewed. Then recent trend of multiple-parameter simultaneous monitoring is examined.

Among all kinds of metro-ring networks, resilient packet ring (RPR) technology possesses excellent market prospect which is integrated with many advantages, such as the intelligence of Internet Protocol (IP), economy of Ethernet and high bandwidth and reliability of SONET/SDH. A RPR network is a dual ring topology with two unidirectional counter-rotating ringlets. This ring network architecture and associated protocol has been standardized by the IEEE 802.17 working group in 2004. One of the main requirements for RPR is to provide fairness in bandwidth allocation for each node, which is ensured by the implementation of a fairness policy in a distributed manner. However, the existing fairness mechanisms suffer from severe oscillations under certain conditions, such as unbalanced traffic scenario and noticeable time delay. In this paper, an improvement to current aggressive fairness algorithm is proposed, especially for networks with noticeable time delay. And the simulation results show that the system performance can be sustained by adjusting the compensating factor accordingly with respect to the delay.

We study and test several P-Cycle generation algorithms from different strategies. The basic approach of P-Cycle algorithm is to identify an elementary cycle-set firstly, and then to search for improvements on this set through different strategies to create the final P-Cycle-set with higher efficiency. The P-Cycle generation algorithms which are presented in this paper are in terms of three aspects that are elementary cycle-set generation, expansion strategies and expansion times. At last simulation and analysis with these different algorithms will be presented.

We discuss a phenomenon of upstream bandwidth waste in a conventional dynamic bandwidth allocation scheme and propose a novel upstream bandwidth allocation scheme to enhance upstream bandwidth efficiency in Ethernet PON, and evaluate performance of the proposed scheme in terms of upstream channel throughput, mean queueing delay, and mean queue length of ONUs.

This paper presents the architectural designs and enabling technologies to implement the next generation metro WDM networks to satisfy the needs of emerging broadband applications.

Ethernet is a permanent success story, extending its reach from LAN and metro areas now also into core networks. 100 Gbit/s Ethernet will be the key enabler for a new generation of true end-to-end carrier grade Ethernet networks. This paper first focuses on functionality and standards required to enable carrier-grade Ethernet-based core networks and possible Ethernet backbone network architectures will be discussed. The second part then evaluates the CAPEX and OPEX performance of Ethernet core networks and competitive network architectures. The results propose that Ethernet will not only soon be mature enough for deployment in backbone networks but also provide huge cost advantages to providers. A novel complete, cost-effective and service-oriented infrastructure layer in the area of core networks will arise. The industry-wide efforts to cover remaining challenges also confirm this outlook.

The robust of the optical networks is one of the most important issues the optical networks should take into account when they are put into practice. Two typical causes for the instability of the WR-ION are analyzed in the paper: One is associated with something abnormal in the network and resulting in some measures for the survivability of the networks, and the other results from the dynamic characteristics of the network, such as dynamic routing. And some algorithms were proposed by Tsinghua Univ. to enhance the robust of the ION, for example, a Low Priority Hello Reduction Algorithm to decrease the number of false alarms resulting from LSA storm, and an Active Choke of Inter-domain Routing algorithm to overcome inter-domain routing instability. And some assistant methods were also developed, for example a Soft Preempt Algorithm to modify congestion degree of the ION in case congestions occur, and a software solution to decrease the processing time of the RSVP-TE. Experiment and simulation results proved the algorithms effective.

This paper describes the MPLS/GMPLS multi-layer network architecture and its control and management technologies. The recently investigated results are presented including GMPLS network migration into existing IP/MPLS network, MPLS/GMPLS multi-layer network management system and related standardization work.

An international field demonstration on lambda-based Internet eXchange (IX) was conducted between China and Japan for the first time, by using Generalized Multiple Protocol Label Switching (GMPLS)-controlled Photonic Cross-connects (PXCs) and Layer 2 switches (L2SWs). The IX operation could be demonstrated to provide the resilient lambda interconnection as well as L2 interconnection to the Internet Service Providers (ISPs). Stable lambda LSP establishment, dynamic bandwidth management and fast restoration were successfully achieved in the field trial. Traffic transmission of video stream between two ISPs via the IX was also verified.

A notification mechanism of topology information based on speaker node is proposed, which is aimed to realize topology discovery, synchronization and routing computation in hierarchical ASON networks. The simulation shows that with the increase of routing layers, the size of routing load and link state database are rapidly decreased. So the mechanism can save the memory space of the node and improve the routing efficiency.

With the overwhelming success of Ethernet technology in local access networks (LANs), owing to its ease of management and its much lower line rate cost, there has been a continuous effort in migrating Ethernet technology into metro-area networks (MANs) and wide-area networks (WANs). However, current Ethernet technology has to overcome the scalability and reliability deficiencies in order to be recognized as a viable MAN/WAN technology. Recently these concerns are being addressed under the framework of Generalized-MPLS (GMPLS) and its traffic-engineering (TE) intelligence. In this paper we propose an optical Ethernet solution viable for MAN/WAN based on the concept of a reconfigurable Ethernet node, integrating reconfigurable optical cross-connects (OXCs) with traditional Ethernet switches. We subsequently proposed a dynamic TE scheme that utilizes both the simplicity of all-optical switching and the flexibility of optical-electrical-optical (OEO) traffic grooming realized by the proposed optical Ethernet node. We showed through simulations that with our proposed TE scheme, the number of OEO transceivers needed by such an optical Ethernet node is only about 20% of a fully-populated one in the extreme case (very high load) and about only 10% in normal load conditions, without degrading the performance. This actually implies a tremendous cost saving on Ethernet OEO transceivers, and on the other hand indicates that a highly efficient and scalable MAN/WAN Ethernet network system could be well achieved by using Ethernet switches of only modest switching capacity (as legacy Ethernet switches have) along with reconfigurable OXCs. To demonstrate and test our proposed ideas we have built a GMPLS testbed using MEMS-based optical cross-bar switches and legacy Gigabit Ethernet switches. The testbed consists of three core nodes and six edge nodes. Performance experiments have been conducted on the testbed as well.

The Ethernet technoglogy rapidly gains importance as becoming a dominant solution for a converged transport network. Recently added features such as QoS handling and OAM functions in the framework of ITU-T NGN provides a means for performance improvement to meet carrier-class network requirements. In addition, integration with newly developed T-MPLS by ITU-T offers a potential to replace current SDH/SONET-based network infrasctructure.

IP+Optical networking technology is a key technology for realizing high-performance Internet backbone networks. Dynamic optical path cut through can create high-throughput as well as low power consumption networks. National Institute of Information and Communications Technology (NICT) Kei-han-na Info-Communication Open Lab, Interoperability Consortium, is shooting for the leading edge photonic Generalized Multi-protocol Label Switching (GMPLS) Inter-Carrier Interface that utilizes wide-bandwidth, cost-effective photonic technology to implement IPcentric managed networks. Kei-han-na Open Lab is a consortium for researching the GMPLS protocol and advancing a de facto standard in this area. Its experiments, new ideas, and protocols are submitted to standardization bodies such as International Telecommunications Union-Telecommunication standardization sector (ITU-T), Internet Engineering Task Force (IETF), and Optical Internetworking Forum (OIF). This paper details a nationwide GMPLS field trial that used multi-vender, multi-switching capable equipment.

Neighbor discovery in IP networks means the activity of identifying adjacent IP layers using the very Hello protocol. Neighbor discovery in optical networks differs from that in IP networks due to the GMPLS architecture that separates control and transport planes. The discovery of control plane is similar to that in IP networks from a perspective of basic mechanism although message flows are different each other. However, the discovery of transport plane has a different situation due to the physical characteristic of optical fibers that lead to identify adjacent peer-to-peer layers using OAM facility. This paper, based on the standardization technology of relevant bodies, defines functional requirements and its structure for neighbor discovery in optical networks. In addition, the paper presents a verification course applied to the proposed structure using a modeling tool, called SPIN.

Wireless sensor networks (WSN) provides a global view of the monitors area based on local observations measured by each sensor. In this paper a novel solution of WSN in GMPLS and EPON based integrated Network Access Architecture is proposed. We emphasize on the Routing of data aggregation for WSN in GMPLS (Generalized Multi-protocol Label Switching) which is developed from MPLS and is an inevitable result of MPLS extension to optical networks. By the use of control plane we can employ the GMPLS on the optical communication network and control the optical transport network. By combining the advantages provided by EPON and GMPLS, the proposed scheme can realize fast soft handoff, paging and expected QoS request of subscribers quickly and efficiently. The architecture that extends GMPLS and EPON-based access network to support wireless access is presented in this paper.

We present control plane architecture which is utilized to form a grid infrastructure enabled ASON and execute optical resource scheduling for grid community. ASON network is a good mode to solve the bandwidth deficient or unbalance problem in current grid service and implant large scale intelligent and automatic switching on optical layer, which make the communication resources evenly allocating and sharing in grid community for increasing resource utilizing efficiency. Grid services show the distributed and parallel attribution, which are being employed in many researching areas, such as parallel and distributed computing and processing. Thus, to construct a realizable and flexible ASON network infrastructure and support grid applications, the present control architecture will provide the parallel service, introducing automatic adjacent discovery and resource parallel reservation mechanism. At last, we test a grid file transfer by ASON mechanism in a test system by two parallel light paths for different file slices and validate the feasibility.

ASON is new type of optical network which can offer the flexibility for bandwidth allocation and fast provision of the new service. However, until now there still are many non-ASON optical networks. It is a challenging issue to reconstruct them into ASON smoothly. In this paper, we propose a new reconstructing technology. This technology performs the function of the control plane such as link management, path management and interface management by an embedded top-set-box (ETSB). The ETSB is located between EMS and the traditional NE such as DWDM, WDM, SDH, etc. By this technology the hardware module of the existing optical network element (NE) need not modification. Thus, compared with other reconstructing technologies, the cost and the risk of this reconstructing technology are smaller.

Because any link failure on the multicast session may disrupt the signal transmission to several downstream nodes, it is imperative to effectively protect the multicast sessions against link failure. In this paper, we study schemes for establishing primary and backup multicast trees for multicast sessions in a optical mesh network against link failure, e.g., fiber or conduit cut, with taking the different leaf availability requirement and availability guarantee into account. We propose an Mixed Integer Linear Program (MILP) approach to solve the problem of provisioning survivable multicast sessions with differentiated leaf availability guaranteed. Different from the previous schemes, our scheme finds out the complete (the tree spans the root and all the leaf nodes) primary and complete or incomplete (the tree spans the root and part of the leaf nodes) backup trees for multicast sessions guarantees the availability requirement. Because of taking the different leaf availability requirements into ccount, the proposed algorithm finds out more efficient feasible solution requiring less network resources, and even find a feasible solution where the previous algorithms fail.

The survivability is one of the important issues in Resilient Packet Ring (RPR) networks. This article analyzes a new failure scenario and put forward a new restoration mechanism named as C-steering. The mathematical model has been established to investigate the survivability of the RPR network in three operation methods. The throughput-delay performance and link utilization are discussed theoretically and experimentally.

Segment protection is an intermediate protection scheme between path and link protection. The major advantage of segment protection comes from its limited rerouting scope. It then leads to faster recovery over path protection and greater resource utilization efficiency over link protection. Overlapped Segment Shared Protection allows a protection of all nodes and links in addition to bandwidth savings. Routing for Overlapped Segment Shared Protection consists of finding, for each user request, a working path and a set of backup segments to protect it while minimizing the total required bandwidth. The problem in multi-domain optical mesh networks has not received a lot of interest so far although it is more difficult than in single-domain network. The main difficulty lies in the lack of the complete and global knowledge of the network topology as well as the bandwidth allocation meanwhile this knowledge are assumed to be easily available in single-domain networks. To overcome this difficulty, we propose a two-step routing heuristic using aggregate routing information. In the first step, a rough routing solution is sketched out on a compact virtual network which relies on an aggregate topology of the multi-domain network. Then the routing is refined within the different domains using the original domain networks. The comparison of the proposed heuristic with the optimal single-domain solution1 shows that our heuristic leads to resource efficient solutions that are close to the optimal ones while it requires a quite small computational effort. We also find that long overlapping does not necessarily leads to waste of resources and more segments in comparison with short overlapping.

This paper presents traffic analysis of Frame Bursting (FB) in Single-Input Single-Output (SISO) IEEE 802.3z (Gigabit Ethernet, GbE) Networks. This analysis characterizes the Frame bursting traffic behavior and performance measurement, shows its implications for future research issues. GbE is one of the world's largest Enterprise LAN solutions in terms of the number of concurrent users. FB Mechanism improves the performance of GbE CSMA/CD networks when transmitting short frames by reducing the Extension Field (EF) overhead, and tries to accord the controversy over the cross-layer (Layer2/Layer3) scheme. But FB get some negative effect like Jumbo Frame, long burst will affect the equal opportunity of other transmission. We simulate about 1 Tera-packets by random generation, let the packet pass through form non-FB domain to FB domain, observe that FB behavior like the burst per 100 packets (BPHP), packet per burst(PPB) and its distribution, the burst length in different Input Rate, Input Channel, and Packet Length Distribution Input, The analysis of the burst performance reveals that the geometrical proportion between burst size and burst length, and the inverse proportion between the percentage of Burst and the output utilization after bursting. We find that there is a linear relationship between Input Rate and the burst behavior. As for the burst behavior is highly dynamic complex in variable Number of Inputs, and Packet Length Distribution types.

Our proposed soft preemptive scheme was demonstrated highly effective at reducing the blocking probability and meanwhile guaranteeing the existing traffics' quality of service in wavelength-routed networks. In this paper, we focus our study on combining Soft Preemption and Wavelength Conversion. The performance analysis shows that the introduction of Wavelength Conversion can help enhance the advantages of Soft Preemption in reducing blocking and improving other performance metrics.

The backup paths just SRLG (Shared Risk Link Group)-disjointed with working paths can be concentrated on a specific link. Thus, the idle resource is not used efficiently so that the resource utilization of the network is not so good. We propose the resource share backup path provisioning mechanism to guarantee the survivability and to utilize the network resource. We consider SDLG (Sub-Domain Link Group) as the information to eliminate the link accommodated the unbalanced sharing backup paths. We compare our mechanism with the existing mechanism, which allocate the backup path just SRLG-disjointed with working path. We also apply the diversity network plans to the mechanism to select the backup paths. In addition, to control the backup paths we use GMPLS (Generalized Multi Protocol Label Switching) according to the consensus, which is emerging in the industry on utilizing an IP-centric control plane within optical networks to support dynamic provisioning.

Waveband switching (WBS) is proposed as a promising technique to reduce the number of switching ports, which could translate to the switching fabric size and cost of the nodes in the dense wavelength division multiplexing (DWDM) network. We propose a routing and wavelength/waveband (RWA) heuristic algorithm, called Maximize the Number of Waveband Route (MNWR) for the dynamic arriving traffic demands in the multi-granularity WBS optical network. We study the performance of various MG-OXC architectures including the serial three-stage MG-OXC and the interconnecting three-stage MG-OXC proposed by our group employing the on-line MNWR algorithm. Simulation results indicate that the interconnecting three-stage MG-OXC outperforms the serial three-stage architecture in terms of blocking performance for dynamic requests.

OBGP is a distributed protocol, which can provide an inter-domain routing /signaling solution and allow the edge network customer to establish and manage a lightpath though multi-heterogeneous domains. In this paper, we propose a new scheme called DiffServ-aware OBGP by extending the OBGP. It can resolve the open problems of customer access admission in domain and the conflicting resource requests by distinguishing the priority of customer requests. The paper depicted the basic extension requirements for current OBGP message and the end-to-end lightpath establishment process at length. The simulation shows that the new scheme can establish adaptive end-to-end lightpath according to the request of customer and the higher priority requests have more probability of establishing lightpath when resource competition happened.

We developed the optical switching technologies of 3-dimentional micro-electro mechanical system switch, acousto-optic tunable filter, PLZT electro-optics deflector switch, and optical parametrically amplified fiber switch. We evaluated their potentials for application to photonic networks based on their optical switch characteristics.

RSVP-TE Signaling involves transporting control messages between all entities communicating through an ASON's control plane and is used to create, maintain, restore, and release connections. Control plane restoration has not been studied in details in the literature except for using protection switching or the source-initiation mechanism. Such schemes take a big bandwidth waste or long restoration to the networks. We provide a fast restoration mechanism based on (extended) local restoration using RSVP-TE as the signaling. This mechanism can reduce the restoration time by the theoretical analyses.

Today, as networks grow rapidly in size, hierarchical network structures (e.g. PNNI) have been proposed to solve the problem of network scalability as well as security in large networks. One of the most important requirements of hierarchical networks is survivability. In this paper, we first present a survey on some restoration schemes, and then propose a hierarchical hybrid restoration scheme (HHRS) for hierarchical networks. The performance of these restoration schemes in hierarchical networks is analyzed and compared theoretically. Restoration success rate, restoration time, fault notification message overheads are the major performance measures. HHRS can reduce the number of fault notification signal messages by sending notification signal messages vertically up and down the network hierarchy instead of horizontally along the paths. It can also maximize the restoration success rate with a fast restoration speed by dynamically determining the restoration scope.

The restoration time is an important network survivability index in large-scale Metropolitan Area Network. The early study indicates that the hierarchical restoration mechanism have lower restoration time, comparing with global restoration. But the restoration time increases rapidly when the restoration scope expands. In this paper, Overlap-extend hierarchical restoration mechanism is proposed to reduce the restoration time, by restricting the restoration in a definite scope. A theory model is established to describe the average restoration time of Overlap-extend mechanism and existing hierarchical restoration mechanism, which can be used to analyse the influencing factors in our mechanism. Simulation result is also presented, which shows that overlap-extend mechanism can observably reduce restoration time, especially in light traffic load.

This paper focuses on the survival mechanisms against single link failure for optical QoS services in ASON (Automatically Switched Optical Network). The new protection and restoration methods and optical QoS services enabled by ASON also bring new requirements. Correspondingly, the component functions in ASON control plane, such as Connections Controller, Link Resource manager and Routing Controller are extended. According to the survival level of the QoS service requested, we divide the traffic into five types, viz. 1+1, 1:1, shared-mesh, rerouting and extra traffic. Optical QoS services and resource preemption are realized in our simulation platform. Extensive simulations are performed concerning failure localization time, failure recovery time, recovery success ratio and network resource utilization.

One approach to effectively utilize WDM networks is to transfer the data on-demand basis through a fast wavelength reservation. Then, the data is transferred using the assigned wavelength channel. If the wavelength reservation fails, the data transfer delay, which is defined as the time from when the data transfer request arises at the source node to when the data is successfully received by the destination node, is much affected since retrial of the wavelength reservation is delayed by propagation delay. We have proposed a fast lightpath setup method that tries to establish a lightpath twice during a round-trip propagation time, and have evaluated the method by computer simulations where there is neither packet processing delay nor OXC configuration delay. In this paper, we present overview of our implementation and experimental results showing that our setup method takes smaller lightpath setup delay than the backward reservation protocol.

A new analysis model in which the link time delay is taken into account is proposed to investigate ASON blocking probability. By NS2 simulation, how the routing protocol such as OSPF and OSPF-TE influence the blocking probability is discussed. The result reveals that the OSPF-TE cannot reduce the whole ASON network blocking probability but it can reduce the connection lose and improve the network performance.

Broadband wireless access operating in the microwave and millimeter-wave frequency windows has been actively investigated for future ultra broadband communications. The drastic increase in the throughout of each base station in these systems necessitates the use of an optical fiber backbone to provide broadband interconnections between the central office and all the antenna base stations. With such a network layout, significant reduction of the antenna base station complexity can be achieved by moving the routing, switching and processing functionalities to the central office. By taking advantage of optical networking techniques such as wavelength division multiplexing (WDM), the total capacity of the hybrid fiber-wireless network can be greatly enhanced and efficient optical fiber architectures can be realized. In this paper we present an overview of the research that has been carried out in fiber-wireless networks incorporating WDM, with a particular focus on the optical interfaces in such networks.

Recently, service-providers network is gradually transforming/migrating into the Next Generation Network. This transformation/migration has been driven by the future services convergence and expected broadband traffic growth with all-IP network. Significant proportion of the large traffic volume of coming years will be carried by wireless access network technologies such as 3G cellular mobile, WiFi, and WiMAX. In this scenario, wireless network and optical network cannot be architected as simple overlay to obtain maximum efficiency. In this paper, we are proposing integration of the benefit of both technologies to realize future proof broadband Optical/Wireless converged network. We will also discuss on the optical edge node architectures.

Since the packages from different nodes collide with each other frequently in Ad Hoc networks, it is hard to guarantee QoS of Real-Time multimedia services if only adopting traditional multi-channel MAC protocols such as DCA, MMAC, etc. In this paper, a new multi-channel MAC technology called MAC-MC is proposed. Under MAC-MC protocol, the wireless channel is divided into one control sub-channel and N service sub-channels. The nodes in Ad Hoc network exchange RTS/CTS messages in the control sub-channel to reserve the service sub-channel for dada package. The access mechanism in the control sub-channel is designed basing on DIFFSERV mode. The parameters value of the Real-Time service package CW is different to that of Best-Effort service packages, so that the Real-Time service packages can obtain the higher priority to access the control sub-channel. In addition, a bi-dimension Markov mode is presented to analyze the performances of MAC-MC protocol theoretically. The results via simulation show that: Compared with MMAC protocol, the transfer delay of Real-Time service package is decreased greatly under the MAC-MC protocol; the networks throughput under MAC-MC protocols is larger than the networks throughput under IEEE 802.11 EDCF protocols.

The paper proposes a close-looped decision-directed pre-equalization scheme for OFDM systems, which can be divided into two stages: i) initialization stage; ii) calibrating and tracking stage. At the first stage, the transmitter set the pre-load information to all ones, and the receiver estimates the real channel information and returns it to the transmitter; after that the receiver would view an almost-flat fading channel and directly decode the constellations, and when no error found, it remap the data to constellation to create a local pilot to obtain a better estimation of apparent channel for the transmitter to repeatedly adjust its pre-load information. Simulation results show that the performance of iterative pre-equalization is better than that of conventional pre-equalization and post-equalization in the receiver and will be much better at high SNR.

There is an increasing demand for DWDM systems to support a set of network requirements (span length, total distance, capacity, etc) typically associated with previously distinct network application categories such as access, metro, regional, and long haul. This has led to the development of a multi-haul DWDM system, defined as an agile optical platform, able to combine multiple versions of transponders, amplifiers, and optical add/drop multiplexers (OADM) on the same optical link. The concept of a multi-haul system is applied in a study of DWDM networks that can employ, besides fixed OADM, two types of reconfigurable OADM (ROADM): a two-degree ROADM based on arrayed-waveguide gratings (AWG) and a multi-degree ROADM built with 5x1 wavelength-selective switches (WSS). A cost analysis on a network example calculates the savings obtained if an optimum mix of ROADMs is used on the same DWDM ring instead of deploying one single OADM type at all nodes. A technical feasibility study is performed to validate the performance of a DWDM system with up to 16 ROADMs in a network. To this purpose, OSNR penalties are experimentally determined for AWG and WSS ROADMs due to cascaded bandwidth narrowing, and crosstalk effects, with wavelength detuning values corresponding to locked and unlocked lasers.

Supporting QoS (Quality of Service) and improving bandwidth utilization are necessary in IP/DWDM optical Internet. In this paper, with the introduction of game theory and layered graph, a static traffic grooming scheme is proposed based on artificial immune algorithm to minimize network resource occupancy and maximize comprehensive QoS satisfaction degree, achieving Nash equilibrium between network provider utility and user utility. Simulation results have shown that the proposed scheme is both feasible and effective.

NTT has proposed a photonic MPLS router (PMR) to support IP over optical layer networks. There are two routing policies implemented in PMR, which both consider IP layer and optical layer resource separately. We found in the PMR architecture, PSC port is significant resource. In this paper, we propose an adaptive routing policy for PMR. Our routing policy has two features: integrated routing and PSC port number sensitive. Simulation results show that the adaptive routing policy has a better overall performance in resource utilization.

Using effective port number, effective BHCA and local traffic ratio, a general equation for calculating capacity of softswitch network is presented in this paper. Furthermore, two types of network extension are considered. The first one is extended by m individual systems, and the second one is extended by another network with M interlinked systems. The approaches for network capacity estimation are proposed with respect to such two cases.

A method for enhancing downstream TCP throughput has been proposed. About 900Mbit/s of downstream TCP throughput was expected by using the proposed method in a 32-ONU GE-PON system with keeping high upstream bandwidth. The effectiveness of the proposed method can be achieved in various transmission lengths as we have confirmed the case of 2km, 10km, and 20km.

Ethernet Passive Optical Network (EPON) is an emerging access network technology that provides high bandwidth and cost-effective access lines between a carrier's central office (CO) and a customer site. But limited bandwidth is still a problem in EPON system. In this paper, we propose a new architecture for EPON system with storage function. Storage is embedded in optical network unit (ONU) to store data especially video data by checking the Logical Link Identifier (LLID). Subscribers can retrieve the data directly from the storage by sending requests to ONUs.

In this paper, we will present the results of WDM-PON based FTTH field trial test which held in the city of Gwangju. We have implemented injection locked FP-LD based WDM-PON system and reliably delivered IP-TV, N-PVR, HD-VoD, EoD and Internet service as FTTH service through the system during the field trial test. We have also verified that the WDM-PON system worked well to provide QoS guaranteed 100Mbps bandwidth per subscriber. Furthermore, we have presented network designing issues in OSP and CPN that should be overcome to efficiently deploy FTTH service. Finally, based on the field trial test results, we proposed FTTH service deployment strategies.

As a cost-effective and broadband access network, Ethernet Passive Optical Network (EPON) has been attracting more and more attentions. Meanwhile, VLAN is being widely used in network configuration to meet the QoS and network management. Currently, with the growing of the network scale, basic VLAN service can not satisfy the requirements of most large-scale network deployment any more. So it is very important to provide enhanced VLAN service over EPON. In this paper, we propose a novel EPON system which can provide the automatic VLAN translation service. By comparing with the traditional way, it can be shown that the proposed system is much more economical and efficient to support the stacked VLAN function and VLAN translation function.

We demonstrate an optimization method of the decision threshold level in optical receivers for WDM-PONs based on wavelength locked Fabry-Perot laser diodes. The decision threshold level is controlled by the average optical power. For the WDM-PON with 100 GHz channel spacing, we reduced required injection power for color-free operation by 6 dB using the proposed method.

Dynamic traffic grooming in optical mesh networks is one of the most important and practical problems for designing WDM networks. Most of previous work solves it by applying the Dijsktra's algorithm on an auxiliary graph. Although those algorithms can give very good performance since they have a global view of the whole network, they are very time-consuming and thus cannot be applied in large networks. Therefore, we propose a heuristic algorithm to reduce the required computations by minimizing the size of the graph. We compare our algorithm with existing algorithms by extensive simulations. The results demonstrate that our algorithm can significantly reduce the computational complexity and outperform existing algorithms by large margins since it can easily avoid resource-inefficient lightpaths.

As to the traditional unicast and broadcast, multicast is also a kind of data transfer mode of IP network. Because multicast can save bandwidth, reduce network load, multicast is widely used on real time data transfer, video conferencing, distance education and Internet living broadcast. But multicast encounters more security challenges than unicast, such as unauthorized data sources and unauthenticated users. This paper discusses in detail about the multicast source control, multicast routing control and multicast user control. The main contribute of this paper is that a new multicast user control scheme is proposed and fully illustrated. And a whole mechanism to manage constrained-based multicast application is clearly described and implemented in this paper to achieve multicast source control, routing control and user control.

Ethernet has been a hotspot in industrial communication. Its intrinsic non-determinism and slow failure recovery mechanism are two major obstacles of Ethernet's application in the industrial environment. To address these two problems, this paper proposes a novel fast recovery and real-time optical industrial Ethernet architecture based on dual-ring topology, and presents some test results from our partly implementation of the architecture. First, resource utlilization of the FPGA implementation shows that the proposed architecture is cost effective. Second, it is seen that recovering from a single failure costs no more than 30 ms, far less than traditional resilience techniques in Ethernet. Besides, end to end delay with no background traffic, which is instructive to the future design of the scheduling algorithms, is also presented.

Optical interconnects are being considered for short link data networks as a solution enabling higher aggregate bit rates and lower power consumption. For short link length interconnects, as used in chip to chip interconnects, internal system backplanes and inter-system interconnects such as blade server backplanes, storage area networks and processing clusters, requirements are quite different to those for long distance telecommunications systems. Low power consumption, latency, and size become important criteria in addition to ultra high bandwidth. In order to achieve the projected ultra high capacity and low latency needs, we are considering optical switching fabrics. The optical switch, however, brings significant changes to the interconnect architecture in terms of how routing decisions are made and how contention resolution is managed. We discuss these issues and present our results for a multiwavelength optically switched interconnect.

Multi-channel output of time division multiplexed fiber Bragg grating sensing network was realized using a cascaded electrical switches array. The emission of a broadband light source modulated by an electro-optic modulator was injected into a four-element fiber Bragg grating sensor array spaced 10m apart. The clock-signal, which is the same as the modulating signal from the electro-optic modulator, was exploited to control the secondary cascaded switches. The signal outgoing from switches was allocated by the pulses and reflected by the sensor elements into a cascade electrical switches array. The sensor signal was then transmitted to the corresponding parallel linking switch that was controlled by the time-delay signal generator on the basis of the time delay of the sensor signal, arriving at the cascaded electrical switches array. By using demodulation with the unbalanced Michelson interferometer, which converted the wavelength shift to phase changes, the measurand was attained by the phase meter. Performance of the proposed system with a sensing sensitivity at the wavelength of 1560 nm found to be 1.654 Deg per micro-strain, which has good agreement with theoretical estimation of 1.673 Deg per micro-strain.

Telecommunications service providers (telcos) have long dreamed of offering the "Triple Play," i.e., bundled voice, data and video services, including high-definition digital broadcast and on-demand video services. However, until recently, telcos have been unable to offer Triple Play services due to technical obstacles, including bandwidth limitations in their access networks and the high cost of Triple Play CPE devices. Recent deployments have demonstrated that passive optical networks (PON) can be cost-effective and can reliably support the transmission of high-speed data in excess of 100 Mbps per subscriber, which is sufficient to support Triple Play services. Additionally, innovations in semiconductor device technology have dramatically decreased the cost of Triple Play CPE. With the realization of a robust, flexible broadband access network and low-cost CPE that support data, voice and video services, what was once a dream is now possible. In order to make this dream a reality, PON protocol and voice services processor (VSP) system-on-chips (SoC) must be integrated into CPE devices that terminate the PON and enable the end-to-end delivery of data, voice and video services from the service provider to the subscriber's PC or other Internet appliance. These CPE devices, referred to as optical services gateways (OSGs), must cost-effectively support a wide variety of subscribers and applications, including detached single and multi dwelling unit structures.

We experimentally demonstrate a novel decimal optical buffer scheme based on multi-loop configuration and single switch element--an optical crosspoint switch (OXS) matrix. Our results show that by using a differential phase-shift keying (DPSK) payload in the buffer can outperform OOK payload with 3.2 dB sensitivity improvement owing to its alleviation of patterning induced degradation compared to OOK payload, clearly validating DPSK as a promising modulation format to overcome nonlinear impairments and to extend number of hops in all-optical packet switching network.

This paper first outlines the next generation home network from the viewpoint of services accommodated, and then clarifies the requirements placed on the HGW (Home Gate Way), a key player in controling all sevice traffic in the home. Finally, some experimental results already obtained for next generation home network are also described.

IP multicast suffers from scalability problems when the number of simultaneously active multicast groups is very large. In this paper, we propose an algorithm called SGTM (Scalable Group-Tree Match algorithm) which reduces the number of trees by allowing several groups to be aggregated to the same delivery tree with controllable cost and introduce metrics to measure multicast state and tree management overhead for multicast schemes. SGTM performs faster aggregations than previous aggregation algorithms by evaluating fewer trees for each group, while keeping the same performance. We then show the scalability and the fastness of SGTM by several simulations and we compare its performance to the previous algorithm.

Existing multicast models have taken traffic concentration, source-end delay, delay jitter into consideration, while some dynamic application like digital TV delivery poses a new challenge. Users can join/leave multicast group dynamically and arbitrarily. When users have left the multicast group, multicast protocols will delete the corresponding delivery edge in the multicast tree. This leads to great control overhead in delivery network. This overhead comes from several aspects, like forwarding tree maintain, update, membership management. Even if the multicast tree is pre-calculated and cannot delete edge in runtime, the users' leaving action can lead to resource utilization problem, especially when the delivery network's bandwidth is expensive. In this paper we designed an algorithm to find the optimized multicast tree to ensure stability of network under dynamic user behavior. With this algorithm, we can smooth out effect of users' random behavior, thus increase performance of the delivery network.

A good dynamic routing scheme is very important to improve the provisioning efficiency of wavelength-routed optical networks. The existing dynamic routing algorithms are usually based on first-come-first-serve (FCFS) scheme to process the lightpath requests one by one. However, multiple lightpath requests may arrive simultaneously and burstly in data-intensive applications, and can not be treated efficiently by using the FCFS scheme. We will propose a new online dynamic routing scheme to process the lightpath requests in batch instead of one by one, which is termed batch-come-batch-serve (BCBS) scheme. A mathematic model and several adaptive routing algorithms are proposed and investigated comparatively. The simulation results suggest that the proposed scheme achieves better network blocking performances.

Blocking probability is one of the key factors to evaluate the routing and wavelength algorithms for intelligent optical network. Two kinds of Dynamic K-Shortest Path (DKSP) Algorithms were designed. One is based on Linear Link Weight Function (LW) and the other is based on Piecewise Linear Link Weight Function (PLW). It was found that the two kinds of DKSP can significantly decrease the blocking probability of optical network comparing to the static KSP for the same number of alternate routes. Compared to routing with LW, the coefficient of PLW has larger effect on the blocking probability of optical network when the number of alternate route is small, but the effect is weakened with the increase of the number of alternate route. As far as the two kinds of DKSP algorithms are concerned, DKSP with PLW has some advantage over DKSP with LW on decreasing the blocking probability. It was also found that the optimized performance can almost be got by DKSP with only 2~4 alternate routes for NSFNET.

In this paper, the guideline of wavelength assignment for WDM distribution networks is studied and a novel wavelength assignment algorithm is proposed. The numerical and simulations results demonstrate that this algorithm can improve the system's performance.

IP over DWDM optical Internet is one of the main networking techniques for NGI (Next Generation Internet), and how to improve its fault-tolerance capability and QoS (Quality of Service) becomes critical. Fault-tolerant QoS routing is one of the effective solutions. In this paper, a reactive fault-tolerant integrated QoS unicast routing scheme is proposed based on heuristic A algorithm to deal with the case of single-link/single-node failure. Its objective is to make the best balance among delay, load and the cost of wavelength conversion, trying to improve the wavelength utilization and failure restoring rate. Simulation results have shown that the proposed scheme is both feasible and effective.

Optical burst switching is a promising paradigm for the next-generation Internet. Path length priority effect is investigated firstly of conventional JET scheme in multi-hop optical burst switching networks. Then a novel scheduling mechanism with multiple queues is proposed to avoid the effect. Simulation results show that a better performance is achieved.

With the development of Internet application, user needs more and more bandwidth. 10G EPON is a good choice for next generation access-network. The architecture of the WDM-based 10G EPON is proposed in this paper and we also provide the configuration of the upstream. WDM-based 10G EPON operate in different speed on different direction, and the logical link is point to point communication in the upstream while behaving as multipoint to point in physical topology. We put forward the protocol stack of this architecture. We proposed a sub-layer named MWMC (Multi-Wavelengths MAC Control). The MWMC sub-layer need not deal with Timing, Ranging, Report or Gating processing. But LLID (Logical Link Identifier) is also needed to implement the P2PE (Point to Point Emulation) in the downstream. We detailed dissertate how to implement the P2PE in this architecture using the concept of LLID. The WDM-based 10G EPON is easy to implement and need not high speed burst mode transceivers, and its cost is not very high. The WDM-based 10G EPON has better performance than the TDMA-based 10G EPON for its low delay and high upload bandwidth with no collision between different ONUs in the upstream.

In order to support the delivery of emerging network service, such as VoIP, video, IPTV, the EPON system must provide classes of service that are better than the traditional Ethernet-based technology. So how to design high quality of service (QoS) is very important in EPON system. This paper discussed design of QoS for different services in EPON system, the design is implemented QoS from the downstream direction and the upstream direction respectively, integrates seamlessly with standard QoS mechanisms in the operator's backbone network, and also give the service provider maximum flexibility.

A Fairness Guaranteed Scheme is introduced for the Dynamic Bandwidth Allocation (DBA) in an Ethernet Passive Optical Network (EPON). The scheme is simple and of low computational complexity, it can guarantee both the efficiency and fairness of the DBA. Especially, it can be used in both inter-ONU scheduling and intra-ONU scheduling. Simulation results using synthetic traffic confirm its good performance against existing bandwidth allocation scheme.

The single-direction, self-healing all optical ring networks with double optical fibers based on the wavelength routing character of fiber gratings is introduced in this paper. The four-node network with ring topology can provide 16×10Gb/s optical transmission. The wavelength-selecting character of chirped fiber gratings is used for wavelength routing, and the function of dispersion compensation and multi-channel add/drop is achieved, too. The SNMP (Simple Network Management Protocol) model is referred to manage this network. Some important parameters are real-time observed to control the network. The results show that, if any optical fiber in the ring is broken down, the interrupted telecommunication service can be recovered automatically in less than 20ms.

The point-to-point LAN emulation and shared LAN emulation over EPON solution are introduced. Two different kinds of LAN function are placed in a single model named IULSLE upper MAC layer to simplify the design, whose functions like a bridge and can be attached to any device, whether a bridge, a router, or a host computer. A Logical Link is established between OLT and ONU which is identified with a LLID attaching MAC address. In this model, the function of RS sublayer is only processing LLIDs according by the MAC ADD and LLID table in IULSLE module, and MAC layer is as normal bridge. The main LAN emulating function is accomplished by IULSLE block making OLT operates as a bridge. Not only the hardware block diagram but also the actually circuit are accompanied in detail.

Wavelength Division Multiplex Ethernet Passive Optical Network (WDM EPON), due to its simple configuration and enormous capacity advantage over present access network technology, is considered by many experts to be the promising solution to realize FTTH. In this paper, we proposed a model of WDM EPON system using OPNET, collected the statistical parameters and analyzed the network capacity through simulation. Based on the network topology and WDM technology features, we designed the network configuration to be P2MP in the downstream direction using broadcasting mechanism and P2P in the upstream direction using independent wavelength channels. We studied the MAC protocol stacks under WDM EPON hierarchy and designed the OLT and ONU node modules based on the theoretical models. ONU dynamic registration and MAC mappings of data switching in OLT are the two key technologies introduced in the model to realize the communication within the system. Simulation results approve that WDM EPON system has great bandwidth capacity and extremely little terminal-to-terminal latency, thus displaying great capability advantages and developing prospects.

Recently, performance evaluation of TCP over Optical Burst-switched Network (OBSN) has drawn more and more attention, but previous work mainly focused on single TCP flow or static traffic model. In this paper, performances of different TCP implementations deployed in OBSN under dynamic competing traffic are investigated.

The G.7713 recommendation specifies operations for call setup and release based on a call having a single connection per call, but a call embody any number of connections aren't defined. To enhance network connections establish efficiency and lessen establish time of multiple connections having same properties, multiple connections per a call based on DCM are proposed in ASON. To support multiple connections per a call, DCM message and procedure of process are extended based on traditional scheme. We adopt emulator to simulate the condition of multiple connections per a call in network having 10 nodes and 22 links. Simulate results show that the total time to create multiple connections using such call and network traffic is less than using the traditional call multiple times.

IPSec (IP Security) provides a standard, robust, and extensible mechanism in which to provide security to IP and upper-layer protocols. But the encryption and message authentication services provided by IPsec require significant computation time. Consequently, IPsec can degrade performance obviously. The paper presents a parallel hardware structure of high performance IPSec VPN gateway to speed up the IPSec packets process, and introduces the IPSec software design in detail includes modified FreeS/WAN IPSec implementation and extended Internet Key Exchange protocol. The result of network performance test proves that the structure can fulfill the need of gigabit fast network. The paper also proposes multiple small packets assembling algorithm which is used to accelerate small packets process. The algorithm significantly improves the performance of small packets.

In recent years, range digitization efforts have been undertaken to upgrade the strategic telecommunication infrastructure of training and testing ranges. The goal is to provide the necessary communication bandwidth and state-of-the-art technology to support the ever increasing demands in high-speed transmission of multimedia range instrumentation data in real time. Meanwhile, recent years have also witnessed a tremendous growth of research and development in wireless communications and networking. To complement the aforementioned range digitization efforts, while fully benefiting from recent technological advancements in wireless communications, there is a need to develop broadband wireless networks for seamless integration with existing "hard-wire" range communication networks. In this paper, we consider the modeling and simulation of a hybrid wireless/optical network for range communications using OPNET. The hybrid network consists of WLAN-based broadband wireless networks and a SONET-based infrastructure network. We discuss several relevant issues, such as wireless extension of a SONET network and WLAN access point node modeling. Simulation results and wireless link performance analysis (e.g., throughput and delay) are presented for the proposed hybrid network for range communications.

Current trend of integrating IP and WDM technology is to evolve core IP networks away from the overlay model and towards more integrated solutions - IP/GMPLS over WDM, which enables more efficient usage of optical bandwidth. However, the removal of ATM and/or SONET/SDH layers implies possible coupling of optical and network layers. This work aims to raise the necessity and elaborate a cross-layer approach of counting optical impairments into the performance evaluation of IP/GMPLS over WDM network. Normal procedure to calculate the network performance always takes one assumption for granted - traffic transmission in underlying optical network is perfect. However, the removal of SONET/SDH layer implies its error detection/correction function of is no longer used, which may result in useless information received by destination node. We set up a model and present a three-step cross-layer approach for analyzing the performance of IP/GMPLS over WDM network. The performance of IP traffic with and without considering optical impairments are compared and the numerical results demonstrate the network metrics, in terms of effective normalized throughput, are indeed affected by the characteristics of the underlying optical layer.

Nowadays IEEE 802.11 Wireless Local Area Networks (WLANs) become pervasive driven by huge demands for portable access to the Internet. Meanwhile, Voice over Internet Protocol (VoIP) is one of the fastest growing Internet applications because of its high resource utilization and low cost. This paper focuses on the combination of these two technologies. Aiming to support more voice calls in IEEE 802.11 infrastructure networks, voice capacity in IEEE 802.11 WLAN is studied. Through simulation, it is found that Access Point (AP) is a bottleneck that limits the number of concurrent voice calls. This is because in infrastructure networks, all frames must go through the AP so that the AP has much more traffic, but the AP has no advantage on accessing the medium. In this paper an enhanced DCF protocol is proposed to give AP higher priority to access wireless medium and mitigate AP bottleneck effect. In proposed scheme, AP's priority is adjusted dynamically by changing some Distributed Coordination Function (DCF) parameters according to the length of the AP queue. Simulations in various scenarios well verify the improvement achieved with increased voice capacity and decreased access delay.

We theoretically investigate the generation, transmission and detection of the label signal in the optical SCM label switching system and clarify that the degradation of the label signal results from the fiber chromatic dispersion and the incomplete filtering out of the payload carrier. Our theoretical results show that the signal degradation is mainly caused by the fading effect and the expansion of the code edges. We also quantitatively analyze these theoretical results. The deep suppression of the optical carriers at receiver can greatly reduce the fading effect, and the electrical filtering and heterodyne detection techniques can improve the performance of the label signal. The time shift of the code edges leads to the closure of the label codes, which greatly limits the transmission distance as well as the radio frequency to generate the label subcarriers especially for the label with a high bit rate. SSB SCM can not only eliminate the closure of the label codes, but also reduce the fading effect. To our knowledge, this is the first time to develop a detail theoretical model to well explain the experimental results for SCM label switching systems.

Some grid applications need a reliable, real-time and large bandwidth network as infrastructure for mass data exchange between local and remote resources. Deploying grid applications on the optical network has a great significance. In this article, we propose the network architecture that integrates optical network with grid computing resources. Based on the network architecture, we present a model of service interface for grid over ASON.

p-cycle provides a new protection scheme which provides fast protection switching time as that in ring networks and high resource efficiency as that in mesh networks. Extensive research has shown that the concept of p-cycle can also be applied to Automatically Switched Optical Network (ASON), which is the direction of the next generation optical network. This paper proposes a novel dynamic p-cycle algorithm in ASON named Routing in Spare plus Protecting Capacity Dynamic p-cycle Algorithm (RSPC-DP). Different from traditional dynamic p-cycle algorithms, the proposed algorithm takes traffic forecast matrix into account, and it is capable of tracing the changes of network environment and dynamic traffic matrix on-line. Extensive simulation results show that the proposed algorithm outperforms the existing algorithms significantly.

Hybrid TDM/WDM PON is a promising optical access network solution which taking advantages of both TDM-PON and WDM-PON, and suitable for near future deployment in pragmatic migration from current TDM-PONs to future WDM-PONs. In this paper, we review and compare five types of the representative hybrid TDM/WDM PON architectures: TDMA based hybrid PON, WDMA based hybrid PON, TDM over WDM hybrid PON, WDM over TDM hybrid PON, and SUCCESS hybrid PON. Several key issues and enabling technologies for deploying hybrid TDM/WDM PON, including wavelength assignment, media access control and wavelength management protocols, light sources, and protection, are also discussed in the paper.

The ILP based on source formulation is newly proposed in recent literatures. This paper firstly applies the ILP based on source formulation into the current popular Waveband switching (WBS) network. Our research shows that the ILP based on source formulation can effectively improve the network performance. Two optimized WBS network scenarios are discussed in this paper, including the networks constructed with multi-granular OXCs (MG-OXC) and the networks which is not limited to MG-OXCs but constrained by the condition that all wavebands only contain lightpaths to the same destination. Numeric results show that source-formulation ILP can require less computational effort compared to flow-formulation ILP.

The inter-domain and intra-domain routings are treated jointly with dynamically distributed algorithms in automatic switched optical networks (ASON) based on source routing. The simulation results show that the performance of the blocking probability is improved. Furthermore, the routing loops can be avoided efficiently and the inter-domain signaling complexity is reduced significantly by the proposed algorithms.

The design of security protocols is difficult and extremely complicated. In this paper, we presents a framework for modeling security protocol, UML extension for security protocol (USP), which makes it possible to the development of security protocols in an intuitive and visual way. For further security analysis of USP model, we refer to a precisely defined semantics of behavioral aspects. The formal semantics of a simplified fragment of UML builds on dynamic semantics of UML State Machines. As a case study, Denning-Sacco protocol will be described with USP. Moreover, the security protocol described with USP can be converted to an implementation or connected with existing formal analysis framework if appropriate converter tools are available.

A novel Optical network unit based on self-seeded RSOA for WDM-PON was proposed. The RSOA was self-seeded by amplified spontaneous emission of itself using fiber Bragg grating (FBG) without additional optical source.

Waveband switching routing is a new problem for research community. It is has some different with the routing of wavelength assign problem. In this paper, we propose a new ideal for agent based Waveband switching network construction. Primary simulation shows that in this way complexity of virtual network topology and blocking probability reduced.

This paper proposes a DiffServ-based multicast media gateway, called DiffServ-based Multicast Router (DSMRouter), to guarantee QoS and scalability for multimedia presentation. To reach the QoS goals, the proportional fairness scheduling strategy is proposed for layered media flows, including I-frame, P-frame and B-frame flows, to determine the approximate reserved bandwidth. Additionally, the DSMRouter system dynamically changes the sending rates of various service queues to ensure that layered media packets with higher priority are always sent before those with lower priority. The proposed PFS strategy has been experimentally tested on several layered-video streams. The results reveal that the proposed scheme outperforms others with a substantial reduction of bandwidth reservation even given tight delay bounds. The experimental results of the DSMRouter system on DiffServ networks also reveal the capability for dynamic bandwidth adjustment in various networking situations.

With the rapid development of the network technology, it is increasingly important to dynamically upgrade router's software. In this paper, the authors propose new software architecture applying to component router. The novel feature of the architecture is the ability to dynamically load and configure extensible components at run time. Each component implements one function such as packet classification, packet scheduling and routing protocol etc. We design a simple Component Router Configuration Language (CRCL) to configure and manage the router. The Component Router can be configured in according to per network flow. At present, a prototype system based on highly efficient router operating system (HEROS) has been finished.

In order to guarantee the global communication, intersatellite links (ISLs) is a significant method in the satellites constellations communication network. Two types are distinguished: Intraorbit ISLs and Interorbit ISLs. Interorbit ISLs represent the biggest challenge in terms of ISL terminal implementation. This paper comes up with an optical solution to interorbit ISLs which will offer the practical importance.

Korea has been one of the early providers of the broadband Internet services in the world. Over 10 million subscribers use the internet data service using xDSL and AON. So far, xDSL system is considering the dominant access network transmission system. But from the 2005, TELCOS are more considering AON system at apartment area. They call Optical LAN. The brand name is very popular in Korea. KT has been provided Optical LAN service for apartment area. We call the name of Ntopia. We install L3 switch apartment main distribute frame (MDF) and FES in the each building. In general this service is target for new apartment area. But the AON system does not proper out of the CO. However, Passive Optical Network (PON) system has reliability in terms of OPEX comparing with AON. So I will introduce the Optical LAN using 100M WDM-PON.

A novel hybrid WDM/TDM optical access network architecture called wavelength shared WDM PON and its media access control mode is proposed. The system is based on a two-stage distribution tree connecting OLT and ONUs.and uses ALOHA protocol for control channel and FIFO scheduler to efficiently assign bandwidth. The packet delay in the system is analyzed and the numerical results demonstrate that the system possesses well performance of packet delay.

After an introduction and analysis of bandwidth requirement to VLB scheme, we discuss main problems to be solved before VLB can be deployed in a real network. And we put forward several possible schemes with the idea of VLB, including alternate interface method.

In this paper, we propose a new scheme to realize the robust design for the WDM optical network. Instead of traditional virtual topology based optical network design approaches which depend on the traffic matrix estimation technology, we take advantage of the load balance idea of Valiant to design the network, which can accommodate the dynamic traffic matrix. Considering the specific features of the optical network, we carefully design the full-connected virtual topology to balance the virtual link distribution on the physical topology. In order to achieve this goal, an Integer Linear Programming model is used. Then we decide the capacity for each physical link according to Valiant Load-Balanced principle. At last, the traffic division delivery mode is employed to deliver the traffic on this well designed network. The whole design approach realizes the idea of robustness; it fully utilizes the resources of the network, and can meet the requirements of variable traffic.

We present a low-cost WDM-PON employing colorless uncooled RSOA-based spectrum sliced sources. Colorless operations over 32 WDM channels are demonstrated from 0 to 60 ^oC in 155-Mb/s transmissions over 25 km.

The multicast capability of a multicast-capable optical add/drop multiplexer (MC-OADM) is analyzed and the dynamic network performance on the WDM ring employing such MC-OADMs is investigated. The MC-OADM multicast scheme can provide more multicast services while consume less resources in comparison with that of the normal OADM ring without multicast capability.

A new scheme to mitigate the connection setup time overheads in distributed wavelength reservation schemes for WDM multi-fiber optical networks is proposed in this study. In this scheme, we consider the reconfiguration delay of switch fabric in distributed signaling protocols, which designated as signaling with switch fabric status (SWFS). Protocol realization selects and reserves the available wavelength that has the least switch fabric reconfiguration times along the path to shorten the connection establishment time. In this paper, we proposed four wavelength reservation schemes with SWFS for multi-fiber optical networks, which are S-FW-FF, S-FW-RF, S-RW-FF, and S-RW-RF. Simulation results indicate that schemes with SWFS have the shorter setup time, lower switching ratio as well as better blocking performance than those of without SWFS. Especially, the proposed schemes significantly reduce numbers of switch fabric that need to be reconfigured.

Multiple services ring (MSR) has been standardized in ITU-T numbered as X.87. As a novel multi-service provisioning method based on RPR, MSR proposes an effective mechanism of transporting various voice, data, video services with tributary multicast, protection and performance monitoring functions. In this paper we present the layered model of a MSR and introduce the main enhancements based on RPR. Then we propose a novel Parallelized Processing Mechanism (PPM) for design of MSR using network processor. Our design adopts a combination of layered parallelism and functional parallelism. And this paper also describes the simulation model for performance evaluation with OPNET as well as the implementation of MSR using network processor. System simulations and field trial measurements show that TDM Circuit Emulation (TCE) services and Ethernet services are given the QoS and fast recovery guarantee based on MSR.

One of the critical challenges facing the carriers today is to increase the revenue of services. As the expansion of deployment of packet based bearer networks in the MAN, network resilience becomes a significant contributor to revenue and profit. In this paper, we propose a revenue-based quality of protection (QoP) for capacity design model to provide various protection classes in the multiple services ring (MSR) networks. Based on this model, this paper provides an Enhanced Greedy Algorithm (EGA) to solve revenue-based bandwidth allocation (RBA) problems. All experimental results on the test bed show that EGA is efficient and applicable for embedded systems.