Based on a media access and control(MAC)protocol,an arrangement of channels and transceivers in optical packet switching dense wavelength division multiplexing(DWDM)networks is proposed in this paper.In order to r...Based on a media access and control(MAC)protocol,an arrangement of channels and transceivers in optical packet switching dense wavelength division multiplexing(DWDM)networks is proposed in this paper.In order to reduce the cost of nodes,fixed transmitters and receivers are used instead of tunable transmitters and receivers.Two fixed transmitters and many fixed receivers are used in each node in the scheme.The average waiting delay of this scheme is analyzed through mathematics and computer simulation.The result shows that the property of the scheme is almost the same as using tunable transmitter and receiver.Furthermore,if the tuning time of tunable transmitters is taken into account,the performance of the tunable transmitter scheme is poor than this scheme at the average waiting delay and throughput of the network.展开更多
In order to apply compressive sensing in wireless sensor network, inside the nodes cluster classified by the spatial correlation, we propose that a cluster head adopts free space optical communication with space divis...In order to apply compressive sensing in wireless sensor network, inside the nodes cluster classified by the spatial correlation, we propose that a cluster head adopts free space optical communication with space division multiple access, and a sensor node uses a modulating retro-reflector for communication. Thus while a random sampling matrix is used to guide the establishment of links between head cluster and sensor nodes, the random linear projection is accomplished. To establish multiple links at the same time, an optical space division multiple access antenna is designed. It works in fixed beams switching mode and consists of optic lens with a large field of view(FOV), fiber array on the focal plane which is used to realize virtual channels segmentation, direction of arrival sensor, optical matrix switch and controller. Based on the angles of nodes' laser beams, by dynamically changing the route, optical matrix switch actualizes the multi-beam full duplex tracking receiving and transmission. Due to the structure of fiber array, there will be several fade zones both in the focal plane and in lens' FOV. In order to lower the impact of fade zones and harmonize multibeam, a fiber array adjustment is designed. By theoretical, simulated and experimental study, the antenna's qualitative feasibility is validated.展开更多
This letter proposes a new burst assembly technique for supporting QoS in optical burst switching (OBS) networks. It consists of the adaptive-threshold burst assembly mechanism and QoS-based random offset-time scheme....This letter proposes a new burst assembly technique for supporting QoS in optical burst switching (OBS) networks. It consists of the adaptive-threshold burst assembly mechanism and QoS-based random offset-time scheme. The assembly mechanism, which is fit well to multi-class burst assembly, not only matches with IP QoS mechanism based on packet classification, and also utilizes fairly and efficiently assembly capacity. Based on token-bucket model and burst segment selective discard (BSSD), the offset-time scheme can smooth the traffic to support OBS QoS. The simulation results show that the technique can improve the performance in terms of packet loss probability (PLP).展开更多
An optical burst switching (OBS) network platform is established with a ring topology of three nodes. A congestion Mleviated scheme using advanced token protocol and wavelength tunable receivers is demon- strated to...An optical burst switching (OBS) network platform is established with a ring topology of three nodes. A congestion Mleviated scheme using advanced token protocol and wavelength tunable receivers is demon- strated to optimize the network platform. Experimental results testify that this scheme can resist collision at the level of 0.1% congestion rate.展开更多
A novel optical burst switching (OBS) high speed network architecture has been proposed. To verify its feasibility and evaluate its performance, just-enough-time (JET) signaling has been considered as a high perfo...A novel optical burst switching (OBS) high speed network architecture has been proposed. To verify its feasibility and evaluate its performance, just-enough-time (JET) signaling has been considered as a high performance protocol. In the proposed architecture, to avoid burst losses, firstly, a short-prior- confirmation-packet (SPCP) is sent over the control channel that simulates the events that the actual packet will experience. Once SPCP detects a drop at any of the intermediate nodes, the actual packet is not sent but the process repeats. In order to increase network utilization, cost effectiveness and to overcome some limitations of conventional OBS, inherent codes (e.g., orthogonal optical codes (OOC)), which are codified only in intensity, has been used. Through simulations, it shows that a decrease in burst loss probability, cost effectiveness and a gain in processing time are obtained when optical label processing is used as compared with electronic processing.展开更多
A scheduling algorithm for the edge nodes of optical burst switching (OBS) networks is proposed to guarantee the delay requirement of services with different CoS (Class of Service) and provide lower burst loss ratio a...A scheduling algorithm for the edge nodes of optical burst switching (OBS) networks is proposed to guarantee the delay requirement of services with different CoS (Class of Service) and provide lower burst loss ratio at the same time. The performance of edge nodes based on the proposed algorithm is presented.展开更多
To achieve lower assembly delay at optical burst switching edge node, this paper proposes an approach called current weight length prediction (CWLP) to improve existing estimate mechanism in burst assembly. CWLP metho...To achieve lower assembly delay at optical burst switching edge node, this paper proposes an approach called current weight length prediction (CWLP) to improve existing estimate mechanism in burst assembly. CWLP method takes into account the arrived traffic in prediction time adequately. A parameter 'weight' is introduced to make a dynamic tradeoff between the current and past traffic under different offset time. Simulation results show that CWLP can achieve a significant improvement in terms of traffic estimation in various offset time and offered load.展开更多
This paper proposes a novel scheme based on minimum delay at the edges (MDE) for optical burst switching (OBS) networks. This scheme is designed to overcome the long delay at the edge nodes of OBS networks. The MDE sc...This paper proposes a novel scheme based on minimum delay at the edges (MDE) for optical burst switching (OBS) networks. This scheme is designed to overcome the long delay at the edge nodes of OBS networks. The MDE scheme features simultaneous burst assembly, channel scheduling, and pre-transmission of control packet. It also features estimated setup and explicit release (ESXR) signaling protocol. The MDE scheme can minimize the delay at the edge nodes for data packets, and improve the end-to-end latency performance for OBS networks. In addition, comparing with the conventional scheme, the performances of the MDE scheme are analyzed in this paper.展开更多
A new integrated scheme based on resource-reservation and adaptive network flow routing to alleviate contention in optical burst switching networks is proposed. The objective of the proposed scheme is to reduce the ov...A new integrated scheme based on resource-reservation and adaptive network flow routing to alleviate contention in optical burst switching networks is proposed. The objective of the proposed scheme is to reduce the overall burst loss in the network and at the same time to avoid the packet out-of-sequence arrival problem. Simulations are carried out to assess the feasibility of the proposed scheme. Its performance is compared with that of contention resolution schemes based on conventional routing. Through extensive simulations, it is shown that the proposed scheme not only provides significantly better burst loss performance than the basic equal proportion and hop-length based traffic routing algorithms, but also is void of any packet re-orderings.展开更多
In this letter, we analyze the drawback of tail-dropping contention resolution in optical burst switched networks. Once contention occurs, we adopt modified head-dropping policy to resolve contention. This policy drop...In this letter, we analyze the drawback of tail-dropping contention resolution in optical burst switched networks. Once contention occurs, we adopt modified head-dropping policy to resolve contention. This policy drops the head of the contending burst only if the overlapping region of the two bursts is less than the whole contending burst size, otherwise drops the whole contending burst. In order to have a better support of differentiated service, a new burst assembly policy, namely, Priority-based proportional mixed burst assembly, is proposed. Simulation results show that the proposed scheme performs very well in terms of performance metrics such as the times of contention and packet loss probability.展开更多
This article discusses the issue of resource conflict in the generalized multi-protocol label switching (GMPLS) controlled optical network. Based on the analysis of the current random rebuilding mechanism and its dr...This article discusses the issue of resource conflict in the generalized multi-protocol label switching (GMPLS) controlled optical network. Based on the analysis of the current random rebuilding mechanism and its drawbacks, this article presents two enhanced solutions for improvement, namely, the priority-based resource allocation mechanism and the network management system (NMS) based sequential resource allocation mechanism. Experimental results show that the presented mechanisms perform better than the original random rebuilding solution in terms of the connection setup/recovery time and successful rate.展开更多
In order to have a better support of differentiated service, we propose Priority-based mixed burst assembly, in which packets of different priorities are assembled in a burst with an assigned proportion, and the prior...In order to have a better support of differentiated service, we propose Priority-based mixed burst assembly, in which packets of different priorities are assembled in a burst with an assigned proportion, and the priorities are lined in an ascending order in a burst from head to tail. Simulation results show that the proposed scheme performs very well in terms of latency and packet loss probability.展开更多
We build an automatically switched optical network (ASON) testbed with four optical cross-connect nodes. Many fundamental ASON features are demonstrated, which is implemented by control protocols based on generalized ...We build an automatically switched optical network (ASON) testbed with four optical cross-connect nodes. Many fundamental ASON features are demonstrated, which is implemented by control protocols based on generalized multi-protocol label switching (GMPLS) framework.展开更多
Risk-disjoint routing is an efficient way to improve network survivability. In this article, a partial risk-disjoint routing algorithm based on link availability (PRDRA-LA) is proposed based on the complete risk-dis...Risk-disjoint routing is an efficient way to improve network survivability. In this article, a partial risk-disjoint routing algorithm based on link availability (PRDRA-LA) is proposed based on the complete risk-disjoint routing algorithm (CRDRA). While calculating the protection path with PRDRA-LA, the links that share risks with the links in the working path are filtered by link availability. In addition, the risk disjoint degree between the protection path and the working path can be adjusted freely. Simulation results showed that when compared with CRDRA, routing connections with PRDRA-LA can achieve improved survivability while the number of connections that can be successfully routed over the current network is kept from serious decline.展开更多
文摘Based on a media access and control(MAC)protocol,an arrangement of channels and transceivers in optical packet switching dense wavelength division multiplexing(DWDM)networks is proposed in this paper.In order to reduce the cost of nodes,fixed transmitters and receivers are used instead of tunable transmitters and receivers.Two fixed transmitters and many fixed receivers are used in each node in the scheme.The average waiting delay of this scheme is analyzed through mathematics and computer simulation.The result shows that the property of the scheme is almost the same as using tunable transmitter and receiver.Furthermore,if the tuning time of tunable transmitters is taken into account,the performance of the tunable transmitter scheme is poor than this scheme at the average waiting delay and throughput of the network.
基金supported by the National Natural Science Foundation of China(61372069)and the"111"Project(B08038)
文摘In order to apply compressive sensing in wireless sensor network, inside the nodes cluster classified by the spatial correlation, we propose that a cluster head adopts free space optical communication with space division multiple access, and a sensor node uses a modulating retro-reflector for communication. Thus while a random sampling matrix is used to guide the establishment of links between head cluster and sensor nodes, the random linear projection is accomplished. To establish multiple links at the same time, an optical space division multiple access antenna is designed. It works in fixed beams switching mode and consists of optic lens with a large field of view(FOV), fiber array on the focal plane which is used to realize virtual channels segmentation, direction of arrival sensor, optical matrix switch and controller. Based on the angles of nodes' laser beams, by dynamically changing the route, optical matrix switch actualizes the multi-beam full duplex tracking receiving and transmission. Due to the structure of fiber array, there will be several fade zones both in the focal plane and in lens' FOV. In order to lower the impact of fade zones and harmonize multibeam, a fiber array adjustment is designed. By theoretical, simulated and experimental study, the antenna's qualitative feasibility is validated.
基金This work was supported by National Hi-Tech Research and Development Program of China (863 Program) under contract No. 2002AA122021.
文摘This letter proposes a new burst assembly technique for supporting QoS in optical burst switching (OBS) networks. It consists of the adaptive-threshold burst assembly mechanism and QoS-based random offset-time scheme. The assembly mechanism, which is fit well to multi-class burst assembly, not only matches with IP QoS mechanism based on packet classification, and also utilizes fairly and efficiently assembly capacity. Based on token-bucket model and burst segment selective discard (BSSD), the offset-time scheme can smooth the traffic to support OBS QoS. The simulation results show that the technique can improve the performance in terms of packet loss probability (PLP).
基金National Natural Science Foundation of China(No.90704006,60572021,and 60711140087)National"973"Program of China(No.2007CB310705)+3 种基金National"863"Project of China(No.2006AA01Z238)PCSIRT(No.IRT0609)ISTCP(No.2006DFAl1040)111 Project(No.B07005).
文摘An optical burst switching (OBS) network platform is established with a ring topology of three nodes. A congestion Mleviated scheme using advanced token protocol and wavelength tunable receivers is demon- strated to optimize the network platform. Experimental results testify that this scheme can resist collision at the level of 0.1% congestion rate.
文摘A novel optical burst switching (OBS) high speed network architecture has been proposed. To verify its feasibility and evaluate its performance, just-enough-time (JET) signaling has been considered as a high performance protocol. In the proposed architecture, to avoid burst losses, firstly, a short-prior- confirmation-packet (SPCP) is sent over the control channel that simulates the events that the actual packet will experience. Once SPCP detects a drop at any of the intermediate nodes, the actual packet is not sent but the process repeats. In order to increase network utilization, cost effectiveness and to overcome some limitations of conventional OBS, inherent codes (e.g., orthogonal optical codes (OOC)), which are codified only in intensity, has been used. Through simulations, it shows that a decrease in burst loss probability, cost effectiveness and a gain in processing time are obtained when optical label processing is used as compared with electronic processing.
文摘A scheduling algorithm for the edge nodes of optical burst switching (OBS) networks is proposed to guarantee the delay requirement of services with different CoS (Class of Service) and provide lower burst loss ratio at the same time. The performance of edge nodes based on the proposed algorithm is presented.
基金This work was jointly supported by the National Natural Science Foundation of China (No. 69990540)the Optical Technology Plan of Shanghai.
文摘To achieve lower assembly delay at optical burst switching edge node, this paper proposes an approach called current weight length prediction (CWLP) to improve existing estimate mechanism in burst assembly. CWLP method takes into account the arrived traffic in prediction time adequately. A parameter 'weight' is introduced to make a dynamic tradeoff between the current and past traffic under different offset time. Simulation results show that CWLP can achieve a significant improvement in terms of traffic estimation in various offset time and offered load.
文摘This paper proposes a novel scheme based on minimum delay at the edges (MDE) for optical burst switching (OBS) networks. This scheme is designed to overcome the long delay at the edge nodes of OBS networks. The MDE scheme features simultaneous burst assembly, channel scheduling, and pre-transmission of control packet. It also features estimated setup and explicit release (ESXR) signaling protocol. The MDE scheme can minimize the delay at the edge nodes for data packets, and improve the end-to-end latency performance for OBS networks. In addition, comparing with the conventional scheme, the performances of the MDE scheme are analyzed in this paper.
文摘A new integrated scheme based on resource-reservation and adaptive network flow routing to alleviate contention in optical burst switching networks is proposed. The objective of the proposed scheme is to reduce the overall burst loss in the network and at the same time to avoid the packet out-of-sequence arrival problem. Simulations are carried out to assess the feasibility of the proposed scheme. Its performance is compared with that of contention resolution schemes based on conventional routing. Through extensive simulations, it is shown that the proposed scheme not only provides significantly better burst loss performance than the basic equal proportion and hop-length based traffic routing algorithms, but also is void of any packet re-orderings.
基金This work was partially supported by the National Natural Science Foundation of China under Grant No. 69990540.
文摘In this letter, we analyze the drawback of tail-dropping contention resolution in optical burst switched networks. Once contention occurs, we adopt modified head-dropping policy to resolve contention. This policy drops the head of the contending burst only if the overlapping region of the two bursts is less than the whole contending burst size, otherwise drops the whole contending burst. In order to have a better support of differentiated service, a new burst assembly policy, namely, Priority-based proportional mixed burst assembly, is proposed. Simulation results show that the proposed scheme performs very well in terms of performance metrics such as the times of contention and packet loss probability.
基金National Natural Science Foundation of China (60572021, 60710047)the National Basic Research Program of China (2007CB310705)+3 种基金the Hi-Tech Research and Development Program of China (2006AA01Z243)NCET (06-0090), PCSIRT (IRT0609)ISTCP (2006DFA11040)111 Project (B07005)
文摘This article discusses the issue of resource conflict in the generalized multi-protocol label switching (GMPLS) controlled optical network. Based on the analysis of the current random rebuilding mechanism and its drawbacks, this article presents two enhanced solutions for improvement, namely, the priority-based resource allocation mechanism and the network management system (NMS) based sequential resource allocation mechanism. Experimental results show that the presented mechanisms perform better than the original random rebuilding solution in terms of the connection setup/recovery time and successful rate.
基金This work is partially supported by the National Natural Science Foundation of China under contract 69990540.
文摘In order to have a better support of differentiated service, we propose Priority-based mixed burst assembly, in which packets of different priorities are assembled in a burst with an assigned proportion, and the priorities are lined in an ascending order in a burst from head to tail. Simulation results show that the proposed scheme performs very well in terms of latency and packet loss probability.
文摘We build an automatically switched optical network (ASON) testbed with four optical cross-connect nodes. Many fundamental ASON features are demonstrated, which is implemented by control protocols based on generalized multi-protocol label switching (GMPLS) framework.
基金This work is supported by the National Science Fund for Distinguished Young Scholars(60325104);the National Natural Science Foundation of China (60572021);the Hi-Tech Research and Development Program of China (2006AA01Z243);the PCSIRT Project of M0E (IRT0609);the International Cooperation Project of M0ST (2006DFA 11040).
文摘Risk-disjoint routing is an efficient way to improve network survivability. In this article, a partial risk-disjoint routing algorithm based on link availability (PRDRA-LA) is proposed based on the complete risk-disjoint routing algorithm (CRDRA). While calculating the protection path with PRDRA-LA, the links that share risks with the links in the working path are filtered by link availability. In addition, the risk disjoint degree between the protection path and the working path can be adjusted freely. Simulation results showed that when compared with CRDRA, routing connections with PRDRA-LA can achieve improved survivability while the number of connections that can be successfully routed over the current network is kept from serious decline.