Greedy demand of high speed communication has made electrical interconnection on board a bottleneck. Electro-Optical Printed Circuit Board (EOPCB) was proposed to relieve the pressure by introducing an optical layer to common printed circuit board. Nowadays, most of the proposed EOPCB solutions focused on the design of optical transceiver structure and optical interconnection was used directly to replace high speed electrical interconnection by employing transceiver arrays. This approach would need many VCSEL-PIN pairs for a single high speed chip on board, thus increase the cost and also decrease the efficiency of optical interconnection. To defeat the weakness, a network approach, where only one VCSEL-PIN pair is required for a chip, is proposed in this paper. A novel Optoelectronic integrated circuit (OEIC) architecture is introduced to make this network approach possible.

With the development of broadband services, it is realized that access network becomes the bottleneck. After the introduction of FTTH system, this paper discusses the home gateway in detail. As an extension of FTTH system, the home gateway can be used as a bridge to interconnect intelligent home systems and outside networks. Home gateway has a great potential market. Based on the analysis of the architectures of software and hardware and the implementation models, the paper discusses key technologies and standards of home gateway.

One approach for accommodating IP traffic on the WDM (Wavelength Division Multiplexing) network is to construct a logical topology by establishing a set of lightpaths between nodes. The lightpath carries IP traffoi and does not require any electronic processing at ntermediate nodes, which reduce the load of packet processing at those nodes. However, if IP nd WDM networks have its own routing functions, the lightpaths configured in WDM network may not be fully utilized by IP unless the route of IP packets can be explicitly determined. Therefore, the integration of routing mechanisms is necessary to provide efficient resource utilization and flexible adaptation against traffic changes. In this paper, we propose an integrated routing mechanism for IP over WDM networks. The key idea is to prepare a set of virtual-links based on a resource utilization of the WDM network, and then calculate the minimum cost route on the IP network. Our simulation results show that the performance of our method outperforms those of optimally designed logical topologies when traffic patterns change. Fluid flow network simulation is conducted for simulating IP traffic flow on WDM networks.

Constraint-based wavelength routing comes with the cost of higher blocking probability to provide Quality of Service (QoS) guarantee in Service-guaranteed optical networks; thus a load balancing method is presented in this paper to improve the performance of constraint-based wavelength routing. Also the Modified Backward-Forward heuristic (MBFH) is proposed, which can be utilized to select an optimal lightpath with one constraint. Simulation results show that with the application of load balancing method, constraint-based wavelength routing based on the MBFH can achieve better performances in terms of blocking probability and resource utilization ability.

In this paper, a new scheme to mitigate the connection setup time overheads in distributed control schemes for wavelength-routed optical networks is proposed. In this scheme, we consider the reconfiguration delay of switch fabrics in the distributed signaling protocols, which designated as the signaling with switch fabric status (SWFS). Based on the reconfiguration information being carried by signaling messages along with wavelength availability information, distributed wavelength assignment algorithm at the destination node will select a wavelength with the minimal switch reconfiguration delay along the lightpath to shorten average connection setup time. Simulation results indicate that the first-fit algorithm with switch status (S-FF) and random algorithm with switch status (S-RM) have the shorter setup time, lower switch ratio as well as better blocking performance than those of classic schemes. Especially, the proposed scheme significantly reduces the number of switch fabrics that need to be reconfigured. Moreover, we investigate the effect of number of add/drop ports of optical cross-connects (OXCs) on the blocking performance of the scheme. We find that when the number of add/drop ports of OXCs is larger than a base boundary, the network may achieve almost the best blocking performance of the distributed wavelength provisioning.

A translucent multicasting scheme based on sparsely placed signal re-generable translucent multicasting capable optical cross connect (tMC-OXC) nodes is proposed to provide signal-quality guaranteed multicasting services. We propose a tMC-OXC architecture capable of transparent unicasting and electronic multicasting. The electronic multicasting devices are also used to regenerate the impaired signals. A regeneration weight based MC-OXC nodes placement strategy is designed to construct the translucent network. We propose two multicasting tree construction algorithms to evaluate the performance of the proposed translucent network, where the selected MC-OXC nodes serve as core nodes (we call them hub nodes). Our study shows that no more than 30% nodes need to be equipped with electronic multicasting and electronic 3R regeneration capability, having more than 30% nodes with regeneration capability only slightly enhances the network performance.

Currently the mainstream technology of SAN is SAN storage virtualization and its implementation. The switch-based storage virtualization embeds the virtualizer in the core of the storage networking fabric in an "intelligent switch" rather than an appliance or a host. This paper describes the SV-FC SAN switch's hardware and software architecture. The main aid of design and implementation the switch is to give a new way to realize FC-SAN storage virtualization. Storage virtualization modules are embedded in the switches firmware. The switch can provide simple and friendly interfaces for users to configure and manage the FC SAN.

An innovative optical infrastructure sharing solution for triple play services is described. A "black-link" type of architecture is proposed. We outline the commercial and architectural benefits delivered by this new model. We also present experimental results that demonstrate how wavelength translation (WT) can be used to upgrade existing optical fiber communication systems through improvements in the system dispersion or attenuation tolerances by using dense wavelength division (DWDM) and corase wavelength division multiplexing (CWDM) SFPs.

This paper provides current status and future trends of FTTH in mainland of China. It discusses current FTTH research, development and deployment status in China, including technology choices, deployment considerations, major equipment vendors and carriers, standardizations, market barriers and opportunities.

Small businesses must be extremely efficient and smartly leverage their resources, suppliers, and partners to successfully compete with larger firms. A successful small business requires a set of companies with interlocking business relationships that are dynamic and needs-based. There has been no software solution that creates a secure and flexible way to efficiently connect small business computer-based employees and partners. In this invited paper, we discuss MioNet, a secure and powerful data management platform which may provide millions of small businesses with a virtual workplace and help them to succeed.

Due to the experience in the exploitation of previous European telemedicine projects an open Euro-Mediterranean consortium proposes the Virtual Euro-Mediterranean Hospital (VEMH) initiative. The provision of the same advanced technologies to the European and Mediterranean Countries should contribute to their better dialogue for integration. VEMH aims to facilitate the interconnection of various services through real integration which must take into account the social, human and cultural dimensions. VEMH will provide a platform consisting of a satellite and terrestrial link for the application of medical e-learning, real-time telemedicine and medical assistance. The methodologies for the VEMH are medical-needs-driven instead of technology-driven. They supply new management tools for virtual medical communities and allow management of clinical outcomes for implementation of evidence-based medicine. Due to the distributed character of the VEMH Grid technology becomes inevitable for successful deployment of the services. Existing Grid Engines provide basic computing power needed by today's medical analysis tasks but lack other capabilities needed for communication and knowledge sharing services envisioned. When it comes to heterogeneous systems to be shared by different institutions especially the high level system management areas are still unsupported. Therefore a Metagrid Engine is needed that provides a superset of functionalities across different Grid Engines and manages strong privacy and Quality of Service constraints at this comprehensive level.

At present, the video stream scheme based on Unicast is adopted in VOD systems. It not only increases network load and delay, but also causes user's QoS to be limited by network transmission bandwidth. And networks congestion caused by characteristic of IP networks affects video applications seriously. So a design of network structure of VOD system base on IP Multicast is proposed in the paper. And this system has a predominant scheduler algorithm to Multicast transmission of video stream. At the same time, design and performance of the system's video sever are analyzed. Further, The ways of coding technology and runoff control are proposed, so that QoS will be improved. The main propositions are as follows:1. Propose a design of network structure of VOD system base on IP Multicast. 2. Analyze the design of access sever for system users. including analysis of the most users, analysis of network transmission for users in different regions demanding the same program, and how to access user severs nonblocking for users in different networks, and so on. 3. Propose a way of realizing system QoS, including network optimization, runoff and congestion control of the network, and prior control of different service in the network.

This paper provides a detailed analysis and modelling of the Operational Expenditures (OPEX) for a network provider. The traditional operational processes are elaborated and the expected changes when using a control plane such as ASON/GMPLS are described. Control planes are promoted as a major technology for the automation of network operations. It is often claimed to allow the reduction of OPEX. However, detailed analysis and quantitative evaluation of the changes induced by such technologies is rare. In this paper we quantify the cost reduction potential of an ASON/GMPLS based control plane. Additionally, we show an important impact of the used resilience scheme on the expenses directly related to continuous costs of infrastructure (floorspace, energy,...) and on the planning and reparation costs. Concerning the service provisioning costs, we show that the introduction of a control plane leads to a reduction in the order of 50% of the OPEX cost compared to the traditional case.

This paper analyzes the cost of the PON architectures that are proposed today and suggests the most optimized protection architecture based on the existing network. System fault rates and device costs were considered in estimating the relative cost of the system architecture.

The network planner of the incumbent telecom service provider faces a series of challenges following technology developments, riding demand changes and utilizing existing resources. It is believed that the telecom planning that was started from the early time for PSTN deployment has been contributed to the foundation for the telecom planning but does not provide enough methodologies to help today's planning activities. The planning work for the provider must make innovation for adapting to the dynamic environment and supporting business development. In this paper, the situations and trends faced by the telecom service provider are first reviewed, the planning system restructure and planning methodologies innovation for meeting present situations are then presented, and the issues and directions are finally summarized.

IP Video service has a substantial growth on the internet in the last few years, and this gives a golden opportunity to popularize FTTH. As the hope of FTTH, EPON meets the bandwidth requirement of high quality video service. Using a point-to-multipoint topology, EPON is easy to set up channels for broadcast video. However, if the video stream isn't handled correctly, broadcast storm will occur on the attached link. So a novel scheme of multicasting IP Video over EPON is presented in this paper to solve this problem. It not only guarantees validity of filtering video stream, but also guarantees QoS and security of this service. In the first part of this paper, the key technologies of multicasting IP video over EPON are introduced. Then FPGA implementation of this scheme is described in detail. Finally security of IP video is discussed.

In this article we present our new implementation of Real-time transport protocol (RTP) with its control protocol (RTCP) which enables the real-time delivery of continuous and interactive media over an emerging access network -Ethernet passive optical networks. RTP can provide end-to-end delivery service for data with real-time characteristics, such as interactive audio and video. While RTP is primarily designed to satisfy the needs of multiparticipant multimedia conferences, it is not limited to that particular application. Now we can use it for multimedia delivery over EPON, which represent the convergence of low-cost Ethernet equipment and low-cost fiber infrastructure, appear to be the best candidate for the next-generation access network. Ethernet passive optical networks are an emerging access network technology that provides a low-cost method of deploying optical access lines between a carrier's central office (co) and a customer site. RTP application designers are advised to avoid mechanisms that can only work in unicast mode and will not scale to larger number. Because of some characteristics of EPON architecture, we develop a new RTP which is suitable for this architecture.

Gigabit or Ethernet PON access FFTx networks are being deployed in a number of countries. A number of different concepts and architectures have been used. Architecture selection criteria included the targeted up- and downstream bitrate, the geographical structure of the target area, buried or overhead cabling, planned services and QoS aspects, all under the constraints of the technological state of the art and the economical data. This paper will discuss some of the aspects of different modern PON architectures. There are three basic enhancements in the PON performance: higher bit rates for the end user in up- and downstream direction, higher splitting factors and higher reach. All of the enhancements can be arbitrarily combined, eventually introducing the need for architectural or technological changes.

This paper introduces a novel FTTH-PON network architecture suitable for unlimited user and service scaling. It employs a passive NxN AWG and exploits the wavelength cyclical routing which is made possible by the devices Free Spectral Range (FSR) property at 2.5Gbps. The proposed architecture is based upon the WDM-PON features unique properties including the possibility of offering simultaneously both broadcast and switches services plus additional advantages in term of signal privacy, easy fault location and direct capacity upgrade and also has the potential of offering a wide variety of services on the same physical network. Although the additional AWG in the network posses an extra 5dB power penalty but an optical transmission test demonstrate an error free transmission has been achieved with a 25km passive optical link with a 16×16 AWG and a 1×32 splitter installed.

This paper presents alternative architectures for high split and long range bidirectional single mode fiber (SMF) super passive optical networks (SuperPONs). The erbium doped fiber amplifier (EDFA) is introduced to enhance power budget. Three different alternative architectures are studied: 1) using transmission speed of 10 Gbit/s and 2.5 Gbit/s at same wavelength of 1550 nm; 2) using same transmission speed of 10 Gbit/s at wavelength of 1550 nm for downstream and 1530 nm for upstream; 3) using bidirectional EDFA at transmission speed of 10 Gbit/s and 2.5 Gbit/s with same wavelength of 1550 nm. The elaboration of architectures together with their advantages and disadvantages are included. The feasibility of deploying a SuperPON with 512 optical network units (ONUs) at transmission length of 100 km was observed from power budget studies.

Current optical transport networks are based on non-transparent SONET/SDH technology. Wavelength multiplexed systems (WDM) modulate optical signals with SONET/SDH digital formats at 2.5 and 10Gb/s rates. Transparent Optical Networks have been actively researched as a way to make optical transport independent from the electronic signals transmitted. In this article, we review recent developments in optical components that facilitate a flexible spectrum usage of DWDM systems. In addition, we discuss emerging optical transport services and how they can be best served by a state-of-the-art transport network.

In this paper we propose a new scheduling mechanism that combines priority scheduling with dynamic bandwidth allocation in EPONs. The multi-point control protocol (MPCP) is adopted to facilitate the cooperation between OLT and ONUs. A delta cycle time algorithm (DCTA) is proposed to get adapted to the burst nature of VBR streaming media traffic. An enhanced GATE generation (EGG) method is discussed to increase the channel utilization. Simulation results show that our method leads to significant decrease of packet delay for streaming media traffic especially under heavy traffic load.

Ethernet-based Passive Optical Network (EPON) technology is being considered as a promising solution for next generation broadband access network as it offers a highly flexible, cost effective solution. In this paper, in order to support different services and bandwidths in the users' request, we propose a new approach to the problem of optimal bandwidth allocation in EPON. We show that by moving all the access control functionality to the Optical Line Terminator, a flexible solution could be achieved which offers full support for Service Level Agreements and removes the burden of managing the configuration of every Optical Network Unit (ONU). We conduct detailed simulation experiments to study the performance and validate the effectiveness of the proposed Scheme.

EPONs use a point-to-multipoint topology, in which multiple optical network units (ONUs) share one uplink channel to transmit multimedia traffic to a control element, the optical line terminal (OLT). Hence, to avoid data collision on the shared uplink, ensure a contention-free transmission and so on, medium access control arbitration mechanisms are essential for the successful implementation of EPONs. In this paper, a novel dynamic bandwidth allocation algorithm, the Integrated Two Classes Dynamic Bandwidth Allocation (ITCDBA), is put forward, in which the multipoint control protocol is used defined in the IEEE802.3ah standard. ITCDBA is a hierarchical allocation scheme which dynamically allocates bandwidth according to the instantaneous demands of ONUs, supporting inter-ONU priority scheduling as well as intra-ONU priority scheduling. The simulation result shows that the system throughput of EPON is improved with ITCDBA scheme and the drop rate of the traffic with the highest priority is lower than that with Two-layer bandwidth allocation (TLBA) scheme [11]. In a word, ITCDBA not only can allocate bandwidths between end users effectively and fairly, but also can support differentiated services. Besides, the system performance of EPONs with ITCDBA scheme is improved.

In the downstream direction of EPON, all ethernet frames share one downlink channel from the OLT to destination ONUs. To guarantee differentiated services, a scheduling algorithm is needed to solve the link-sharing issue. In this paper, we first review the classical WFQ algorithm and point out the shortcomings existing in the fair queueing principle of WFQ algorithm for EPON. Then we propose a novel scheduling algorithm called Priority-based WFQ (PWFQ) algorithm which distributes bandwidth based on priority. PWFQ algorithm can guarantee the quality of real-time services whether under light load or under heavy load. Simulation results also show that PWFQ algorithm not only can improve delay performance of real-time services, but can also meet the worst-case delay bound requirements.

The quality of service (QoS) requirements of end users and services are totally different, and thus the multi-oriented (user-oriented and service-oriented) scheduling for access networks based on a remote scheduling system especially for EPONs is desired to replace the single-oriented (user-oriented or service-oriented) scheduling. In this paper we introduce a novel hierarchical algorithm of intra-ONU scheduling for multi-oriented QoS, which can guarantee both the priority of the differentiated services and the fairness of the different users. Numerical results have shown that our overall scheduling algorithm can fulfill various requirements of delay and throughput for the transmission of multimedia traffic for each end user.

In this paper a novel hybrid WDM/TDM optical access network architecture and its media access control (MAC) alogrithm is proposed. Extensive simulations are conducted and the results show that the algorithm can provide determinate delay bound for each flow, possesses throughput fairness and decreases the packet delay of low priority flow.

As EPON system becomes attractive integrated broadband access solution in worldwide Fiber To The Home(FTTH) and Fiber To The Building (FTTB) deployment, the QoS guarantee and the management of multiple services is inevitably a urgent issue in EPON system implementation. Instead of only using priority method as defined in IEEE802.1p, this paper proposes a native model for multi-service access platform with SLA enforcement, which specifying Service Level Agreements (SLAs) on logical links in EPON transmission segment and strictly enforcing SLAs by EPON MPCP protocol and DBA algorithm in both upstream and downstream. SLA normally uses multiple parameters to describe requirements of service bandwidth, delay and jitter. In EPON, the specification of SLA for service may use 4 parameters: the minimal Guarantee bandwidth, maximum allow bandwidth, sensitivity of delay and maximum burst size. As EPON schedules traffic on logical link basis, the right QoS demand of each service will be the same as its logical link. To guarantee different services' different SLAs, it was supposed to use multiple logical link IDentifies (LLIDs) in each remote ONU, each service is mapped to its own LLID. By classifying services packet into different links, combining with powerful Hierarchical WRR schedule algorithm it is possible to guarantee the bandwidth and control transmission delay and jitter for each service bidirectional. The proposed scheme has overcome the best-effect forwarding deficiency of the Ethernet, brought the management of multiple services and the management of remote ONUs into a new framework, given cost efficient and effective solution for EPON multiple services access.

This paper studies the gradual migration from a link-by-link grooming network without OXCs towards OXC introduction in some nodes, using end-to-end grooming. A migration path introducing OXCs in so-called end-to-end grooming islands is proposed.

In this paper, we study the dynamic performance of self-similar traffic under different integrated routing algorithms in IP/WDM networks for the first time. The self-similar traffic is generated by FFT-FGN method characterized by three parameters (H, M, V) namely Hurst parameter, Mean Value and variance Value. Through extensive simulation in three respective network topologies, the effects on the dynamic performance by the parameters of self-similar traffic (Hurst, Mean, Variance) and the parameter of network (connectivety of the topologies) are analyzed. we know that the network blocking probability increases with the rise of H and V due to the bursty of traffic becomes more obvious. And the increasing of M makes the network blocking probability higher because of increasing of traffic volume. Moreover different IR algorithms have different performance using self-similar model, and integrated min-hop routing (IMH) algorithm outperforms the others. All these trends are not changed with the connectivity of the network topologies. In addition, in order to know the difference of dynamic performance between the Poisson and self-similar model, we compare the performance of the two modes under the same condition. Simulation results show that network blocking probability of self-similar traffic is lager than that of Poisson due to the property of long-rage dependence of self-similar traffic.

In this paper, a soft preemptive scheme for providing service differentiation in wavelength-routed networks is proposed and it is shown that the scheme is capable of reducing the call blocking probability of high-priority connections while keeping low-priority connections unaffected.

Future backbone networks shall require full-survivability and support dynamic changes of traffic demands. The Generalized Survivable Networks (GSN) was proposed to meet these challenges. GSN is fully-survivable under dynamic traffic demand changes, so it offers a practical and guaranteed characterization framework for ASTN / ASON survivable network planning and bandwidth-on-demand resource allocation⁴. The basic idea of GSN is to incorporate the non-blocking network concept into the survivable network models. In GSN, each network node must specify its I/O capacity bound which is taken as constraints for any allowable traffic demand matrix. In this paper, we consider the following generic GSN network design problem: Given the I/O bounds of each network node, find a routing scheme (and the corresponding rerouting scheme under failure) and the link capacity assignment (both working and spare) which minimize the cost, such that any traffic matrix consistent with the given I/O bounds can be feasibly routed and it is single-fault tolerant under the link restoration scheme. We first show how the initial, infeasible formal mixed integer programming formulation can be transformed into a more feasible problem using the duality transformation of the linear program. Then we show how the problem can be simplified using the Lagrangian Relaxation approach. Previous work has outlined a two-phase approach for solving this problem where the first phase optimizes the working capacity assignment and the second phase optimizes the spare capacity assignment. In this paper, we present a jointly optimized framework for dimensioning the survivable optical network with the GSN model. Experiment results show that the jointly optimized GSN can bring about on average of 3.8% cost savings when compared with the separate, two-phase approach. Finally, we perform a cost comparison and show that GSN can be deployed with a reasonable cost.

1+1 protection is usually used to implement fast failure recovery and provide high reliability to data connections. A typical scheme of 1+1 protection employs a primary working lightpath and a dedicated diversely-routed backup ligthpath to carry the same data, in which the same wavelengths are always used for the two lightpath, thus putting edge-disjoint restrictions on the wavelength routing. Because current standard requires <50-ms protection-switching time, a mechanical switches with several millisecond switching time can be used before the receiver for channel switching. However, with the transmission speed of single wavelength channel increasing to tens of Gb/s, a faster switching time is highly desired to reduce the amount of data loss. In this paper, we propose an out-of-band 1+1 protection scheme, which employs two different wavelengths for primary working lightpath and protection backup path, respectively. At the destination node, a fast tunable heterodyne-detection receiver is used to select the desired wavelength lightpath. The proposed fast tunable receiver significantly reduces the protection switching time between the two paths. To investigate the performance of the proposed protection scheme, a fast channel selection experiment is performed. Two optical wavelength channels were modulated simultaneously by a Mach-Zehnder (MZ) external modulator with data rate 1.25Gb/s. The tunable heterodyne receiver switches between the working lightpath and protection lightpath to demonstrate the capability of 1+1 protection. A <0.8-ns switching time is obtained which demonstrates the potential of hitless protection switching, if the switching occurs at the transition of two neighboring '1's.

A variety of traffics from different communications networks have been demonstrated to show the self-similarity. A novel method to estimate the degree of self-similarity based on the index of dispersion for counts, a second-order statistic, is proposed in this paper. Its principle is introduced in brief and validation is made in detail on the basis of two self-similar process models, Sup_FRP and FBNDP. Qualification and comparison show that the method possesses simpler algorithm than the wavelet-based estimator and that it exhibits higher accuracy and reliability than the R/S estimator and the Variance-time analysis.

BACnet is an open building automation and control network protocol used extensively in building automation and control systems. To guarantee security and reliability of BACnet network, congestion control is important in BACnet network. Considering BACnet router's out-port rate and packet's priority, this paper proposes a rate based priority random early detection (RPRED) algorithm to realize congestion control in BACnet network. RPRED algorithm detects congestion according to the average queue length, and estimates congestion trend according to relationship between packets arriving rate and out-port rate. In congestion control, RPRED randomly drop packets and manage queue according to packets' priority. These features of RPRED algorithm ensure the security and reliability of BACnet network. Some experimental investigation was undertaken to compare RPRED algorithm with conventional Drop Tail algorithm. Test result shows that when traffic load increased in BACnet network, RPRED algorithm could decrease time delay and drop ratio of high priority BACnet packets.

To mitigate TCP global synchronization and improve network throughput, an improved TCP congestion control mechanism is proposed, namely P-TCP, which adopts the probability-based way to adjust congestion window independently when the network occurs congestion. Therefore, some P-TCP connections may decrease the congestion window greatly while other P-TCP connections may decrease the congestion window lightly. Simulation results show that TCP global synchronization can be effectively mitigated, which leads to efficient utilization of network resources as well as the effective mitigation for network congestion. Simulation results also give some valuable references for determining the related parameters in P-TCP.

Based on the mature user equilibrium (UE) theory in transportation field as well as the similarity of network flow between transportation and communication, in this paper, the user equilibrium theory was applied to communication networks, and how to apply the stochastic user equilibrium (SUE) to flow assigning in generalized communication networks was further studied. The stochastic link equilibrium (SLE) flow assignment strategy was proposed in this paper, the algorithm of SLE flow assignment was also provided. Both analyses and simulation based on the given algorithm proved that the optimal flow assignment in networks can be achieved by using this algorithm.

In this paper, based on Pareto traffic model, the self-similar traffic was generated by modeling on the Application Layer, the impact of Application Layer, Transport layer and Network layer on network traffic was considered. By simulation, the impact of the self-similarity of network traffic as well as the changes of network resources on network performance was studied. The main factors which impact the network performance was deeply analyzed and the accordingly strategy was also given, to provide reference for controlling the impact of the self-similarity of network traffic on the network performance.

Network integral performance evaluation has been the area receiving considerable attention recently. Based on fuzzy theory, an improved fuzzy AHP was present in this paper, and it was proved that theoretical weight value of the improved AHP is tally with actual value. So, by analyzing the degrees of each index impacting on network performance, and directly using the conclusions of the improved AHP for weighting, more efficient network evaluation could be achieved. In this paper, a method and basis for network management decision-making is provided, thus to evaluate and analyze network performance. What's more, the method of network performance evaluation using network simulation was proposed, and this method was applied to a real multimedia network.

In this paper, the existing problems of the transmission network and the necessity of ASON will be systematically analyzed. The key technologies of ASON and the evolution of the standardization of ASON will be also explained. Otherwise, the new problems and new functions ASON brings in will be discussed. The applications and the prospect of ASON will be also included in this paper.

This paper presents a large scale automatically switched optical network (ASON) test-bed made by Tsinghua University. The testbed is composed of hardware platform, control plane and management plane. The hardware platform is constructed with switches, computers and optical nodes as well. The software modules of the control plane for the testbed mainly include hierarchical routing, signaling with the separation of the call control and the connection control, and the link management supporting hierarchical control. The management plane is a distributed system with locally centralized management functions. The testbed can provide main large scale ASON functions and record the kinds and the amount of signaling, total and separate block probabilities for the sake of research.

IPv6 transport over the GMPLS-controlled optical network of JGN II was experimentally investigated, and four FastEthernet IPv6 streams were successfully transported with OSPFv3 routing information exchange.

Automatic Switched Optical Networks, or ASON, is regarded as one promising networking technology for future optical networks. From network operators' perspective, it is well agreed that ASON should provide the following features: fast provisioning, easier network operation, higher network reliability, scalability, simpler planning and design, and multi-vendor inter-operability. Fast provisioning enables ASON to meet the requirements of more dynamic applications such as bandwidth on demand and content distribution. Protection and restoration is crucial because of the extremely high data-rate the network will carry. Mesh type network and fast provisioning capability leave more space for a more reliable and flexible network. Unlike traditional transport networks that are constructed purely for point-to-point connectivity, ASON deployed in regional or metro-area networks needs to provide high connectivity to its clients. And, as a result, the planning and designing problem becomes very complex due to the large number of devices, the variety of interface types and network protocols. It is also important that the network will be able to inter-connect devices from different vendors and provide support to different client signals such as SONET/SDH, Ethernet, IP, ATM and Frame Relay.

We studied the conformance test cases development and abstract test suite (ATS) generation methods, and we considered the External Network-Network Interface (E-NNI) signaling protocols for Automatic Switched Optical Networks (ASON). Then we developed the conformance test suite using TTCN-3 (Testing and Test Control Notation version 3) language. These codes are used to test the E-NNI interface between kinds of devices, which are developed by multiple vendors.

A testbed for metro wavelength division multiplexing (WDM) network is realized and tested. The testbed contains a reconfigurable optical add/drop multiplexer (ROADM) node, a 2x2 wavelength cross-connect (WXC) node, and two interconnected two-fiber bidirectional path protected switching ring networks (TF-BPSR). Both the ROADM and WXC node are bidirectional nodes, so they can select channels from the working and the protection ring networks simultaneously, and they support both protected and unprotected services. The ROADM node uses a flexible band tunable filter (FBTF) to drop a waveband from the input WDM signals and send the express channels directly to the output port. As a result, the physical impairment accumulated on the express channels can be minimized. It also has a modular structure, so additional modules can be cascaded to expand the capacity and functionality of the node without any interruption to current services. The WXC node is realized with interconnected ROADM modules that are comprised of wavelength selective switches (WSSes). Arbitrary wavelength or wavelength sets can be either dropped in the node or cross-connected in a non-blocking manner. Multiple services, such as OC-48 and OC-192 SONET signals, gigabit Ethernet streams carrying interactive movie signals, and live video broadcasting services, are carried in the network, dropped in the ROADM and WXC node, and switched between the two ring networks. The testbed is controlled by a websever based network management system that facilitates remote control and monitoring. Experiments demonstrate that the performance of the nodes and the testbed meets the requirement of the services.

We study the optimization issues of ring networks employing novel parallel multi-granularity hierarchical OADMs. In particular, we attempt to minimize the number of control elements for the off-line case. We present an integer linear programming formulation to obtain the lower bound in optimization, and propose an efficient heuristic algorithm called Global Bandwidth Resource Assignment (GBRA) that is suitable for the design of large-scale OADM networks.

A detailed management system implementation process for a realized reconfigurable optical add-drop multiplexer (ROADM) is presented. The ROADM is capable of freely adding/dropping any of 40 wavelengths within C-band at ITU_T standard spacing according to the user's configuration demand from the management system. SNMP and Java language are used in the deployment of the management system. The management system framework and its implementation process are introduced in template-based form, so they are generic enough to be deployed in managing such reconfigurable elements in optical transport network, and be of value to others who are contemplating managing such kind of reconfigurable elements.

R and D activities on photonic networks in Japan are presented. First, milestones in current, ongoing R and D programs supported by Japanese government agencies are introduced, including long-distance and WDM fiber transmission, wavelength routing, optical burst switching, and control plane technology for IP backbone networks. Their goal was set to evolve a legacy telecommunications network to IP over WDM networks by introducing technologies for WDM and wavelength routing. We then discuss the perspectives of so-called PHASE II R and D programs for photonic networks over the next five years until 2010, by focusing on the report which has been recently issued by the Photonic Internet Forum (PIF), a consortium that has major carriers, telecom vendors, and Japanese academics as members. The PHASE II R and D programs should serve to establish a photonic platform to provide abundant bandwidth on demand, at any time on a real-time basis through the customer's initiative, to promote bandwidth-rich applications, such as grid computing, real-time digital-cinema streaming, medical and educational applications, and network storage in e-commerce.

Constructing multi-Terabit switches and routers entirely out of electronic cross-bars require multiple racks of switches and huge number of interconnects. The cost and power consumption of such a system is very high and has a limited scalability. The all-optical switching has the problem of buffering and processing and the construction of multi-terabit switches and routers based on all-optical switching is not feasible in the near future. However, based on a hybrid approach, using optical cross-bars with nanosecond switching time and large bandwidth and DWDM interconnects in conjunction with electrical memory, one can construct huge and highly scalable switches and routers.

The combination of broadband optical access and core networks is considered to be one of the most promising solutions for end-to-end transportation of high bit-rate data, video, and voice signals across optical networks of the future. Optical label switching technology (OLS) is an important aspect of optical packet switching and it involves the extraction and processing of the labels so that the packets can be routed to their destinations. OLS enables the routing and forwarding of the ultra-high bit rate payloads from source to destination entirely in the optical domain, thus alleviating the need for expensive optical-to-electrical conversions for processing. We have developed key enabling technologies for merged core and access networks including optical label generation, label swapping, optical buffering, clock recovery and wavelength conversion. We have experimentally demonstrated that these enabling techniques that can provide efficient broadband services in the future access and core networks.

The wavelength transfer matrix is a powerful approach to designing and verifying the wavelength routing needed for complicated WDM networks¹. This paper first describes the wavelength transfer matrix, its basic form and some extensions. A full-mesh WDM PON system that can directly connect ONUs and an OLT is proposed and analyzed in terms of wavelength by using the wavelength transfer matrix method.

IPTV-based broadband services such as interactive multimedia and video conferencing are considered as promising revenue-adding services, and multicast is proven to be a good supplier to support these applications for its reduced consumption of network bandwidth. Generally there are two approaches to implement optical layer multicast. One is space-domain multicast using space-splitter which is low cost but has wavelength continuity constraint, the other is frequency-domain multicast using wavelength converter which resolves the wavelength continuity but with high costs. A new multicasting node which adopts both space-domain multicast and frequency-domain multicast is recently discussed. In this paper we present an experimental demonstration of the new multicasting node architecture based on space splitters and wavelength converters, measurements to characterize such a node are provided.

The emerging broadband real-time streams applications require the supporting networks to provide multicasting communication at optical layer. The multicasting capable optical cross-connect (MC-OXCs) is the necessary device to implement multicasting at optical layer. The functional building blocks for MC-OXC are light splitters, which can be space splitters or multiwavelength converters (frequency splitters). The space splitter has no wavelength conversion ability, while the frequency splitter has limited fanout, decreased optical signal-to-noise ratio and also is expensive. We proposed a tradeoff architecture called joint multicasting capable optical cross-connect (jMC-OXC) integrating both space splitters and frequency splitters in our previous work. This paper further studies the network performance in terms of member blocking ratio for the jMC-OXC architecture. Three simulation schemes are designed and the results show that the network performance of the jMC-OXCs with limited frequency splitters can obtain a close performance to that with full frequency splitters.

This paper proposes a dynamic traffic sharing routing algorithm to balance the load of optical internet. By sharing traffic on 2 or 3 SRLG-disjointed paths, we improve the networks survivability. By adjusting the links' weights, the algorithm can avoid generating bottlenecks on shorter links. The simulation result shows that the network performance can be improved significantly by the DTS algorithm.

Multi-granularity switch technologies decrease the control complexity and cost of optical cross-connects (OXCs) by employing waveband and fiber routing techniques. In this paper, we study the routing and resource assignment problem in multi-granular optical networks. A novel integrated multi-layer routing and resource assignment algorithm named Dynamic Minimum Weight (DMW) is proposed. With the DMW algorithm, waveband tunnel allocation problem and wavelength channel establishment problem can be settled simultaneously. Based on the proposed DMW algorithm, the network performance with different multi-granular OXC architectures are evaluated by simulation. The simulation results also demonstrate the effectiveness of the proposed DMW algorithm.

Recently, several existing and proposed network architectures of IP over WDM are discussed. The twolayer model, which aims at a tighter integration between IP and WDM layers, offers a series of important advantages over the multi-layer architecture. Multiprotocol Label Switching (MPLS) and its extension, Generalized Multiprotocol Label Switching (GMPLS), have been proposed as the integrating structure between IP and WDM layers. Several integrated routing algorithms (IR) have been proposed to solve the routing problem in IP/WDM networks. But few of these algorithms consider the physical hop and the bandwidth fragments, which will results in some drawbacks. This paper develops a new integrated on-line routing algorithm, called hop-based bandwidth defragment algorithm (HBD). It makes uses of the statistic information of link-state and resource availability to determine whether it is better to route an arriving request over the existing topology or to open new wavelength paths. The HBD algorithm is not only to minimize the total number of physical hops used by the existing lightpaths and new lightpaths created for routing LSPs, but also to minimize the number of bandwidth fragments, which will possibly lead to increased acceptance of requests that arrive later. Simulation results show that HBD performs better in terms of blocking probability and bandwidth blocking ratio than other existing approaches.

A novel switching architecture of multi-granularity optical cross-connects (MG-OXCs) is proposed, which cooperate with the generalized multi-protocol label switching (GMPLS) control plane. We study the performance using both analysis and simulations. The result demonstrates a significant cost reduction that could be achieved for a moderately small reduction of throughput.

Applying CDMA techniques to optical communications and combining CDMA techniques with optical communication has its advantages, which not only keeps the characteristics of CDMA techniques in wireless communication, such as interference immunity, secrecy, soft capacity and simple network protocol, but also make use of the huge bandwidth of fiber. Therefore, optical CDMA communication system has the virtue of asynchronism, broad band and reliable. In this paper, we have done tasks as below: first we thoroughly study the development and recent progress in 2-D time / frequency domain optical CDMA encoding schemes. Then we put forward an implement encoding/ decoding scheme based on optical time spreading/ frequency hopping to solve the problem in current schemes. The scheme adopts 2-D time / frequency domain combination codes as address codes, by assigning two orthogonal address codes to each user and encoding "1" and "0" to these address codes respectively, in sink side differential detection technique is adopted. The scheme has the advantage of increasing power efficiency and improving system performance. While under the condition that two branches are balance, the best judge threshold of system is not variety with the environment, so the scheme also has the merit of lower systemic complexity.

A new generation of scientific applications is emerging that couples scientific instruments, data and highend computing resources distributed in a global scale. Developed by collaborative, virtual communities, many of these applications have requirements such as determinism (guaranteed QoS), shared data spaces, large data transfers, that are often achievable only through dedicated optical bandwidth. High capacity optical networking can satisfy bandwidth and latency requirements, but software tools and frameworks for end-to-end, on-demand provisioning of network services need to be developed in coordination with other resources (CPU and storage) and need to span multiple administrative and network technology domains. In response to the above requirements, this paper will address some of the key technical challenges to enable on-demand e2e network services. The proposed network concept will make applications aware of their resources (computational and networking) environment and capabilities, and able to make dynamic, adaptive and optimized use of network infrastructures connecting various high-end resources.

We show the principal methodology for providing connections with minimum cost and subject to target availability constraints, that can be used to guarantee service availability in a service level agreement (SLA). For connections without protection and for connections with dedicated protection, we develop path-based design models and evaluate the gain of availability-based provisioning.

Although recent advancements in WDM technology have significantly enhanced the performance and reliability of optical components and systems it remains inevitable that failures occur. Due to the massive increase of bandwidth supported by fiber networks it becomes extremely important to identify the impact individual failures may have on the network performance. This paper focuses on understanding the different parameters that affect the reliability of optical networks with emphasis on failures caused due to the optical components comprising the network infrastructure. As part of this study the reliability parameter associated with individual optical components is associated with the reliability of a link. Through extensive simulations it is shown that there is a direct impact on the traffic distribution across the network depending on the reliability characteristics of the network infrastructure. Several reliability scenarios and their relevant results will be presented, discussed and compared. The different scenarios under study are based on a national USA network topology and include both protection and no protection routing.

In this paper, we study the problem of dynamic survivable routing in optical networks with Shared Risk Link Groups (SRLG). Survivability and service continuity have been well recognized as the most important issues in the design of control and management planes for the next-generation optical networks with wavelength-division multiplexing (WDM) as the core technology. To make the connections survivable after various failure scenarios such as fiber cut and duct cut, it is necessary to consider SRLG diverse routing constraints in the traffic grooming problem. To jointly consider the working and backup paths, we first formulate the diverse routing problem into an Integer Linear Programming (ILP) process, in which the working and shared backup paths corresponding to a connection request are solved in a single step. We proposed failure-dependent SRLG protection heuristics algorithms for fiber selection. We compared the performance of various routing algorithms through simulation studies based on different metrics. Another contribution of this paper is a well-designed link-state metric is proposed for allocating the backup path and two selection schemes considering path costs are developed.

Multicast protection strategies have been widely explored in current literature. However, the leaf availability requirements are not taken into account. In this paper, we investigated approaches and algorithms for establishing a multicast session with differentiated leaf availability requirements in WDM mesh network while protecting it against single link failure. An effcient and cost-effective heuristic is presented to solve the problem and is compared with two other schemes, one with no protection (Scheme I) and the other with dedicated protection (Scheme II). We also formulated a possible improvement of the proposed algorithm. Simulation results based on 14 node NSFNET topology and comparisons among these schemes are also discussed. The performance of an algorithm is measured in terms of Average Cost and Average Satisfaction Ratio. The improved algorithm shows much better performance than the other ones, thus achieving the goal of effectively establishing protected multicast sessions with differentiated destination availability requirements. Finally, through numerical simulation results, we find that some links are critical to the performance of the network. Increasing the availability and capacity of these links will greatly enhance the network performance. This result is helpful to network planning and design.

It has been widely recognized that survivability is of great importance in survivable mesh WDM networks. Among various survivable schemes proposed in the literature, segment shared protection is reported to have the best performance in terms of making trade offs between spare capacity utilization and restoration time. This paper proposes a novel technique, called backup segment backup cost adjusting (BSBCA), to further reduce the spare capacity consumed for shared segment protection. To guarantee the BSBCA technique can be used in real networks, we further propose a novel approach to select appropriately the backup segment whose backup cost will be adjusted. Simulation results demonstrate the good performance of the BSBCA technique.

In this paper, a novel protection capacity reservation algorithm is proposed for the link protection schemes in WDM (wavelength division multiplexing) mesh networks with dynamic traffic demands. The algorithm called MST-DP (Minimum Spanning Tree-Dynamic Programming) is given by combination with spanning tree and dynamic programming algorithm. In this scheme, a protection capacity tree is pre-planned based on MST-DP algorithm to assure that every node-pair on networks keep connection by at least two different protection routes. So the networks can be protected from any single link or node failure event through reserving protection capacities in the pre-planned protection capacity tree. This algorithm run in WDM optical network based on matrix model. Compared with other protection capacity reservation algorithm, such as p-cycle and redundant tree, MST-DP algorithm is more simple and easy to be realized. Simulation results indicate that the MST-DP protection scheme can improve network restorability and reduce service disruption ratio on the basis of fully utilizing resources of the network.

A distributed lambda-IX consisting of generalized multi-protocol label switching (GMPLS)-controlled photonic cross connects (PXCs) and GMPLS-controlled Layer-2 switches (L2SWs) is proposed, which enhances the conventional L2-IX features by interacting between GMPLS control plane and L2SW functionalities. The proposed IX enables lambda based connections to be automatically created via PXCs between L2SWs in the IX accommodating an Internet service provider's (ISP's) border routers, which indicates that the high reliable interconnection with low latency can be provided for ISPs, thanks to the PXC technologies and GMPLS functionalities. Furthermore, by interacting with L2SW functionalities such as traffic monitoring and link aggregation, the proposed IX can provide the enhanced functionalities of a dynamic bandwidth modification according to traffic on a real time basis and a fast fault restoration of less than 50 milliseconds.

This paper deals with resilience in all-optical networks. The main disadvantage when designing all-optical label swapping networks is the enormous dimensions an all-optical node can have. The node's size relates directly to the number of Label Switched Paths passing through the node. In this paper, we discuss how the dimensions of the all-optical node alter when introducing resilience in label swapping and stripping networks. We compare the node dimensions for different recovery strategies and different all-optical networking approaches.

We study the configuration and dual-span failure performance of pre-configured protection cycles (p-cycles) in survivable WDM optical networks with partial wavelength conversion. We formulate the problem as an integer linear program using a non-joint optimization approach. p-cycles and wavelength converters are then optimally determined. The objective is to minimize the total cost of link capacity used by p-cycles and the cost of wavelength converters required to accommodate a set of traffic demands, and to select from the set of optimal cost solutions, the solution which has the best survivability performance against dual failures in terms of the average capacity loss, the average restorability, and the efficiency of the protection capacity. The proposed p-cycle configuration architecture takes full advantage of converter sharing, requiring as few converters as possible. Two different performance improvement cost functions are applied as dual-failure protection performance predictors. One is based on the number of unique p-cycles selected; the other is based on the maximum working capacity protected by any single selected p-cycle. Our numerical results indicate that the latter shows the best performance throughout the simulations. The performance of the methodology and the best prediction function depend on which of the performance metrics is considered to be the most important. The size of the network, the maximum allowable p-cycle length and the number of demands all influence this performance.

We address the problem of routing and wavelength assignment (RWA) considering differentiated reliability (DiR) in WDM mesh networks. The backup resource can be shared by the primary lightpaths. However, both the primary-backup sharing and the different levels of fault tolerance requirement have never been considered together in the literature. In the paper, we consider the dynamic character of the link availability, which is caused by primary-backup sharing. Moreover, the priority of traffic is considered in the paper. The paper focuses on routing under dynamic availability of wavelength resource while the requested reliability of traffic has to be met, using the modified shortest path algorithm. A layered availability model is established based on wavelength layered graph model. Using this model, we propose a new algorithm called dynamic layered availability (DLA) algorithm. We evaluate the performance of the proposed algorithm on the NSFNET.

This paper studies the routing and wavelength assignment (RWA) problem in wavelength-routed all-optical networks with dynamic traffic demand. As well known, the performance of network restoration strongly depends upon the routing and rerouting policies. In this letter, we comprehensively analyzed the restoration performance under two main alternate dynamic routing algorithm, LLR(Least Loaded Routing) and FPLC(Fixed-Paths Least-Congestion routing), and two rerouting policies, based on K-path backup or Dijkstra algorithm. Through modelling and simulation, we compute the restoration efficiencies of four combinations on the NSFNET T1 backbone network, with different traffic load. The numerical simulation result shows that the rerouting policy based on Dijkstra algorithm has improved more 10%-20% performance than the rerouting policy based on K-path backup. The LLR and FPLC routing algorithm achieve the same performance by and large when the same rerouting policy is used.

This paper investigates the problem of protecting multicast sessions in mesh WDM (wavelength-division multiplexing) networks against single link failures, e.g., a fiber cut in optical networks. Firstly, we study the two characters of multicast sessions in mesh WDM networks with sparse light splitters configuration. Traditionally, a multicast tree does not contain any circles. The first character is that the multicast tree has better performances if it contains some circles. What is more, a multicast tree has several branches. If we add a path between the leaves nodes on different branches, the segment between them on multicast tree is protected. Based the two characters, the survivable multicast sessions routing problem is formulated into an Integer Linear Programming (ILP). Then a heuristic algorithm, named adaptive shared segment protection (ASSP) algorithm, is proposed for multicast session. ASSP algorithm does not identify the segment for multicast tree previously. The segments are determined during the process of algorithm according to the multicast tree and the sparse networks resource. Comparisons are made between ASSP and other two reported schemes link disjoint trees (LDT) and shared disjoint paths (SDP) in terms of blocking probability and resource cost on USNET topology. Simulations show that ASSP algorithm has better performances than other existing schemes.

Resilient Packet Ring (RPR) has been standardized in the IEEE 802.17 working group. In multi-ring networks, similarly with other ring-based technology, intra-ring traffic demand is protected against single node and span failures within 50 ms by the "steering" and "wrapping" protection. Inter-ring traffic demand, however, is susceptible to failures at nodes or links where the traffic demand transits from one ring to another. Normally, the survivability of interconnecting node or link failure has to be provided by other technologies, such as MPLS and Spanning Tree Protocol. Unfortunately, most schemes cannot provide a cost-effective solution with guaranteeing the restoration within the 50 ms timeframe. In this paper we proposed a cost-effective and fast Recovery Mechanism for Multi-ring Interconnection Networks Based on RPR. Differential from Spanning Tree Protocol (STP) and other protection technologies, this mechanism has the ability of sub-50ms protection provisioning and scalability based on the bridging function in RPR. Particular with enhanced bridging support, this mechanism can provide efficient bandwidth spatial reuse on multi-ring RPR networks. The proposed novel mechanism has been implemented on our 10Gbps network processor (NP) based multi-service provisioning platform. All experimental results presented in this paper come from actual testing on the network test bed and show that the all the inter-ring traffic are given the sub-50ms recovery guarantee as intra-ring traffic in normal case.

The Resilient Packet Ring (RPR), standardized by the IEEE 802.17 work group, is a new topology technology for bidirectional packet-switched metropolitan backbone networks. The key objective of RPR is to achieve high bandwidth utilization, optimum spatial reuse and fairness simultaneously. Fairness algorithm is one of the core technologies of RPR. One major problem is that the bandwidth allocated by the algorithm oscillates tremendously and permanently under unbalanced traffic scenarios. So the challenge is to design a fairness algorithm in the distributed nature. This paper presented a new dynamic bandwidth allocation algorithm and the analytic results show it is effective in reducing the oscillation in RPR with low computational and time complexity.

The protocol of RPR lacks the definition on the interconnection among multi RPR rings. Compatible with RPR protocol, a scheme which could implement interconnection among multi RPR rings is proposed. The simulation results are given to prove the scheme.

Resilient packet ring (RPR) is a good capacity solution to next generation metropolitan area network (MAN). This paper introduces the back end design of RPR application specific integrated circuit (ASIC) designed independently by Department of Electronic Engineering of Tsinghua University. It draws a back end design flow chart and relates about three key techniques: simultaneous switching output (SSO), design for testability (DFT) and static timing analysis (STA). It makes a brief introduction to each technique. It discusses the ways to avoid SSO problems, to calculate scan chains number, to achieve qualified test pattern fault coverage, and to solve STA violations. In the end, it shows design results and layout figure.

Work on optical network control plane protocols has enabled faster and more efficient provisioning and management of carrier core optical networks, thereby reducing operational costs and capital expenditure. Many potential data applications for such capabilities, however, require Ethernet as the physical interface into the network, rather than SONET/SDH or OTN (Optical Transport Network) interfaces. Support of such services over an optical network becomes a multi-layer networking problem, wherein the client layer is packet based (e.g., Ethernet) and the server layer is optical (SONET/SDH or OTN). This paper discusses the enhancements that have been created in SONET/SDH and OTN networks (e.g., GFP, VCAT, LCAS) for the efficient transport of Ethernet and other data networking protocols, and the related extensions to control plane protocols that are necessary to allow for the support of multi-layer networking. Different control-plane models are being pursued in standards bodies such as ITU-T and IETF, and prototyping is being carried out and tested in the OIF. These various approaches are discussed in detail here, with focus placed on the prototyping work that has been done in the OIF, especially for the OIF 2005 Interoperability Demonstration.

The rapid and aggressive penetration of broadband access services such as fiber to the home (FTTH) has been accelerating the increase in IP traffic volume and new networking technologies are required in order to accommodate future traffic in a cost-effective manner. This paper overviews the advanced IP optical network architecture and technologies for very-large-scale IP backbone networks. These technologies are the key to accommodate the huge volumes of IP traffic expected and control network resources in an effective and dynamic manner. We describe advanced IP optical networking technologies which accommodate multiple service networks using multi-instance technologies, and enable multi-layer traffic engineering using virtual network topology technologies. The migration scenario is described from the existing networks to GMPLS networks; reference is made to the advanced Path Computation Element (PCE) which enables multi-layer traffic engineering and MPLS/GMPLS migration. New network concepts such as Layer 1 Virtual Private Network (L1VPN) and GMPLS interoperability issues, which are being discussed in IETF, are also described.

Due to a continuous stream of technological advances, enormous amounts of traffic are aggregated onto a single fiber. The main drive for this is the cost savings that are realized due to the economy of scale. However, a major drawback is the impact of a single failure (e.g., cable cut), which can become very and even unacceptably large. This paper aims at discussing the different techniques that can be applied to deal with such circumstances.

Optical network will revolute from TDM transmission to any-service provision, from data aware to service aware. A new any-service providing platform (ASPP) is introduced, and the key feature and technology such as PWE3, WDM/ROADM and GMPLS control plane are described.

This paper proposes a novel parallelized architecture for control protocols in high-performance routers (HPRs). Unlike traditional centralized manner, this approach distributes the functionality of control plane protocols within a router and achieves scalability by selectively off-loading certain link-layer and interface operations to data plane processing components. This paper presents the design and implementation of this method on a 320Gbps distributed router. The experiment results show that the proposed scheme can yield better performance and faster response than the centralized approach.

Based on the analysis of the MIL-STD-1773 data bus modulation scheme, two optical modulation schemes are proposed for designing this kind of data bus, namely, partial tri-level Manchester II bi-phase coding (PTMBC) and extended Manchester II bi-phase coding with beginning-stopping flags (EMBC-BSF), which can efficiently solve the problem related to three outputs at a MIL-STD-1773 optical receiver with low complexity. Then we focus on the analysis of error probability and optical receiver sensitivity for MIL-STD-1773 data buses with three modulation schemes of Manchester II bi-phase coding, PTMBC , and EMBC-BSF. The results show that both the PTMBC and EMBC-BSF modulation schemes have almost the identical and worse receiver sensitivity than that of the Manchester bi-level coding by ~3dB.

This paper presents an extensible routing software platform called EROS (Extensible Routing Operation System), which is a modularized and layered system. EROS innovatively utilizes Data Forwarding Adaptation Layer to hide concrete hardware forwarding details and thus can be used in different network processor unit (NPU) based systems. This paper describes the architecture design of EROS and introduces some of the implementing issues. The experiments on two different NPU-based distributed routers illustrate that EROS is logically independent from specific hardware platforms and could deliver excellent forwarding performance without any isolation on the protocol conformability.

Specification and description language (SDL) is an object-oriented formal language defined as a standard by ITU-T. Though SDL is mainly used in describing communication protocols, it is an efficient way to simulate the network performance with SDL tools according to our experience. This paper presents our methodology of SDL-based network performance simulation in such aspects as the simulation platform, the simulation modes and the integrated simulation environment. Note that Telelogic Tau 4.3 SDL suite is used here as the simulation environment though our methodology isn't limited to the software. Finally the SDL-based open shortest path first (OSPF) performance simulation in the wireless private network is illustrated as an example of our methodology, which indicates that SDL is indeed an efficient language in the area of the network performance simulation.

The use of radio over fiber to provide radio access has a number of advantages including the ability to deploy small, low-cost remote antenna units and ease of upgrade. And due to the great potential for increasing the capacity and quality of service, the combination of Orthogonal Frequency Division Multiplexing (OFDM) modulation and the sub-carrier multiplexed optical transmission is one of the best solutions for the future millimeter-wave mobile communication. And this makes the optimum utility of valuable radio resources essential. This paper devises a cross-layer adaptive algorithm for optical-wireless OFDM system, which takes into consideration not only transmission power limitation in the physical layer, but also traffic scheduling and user fairness at the data-link layer. According to proportional fairness principle and water-pouring theorem, we put forward the complete description of this cross-layer adaptive downlink transmission 6-step algorithm. Simulation results show that the proposed cross-layer algorithm outperforms the mere physical layer adaptive algorithm markedly. The novel scheme is able to improve performance of the packet success rate per time chip and average packet delay, support added active users.

For reaching the destination that user can operate simply to complete complicated work with high quality in time, elements for pervasive computing should be integrated into an active system. Embedded, nomandic, adaptive and broadband intelligent services will be necessary in the system. The novel Intelligent Pervasive Computing Technologies (IPCT) make those services including high speed services and low speed services etc be provided well. The crucial component parts are the Backbone Mobile Managing technologies (BMM), the Access Mobile Managing technologies (AMM), The Supplementary Independent Mobile Managing Technologies (SIMMT) and so forth. Wireless optical networks are necessities of implementing IPCT. Another key of running IPCT is to optimize the configuration, especially the logic. The pivot of operating is Wireless Optical Agent (WOA) and corresponding contributories. Experiments with simulation indicate IPCT bring high performances for pervasive computing.

Turbo codes are used to guarantee the performance in the power-limited radio-optical communication system, but the traditional parallel structure is difficult to overcome the 'error floor'. In this paper, a hybrid structure is studied, it is the combination of the parallel structure and the serial structure. Turbo codes with the hybrid structure can improve the system performance validly, but the complication is the cost. Through the theoretic analyses and computer simulation, the hybrid structure is proved to be valid.

Access control is an important method to improve network security and prevent protected resources from being used by some nodes without authority. Moreover, mobility is an important trend of internet. In this paper, based on the architecture of hierarchical mobile IPv6, we proposed an effective access control approach to support mobility in IPv6 networks, which can ensure the operation of access control when a mobile node roams in these domains with different polices, with decreased delay of access negotiation and cost of delivering messages.

With different vendor equipments being deployed in the core and metro networks, automated end-to-end service provisioning across multi-vendor optical networks poses new challenges from an architectural and protocol standpoint. Traditionally, telecommunications networks have been managed in a proprietary fashion using centralized Network/Element Management Systems (NMS/EMS). The Telecommunications Management Forum (TMF) is standardizing NMS/EMS interaction with the aim of achieving multi-vendor equipment interoperability. This standardized management plane based end-to-end architecture appears to be the quickest path to short-term core and metro network interoperability (compared to a longer-term distributed control plane provisioning approach of GMPLS being developed at IETF). We consider the problem of routing end-to-end metro sub-rate circuits (STS-1/3/12) across the wavelength switched (STS-48/192) core under various NMS/EMS interaction and information exchange models. We propose an algorithm framework for efficient packing of sub-STS-48 paths onto STS-48/192 paths in the core network so as to improve capacity utilization and reduce blocking. At any given time, there will be a number of provisioned STS-48/192 paths in the core network that are partially used up and have available capacity. We call such paths "fragmented paths". The objective of efficient packing is to minimize the number of fragmented paths in the core network at any given time, while trying to minimize end-to-end path costs also. To achieve this, the portion of a sub-STS-48 circuit through the core network may be multiplexed within one or more provisioned STS-48/192 paths. The way these circuits are multiplexed depends on the grooming capability of the core and metro networks.

VPLS is the key technology implemented to provide Layer 2 bridge-like services, connecting dispersed locations to work in a switched LAN over an MPLS backbone. However, implementing VPLS requires creating a complex matrix of services and locations that quickly becomes difficult to configure and maintain. To address this complexity, this paper proposes a new approach to automate the configuration and maintenance of VPLS networks, a node-discovery process in which each router advertises its VPLS-enabled status and capabilities to all other routers. Our approach can be summarized into four steps. (1) Discover other VPLS PE nodes with VPLS capabilities and create the VPLS capable PE routers list. We introduce a finite state machine which includes four states to illustrate the process how a VPLS peer can be discovered and the peer relations be kept alive. (2) Build MPLS LSP tunnels to all the PE routers in the list, according to the advertised VPLS protocol capabilities. (3) Use the lists to create targeted-LDP sessions for VPLS services discovery. (4) VC label assignment. The PE edge routers exchanges messages to define VC labels and bind them with each built PWE. The suggested auto-discovery mechanism is sensitive to any service provider's topology change and customer's service modification. The dynamic process for the FIB building, MAC address learning and withdrawal, is also covered as the result of VPLS auto-discovery. The suggested mechanism can be implemented as a software module and could be seamlessly integrated with currently deployed Metro Ethernet routing and switching platform.

The technology of link capacity adjustment scheme (LCAS) is one of the key technologies of the next generation of MSTP solution in MAN.In this paper, it first summarizes the next generation of MSTP, then introduces the EoS network testlab and expatiates the function designing for the testlab according to the characteristic of LCAS, then particularly describes critical points of the realization. Then, it analyses the plan of the function testing and brings forword some evaluations a of the LCAS technology points based on the testing result. Finally, it gives some conclusion for the LCAS technology.

In this paper, we propose two novel dynamic adaptive routing grooming algorithms for optical WDM mesh networks using the fixed alternate routing (FAR) approach. The algorithms consider both load balance and resources utilization in the network and use FAR mechanism to reduce computation complexity and transmission delay. The simulation results show that the network performance can be improved significantly by these algorithms.

A Quality of Service (QoS) multicast routing algorithm in IP/DWDM optical Internet is proposed in this paper, taking QoS requirement and cost into account. Due to the NP-hard nature of this problem, a QoS and cost optimized or sub-optimized multicast routing tree is constructed based on tabu-hierarchy genetic algorithm with network load balance supported. Simulation results have shown that the proposed algorithm is both feasible and effective, and is advantageous over its counterpart based on the traditional genetic algorithm.

This paper investigates the dynamic multicast traffic grooming problem for optical mesh networks, which are configured with partial wavelength converters and partial light splitters. In the dynamic provisioning context, a typical multicast connection may require bandwidth less than that of a wavelength channel. Unlike the case of unicast, a multicast session has multiple destinations. We note a fact that the session has less blocking probability if it has fewer destinations. Then we develop a grooming scheme for multicast traffic on mesh WDM networks with sparse wavelength converters and light splitters configuration, named Multicast Tree Decompose (MTD) algorithm. The main idea of MTD is to try to decrease the destination number using the working multicast tree. Firstly, a simple layered auxiliary graph (layered-AG) is proposed to address the generalized wavelength continuity (GWC) constraint. What is more, a novel multicast tree algorithm is proposed to build more efficient multicast routing under the constraints of sparse multicast capable OXCs. Then we can decrease the destination number using "to partial destinations from source tree" (TPDST) and "to partial destination tree" (TPDT). From the simulation results, MTD algorithm has better performance compared with existing grooming schemes.

In this paper we present a resource scheduling mechanism for providing dynamic lightpaths to photonic grid network and point out that grid enabled by optical network has huge potential effect on pushing the next optical network applications. Furthermore we investigate photonic grid architecture and control plane based on peer-to-peer is also provided to control optical network communication resources dynamically. We also certificate the idea of extending BGP towards optical network, which is called Optical Border Gateway Protocol used to provide IP-based protocols to control optical network, and gives a dynamic lightpath scheduling approach over multi-wavelength optical network as a new grid service based on OBGP.

Optical Burst-switched (OBS) is a promising switching technology and expected to support the future Internet backbone with dramatically increasing bandwidth demand. In an OBS network, burst contention causes burst loss due to bufferless nature of OBS core network. This kind of burst loss will interact with the above TCP layer. In this paper, we study the impact of this interaction on TCP fairness. We find significant unfairness among TCP flows that share the OBS core network, i.e. one flow obtains higher throughput while any others with much lower throughputs. The cause is the phenomenon called "the bigger eats the smaller (BES)", in which a TCP flow with higher rate occasionally will "see" less burst contentions and increase its rate further, while a TCP with lower rate will see more burst contentions and decrease its rate continually. Discuss a simple model to explain BES and verify that a continuous sequence of bursts will enhance BES. Then observe that offset time will be a good choice to control TCP fairness by a curve of unfairness control with offset time adjustment. Finally an adaptive offset time scheduling (AOS) algorithm is proposed. AOS assigns burst offset time value adaptive to the rate of TCP flow. The simulation results show that the fairness can be significantly improved by our AOS scheme.

Optical burst switching (OBS) network has been proposed as a novel network scheme which can realize IP over WDM and also been regarded as the trend of the next optical generation network. In OBS network, burst contention phenomena may often occur at the output data channel in core routers and the contention can bring on the data losing. Optical composite burst switching (OCBS) has been regarded as an efficient approach for the resolution scheme in burst contention, which segments and drops the header of contending burst, but OCBS may bring unfairness to burst dropping, this unfairness causes the OBS network can't well support quality of service (QoS). The previous works that focus on the resolution approaches for the unfairness have some limitations and also could bring unfairness to OBS network. An improved resolution approach has been proposed to solve the unfairness of burst segmentation and dropping in optical burst switching multi-hop network in this paper, this approach not only could maintain the advantage of conventional resolution approach, which could make the packets loss probability coherence in multi-hop network but also could decreases the data losing and increase the throughput for OBS network. At last, some simulations prove the validity of the proposed approach and it has the theoretic meaning to design the real OBS network in practice.

Generally speaking, the iSCSI initiator function can be fulfilled in about 3 different ways, they are software iSCSI for various OSs (operating systems), software iSCSI with TCP/IP offload engine (TOE) and hardware iSCSI with TCP/IP offloading, and the third one can be regarded as an iSCSI HBA (Host Bus Adapter). Based upon Intelligent I/O (I2O) Architecture Specification and Intel^(R) IQ80321 I/O processor evaluation board (PEB), a prototype of an iSCSI HBA implementation is presented in this paper. An OSM (OS Service Module) design introduction under Linux OS is put forward, and an embedded Linux DDM (Device Driver Module) development is also explained. By comparing with both the Intel^(R) PRO 1000T IP storage NIC and Microsoft iSCSI Initiator version 1.06, some testing analysis of this iSCSI HBA in the 100/1000Gbps Ethernet network circumstance are given in the end.

Fiber to the home (FTTH) is the technology orientation that people have continuously pursued and explored for 20 years, and it is beginning to make significant strides in the field of high-speed broadband access to the Internet. Due to the carriers' competition, the price of optical devices reduced gradually, FTTH develops very quickly. With the emergence of next generation network (NGN), softswitch plays an important role in the evolvement from PSTN to NGN. The combination of FTTH and softswitch can solve many problems in FTTH applications, which guarantees the evolvement from the existing network to NGN and provides service functions to meet the further requirements of various carriers and customers. This paper mainly introduces the application of softswitch in FTTH, outlines the developing background of FTTH and softswitch, and discusses the voice bearing solution based on FTTH. At last it focuses on the key problems and solutions of the application with the example of the implementation of voice service.

As Fibre Channel (FC) becomes the protocol of choice within corporate data centers, enterprises are increasingly deploying SANs in their data central. In order to mitigate the risk of losing data and improve the availability of data, more and more enterprises are increasingly adopting storage extension technologies to replicate their business critical data to a secondary site. Transmitting this information over distance requires a carrier grade environment with zero data loss, scalable throughput, low jitter, high security and ability to travel long distance. To address this business requirements, there are three basic architectures for storage extension, they are Storage over Internet Protocol, Storage over Synchronous Optical Network/Synchronous Digital Hierarchy (SONET/SDH) and Storage over Dense Wavelength Division Multiplexing (DWDM). Each approach varies in functionality, complexity, cost, scalability, security, availability , predictable behavior (bandwidth, jitter, latency) and multiple carrier limitations. Compared with these connectiviy technologies,Coarse Wavelength Division Multiplexing (CWDM) is a Simplified, Low Cost and High Performance connectivity solutions for enterprises to deploy their storage extension. In this paper, we design a storage extension connectivity over CWDM and test it's electrical characteristic and random read and write performance of disk array through the CWDM connectivity, testing result show us that the performance of the connectivity over CWDM is acceptable. Furthermore, we propose three kinds of network architecture of SAN extension based on CWDM interface. Finally the credit-Based flow control mechanism of FC, and the relationship between credits and extension distance is analyzed.

As organizations increasingly face an enormous influx of data that must be stored, protected, backed up and replicated. One of the best ways to achieve the goal is to interconnect geographically dispersed SANs through reliable and high-speed links. In this storage extension application, flow control deals with the problem where a device receives the frames faster than it can process them, when this happens, the result is that the device is forced to drop some of the frames. The FC flow control protocol is a credit-based mechanism and usually used for SAN extension over WDM and over SONET/SDH. With FC flow control, when a source storage device intends to send data to a target storage device, the initiating storage device must receive credits from target device. For every credit the initiating device obtains, it is permitted to transmit a FC frame, so congestion is always avoided in the network. This paper analysis the mechanisms of FC flow control and it's limitation in SAN extension when the extension distance increases. Computing result indicates that the maximum link efficiency and throughput in SAN extension have relation to credits, frame size and extension distance. In order to achieve the maximum link efficiency and throughput, an extended FC flow control mechanisms are proposed.

This paper points out the HFC network's current situation that the HFC network is lack of unification management. And this paper also puts forward a method that puts second development on the HP Openview, which is a wildly used network management software, to make it have the ability to manage the HFC device. The current situation in the HFC network can be solved through this method. Meanwhile the realization of the method is described.

Our researches are based on such a system architecture that is intended to utilize the good characteristic of the interaction between millimeter-wave and lightwave to implement the 60GHz short millimeter-wave broadband wireless access system over fiber links. The networks include fiber optic links between the center stations (CS) and the base stations (BSs) and millimeter-wave air channel between the BSs and the networks terminals. The polymer optical fiber (POF) is deployed as optical fiber link medium due to its marked competitiveness in short haul, large capability communication systems. In this paper, we focus on suppressing dispersion of the radio-over-fiber transmission system. The POF is a dominant fiber chromatic dispersion source, which behaves multi-mode properties and produces inter-mode dispersion to heavily cause the POF bandwidth degradation. We present analysis on modal dispersion characteristics of 60 GHz short millimeter-wave broadband wireless access system over polymer optical fiber (POF) transmission link and present our scheme, which chooses proper launch condition to control the number of low-order modes and high-order modes excited in the POF link to improve system dispersion characteristic.

This paper uniforms the communication between devices by the already existing objects and services in BACnet protocol and two new proprietary objects to realize the interoperability of home control subsystem. As the major challenge in developing home network is supporting automated maintenance to control device, a new architecture is designed to integrate the middleware into the subsystem based on these objects and services.

FTTH supports present and future all services and becomes the finally solution of connecting the first kilometer wide band by its giant bandwidth ability. Through analyzing each kind of FTTH network plan, this article proposes four constitute ways of the FTTH: two waves single stages P-P, two waves two stages P-P, two waves PON and three waves PON. Then, we analyze transmission protocol of FTTH system. Finally we introduced FTTH overall request for FTTH system.

A share-controlled PFQ algorithm is proposed for IntServ EPON. It divides packet scheduling into high-priority phase and low-priority phase. In the high-priority phase, an improved PFQ algorithm is presented, which introduces a new constraint and a control factor into the scheduling discipline to overcome bandwidth preemption and to freely distribute excess bandwidth. Computer simulation results show that both the reserved services and non-reserved service can obtain excellent QoS performance when scheduled with the proposed algorithm.

In this paper, we propose an approach of user traffic segregation, which uses a dedicated logical link identified by LLID to deliver specific service. Illustration and testing are given to show that providing multiple logical links per ONU is more flexible and scalable, comparing with single logical link per ONU cooperating with IEEE 802.Q/p VLAN.

Ethernet Passive Optical Network (EPON) must be equipped with Operations, Administration and Maintenance(OAM) features. Functions of 802.3ah OAM protocol in EPON system are Link performance monitoring, Fault detection and Fault signaling, Loopback testing. The related five types of OAMPDUs are Variable Request/Response, Information, Event Notification, Loopback Control and Organization Specific. Both OAM functions and OAMPDUs described in detail. The main functions provided by OAM are partitioned into three components: multiplexer, parser and client and control. As a part of our EPON system, the OAM sublayer components has been implemented using FPGA which can manage high speed Non-OAMPDUs and slow protocol at the same time. The OAM sublayer module and implemented its function are designed by using Xilinx PPGA. Not only the hardware block diagram but also the actually circuit are accompanied in detail. The result indicates that the data is the same as the protocol description.

An AC-Coupled burst mode optical receiver originally designed for OBS is demonstrated competent for EPON in this paper. The power penalty induced by AC coupling is compensated by broadened receiver's bandwidth, and it is robust against the low frequencies losses of 8B/10B coded data.

There are two primary methods of transmitting signal of digital television to the home in China. The first one is HFC mode, which is widely used. The other is IPTV mode, which is emerging. In this paper, the scheme of digital television over Ethernet PON is proposed. There are several differences from this system to IPTV and Video over LAN: the real-time transmission of equal-bandwidth based on statistical multiplexing, channel switching based on multicast and IP CA system, etc.. And these are also the key techniques used in this system. The architecture of DTV over EPON system, the function of every component, the framing process and the multiplexing of Ethernet frame are described. The implementation procedure of the system is shown. The mechanism of channel switching using multicast technique is designed and realized. We also present the method of using static VLAN and IGMP snooping mechanism to implement statistical multiplexing on Ethernet layer, and put forward the concept of IP Conditional Access System and define it. An experimental system of DTV over EPON is set up and the experimental result is significant.

With the increasing demands of new broad-band services, the construction of optical acess networks becomes one of key issues. Passive optical network (PON) technologies realize effective and economical optical access networks for these purposes. A novel protection switching scheme for PONs with ring plus tree topology is presented in this paper, which matches the fiber construction layout of access network and ensures high network surviability at low cost. The operating principles as well as protection swicthing methods that under certain circumstances are discussed in details. Reliable and economical optical access networks, PONs, can be applied for broad-band applications with this protection switching scheme.

Link Capacity Adjustment Scheme (LCAS) is a protocol to provide hitless bandwidth adjustment of virtual concatenated (VCAT) signal under the control of network management system (NMS). It has much larger flexibility to dynamically assign resources and becomes an important feature for multi-service transport platform (MSTP) systems. However, the scheme is a two-way handshake signalling with status messages exchanged continuously, which can hardly be implemented within a single chip. Aiming at an easier implementation in ASIC, we revise the LCAS protocol to have a shorter handshaking procedure by adding MST bits in the reserved K4 bits and remove the complex mappings between TU12s and theirs SQs. Simulation results show that the revised LCAS shortens the period of handshaking procedure and synthesis results show that the size of logic is greatly reduced. We believe the new scheme will be accepted and applied in future.

As storage environments and storage area networks (SANs) grow, enterprises increasingly have the need to extend data transfers beyond the confines of the enterprise over longer distances such as metropolitan area networks (MANs) and wide area networks (WANs) for disaster-recovery and business-continuity applications. By using virtual concatenation (VCAT), link capacity adjustment scheme (LCAS) and generic frame procedure(GFP), Next generation SONET/SDH can move SCSI commands and block-level data over long distances in an efficient and cost-effective manner. This paper analyses the limitation of traditional SONET/SDH for storage services and the new characteristics of Next generation SONET/SDH. The design approach and steps of GFP interface based SOPC are proposed, furthermore the architecture of SAN extension based on Next generation SONET/SDH is presented.

Resilient Packet Ring (RPR) specified by IEEE 802.17 is a new standard for Metropolitan Area Networks (MANs). One of RPR's characteristics is that it can support three priorities traffic in a single datapath, i.e., class A, class B and class C, ranging from high priority to low priority, respectively. Different entities such as shaping, scheduling, fairness, topology and protection coordinate to guarantee the Quality of Service (QoS) for different services. Various pieces of the datapath in RPR are tied together through logical queues, thus we investigate the datapath from the view of logical queues in this paper. With a detailed analysis of the MAC shaping mechanism in RPR, we propose some improvement to achieve better transport performance for RPR's three priorities traffic. Simulation results show that our improvement is efficient.

Many network architectures have been designed for the future high capacity transmission. Hybrid Opto-electronic Ring NETwork (HORNET), a kind of IP/WDM metro network, is one of them. The inherent defects in WDM network, like unfairness and low efficient, are conquered by using Distributed Queue Bidirectional Ring (DQBR). But that way with a high complexity is difficult to be realized both in hardware and software. In this paper, a modified Round Robin scheme, called Simple Round Robin (SRR) with configuration is proposed and simulated in HORNET. Round Robin is a comprehensively researched method to solve the unfairness, and with low complexity, but much low efficient. SRR aims to realize the fairness control, and achieve a high throughput with accurately designing and initializing as well. It seems satisfactory that SRR with config does well both in fairness and efficiency.

Resilient Packet Ring (RPR), defined by the IEEE 802.17 working group, is a new solution to metropolitan area network. RPR adopts the packet-based dual ring structure so that it can provide the protection capability similar to the SDH as well as dynamic bandwidth allocation. The design of fairness control mechanism to allocate the bandwidth is a key problem for RPR. Currently, two different modes of fairness algorithm have been proposed in the RPR standard, the aggressive mode (AM) and the conservative mode (CM). However, there are several limitations for these modes, such as the amount of the bandwidth allocated oscillates permanently under unbalanced traffic scenarios. In this paper, we propose a novel fairness control mode. The simulation experiment shows the range of traffic oscillation controlled by our mode is significantly damped compared to current RPR algorithm.

Specified as a new ITU-T standard, Multiple Services Ring (MSR) proposes the mechanism of multi-service provision over Resilient Packet Ring (RPR). MSR over RPR is a packet based network which is flexible and efficient for burst data transport, but it is vital to MSR providing a good Quality of Service (QoS) for real-time services. ITU-T defined MSR Service Data Unit (SDU) lengths in X.87 for real-time services, such SDU lengths play an important role in QoS provision. Moreover, the impact of the MSR-SDU length on MSR's performance for real-time services has not been addressed. The characteristics of MSR are first reviewed, and two core concepts in MSR, Tributary and Tributary Cross Connection Relationship (TCCR) are introduced. Accordingly, the MSR protocol model and generic frame format are presented, followed by briefly comparing the similarities and dissimilarities between MSR and ATM. A simulation model is set up for performance evaluation, in which ten nodes are connected to form a ring with STM-64 links and a distance of three kilometers between adjacent nodes. The frame loss ratio, delay, and jitter characteristics are investigated by increasing the load of TDM circuit emulation (TCE) services or changing the MSR-SDU length while keeping the loads of Ethernet B and C tributaries unchanged. Some conclusions are drawn from the simulations made.

The benefits of using multi-granularity switching to reduce the number of ports, including both electronic and optical ports, have been investigated. A multi-layer ring architecture with multiple switches is suggested and two equations to count the number of ports are derived. Comparisons are made among multi-layer multi-granularity switching (MM-XC), multi-switching (M-XC), and single switching (S-XC).

The private network serves as an information exchange platform to support the integrated services via microwave channels and accordingly selects the open shortest path first (OSPF) as the IP routing protocol. But the existing OSPF can't fit the private network very well for its special characteristics. This paper presents our modifications to the standard protocol in such aspects as the single-area scheme, link state advertisement (LSA) types and formats, OSPF packet formats, important state machines, setting of protocol parameters and link flap damping. Finally simulations are performed in various scenarios and the results indicate that our modifications can enhance the OSPF performance in the private network effectively.

Multicast services have been increasingly used by many multimedia applications. As one of the key techniques to support multimedia applications, the rational and effective multicast routing algorithms are very important to networks performance. When switch nodes in networks have different multicast capability, multicast routing problem is modeled as the degree-constrained Steiner problem. We presented a genetic algorithm, named DCGA, for the degree-constrained case in multimedia communications. The algorithm is used to generate degree-constrained multicast trees with bandwidth and end to end delay bound. Simulations over random networks were carried out to compare the performance of the proposed algorithm. Experimental results show that DCGA has better ability in balance load among the nodes in networks, and has capability of finding unsaturated links and (or) unsaturated nodes to generate multicast trees than BMSTA. Moreover, the proposed algorithm can generate multicast tree with lower cost in any networks and can also achieve optimal multicast tree rapidly with the smaller group size.

Due to easy realization and high bandwidth utilization, SDH/WDM technology becomes the important way to carry IP traffic over the backbone network. On the other hand, the feature of the data traffic which is much different from the voice traffic is dynamic, burst and self-similar, and many proofs show that the self-similar traffic can lead to some adverse effects on the network performance due to the property of long-range dependence (LRD). For this reason it is widely recognized that self-similarity of the traffic is a significant problem as far as network engineering is concerned. So any reduction in the degree of self-similarity will be greatly beneficial. One possible strategy for mitigating the deleterious effects of the self-similarity is to reduce the burstiness of the input traffic through traffic shaping function at the edge nodes. According to this scheme, in this paper, we present a new self-similar traffic shaping mechanism with QoS in transport networks, called double threshold algorithm (DTA). Simulation results show that the proposed mechanism can effectively reduce the degree of input self-similar traffic, and performs better in the terms of network packet-loss rate and blocking probability than the non-traffic shaping schemes. At the same time it guarantees good quality of service.

GRID technology provides a kind of convenient method for managing GRID resources. This service is so-called monitoring, discovering service. This method is proposed by Globus Alliance, in this GRID environment, all kinds of resources, such as computational resources, storage resources and other resources can be organized by MDS specifications. However, this MDS is a theory framework, particularly, in a small world intranet, in the case of limit of resources, the MDS has its own limitation. Based on MDS, an improved light method for managing corporation computational resources and storage resources is proposed in intranet(IMDS). Firstly, in MDS, all kinds of resource description information is stored in LDAP, it is well known although LDAP is a light directory access protocol, in practice, programmers rarely master how to access and store resource information into LDAP store, in such way, it limits MDS to be used. So, in intranet, these resources' description information can be stored in RDBMS, programmers and users can access this information by standard SQL. Secondly, in MDS, how to monitor all kinds of resources in GRID is not transparent for programmers and users. In such way, it limits its application scope, in general, resource monitoring method base on SNMP is widely employed in intranet, therefore, a kind of resource monitoring method based on SNMP is integrated into MDS. Finally, all kinds of resources in the intranet can be described by XML, and all kinds of resources' description information is stored in RDBMS, such as MySql, and retrieved by standard SQL, dynamic information for all kinds of resources can be sent to resource storage by SNMP, A prototype resource description, monitoring is designed and implemented in intranet.

The stream control transmission protocol (SCTP) will play an important role in the next generation of the Internet. Up to now, there are no literatures about differentiated services for SCTP associations. Regarding the throughput as SCTP criteria to support differentiated services, the differentiated services between SCTP associations can be obtained by introducing the weighted factor to a or b for AIMD(a,b)-based SCTP congestion control. Theoretic analysis and simulation results show that the proposed scheme can achieve well proportional differentiated services for SCTP associations with few additional overheads, and it is easy to regulate the fluctuation of data sending rate or SCTP response to networks.

MPLS forwards the labeled packets on the Label Switching Paths (LSPs) which are built between ingress/egress Label Edge Router (LER) peers. As MPLS is the mirror of the IP layer, supporting the reachable capability to n destinations means that the MPLS network needs to build O(n) LSPs (n is determined by the granularities of the labeled packets). As the result, if it needs to set up a full mesh connection between each ingress/egress LER peer, O(n2) LSPs are required. When the size of the MPLS network increases, the cost for maintaining the LSPs will severely increase. It is a serious problem for the scalability of MPLS networks. In order to achieve the scalability of MPLS networks, a network aggregation scheme based on weighted LER dominating set is proposed. The distributed construction method of the LER dominating set is introduced. The aggregation scheme can reduce the amount of the egress nodes when establishing LSPs so as to form an aggregated virtual backbone topology. At the same time, considering the bandwidth between the dominator and its dominatees, a bandwidth-constraint weight is used when constructing the dominating set. As the result, the dominating set has the optimal bandwidth feature and this scheme can apply to the network aggregation with other single constraint.

A multi-wavelength optical label switching test-bed is introduced. The optical label is constructed by a series of optical pulses with different wavelengths that are in the same WDM optical channel. High speed optical switches and DSP chips are used to process the optical label signal. The four-node programmable optical label switching network is demonstrated by transmitting PC capture signal and multimedia video flow with standard Gigabit Ethernet frame. Furthermore, an optical packet assembly and segmentation method is proposed for Gigabit Ethernet Optical Label Switching networks. Two timers are used to realize the exact timing on microsecond magnitude between optical label and programmable optical Ethernet packet. The experimental system executes the real time process and the Gigabit Ethernet data packets with optical label are switching and transmitting successfully. The optical packet programmable method enhances bandwidth utilization and throughput, increases the intelligence, flexibility and multi-service bearing ability of the Optical Label Switching network.

This paper tackles the problem of robust video streaming over error-prone channels. A new MDC scheme-auto-resilient multiple-description coding (ARMDC) with optimized transmission strategy is proposed. ARMDC combines the individual benefits of MDC and LC, making little change to current standard encoders/decoders. More important, it can automatically perform error resilience at receiving end even if feedbacks are not received. Sample intervals of sub-bitstreams and coding of difference between common frames are considered carefully to acquire best ARMDC coding effect and to exactly rebuild corrupt frames without drift. A self-adapt coding and transmission system is then constructed, in which ARMDC is combined with multi-path transmission to efficiently confront the bad channel condition. Both bit-rate (R) and distortion (D) are calculated to minimize the value of Lagrangian formulation when the two technologies are applied respectively. A unitary-optimized operation of the whole system is then proposed after the R-D calculation. Basing on the operation, our system gain fine self-adaptation to the error-prone mobile channel. Experiment results show that the performance of our ARMDC with optimized multi-path selection system has better performance over other self-adapt systems.

To gain more security in application-layer, current firewalls employ deeper inspection into the application layer, which can impact the customer network due to the additional processing burden, especially during traffic peaks or attacks. To figure out the trade-off between the network security and performance, we present a new method in this paper to generate testing traffic for the stateful firewall evaluation which can both be used to explore the boundary performance of the stateful firewall under certain security level, and characterize a specific customer network to evaluate the performance of the stateful firewall before its implementation to this customer network.

A new one-dimensional optical orthogonal codes named extend modified hyperbolic congruence codes(EMHC), is first constructed, and its performance is analyzed. Using EMHC for time spreading and prime codes (PC) for wavelength hopping, a new two-dimensional optical orthogonal codes named EMHC/PC is constructed. Then, the performance of EMHC/PC is analyzed, and is also compared with EQC/PC. It is shown that EMHC/PC has the same code cardinality and code length, but has better cyclic cross-correlation performance. Therefore, EMHC/PC can support more simultaneous users in optical CDMA networks.

Proposed in this paper is a novel burst assembly scheme called longest queue first scheduled assembly (LQF-SA) mechanism, where burst assembly and burst scheduling for optical burst-switching networks are integrated. In the proposed mechanism, ingress edge nodes have multiple assembly queues where IP packets are stored according to their egresses and QoS classes. Among these queues, the longest one is scheduled to assemble bursts by a scheduler at a fixed interval. In real networks, traffic usually distributes non-uniformly and there exists heavier traffic between some source and destination pairs. Simulation results show that LQF-SA could adapt well to the non-uniform traffic profiles. Furthermore, even under uniform traffic, LQF-SA is also super to round-robin scheduled assembly (RR-SA) in terms of burst size distribution, assembly efficiency, and burst loss rate.

Multi-Granularity optical switching technology has only recently attracted attention from the optical networking industry for its practical importance in reducing port count, the associated control complexity, and the cost of optical cross-connects (OXC). In this paper, the advantage of MG-OXC comparing to the ordinary OXC is introduced and the Multi-Granularity Optical Switching test-bed based on ASON (Automatically Switching Optical Network) is presented. This test-bed is composed of three different plants, namely the transport plane, the control plane and the management plane. We have analyzed the architecture of MG-OXC and provided the scheme of multi-granularity optical switching node. In the end some experiments have been done. We firstly have done the experiment in the creation and release of optical path. The optical path could be a wavelength path or a waveband path. And the second experiment has been done to test the capacity of the traffic grooming in the multi-granularity optical networks. The last experiment is performed to test the protection and restoration under the conditions of the node failure, the wavelength failure and the waveband failure, etc. Finally the results are reported and they show that the test-bed can achieve the expected functions under the control of the control plane of ASON.

With the prevalence and development of IP applications based on Internet, traditional Internet Infrastructure can not address the demand of many high bandwidth and data-incentive applications. Grid technology is introduced to meet the demand of such applications, but bandwidth and transmission speed is still a serious problem. With the big growth in optical network technology, the trend becomes evident to integrate the grid technology and that of optical network, which results in the research of next generation infrastructure for optical network: Photonic Grid. This article presents the key techniques and emphases of research in the new infrastructure and mainly talks about the infrastructure, the way of switching and routing, the scheme of control and management and middle ware. In the end, we give some appropriate advice in future research orientation of theory and techniques for Photonic Grid.

Wavelength-Division multiplexing (WDM), which allows a single fibre to carry multiple signals simultaneously, has been widely used to increase link capacity and is a promising technology in backbone transport network. But designing such WDM backbone network is hard for two reasons, one is the uncertainty of future traffic demand, the other is difficulty of planning of the backup resource for failure conditions. As a result, enormous amount of link capacity for the network has to be provided for the network. Recently, a new approach called Valiant Load-Balanced Scheme (VLBS) has been proposed to design the WDM backbone network. The network planned by Valiant Load-Balanced Scheme is insensitive to the traffic and continues to guarantee performance under a user defined number of link or node failures. In this paper, the Valiant Load-Balanced Scheme (VLBS) for backbone network planning has been studied and a new Valiant Load-Balanced Scheme has been proposed. Compared with the early work, the new Valiant Load-Balanced Scheme is much more general and can be used for the computation of the link capacity of both homogeneous and heterogeneous networks. The abbreviation for the general Valiant Load-Balanced Scheme is GVLBS. After a brief description of the VLBS, we will give the detail derivation of the GVLBS. The central concept of the derivation of GVLBS is transforming the heterogeneous network into a homogeneous network, and taking advantage of VLBS to get GVLBS. Such transformation process is described and the derivation and analysis of GVLBS for link capacity under normal and failure conditions is also given. The numerical results show that GVLBS can compute the minimum link capacity required for the heterogeneous backbone network under different conditions (normal or failure).

Recently, TCP performance over Optical Burst-Switched Networks (OBSN) has drawn more and more attention, but most of previous work were based on small linear network under static traffic, which was much different from the real condition. In this paper, a more realistic OBSN model was set up and dynamic TCP performance over it was investigated with the help of a ns2-based OBSN simulation platform. The impacts of OBSN configuration parameters and different TCP implementations on the overall throughput were discussed.

The current edge assembly granularity preserved beforehand in optical burst switched (OBS) networks lacks flexibility to actual network traffic and increases assembly overhead and delay. Offset time generating mechanism after traffic shaping increase network delay and cut down its robustness. Consequently, it is significant to present an effective dynamic burstification scheme to process real-time traffic, reduce assembly delay and provide QoS guarantee for different priority traffic at edge node. This paper focuses on dynamic burst assembly at edge node in optical burst switching networks, which can be implemented to improve the performance of the whole network. Based on traffic prediction, a new dynamic adaptive assembly mechanism on load estimate, termed Dynamic Adaptive Assembly (DAA), is proposed to reduce assembly delay, estimate real-time network traffic character and dynamically adjust Burst Assembly Time (BAT) at edge node. The dynamic range of BAT for four traffic classes is introduced to make compare among current and previous prediction with different prediction time under QoS based offset time. We investigate the influence of current and previous offered load with different prediction time and offset time. Simulation studies are carried out for various traffic classes. The results show that DAA can achieve little delay and provide adaptivity, flexibility and delay fairness for burst assembly.

Estimating the number of simultaneous users on channel, optimum threshold value in multi-wavelength optical CDMA(MW OCDMA) is achieved according to maximum likelihood principle. When MW OCDMA system has large number of simultaneous users on channel, optimum threshold value will vary with the number of simultaneous users, and the receiver will adjust the optimum threshold accordingly. Theoretical analysis and analogy simulation show that BER of MW OCDMA system will degrade greatly when employing the proposed optimum threshold value by maximum likelihood principle.

Optical encoder and decoder devices based on fiber Bragg gratings is designed. An FFH-OCDMA system scheme is performed with the devices. Transmission of the system is demonstrated over 6.5km of G.652 fiber at data rate 622M bit/s and get the desired results.

Multicast applications have attracted more and more attention due to more efficient bandwidth usage and the increasing popularity of the point-multipoint multimedia applications. Optical multicasting outperforms the electronic multicasting in some aspects. Service level agreement (SLA) and quality of service (QoS) are important to service providers and users. Service providers always first maximize revenue to accept as many as connection requests as possible and then to minimize the capacity of all accepted connection. In this paper, the problem of cost-effective optical multicasting connection provisioning to satisfy the connections' availability requirements on a given physical topology is formally stated. We propose a mixed integer linear program (MILP) based approach for static multicast traffic. The feature of our algorithm lies on without considering any protection schemes, and when the system adapts dedicated protection or the sharing protection, the problem is more complicated.

Researches about infrastructure and applications of next generation Internet is one of the most comprehensive research fields in recent years, IP over WDM is envisioned as the best candidate for next generation Internet. Generalized Multi-Protocol Label Switching (GMPLS) was proposed as an excellent control plane technology for the integration of IP and WDM, which can achieve the on-demand provisioning and management of network resources. And optical burst switching (OBS) is considered as a promising switch paradigm for next generation Internet, which can not only provide statistical multiplexing of network bandwidth resources, but also circumvent the bottleneck of electronic switching effectively. Therefore, how to integrate GMPLS into OBS network and use GMPLS to improve performances of OBS networks becomes an important research direction and have received comprehensive concerns from many research institutions and organizations. This article proposes a new kind of OBS network namely GMPLS-based OBS network, describes its general framework and some work mechanisms, and gives node functional modules and the control plane software components. Some issues related to network management also are discussed.

A novel wavelength availability advertisement based ASON routing protocol implementation is proposed in this paper which is derived from Open Shortest Path First protocol (OSPF) version 2. It can be applied to ASON network with a single control domain and can be easily extended to support routing in the multi-domain scenarios. Two new types of link state advertisement (LSA) are suggested for disseminating wavelength availability and network topology information. The OSPF mechanisms are inherited to ensure that the routing messages are delivered more reliably and converged more quickly while with fewer overheads. The topology auto discovery is realized through LSA flooding interacting with auto neighbor discovery using Link Management Protocol. The new LSA formats are given and how the link state database (LSD) is comprised is described. The new data structures proposed include topology resource list, adjacency list and route table. Then we analyze the differences of ASON in link state exchange, routing information flooding procedure, flushing procedure and new resources participating, i.e. new links or nodes join in an existing ASON. The link or node failure and recovery effect and how to deal with them are settled as well. In order to adopt different Routing and Wavelength Assignment (RWA) algorithms, a standard and efficient interface is designed. After extensive simulation we give the numerical analysis and come to the following conclusions: wavelength availability information flooding Convergence Time is about 30 milliseconds and it is not affected by RWA algorithms and the call traffic load; routing Protocol Average Overhead rises linearly with the increase of traffic load; Average Connection Setup Time decreases with the increase of traffic load because of the decrease of Average Routing Distance of the successfully lightpaths; Wavelength availability advertisement can greatly promote the blocking performance of ASON in relatively low traffic load; ASON operator can make a good trade off between the wavelength availability advertisement Protocol Average Overhead and Blocking Probability by adopting and adjusting the routing update triggers; and the last is that wavelength availability advertisement throughout the optical network is applicable and our ASON routing protocol implementation could be applied in ASON when its scale is not too large and if the calls do not arrive and leave the network in a too frequent pace.

Comparing with the un-slotted WDM (Wavelength Division Multiplexing) network, the slotted WDM network can establish more connections among the nodes at the same time. On the other hand, because of the head of slots, more slots in a frame will reduce the efficiency of optical channels. Based on the ring topology, the optimum slot number in slotted WDM networks is studied in this paper. For symmetrical traffic, the formulation of the slot number that supports the establishment of an all connection among the nodes in the network is brought out through mathematics. The result shows that a few wavelengths can support an all connection among the nodes. The number of wavelengths needed to set up connections for un-symmetrical traffic is discussed also.

An extended layered graph of MPLS over WDM mesh networks is proposed in this paper, in which the label switch path (LSP) with various wavelengths and the limitation of optical transceivers at a routing node are both involved. Label switch paths are classified into different priorities according to each quality of service. The corresponding routing algorithm, differentiating integrated routing algorithm (DIRA), is proposed and studied. The quality of service (QoS) of a label switch path and the optimization of network resources utilization are taken into account comprehensively in DIRA. A comparison of DIRA with the representative optical routing algorithms via simulation shows that it can reduce the blocking probability of delay-constraint LSP and improve the network throughput.

For reasons of scalability and security, the hierarchical routing architecture with topology aggregation is introduced to Automatically Switched Optical Network (ASON). By aggregating the topology and routing information, operators can shield the internal details of their optical networks and configure their networks arbitrarily. This work addresses the problem of topology aggregation in hierarchical ASON network. A novel aggregation scheme based on minimum spanning ring (MSR) is suggested. We compare the proposed scheme, by simulation, with several different schemes studied before in terms of the network throughput, traffic distribution and network stability. The simulation results show that the aggregation scheme based on MSR can yield very good overall network performance. The outstanding performance together with simplicity of calculating for a minimum spanning ring makes it a very attractive candidate for use in practice.

With the drastic increasing of data traffic, the optical transport network will be adjusted to be services-oriented networks. Its traffic engineering system should be able to dynamically react to traffic changes while at the same time fulfilling QoS requirements for different classes of service. So the next generation optical network will handle priority, preemption mechanisms, and traffic rerouting in order to concurrently accommodate the largest amount of traffic. At the same time, transport networks need to evolve so as to drastically reduce both deployment costs and operating expenses. One of a reasonable strategy to achieve the goals is to simplify the network architecture by reducing the number of layers. GMPLS protocols enable the coordination between the IP and the optical layers and provide classified services. The collaboration of both layers in the routing process leads to optimization of network performance. Simulation results show the results of different strategy for resource allocation.

A novel scheme of signaling protocol based on mobile agent and OBS which runs over a core DWDM network is promoted. Design of optical wavelength channels in the scheme is to choose 1310nm band to be control optical wavelength channel to transmit BHPs and 1550nm band to be burst packets optical wavelength channels to transmit BPs. Referring to RSVP-TE in DCM ASON, significations and formats of signaling messages in the protocol are defined. The key design of scheme is to utilize the structure of active packets in the application of mobile agent MANet to encapsulate signaling messages and traffic together into one BHP to shorten the set-up time of an optical path. Such structure is also used to process distributed disposals to alleviate the workload of one node in the network to promote cooperating calculation ability of each node in the network. The communication between a source node and a destination node through one or multiple intermediate nodes is presented as an example to describe the processing procedures of the protocol. The scheme is implemented in a wavelength router, which is briefly introduced.

Multi-granularity switching in optical layer has gain significant importance due to the reduction of size and cost of the optical cross-connect. In this paper, we propose a novel structure of MG-OXC, named two-layer MG-OXC, and also give a new graph model for describing the function of the all kinds of MG-OXC. The network states can be represented completely through our auxiliary graph. In such an auxiliary graph, the optical tunnel allocation in multi-granularity switching network is reduced to the min-cost path find problem, and different traffic grooming policies can be archived simultaneously. We compare the performance of the two-layer MG-OXC to the normal three-layer MG-OXC and single-layer MG-OXC by the algorithm we proposed through simulation, and conclude that the novel MG-OXC can get very close performance to threelayer MG-OXC but smaller size of switching matrix. The simulation also proved the algorithms we proposed performs better than traditional RWA algorithms dealing the routing and wavelength sub problems separately.

In this paper, we proposed a novel architecture of MG-OXC (Multi-Granularity Optical Cross Connect) that can support both the static and dynamic optical switching. It can obviously reduce the complexity of the switching matrix and the number of the switching ports without increasing the network blocking probability. We gave the ILP model to describe the multi-granularity switching optical network. This model is applicable not only to the novel MG-OXC, but also to the traditional MG-OXC network. We also proposed a novel routing and wavelength assignment algorithm for dealing with multi-granularity traffic in optical network that was set up by this kind of novel MG-OXC. It is shown that when the network load is low, the network blocking probability of the novel MG-OXC will be quite lower than the ordinary multi-layer and single-layer MG-OXC with the strategy of the shortest wavelength path and random choice of the wavelength. While when the network load is comparatively higher, the network blocking probabilities of these structures are more or less the same.

A network test bed with 100 network simulative nodes is set up. Convergence time experiments and signalling network flow experiments of Automatically Switched Optical Networks using Hierarchical Routing Protocol have been performed on it, and an experiment analysis is given.

In the physical topology design, the number of OXCs and/or links is takes as the objective. In this paper, we take aim at minimizing the maximal optical port number of each OXC, given the number of OXCs and the traffic. We present a traffic-oriented heuristic algorithm to generate an initial topology. This presented algorithm outperforms the previous algorithm, since our presented algorithm takes into account the traffic pattern. Furthermore, we present a routing strategy that is a balance between the shortest-path routing and the least-congestion routing. The tabu algorithm is adopted to attain the optimal solution. We choose the path-based sharing protection scheme to provide 100% recovery guarantee. Numerical results demonstrate the effectiveness of our algorithm and strategy.

The survivable design is a key issue in reliable WDM optical networks to assure the service guarantee to customers. In this paper we propose a novel heuristic dynamic Sub-Path Protection with Hop Constraint routing algorithm (SPP-HC) to provide a more flexible way to compute the sub-paths and the backup paths. Compared with the conventional equal-length sub-path protection metrics, SPP-HC can further improve the resource utilization ratio and reduce the blocking probability. We evaluate the effectiveness of the SPP-HC and the results are found to be promising.