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Nowadays, EPON technology is regarded as one of the best candidate technology for next generation broadband access technology. In this paper, the architecture of EPON is introduced first. The upstream in EPON adopts TDMA/TDM technology, and it is necessary to know the exact RTT(Round Trip Time), the principle of RTT measurement (ranging) and RTT compensation are introduced. We use Xilinx FPGA Spartan II chip series to realize ranging function module, the main idea of implementation is given in this paper, and this can be used for further study of hardware implementation.

The wide use of network improves security risks, but the traditional network security tools are single-functional and they are difficult to extend and manage. These security tools can’t fulfill the need of users. The paper presents a network security oriented language: NSL (Network Security Language). The language provides a common abstract layer of all kinds of security application. It can be used to construct multifunctional, distributed and extendable security applications, satisfying various and emergent security requirements. The paper describes its network oriented structures, features and three security mechanisms. The NSL interpreter implementation is also analyzed by the performance test. At last, the paper puts forward improving work which will be done in the future.

The significance of Generalized Multi-protocol Label Switching (GMPLS) has been proven by its significant adoption in ASON. In recent years GMPLS has become the most global solution to provide intelligent optical resource configuration through not only devices that perform packet switching, but also devices that perform switching in the time, wavelength, and space domain. This new technology can be used to support services for applications that requiring high QoS performances in any network which using the Internet Protocol (IP), including the Passive Optical Network (PON). In this paper, we will propose a new PON technology that uses GMPLS as layer2 protocol. The focus of this paper is mainly on the issues and key characters that will encounter in the combination of GMPLS technology and PON technology. Compared to other PON technologies, such as APON and EPON, GMPLS-based PON (GMPLS PON) can provide more powerful and efficient service in access network, and it can also provide better QoS support to the video and audio applications. The most significant is GMPLS PON can also provide common control and data and administrative planes between the backbone network and the access network, so it will be more convenient and efficient to operate and manage.

This paper presents a novel Policy-based Flow Switching (PFS) method used in packet networks. Unlike traditional per-packet forwarding method, PFS only performs extensive processing on the first packet of a flow, associates this flow with a policy and applies the result of this processing on subsequent packets in the flow. Thus, PFS has the capability of flexible services offering and can significantly improve data forwarding rate, without introducing any complex signals. In this paper, we present the architecture overview of PFS and introduce some of the implementation issues. Besides, this paper also demonstrates how PFS is implemented on a 128Gbps NPU-based high-end router.

In this paper we propose a new concept of future service-aware transport networks that are built on converged wireless-wired transport networks, enable service layer convergence, and also support application layer convergence. This concept is derived from the emerging trend of business convergence among the telecommunication, cable, and entertainment segments, and technology convergence among the telecommunications, computer, and software industries. We also identify QoS as a technical backbone to future service-aware transport networks, and from the perspective of an integrated carrier having both wireless and wired assets, discuss related research opportunities and challenges, especially those involved in optical networks. We finally present an adaptive apparatus for high availability, capacity efficiency, and QoS-guaranteed protection and restoration for optical networks. This paper is intended to promote academic and industrial attention to some core technical challenges that lie ahead for the telecommunication industry and to spur strategically important research and perhaps also some standards activities.

Virtual Private LAN Service (VPLS) is generating considerable interest with enterprises and service providers as it offers multipoint transparent LAN service (TLS) over MPLS networks. This paper describes an effective technology -- VPLS, which links virtual switch instances (VSLs) through MPLS to form an emulated Ethernet switch and build Scalable Transparent Lan Services. It first focuses on the architecture of VPLS with Ethernet bridging technique at the edge and MPLS at the core, then it tries to elucidate the data forwarding mechanism within VPLS domain, including learning and aging MAC addresses on a per LSP basis, flooding of unknown frames and replication for unknown, multicast, and broadcast frames. The loop-avoidance mechanism, known as split horizon forwarding, is also analyzed. Another important aspect of VPLS service is its basic operation, including autodiscovery and signaling, is discussed. From the perspective of efficiency and scalability the paper compares two important signaling mechanism, BGP and LDP, which are used to set up a PW between the PEs and bind the PWs to a particular VSI. With the extension of VPLS and the increase of full mesh of PWs between PE devices ( n*(n-1)/2 PWs in all, a n 2 complete problem), VPLS instance could have a large number of remote PE associations, resulting in an inefficient use of network bandwidth and system resources as the ingress PE has to replicate each frame and append MPLS labels for each remote PE. So the latter part of this paper focuses on the scalability issue: the Hierarchical VPLS. Within the architecture of HVPLS, this paper addresses two ways to cope with a possibly large number of MAC addresses, which make VPLS operate more efficiently.

In this paper, The Next Generation Optical Network Service Platform(NGOSP) based on the architecture of ASON was studied. The paper presented the layered concept of service function around the telecommunication service requirement base on the analysis for the evolution trend of service optical network and modes of service provision, and definitized the reference model and constructed the function framework of service optical network. The general function components also were abstracted from service perspective and a thought of mapping function of service layer to network technical layers was presented.

Optical packet switching techniques have been studied for many years and many feasibility experiments have demonstrated the viability of this technology at different areas of the network. In this paper an analysis of the optical technology potential in different network areas: metro access, metro core and backbone, is carried out. But the slow emergence of an integrated and available optical fast technology and a lack of standards is a brake for its introduction on the market place. In a society more and more user-centric approach, it becomes then urgent to raise the bottlenecks of a full electronic technologies and to propose hybrid architectures combining optics and electronics to reach all the specifications of the next generation of networks. So in this paper, after a status on optical packet switching techniques, after raising the needs in the metro and backbone areas, concrete solutions will be proposed, and more important some key catalysts for a rapid introduction will be addressed. Finally the paper will give the important steps to cross to really take this technological corner.

This paper provides an overview of recent efforts on the ASON standards for optical network control, including current status of ITU-T specifications and future work. A primary focus of the paper is also recent ASON-related testing in the industry, especially the OIF World Interop Demonstration held at SUPERCOMM 2004, where ASON signaling and routing architecture and protocols were tested across multiple vendors and carrier testing laboratories. Results were highly successful, indicating work on ASON, while not yet complete, is stable and implementable.

A new type of CATV network management system developed by universal MCU, which supports SNMP, is proposed in this paper. From the point of view in both hardware and software, the function and method of every modules inside the system, which include communications in the physical layer, protocol process, data process, and etc, are analyzed. In our design, the management system takes IP MAN as data transmission channel and every controlled object in the management structure has a SNMP agent. In the SNMP agent developed, there are four function modules, including physical layer communication module, protocol process module, internal data process module and MIB management module. In the paper, the structure and function of every module are designed and demonstrated while the related hardware circuit, software flow as well as the experimental results are tested. Furthermore, by introducing RTOS into the software programming, the universal MCU procedure can conducts such multi-thread management as fast Ethernet controller driving, TCP/IP process, serial port signal monitoring and so on, which greatly improves efficiency of CPU.

In this paper, a new type of p-cycles, multi-granularity flow p-cycles (MFP), is presented. A two-step approach is developed for the design of MFP with span failure recovery. Our simulation results show that MFP are more capacity-efficient than conventional span-protecting p-cycles (SP) and flow p-cycles (FP). The impacts of network topology on performance of SP, FP and MFP are evaluated. In this paper, we also propose a new p-cycle pre-selection strategy. Results show that our strategy is more efficient than two existing pre-selection strategy in p-cycle networks.

This paper concentrates on solutions for next-generation IP (Internet Protocol) backbone networks. This is a key issue for many network operators since IP will be the dominating network layer technology on which an ever increasing number of applications with growing bandwidth requirements will be based. Without new network solutions, this trend would lead to a strong increase in number and size of IP routers while already today’s requirements make it difficult to realise large-scale IP backbone networks in a stable and cost-efficient way. This paper investigates the benefits that an appropriate transport network based on ASTN (Automatic Switched Transport Network) and OTN (Optical Transport Network) technology can bring to future IP backbone networks - providing the stable basis on which next generation IP networks can be built. Network modelling is used to show that in addition to qualitative benefits a transport network based IP backbone solution can lead to a significant reduction of network equipment cost.

While the ethernet is applied more and more in public network environment and xdsl service become the most common access mode ,IP kenel DSLAM undertakes some functions such as service distribution and convergence ,security management and customer management.Facing the contradiction of the need of port isolation and the shortage of ip address,VLAN aggregation technology is applied in DSLAM.How to implement the communicatio between the two vlan but share the same ip subnet,proxy arp does this. This paper introduces how to implement proxy arp in the DSLAM. TCP/IP communication detail procedure betweent two host ,the relation of VLAN and network segment are discussed. The proxy arp model and its implementation in IP DSLAM is also expatiated in this paper and a conformance tesing is given.

With the help of an independent control plane, ASON introduces lots of new intelligent functions into the traditional transport network. We use some special protocols such as signaling and routing protocols in control plane instead of network management protocol that only has few primitives to control the network elements in transport plane. During the service provision of ASON, the coordination of management plane (MP) and control plane (CP) is very important. This paper analyses the coordination of MP and CP of ASON. At first, it introduces the meaning of coordination between MP and CP and its classification. Secondly, it puts emphasis upon analyzing traffic engineering (TE) realized through the coordination of MP and CP. In this part, we modify the basic ASON routing architecture and introduce the coordination functions of MP. Thirdly, this paper analyses TE control processes of the coordination between those two planes during the services provision which has not been considered in ASON recommendations but is very important.

For the application in Passive Optical Network (PON), a novel design of OCDMA system scheme is proposed in this paper. There are two key components included in this scheme: a new kind of OCDMA encoder/decoder system based on TCM and FFH and an improved Optical Line Terminal (OLT) receiving system with improved anti-interference performance by the use of Long Period Fiber Grating (LPFG). In the encoder/decoder system, Trellis Coded Modulation (TCM) encoder is applied in front of the FFH modulator. Original signal firstly is encoded through TCM encoder, and then the redundant code out of the TCM encoder will be mapped into one of the FFH modulation signal subsets for transmission. On the receiver (decoder) side, transmitting signal is demodulated through FFH and decoded by trellis decoder. Owing to the fact that high coding gain can be acquired by TCM without adding transmitting band and reducing transmitting speed, TCM is utilized to ameliorate bit error performance and reduce multi-user interference. In the OLT receiving system, EDFA and LPFG are placed in front of decoder to get excellent gain flatness on a large bandwidth, and Optical Hard Limiter (OHL) is also deployed to improve detection performance, through which the anti-interference performance of receiving system can be greatly enhanced. At the same time, some software is used to simulate the system performance for further analysis and authentication. The related work in this paper provides a valuable reference to the research.

All-optical networks, employed wavelength division multiplexing (WDM), is the core part for the next generation backbone networks, the technology concerning how to make the network stronger is the key research topic on the construction of WDM networks. We study the protection mechanism for WDM works with mesh topologies and discuss the algorithms for virtual-circle protection in this paper. The algorithms discussed as following can be applied to networks with arbitrary topology, and meanwhile, avoid searching issue in the "Hamilton" circle.

Based on the ring topology and the applied technology at present, we propose an access and control protocol for optical packet switched metropolitan area DWDM (Dense Wavelength Division Multiplexing) network. In this paper, we have given an access and control protocol first, and explained the reservation of resource, the setting of optical transmitter and receiver, the control message, and then studied the properties of waiting delay through mathematic analysis and computer simulation.

Both protection and restoration are fundamental consideration in designing robust optical networks, especially in challenging GMPLS/ASON architecture. Fast Rerouting technology as one important method of MPLS-Traffic Engineering is an efficient and powerful technology for protecting MPLS-TE LSPs from link and node failures. By supporting locally reparation of the affected LSPs at the point of failure, link and node protection are achieved quickly. The goal of real-time IP applications over native IP unicast/multicast networks or LDP based MPLS networks is to limit the IP packet loss duration in the network to 10s of milliseconds in the event of link/node failures. RSVP signaled LSP is used with explicitly routed path as the re-direct tunnel, while the protected traffic can be either MPLS traffic engineered LSPs, LDP based LSPs, IP unicast, IP multicast traffic or the mix of them. This mechanism can be applied to both point-to-point links and multi-access links in the cases of the link protection and node protection. Besides the above resilience research on IP/MPLS single layer, tests or experiments on multilayer mechanism, i.e. optical and IP/MPLS network layer composing of multi-vendor routers and multi-domain, are carried out by a number of famous organizations and companies where optical dedicated/shared mesh protection/restoration and MPLS fast rerouting survivable techniques are combined to guard against both dual link failures and combined link and IP/MPLS hardware and software router failures. Those techniques used in next-generation backbone network design result in that not only familiar failures such as fiber cuts or amplifier damage but also system failures such as router failures or multiple concurrent failures can be recovered fast and effectively at corresponding layer. In this paper, on the basis of analysis of IETF's internet drafts about fast rerouting algorithm and standards in MPLS-TE and GMPLS, new fast rerouting algorithm and corresponding simulation results are proposed step by step. At the same time, resilient performance in a GMPLS/ASON design especially under mesh optical protection is studied carefully while a few coming function requirements in OXC and router equipments obtained from the above analysis are discussed to some extent. Figures and tables are presented for explaining the enhanced fast rerouting technology reducing confusion of packets and achieving falling delay time of rerouting. Finally, some issues for further work are to identify the importance where to place appropriate resilient mechanism in the next network design.

WDM (Wavelength Division Multiplexing) technology can provide multiple wavelengths on a fiber. IP directly over WDM (or IP over WDM) has become the hot topic of industry. A promising approach for building an IP over WDM network is that a logical network consisting of the wavelength channels (lightpaths) is built on the physical WDM network. Then, IP traffic is carried on the logical topology, by utilizing the MPLS (Multiple Protocol Label Switching) or GMPLS (Generalized MPLS). When the traffic demand pattern changes in the IP layer, the network performance may become poor. In order to improve the network performance, the virtual topology can be reconfigured to suit the changing traffic patterns. In this paper, dynamic slowly-adaptation scheme (e.g. tearing down a lightpath that is lightly loaded or setting up a new lightpath when congestion occurs) is adopted. How to select the source and the destination nodes of the new lightpath to be added and the underutilized lightpath to be deleted if it is necessary to do so is our key issue. Four selection ways are developed. These ways are evaluated through detail simulations and various performances are investigated.

This paper considers the dynamic routing issues in WDM grooming networks. Given network resources, a major objective of a routing algorithm is to minimize the blocking probability of connection requests. Wavelengths and transceivers are usually limited resources in a network. The way to use these resources directly determines the network performance. So the challenge is how to use wavelength resources efficiently while keeping higher transceiver-utilization efficiency. To solve this problem, we develop an approach called Hop Constrain Lightpath Establishment Approach (HCLEA). The main idea of HCLEA is to guide the routing algorithms not to create inefficient long lightpaths. Simulation results show that HCLEA does improve the network performance in terms of transceiver-utilization efficiency, wavelength-utilization utilization, and bandwidth blocking ratio.

The 300-pin Multi Source Agreement (MSA) and other MSAs provide basic requirements from a transponder or transceiver used in 10Gb/s optical networks. These MSAs typically address a wide range of applications, including: SONET/SDH, 10GbE and 10GFC for Metro, long-haul (LH) and ultra-long-haul (ULH) networks. Nonetheless, being a basic standard, the 300-pin MSA addresses the minimal required specifications set and does not cover the whole set of requirements and applications that system vendors are interested in. For example, widely tunable and extended reach transponders are not included in the 300-pin MSA. Chromatic dispersion is one of the major reach limiting factors in optical networks. In reconfigurable optical networks, chunks of DWDM channels may travel through different routes and therefore require tunable dispersion compensation. In static ULH optical networks, the number of dispersion compensation fibers (DCFs) dictates the amount of residual chromatic dispersion. This residual chromatic dispersion differs from one DWDM channel to the other. Unless it is compensated at the receiver, it further restricts the link length and reduces the distance between one regenerator to the other. This results in shorter links and more O-E-O blocks, which dramatically increases the cost of the network. This paper discusses a specially designed optical dispersion compensation (ODC) device that is packaged in a standard butterfly package and can fit into a 300-pin MSA transponder. A transponder with the proposed ODC can still satisfy all the basic requirements that are described in the 300-pin MSA while providing improved chromatic dispersion tolerance.

One of the major bottlenecks in conventional OBS networks is the processing delay of the control packet at each node. This is due to slow electronics of the node processors. In this paper, first we describe our proposed protocols of ultrafast optical path setup using an OC-labeled control packet. The OC-labeled control packet is sent out from the source node to destination node, in which the routing information is mapped onto OC-labels. At intermediate nodes the control packet is processed on the fly in optical domain, and available wavelengths are reserved for the transmission of the burst, which follows the control packet. Next, we will evaluate the performance of the proposed protocols, compared with conventional ones such as Just-Enough-Time (JET) protocol. Finally, we will present the experimental results, demonstrating the optical path setup using bipolar 8-chip-long OC-labeled control packet.

Optical burst switching (OBS) has been emerging as a promising technology that can effectively support the next generation IP-oriented transportation networks. JIT signaling protocol for OBS is relatively simple and easy to be implemented by hardware. This paper presented an effective scheme to implement the JIT protocol, which not only can effectively implement reservation and release of optical channels based on JIT, but also can process the failure of channel reservation and release due to loss of burst control packets. The scheme includes: (1) a BHP (burst head packet) path table is designed and built at each OBS node. It is used to guarantee the corresponding burst control packet, i.e. BHP, BEP (burst end packet) and BEP_ACK (BEP acknowledgement), to be transmitted in the same path. (2) The timed retransmission of BEP and the reversed deletion of the item in BHP path tables triggered by the corresponding BEP_ACK are combined to solve the problems caused by the loss of the signaling messages in channel reservation and release process. (3) Burst head packets and BEP_ACK are transmitted using “best-effort” method. Related signaling messages and their formats for the proposed scheme are also given.

Ethernet over SDH/SONET (EOS), which connects different Ethernets through the existing SDH/SONET infrastructure, is a promising data transmission technology in today’s networks, for it successfully combines the simplicity and affordability of Ethernet with the resilience and scalability of SDH/SONET. Virtual Concatenation (VCAT) is one of the key technologies in EOS, which provides the capability to transmit and receive over several noncontiguous parallel Virtual Container (VC) fragments as a single flow and drastically improves efficiency of over 33 percent against standard concatenations. Link capacity adjustment scheme (LCAS) over VCAT signaling scheme further enhances VCAT to tune bandwidth dynamically at the requests of network management system without disturbing the existing traffic. In addition, the scheme will automatically decrease the capacity if some member of VCAT experiences a failure in the network, and increase the capacity when the network fault is repaired. In this paper, our design of LCAS over VCAT within an EOS chip is provided, which supports four Virtual Concatenation Groups (VCG) to adjust their bandwidth simultaneously. The block diagrams of the total design for LCAS over VCAT are also provided and several open problems that we encountered during implementation and their corresponding solutions are discussed in focus. Thoroughly functional simulations and FPGA verifications have been done to the design to prove its validity. Finally, we have the design synthesized with Synopsys’s Design Compiler, which reveals that the whole design is realizable in ASICs.

The blocking performance of wavelength routing WDM optical networks can be enhanced by applying routing and wavelength assignment. In this paper, we consider wavelength assignment problem in the optical network. Specifically, we propose a dynamic heuristic wavelength assignment algorithm, called Longest Segment (LS) algorithm, for WDM networks. In comparison to other proposed algorithms, the blocking performance of LS algorithm is better. In addition, the LS algorithm minimizes the usage of converters by chaining the minimum number of continuous segments which have at least one same available wavelength. Furthermore, the low algorithm’ complexity is an another advantage of the algorithm

IP/DWDM optical Internet is considered to be one of the most potential candidates for NGI (Next Generation Internet) backbone. However, the bottlenecks caused by the electronics still exist. A solution to this problem is to design an optimal virtual topology. In this paper, a novel virtual topology design method is presented, minimizing the sum of traffic-weighted hop count. Based on the given physical topology and the specific traffic matrix, the corresponding virtual topology is designed, and then, over which the traffic is routed. Due to its NP-hard nature, the design problem is decomposed into three subproblems: virtual topology construction, wavelength assignment and traffic routing, which are solved with heuristic algorithms respectively. To verify the feasibility and the effectiveness of the proposed method, a simulation environment is developed and simulation has been done over some actual network topologies. Simulation results have shown that the proposed method is both feasible and effective.

Ethernet Passive Optical Network (EPON), which combines the low cost Ethernet equipment and economic fiber infrastructure, is being considered as a promising solution for Fiber-To-The-Home (FTTH). However, since EPON is an optical shared medium network, some unique features make it more vulnerable to security attacks. In this paper, the key security threats of EPON are firstly analyzed. And then, considering some specific properties which might be utilized for security, such as the safety of transmissions in upstream direction, some novel methods are presented to solve security problems. Firstly, based on some modification about registration, the mechanism of access control is achieved. Secondly, we implement an AES-128 symmetrical encryption and decryption in the EPON system. The AES-128 algorithm can process data blocks of 128 bits, but the length of Ethernet frame is variable. How to deal with the last block, which is not up to 128 bits, is discussed in detail. Finally, key update is accomplished through a vendor specific OAM frame in order to enhance the level of security. The proposed mechanism will remain in conformance with P2MP specification defined by 802.3ah TF, and can supply a complete security solution for EPON.

Optical Burst Switching (OBS) has been proposed to be a competitive switching technology for DWDM networks. However, the abrupt burst for large traffic loads will result in unbearable performance degradation in the traditional JET network. To combat with the load sensitivity, a wavelength-routed OBS (WR-OBS) network architecture was confirmed effective. In this paper, we have proposed a distributed control WR-OBS network architecture combining JET protocol with a two-way reservation method. Based on this architecture, two new resource reservation protocols are compared by evaluating their performance. Then based on the Reduced Load Approximation, which is often used in the analysis of the circuit switch network, a novel analysis method was derived to evaluate the blocking performance of the network. And then we have developed a simulation model to evaluate the performance of the network and validate the proposed analysis method. Analytical and simulation results have indicated that the proposed architecture outperforms the traditional JET OBS network in burst blocking probability with a good trade-off between efficiency and complexity.

In order to provide better QoS service, optical networks with survivability require complete procedures to provide routing and protection for the traffic carried on the light paths. Thus, the challenging problem of disjoint path routing and protection in WDM networks is pivotal to realize the end-to-end QoS guarantee. In this paper, we propose the novel routing algorithm, CHRTG (Constrained Heuristic Routing with Traffic Grooming). CHRTG with multiple QoS constraints is different from previous routing algorithms, which are based on the traditional single constraint (bottleneck or additive). We describe QoS constraints with different weights and corresponding metrics can be produced for path computation. Better performance can be realized through analyzing the complexity degree of time and space. The traffic load from each node can be expressed in self-similar traffic and several on/off source models. Simulation results show that CHRTG can achieve maximum sharing protection paths. The results of simulation also show that the algorithm is scalable, efficient and survivable.

The combination of optical fiber and coaxial cable is referred to as Hybrid Fiber Coax (HFC) network. The HFC CATV network is considered a promising infrastructure and the most general access path to connect the residential with the Internet. The advantages of the HFC network include using a less number of signal amplifiers, furnishing more bandwidth, and reducing signal attenuation. In this paper, we reported the realization of the Broadband Information System Based on HFC CATV Networks. In such a system, the characteristics of upstream channel noise are the most important. We studied the causes of the noise and interference, and discussed the solution by using Synchronous Code Division Multiple Access (S-CDMA), trellis coded modulation and Interleaver. We used the cable modem equipment based on S-CDMA for the access method, adopted 1550nm and 1310nm fiber optic cables to combined a HFC CATV network and provided Internet services. This Scheme has been used in several districts in Tianjin. It is welcomed for its high-performance and cheaper in prices.

This paper investigates some key issues in designing an OBS edge node, such as burst assembler and burst scheduler, and then demonstrates a prototype of the OBS edge node based on current technology level. Experimental results verify various modules in the proposed OBS edge node.

In this paper, we investigate the wavelength assignment issue in wavelength-routed all-optical WDM networks with Sparse-Partial Wavelength Conversion. Traditionally, wavelength assignment is only designed for the purpose of decreasing the blocking probability. In Sparse-Partial Wavelength Conversion, wavelength assignment can be used to decrease the number of wavelength converters if keeping the same level of blocking probability. We propose three different wavelength assignment algorithms, namely Segment-First First Fit (SFFF), Path-First First-Fit (PFFF), and Minimum Converter Allocation (MCA). Our results show that MCA is the best one among the three, and it can achieve very close performance to Sparse Wavelength Conversion by using a very small number of wavelength converters. The performance of PFFF is very close to MCA, and it is very simple to be implemented.

Generalized Multiprotocol Label Switching (GMPLS), which is developed to support common control of packet, TDM, wavelength, and fiber services, is the key enabler of the new network model. The survivability of IP over WDM networks gains importance as network traffic keeps growing. In this paper, we propose an integrated provisioning scheme to dynamically allocate Label Switched Paths (LSPs) in IP over WDM networks. This scheme takes advantage of information sharing between layers (e.g., link state information, bandwidth usage, and protection capability) to eliminate redundancies and inefficiencies in the traditional layer-independent service provisioning. The integration of information is facilitated by GMPLS signaling. The proposed scheme also uses GMPLS capabilities to provide end-to-end survivability against network failures. The ability to provision across all network layers ensures efficient bandwidth usage. We propose two integrated routing algorithms: availability-based integrated routing algorithm and joint availability-based integrated routing algorithm. The simulation is made to evaluate the performance of our proposed integrated provisioning mechanism. As a result, network performance can be optimized over all layers. This could lead to significant cost savings for service providers.

This paper proposes a collision-free access protocol based on scalable slotted ring network architecture. Multiple QoS classes are supported directly in optical layer. The Qos scheme adopts the fixed home slots strategies to satisfy the requirements of services. Furthermore, efficient slot reuse is proposed. Simulation results show that the protocol can achieve good performance to guarantee the quality of traffic.

Internet only provides users with best effort services, today, with the development of next generation Internet, next generation Internet will provides users with tremendous services, how to manage these tremendous services and provides users with differentiated services automatically, must be solved for service providers and network providers. A two planes’ service management architecture is proposed, the one is application service management based on application plane, and the other is transport service management based on transport plane. In this paper, mapping application service into transport service and issues for QoS are studied, primarily. It is well known that different application services correspond to different QoS requirement during they are transported in network, likewise, the different users need different QoS requirement for the same application service. Therefore, Firstly , application services are classified, and QoS requirement for different application service is studied; secondly , the NPLs(Network Performance Level) are studied, and draw a conclusion, if NPL array corresponding to application service is assured in network, the application service of quality can be assured also. Thirdly , as an interface between application service and transport service can be expressed in policy, thus, mapping application service into transport service can be implemented by configuring the policy. Finally , WFQ (Weighted-Fair-Queue) algorithm is researched primarily based on DiffServ, and several simulation models based on NS2 are designed and different algorithms are simulated, the simulation results show that different application service of quality can be assured by corresponding to scheduling algorithm in DiffServ mechanism model. By means of policy idea, the complicated issues for mapping application services into transport service can be solved, and different scheduling algorithm in DiffServ are fit for different application services’ QoS assurance.

IP/DWDM optical Internet is considered to be a promising candidate for Next Generation Internet backbone. Fault-tolerant mechanisms have become critical technologies in IP/DWDM optical Internet. In this paper, based on preventive and reactive schemes, four fault-tolerant routing mechanisms in IP/DWDM optical Internet are proposed to deal with the problem of routing and wavelength assignment with dynamic single/multiple point failures under dynamic traffic demands, such as link/node/channel failures. The proposed mechanisms take load balancing into account, and a heuristic wavelength assignment algorithm is introduced to reduce the end-to-end delay. Simulation results have shown that the proposed fault-tolerant routing mechanisms are both feasible and effective.

With the emergence of new distributed multimedia applications upon secure group communication, Security becomes more important increasingly. Now most investigations about multicast security focus on key management problem. In this paper, an improved version of CBT is proposed for data communication and key management and named as Dynamic CBT(D-CBT). This approach accepts the advantages of Iolus and CBT approaches, its main characteristic is that D-CBT changes dynamically with group member join/removal frequently when cumulating influence of dynamic membership reaches certain threshold so that the bandwidth/cost of multicast is as least as possible, D-CBT is also very close to realistic application case. Performance analysis will be conducted compared with other methods.

Nowadays multi-protocol label switching (MPLS) technology has achieved great popularity in the world. Because MPLS adopts the scheme of “route once and switch many”, routing is the key element to ensure packets are transmitted to destinations. Though there are many designs of MPLS routing protocol for public networks, they can hardly fit the private network very well for its special characteristics. This paper presents the design of MPLS routing protocol in the private network using the specification and description language (SDL), which is an object-oriented formal language and mainly used in communications area. In our design the whole autonomous system (AS) is regarded as a single area to reduce the number of protocol packets. The SDL module of MPLS routing protocol consists of four kinds of processes, namely Management, Checking, NeigSession and LSADbase. Simulations of the SDL design are run in many scenarios, the results of which indicate that the SDL module is manageable and the overall performance is satisfying. From our design and simulation experience, we find that the software development cycle can be drastically reduced by the use of SDL, and the code is easy to maintain and reuse.

Optical packet-switched networks (OPNs), which consist of edge nodes and core nodes, are regarded as one of the most promising solutions to meet the increasing service requirements of the global Internet and to utilize efficiently the huge bandwidth of dense wavelength division multiplexing (DWDM) technology. In particular, the edge nodes perform adaptation function which interfaces between the legacy packet networks (i.e. IP networks) and OPNs. Namely, the edge nodes assembly IP packets from electronic layer into a larger optical packet. The function of packet assembly has become an important issue to be addressed in OPNs, since it not only increases the bandwidth utilization, but also reduces the self-similarity of the traffic. Studied in this paper are three kinds of typical packet assembly schemes in unslotted OPNs, i.e. the timer-based one, the length-threshold one and the hybrid algorithm. Based on a generic architecture of the edge nodes, these assembly mechanisms are examined by simulations under various self-similar traffic loads. The impacts of these algorithms on the traffic, including statistics of generated optical packets and self-similarity of optical packet traffic, are compared. The simulation results indicate that optical packet assembly can fulfill traffic shaping by improving key traffic characteristics of interest in network performance evaluation, such as the long-term correlation and so on. Moreover, the hybrid algorithm proves to be a better solution when both the assembly time and the packetisation efficiency have been also considered at the same time.

This paper describes our work on the key techniques in ASON control plane and introduces a practicable software simulation-based ASON network framework and node structure. The implementation methods of the control channel and the composition of the control protocol traffic flow are analyzed. Then simulation of the control channel capacity requirements in ASON under different conditions is realized. Relationship between the control channel traffic rate and the network traffic load of the ASON network is introduced. The capacity requirements of the control channel under different connection setup time limits are also analyzed. In the end the approximate equations to describe these relations are developed.

With the tremendous growth of broadband IP services, the impact of bandwidth bottleneck in access network becomes more prominent and largely restricts the network carriers to provide satisfied services for subscribers. Thus, a new access network with sufficient bandwidth resources and efficient network resource management must be designed. In this paper, a Generalized MPLS (GMPLS) and EPON-based optical access network is proposed to provide end-to-end quality-of-service (QoS) guarantee for broadband IP services. The proposed network architecture is presented and the Label Switched Path (LSP) setup procedure is developed. In the proposed access network, GMPLS is used to manage network resources dynamically and to conduct traffic engineering. In addition, an efficient dynamic bandwidth allocation algorithm is designed to accommodate bursty IP traffic and improve bandwidth utilization in the proposed network. The performance analyses show that under the same network load the proposed scheme has lower average packet delay and shorter queue length than current schemes.

In the modern world of telecommunications, the concept of wireless global coverage is of the utmost importance. However, real global coverage can only be achieved by satellite systems. Satellites communication is the most important mean of the communication network. The traditional satellites communication and inter-satellites links are built by microwave. In recent years, laser links for inter-satellites communication are becoming more and more important. Laser communication systems operate in a frequency range above the regulated spectrum. Laser provides many advantages for using in point-to-point ISLs (inter-satellites links) such as for links between satellites and spacecraft in deep space. Such advantages include: high speed; high bandwidth; small antenna size; narrow field of view; and narrow antenna beam. These advantages combined with the advantages in fiber optic components (optical preamplifiers, multiplexers, detectors, etc) have made laser attractive for laser links. Now we can bring WDM (wavelength-division multiplexing) to emerging broadband satellite communication systems. By using the common antenna system and ATP (Aiming, Tracking and Pointing) system, the satellites will get more capacity. In the inter-satellites laser communication, the important performances of the systems such as BER and BL both have direct relation with the optical systems. The optical systems have the function of ATP. The optical antenna is the most important component of the optical system. So the optical antenna is an important key technology to the inter-satellites laser communication. In this paper, we mainly study the optical system in the inter-satellites laser communication. we compare with three kinds of optical antennas: refractor and reflector and Catadioptrics of the passive optical system; we also analyze the effect of bandwidth to the WDM communication systems; we use the correlative software, simulate the curves of the performance of the optical antennas. These analyses will be the base of the system of WDM laser inter-satellites communication.

Disruptive all-optical switching and ultra-long reach WDM transmission technologies enable all-optical networks without OEO conversion along paths that can span thousands of kilometers. Coupled with advances in automatic discovery, distributed routing and signaling mechanisms, the next generation all-optical intelligent networks (AOIN) has been one of the most promising technology innovations. Based on the particular PXC structure, this paper addresses in detail the process of AND in AOIN, which includes three major periods. As far as the simulation is concerned, a GMPLS-based software platform built by us can demonstrate the AOIN performance, and a meaningful result is derived when comparing the speeds of AND under different monitoring schemes.

With the prosperous development and the use of SMS, more and more important information need to be transferred through the wireless and mobile networks by the users. But in the GSM/GPRS network, the SMS messages are transferred in text mode through the signaling channel and there is no integrality for SMS messages. Because of the speciality of the mobile communications, the security of signaling channel is very weak. So we need to improve and enhance the security and integrality of SMS. At present, developed investigation based on SMS security is still incomplete. The key distribution and management is not perfect to meet the usability in a wide area. This paper introduces a high-level security method to solve this problem. We design the Secure SMS of GSM/GPRS in order to improve the security of the important information that need to be transferred by the mobile networks. Using this method, we can improve the usability of E-payment and other mobile electronic commerce.

With the need of more and more high quality services, EPON system is widely favored by most people with its advanced technology of Gigabit and PON, which will replace the traditional techniques of copper and MC gradually. We can realize the MPCP protocol defined in IEEE802.3ah by the hardware scheme, such as FPGA or ASIC. Using SNMP protocol to achieve network management is the popular way. SNMP network manager can perform the long-distance configuration of the parameters in EPON system by sending out SET message; on the other hand, it can research the information by sending out GET message. Consequently, the Nios embedded processor acts as a transmission channel or a bridge between SNMP agent and hardware system. Now SOPC is a popular design method, which processes flexible design mode, reducible, expansible, upgradeable, and have the programmable function between hardware and software synchronously in a single chip. Integrated with the advantages of SOC, PLD, and FPGA, SOPC is provided with the following basic characteristics: an embedded processor core; on-chip high speed RAM resources with small capability; processor debug interface and FPGA programmable interface, etc. The Nios embedded processor is a soft core CPU optimized for programmable logic and SOPC (System-on-a-programmable-chip) designs, which accomplishes the data collection and configuration between SNMP agent and hardware system, the report of registration and alarm information, also the fulfillment of DBA which can be operated with all kind of algorithms. SOPC builder is a tool employed as turning out a system based on bus, thereby many components are included in this design, for instance, CPU, memory interface, peripherals interface etc. Developing applications using the Nios embedded processor is slightly different from the traditional processors, since the designer can configure the processor architecture and specify the peripheral content. That is, a designer can build a microcontroller according to system design requirement, as opposed to selecting a pre-built microcontroller with a fixed set of peripherals, on-chip memory, and external interfaces. In this paper, we introduce an EPON system by way of FPGA, and a SOPC design on the basis of Nios platform is given, in which data transmission channel and DBA functions are achieved. According to the need of EPON system, CPU, memory, and peripheral interfaces are selected from the library of SOPC builder. Once the Nios system is created, it may optionally be combined with other used-defined logic. Designer writes the source code, compiles the application software, and debugs the code to meet the need of EPON system.

RRP has two means to transmit data: store-and-forward and cut-through. In this paper, the high and low priority packet transfer delay of the N nodes Resilient Packet Rings (RPR) in store-and-forward architecture is analyzed based on the queuing theory. According to queuing theory, we set up the nodes model and analyzed the factors that influenced the packet transfer delay in a constrained condition. By calculation and simulation, the result indicates that both high priority and low priority packets’ delay increase with the node number N of the RPR rings. The high priority traffic has less packet delay than the low priority traffic at the same node number N. The increase of the low priority transfer delay is much larger than the high priority traffic with the increase of the node number.

How to assemble different restoration scheme in multi-layer networks effectively is a sticking point to survivability of ASON. Among kinds of multi-layer restoration problems, failures locating is the primary one to be solved. Therefore, fast failures locating scheme is proposed in this paper. The main idea of this restoration scheme is that optical layer communicated with control layer dynamically and the restoration process of optical layer and control layer is mutually exclusive. When a new link is established in control layer, the optical layer’s nodes whose related links is used by this new link will recode the two neighbor nodes of this new link. This information is updated online. Thus, when optical layer find failure, the related nodes can transfer the failure message to the corresponding nodes on control layer immediately. Time parameter was set to start different restoration in different layer of networks. Thus, responsibility of optical layer and control layer is clear. Confusion that may be caused by multi-layer restoration was settled.

In the study of dynamic routing and wavelength assignment (DRWA) algorithms and protocols in optical networks, blocking probability is a chief criterion for performance evaluation. But it does not always capture the full effect of a particular algorithm on other aspects, such as fairness problem, which refers to the variability in blocking probabilities experienced by connection requests between various node pairs. Most commercial routing protocols, such as OSPF, prefers to adopt the shortest path for a particular connection, also brings unfairness to diverse connection requests, and such an unfairness becomes more serious in optical networks without wavelength conversion due to wavelength continuity constraint. Some literature have concerned this fairness problem and proposed several fairness enhancement methods. But unfortunately, they will deteriorate the overall blocking probability. In this paper, we try to optimize the fairness and blocking probability simultaneously via the alternate routing strategy, and a novel classified alternate routing (CAR) approach will be adopted. In our investigations, we will consider the optimization of alternate path set determination strategy, wavelength assignment and path selection method, and link weight function, etc. Comparisons and collaborations with formerly proposed fairness enhancement methods will be also presented.

We have provided the Internet data service for more than 30 million users over broadband network in Korea. At emerging time of introducing Internet data service, downstream data rate was a critical issue. But nowadays, the key issue is not provided the best effort service but guaranteed bandwidth service. PON system can guarantee the both points. In this paper we present the requirement of EPON system for Fiber to The Pole (FTTP) and Fiber to the Home (FTTH). And then we will show some examples of EPON deployment at KT.

This paper discusses the innovation in network architectures, and optical transport, that enables metropolitan networks to cost-effectively scale to hundreds Gb/s of capacity, and to hundreds km of reach, and to also meet the diverse service needs of enterprise and residential applications. A converged metro network, where Ethernet/IP services, and traditional TDM traffic operate over an intelligent WDM transport layer is increasingly becoming the most attractive architecture addressing the primary need of network operators for significantly improved capital and operational network cost. At the same time, this converged network has to leverage advanced technology, and introduce intelligence in order to significantly improve the deployment and manageability of WDM transport. The most important system advancements and the associated technology innovations that enhance the cost-effectiveness of metropolitan optical networks are being reviewed.