Yonggang Li et al. 517 ABSTRACT⎯In this letter, a new sharing mechanism, SRLG sharing, is propose... more Yonggang Li et al. 517 ABSTRACT⎯In this letter, a new sharing mechanism, SRLG sharing, is proposed, which allows the links of the same shared risk link group (SRLG) in a primary light tree to share protections in WDM optical networks. In previous studies, how to share spare resources with SRLG constraints has not been studied in multicast optical networks. In this letter, considering SRLG sharing, we propose a novel algorithm -multicast with SRLG sharing (MSS)-to establish a protection light tree. Finally, the algorithm MSS and the algorithm multicast with no SRLG sharing (MNSS) are compared through a simulation to show that our new sharing scheme of SRLG sharing is more efficient than that of no SRLG sharing in terms of spare resource utilization and blocking probability.
In survivable wavelength-division multiplexed networks, the backup resource can be shared by the ... more In survivable wavelength-division multiplexed networks, the backup resource can be shared by the primary light paths, which is called primary-backup sharing. We find that primary-backup sharing can have an effect on the link availability. We focus on routing under dynamic availability of the wavelength resource while the requested reliability of traffic has to be met, using the modified shortest path
We demonstrate a novel overlay multicasting architecture: IP multicasting over optical networks w... more We demonstrate a novel overlay multicasting architecture: IP multicasting over optical networks with dynamic point-to-multipoint configuration. Experimental results show that the proposed architecture exhibits better performance than pure IP multicasting under heavy traffic load.
The performance of 40-Gb/s RZ signals through cascaded thinfilm filters is investigated by both n... more The performance of 40-Gb/s RZ signals through cascaded thinfilm filters is investigated by both numerical and analytical means. It is observed that the filtering effects can reduce the eye closure penalties caused by the large dispersion slope of the thin-film filters. In addition, the performance can be further improved by proper frequency detuning between the signal and the center of the filter. The combined effects of dispersion slope and filtering on 40-Gb/s signals are investigated analytically and explained for typical bit patterns.
Load-balanced switches have received much attention because they are more scalable than other swi... more Load-balanced switches have received much attention because they are more scalable than other switch architectures. However, a load-balanced switch has the problem of packet missequencing. In this paper, we propose a Dynamic Mailbox Sharing (DMS) scheme to eliminate the mis-sequencing problem of load-balanced switches only at the cost of a very small increase of delay. The key idea is to keep packets of the same flow in order in the load-balanced switch. The DMS scheme is based on two statistical facts in operational networks: the number of simultaneous active flows in the router buffer is far less than that of in-progress flows, and most of the intra-flow packet intervals are longer than the packet delay in the high speed router. In DMS, the packet sequence of the same flow arrived in the input ports is recorded in the mailbox maintained in the output ports. Then, packets of the same flow are delivered according to the order of their arrivals. The mailbox becomes the bottleneck in order to accommodate a large number of flows. We thus propose a dynamic sharing scheme to alleviate the bottleneck and greatly enhance the scalability of the mailbox. By simulations using the real internet traffic traces, we show that with a simple flow splitter mechanism restraining mis-sequencing, the average packet delay using DMS is considerably lower than that of other schemes including Uniform Frame Spreading, Padded Frame and the CR switch, and it is close to the ideal case without resequencing even when the load is very high. The results also demonstrate that the size of mailbox is in the hundreds.
We study the connection establishment of label switched paths (LSPs), and compare the LSP blockin... more We study the connection establishment of label switched paths (LSPs), and compare the LSP blocking performance of the overlay and peer models in IP/MPLS over optical networks. We consider two dynamic routing algorithms for the establishment of LSP connections, of which one is for the overlay model and the other is for the peer model. Our investigations on two typical network topologies, namely NSFNET and ARPA2 networks, show that the number of add/drop ports (or transceivers) on optical cross-connects (OXCs) has a significant impact on the LSP blocking performance for both models. We show by computer simulation that in each case, there is a threshold value for the add/drop ratio, which can achieve almost the best blocking performance. This threshold value remains virtually unchanged as the traffic load varies, but it does depend on the network topology and the number of wavelengths per fiber. This will then indicate the number of add/drop ports to be used so that one can achieve a near optimal blocking performance without incurring unnecessarily excessive network costs. Our investigations reveal that the peer model achieves a much better blocking performance than the overlay model when the number of add/drop ports is relatively high, but that this is not always true when the number of add/drop ports is small.
This paper proposes two optical grid resource allocation and task scheduling algorithms, task-bas... more This paper proposes two optical grid resource allocation and task scheduling algorithms, task-based approaches (TBA) and workflow-based approaches (WBA), for data-intensive workflow-based applications. Not only the efficient allocation for the entire workflow but also the network resources contention are considered. An optical grid simulator is developed to investigate the performance of the resource allocation approaches. Experimental results show that WBA
IEEE Journal on Selected Areas in Communications, 2007
It is widely believed that IP over optical networks will be a major component of the next generat... more It is widely believed that IP over optical networks will be a major component of the next generation Internet. However, it is not efficient to map a single multicast IP flow into one light-tree, since the bandwidth of an IP flow required is usually much less than that of a light-tree.
1. Introduction GMPLS-controlled optical network is considered as a promising infrastructure for ... more 1. Introduction GMPLS-controlled optical network is considered as a promising infrastructure for distributed computing to solve more and more complex scientific problems [1].The key issue of distributed computing is resource scheduling. Recently, the coordinated scheduling ...
This paper studies the routing problems in Internet protocol/wavelength-division-multiplexing (IP... more This paper studies the routing problems in Internet protocol/wavelength-division-multiplexing (IP/WDM) networks based on the overlay routing algorithm (ORA) and the integrated routing algorithm (IRA), respectively. Although IRA usually outperforms ORA in terms of blocking performance, IRA exhibits disadvantages in control information exchange, network privacy issue, and wavelength port efficiency. In this paper, a new mechanism called the short lightpath establishment
Grid is evolving to a more efficient global computing infrastructure by introducing optical netwo... more Grid is evolving to a more efficient global computing infrastructure by introducing optical network technology to support the advanced data-intensive distributed applications. Scheduling such data-intensive applications includes assigning tasks on computational resources, routing lightpaths, and assigning wavelength channels for data communication. The scheduling problem is NP-hard in the traditional grid system, and in optical grids, it is more complicated due to the character of optical networks. In this paper, we formulate the scheduling problem in optical grids and propose a novel scheduling algorithm which modifies the scheduling order according to actual importance of each task to search for a better solution. We call it the scheduled critical path (SCP) algorithm. We compare the scheduling results obtained by the SCP algorithm with the optimal results calculated by OPL studio software on a 3-node optical grid. To evaluate the performance of the proposed algorithm on more complicated systems, we construct a simulator which is able to schedule the application to the optical grid according to a certain scheduling algorithm. The simulation results prove the efficiency of the SCP algorithm.
The Clos network is used for optical cross-connect and optical packet switch node, and has a larg... more The Clos network is used for optical cross-connect and optical packet switch node, and has a large number of crosspoints if the number of wavelengths per fiber is more than that of fibers per node. In this letter, we propose a cost-effective permuted Clos network to reduce the number of crosspoints. We further investigate the placement of fixed wavelength converter groups (WCGs) shared inside the permuted Clos network. On the contrary, a normal Clos network has to be equipped with expensive tunable WCGs. The simulation result implies that equipment of about 50% WCGs achieves similar performance as the full wavelength interchanging node does.
The optical network integrated computing environment has been thought of as a promising technolog... more The optical network integrated computing environment has been thought of as a promising technology to support large-scale data-intensive distributed computing applications. For such an environment involving so many heterogeneous resources, such as high-performance processors and optical links, faults seem to be inevitable. The faults will lead to the failure of the applications or highly delay the applications' finish times. Therefore, it is necessary to analyze resources' fault probability and then to better schedule the tasks of the application onto the appropriate resources so as to minimize the fault probability of the application. We address the task-scheduling problem based on the fault probability analysis for distributed computing applications over an optical network. We quantitatively analyze the fault probability of the processors and optical links in a given interval and propose a minimal fault probability (MFP) task-scheduling algorithm to minimize the fault probability of the application. We develop a simulator to evaluate the performance of the MFP algorithm. The simulation results prove the efficiency of the MFP algorithm.
To support large-scale IP-TV signal delivering, a new multicast-IP over light-tree network model ... more To support large-scale IP-TV signal delivering, a new multicast-IP over light-tree network model was proposed in W. Sun et al. In this paper, we study the problem of topology-independent IP group aggregation in the multicast capable optical network. We first use a tri-partite graph to describe the problem, and then formulate the problem by a mixed integer linear programming (MILP)
It is beneficial, for both customers and carriers, to provide optical virtual private network for... more It is beneficial, for both customers and carriers, to provide optical virtual private network for workflow-based distributed computing applications. We formulate the schedule system and also propose a rescheduling scheme under dynamic shared OVPN scenario.
This paper presents a reconfigurable Photonic Network on Chip architecture and evaluates its ultr... more This paper presents a reconfigurable Photonic Network on Chip architecture and evaluates its ultra-low latency potential. The latency performance simulation shows a 50% decrease compared to static photonic network on chip.
We propose a novel separated unicast/multicast splitter-and-delivery (SUM-SaD) switch for mixed u... more We propose a novel separated unicast/multicast splitter-and-delivery (SUM-SaD) switch for mixed unicast and multicast traffic. Only multicast connections undergo extra splitting loss but are compensated by incorporated optical amplifiers. A typical multicasting-capable optical cross-connect is constructed by using the proposed SUM-SaDs. Theoretically, we prove that it is strictly nonblocking for both unicast and multicast connections if = 2, where and are the dimension of SUM-SaD and the number of SaD input ports, respectively. Therefore, means the maximum accommodated trees in the SUM-SaD. To save cost, can be less than 2, and the throughput performance is investigated by simulation. The results show that the throughput is improved when increases. In the experiment, we construct a 4 4 SUM-SaD prototype and measure the bit-error rate (BER) of unicast connection, multicast connection with or without optical amplifier. There is no clear BER difference between them for the small dimensional SUM-SaD switch.
IEEE Journal on Selected Areas in Communications, 2004
This paper focuses on dynamic integrated routing in multifiber Internet protocol/wavelength-divis... more This paper focuses on dynamic integrated routing in multifiber Internet protocol/wavelength-division multiplexing (IP/WDM) networks, which can be implemented through either one-step routing (OSR) or two-step routing (TSR) approach. Based on an extended layered-graph, two resource assignment strategies, termed channel-level balance (CLB) and link-level balance (LLB), are proposed to balance the traffic in the network at different levels. To further improve the performance, a parameter is introduced to make a dynamic tradeoff between the logical-layer links and the optical-layer links. Simulation studies are carried out for various topologies. The results show that LLB is better than CLB in most cases, and LLB combined with OSR has the optimal performance. Also, we find that the routing approach and the resource assignment strategy individually play different roles with different values of that is introduced to indicate the resource richness of the network.
The optical network based distributed computing system has been thought as a promising technology... more The optical network based distributed computing system has been thought as a promising technology to support large-scale data-intensive distributed applications. For such a system with so many heterogeneous resources and middlewares involved, faults seem to be inevitable. However, for those applications that need to be finished before the given deadline, a fault in the system will lead to the failure of the application. Therefore, fault-tolerant policy is necessary to improve the performance of the system when faults could happen. In this paper, we address to the fault-tolerant problem for the optical network based distributed computing system. We first propose an overlay approach which applies the existing fault-tolerant policies for distributed computing and optical network. Then we present a joint fault-tolerant policy which takes into account the fault tolerance for computing resource and network resource in the same time. We compare the performances of different polices by simulation. The simulation results show that the joint fault-tolerant policy achieves much better performances compared to overlay approaches.
A field trial of dynamic P2MP connections across two domains was successfully achieved in the ASO... more A field trial of dynamic P2MP connections across two domains was successfully achieved in the ASON layer of the 3TNet testbed in Yangtze River Delta, China for the first time using web service mechanism.
Yonggang Li et al. 517 ABSTRACT⎯In this letter, a new sharing mechanism, SRLG sharing, is propose... more Yonggang Li et al. 517 ABSTRACT⎯In this letter, a new sharing mechanism, SRLG sharing, is proposed, which allows the links of the same shared risk link group (SRLG) in a primary light tree to share protections in WDM optical networks. In previous studies, how to share spare resources with SRLG constraints has not been studied in multicast optical networks. In this letter, considering SRLG sharing, we propose a novel algorithm -multicast with SRLG sharing (MSS)-to establish a protection light tree. Finally, the algorithm MSS and the algorithm multicast with no SRLG sharing (MNSS) are compared through a simulation to show that our new sharing scheme of SRLG sharing is more efficient than that of no SRLG sharing in terms of spare resource utilization and blocking probability.
In survivable wavelength-division multiplexed networks, the backup resource can be shared by the ... more In survivable wavelength-division multiplexed networks, the backup resource can be shared by the primary light paths, which is called primary-backup sharing. We find that primary-backup sharing can have an effect on the link availability. We focus on routing under dynamic availability of the wavelength resource while the requested reliability of traffic has to be met, using the modified shortest path
We demonstrate a novel overlay multicasting architecture: IP multicasting over optical networks w... more We demonstrate a novel overlay multicasting architecture: IP multicasting over optical networks with dynamic point-to-multipoint configuration. Experimental results show that the proposed architecture exhibits better performance than pure IP multicasting under heavy traffic load.
The performance of 40-Gb/s RZ signals through cascaded thinfilm filters is investigated by both n... more The performance of 40-Gb/s RZ signals through cascaded thinfilm filters is investigated by both numerical and analytical means. It is observed that the filtering effects can reduce the eye closure penalties caused by the large dispersion slope of the thin-film filters. In addition, the performance can be further improved by proper frequency detuning between the signal and the center of the filter. The combined effects of dispersion slope and filtering on 40-Gb/s signals are investigated analytically and explained for typical bit patterns.
Load-balanced switches have received much attention because they are more scalable than other swi... more Load-balanced switches have received much attention because they are more scalable than other switch architectures. However, a load-balanced switch has the problem of packet missequencing. In this paper, we propose a Dynamic Mailbox Sharing (DMS) scheme to eliminate the mis-sequencing problem of load-balanced switches only at the cost of a very small increase of delay. The key idea is to keep packets of the same flow in order in the load-balanced switch. The DMS scheme is based on two statistical facts in operational networks: the number of simultaneous active flows in the router buffer is far less than that of in-progress flows, and most of the intra-flow packet intervals are longer than the packet delay in the high speed router. In DMS, the packet sequence of the same flow arrived in the input ports is recorded in the mailbox maintained in the output ports. Then, packets of the same flow are delivered according to the order of their arrivals. The mailbox becomes the bottleneck in order to accommodate a large number of flows. We thus propose a dynamic sharing scheme to alleviate the bottleneck and greatly enhance the scalability of the mailbox. By simulations using the real internet traffic traces, we show that with a simple flow splitter mechanism restraining mis-sequencing, the average packet delay using DMS is considerably lower than that of other schemes including Uniform Frame Spreading, Padded Frame and the CR switch, and it is close to the ideal case without resequencing even when the load is very high. The results also demonstrate that the size of mailbox is in the hundreds.
We study the connection establishment of label switched paths (LSPs), and compare the LSP blockin... more We study the connection establishment of label switched paths (LSPs), and compare the LSP blocking performance of the overlay and peer models in IP/MPLS over optical networks. We consider two dynamic routing algorithms for the establishment of LSP connections, of which one is for the overlay model and the other is for the peer model. Our investigations on two typical network topologies, namely NSFNET and ARPA2 networks, show that the number of add/drop ports (or transceivers) on optical cross-connects (OXCs) has a significant impact on the LSP blocking performance for both models. We show by computer simulation that in each case, there is a threshold value for the add/drop ratio, which can achieve almost the best blocking performance. This threshold value remains virtually unchanged as the traffic load varies, but it does depend on the network topology and the number of wavelengths per fiber. This will then indicate the number of add/drop ports to be used so that one can achieve a near optimal blocking performance without incurring unnecessarily excessive network costs. Our investigations reveal that the peer model achieves a much better blocking performance than the overlay model when the number of add/drop ports is relatively high, but that this is not always true when the number of add/drop ports is small.
This paper proposes two optical grid resource allocation and task scheduling algorithms, task-bas... more This paper proposes two optical grid resource allocation and task scheduling algorithms, task-based approaches (TBA) and workflow-based approaches (WBA), for data-intensive workflow-based applications. Not only the efficient allocation for the entire workflow but also the network resources contention are considered. An optical grid simulator is developed to investigate the performance of the resource allocation approaches. Experimental results show that WBA
IEEE Journal on Selected Areas in Communications, 2007
It is widely believed that IP over optical networks will be a major component of the next generat... more It is widely believed that IP over optical networks will be a major component of the next generation Internet. However, it is not efficient to map a single multicast IP flow into one light-tree, since the bandwidth of an IP flow required is usually much less than that of a light-tree.
1. Introduction GMPLS-controlled optical network is considered as a promising infrastructure for ... more 1. Introduction GMPLS-controlled optical network is considered as a promising infrastructure for distributed computing to solve more and more complex scientific problems [1].The key issue of distributed computing is resource scheduling. Recently, the coordinated scheduling ...
This paper studies the routing problems in Internet protocol/wavelength-division-multiplexing (IP... more This paper studies the routing problems in Internet protocol/wavelength-division-multiplexing (IP/WDM) networks based on the overlay routing algorithm (ORA) and the integrated routing algorithm (IRA), respectively. Although IRA usually outperforms ORA in terms of blocking performance, IRA exhibits disadvantages in control information exchange, network privacy issue, and wavelength port efficiency. In this paper, a new mechanism called the short lightpath establishment
Grid is evolving to a more efficient global computing infrastructure by introducing optical netwo... more Grid is evolving to a more efficient global computing infrastructure by introducing optical network technology to support the advanced data-intensive distributed applications. Scheduling such data-intensive applications includes assigning tasks on computational resources, routing lightpaths, and assigning wavelength channels for data communication. The scheduling problem is NP-hard in the traditional grid system, and in optical grids, it is more complicated due to the character of optical networks. In this paper, we formulate the scheduling problem in optical grids and propose a novel scheduling algorithm which modifies the scheduling order according to actual importance of each task to search for a better solution. We call it the scheduled critical path (SCP) algorithm. We compare the scheduling results obtained by the SCP algorithm with the optimal results calculated by OPL studio software on a 3-node optical grid. To evaluate the performance of the proposed algorithm on more complicated systems, we construct a simulator which is able to schedule the application to the optical grid according to a certain scheduling algorithm. The simulation results prove the efficiency of the SCP algorithm.
The Clos network is used for optical cross-connect and optical packet switch node, and has a larg... more The Clos network is used for optical cross-connect and optical packet switch node, and has a large number of crosspoints if the number of wavelengths per fiber is more than that of fibers per node. In this letter, we propose a cost-effective permuted Clos network to reduce the number of crosspoints. We further investigate the placement of fixed wavelength converter groups (WCGs) shared inside the permuted Clos network. On the contrary, a normal Clos network has to be equipped with expensive tunable WCGs. The simulation result implies that equipment of about 50% WCGs achieves similar performance as the full wavelength interchanging node does.
The optical network integrated computing environment has been thought of as a promising technolog... more The optical network integrated computing environment has been thought of as a promising technology to support large-scale data-intensive distributed computing applications. For such an environment involving so many heterogeneous resources, such as high-performance processors and optical links, faults seem to be inevitable. The faults will lead to the failure of the applications or highly delay the applications' finish times. Therefore, it is necessary to analyze resources' fault probability and then to better schedule the tasks of the application onto the appropriate resources so as to minimize the fault probability of the application. We address the task-scheduling problem based on the fault probability analysis for distributed computing applications over an optical network. We quantitatively analyze the fault probability of the processors and optical links in a given interval and propose a minimal fault probability (MFP) task-scheduling algorithm to minimize the fault probability of the application. We develop a simulator to evaluate the performance of the MFP algorithm. The simulation results prove the efficiency of the MFP algorithm.
To support large-scale IP-TV signal delivering, a new multicast-IP over light-tree network model ... more To support large-scale IP-TV signal delivering, a new multicast-IP over light-tree network model was proposed in W. Sun et al. In this paper, we study the problem of topology-independent IP group aggregation in the multicast capable optical network. We first use a tri-partite graph to describe the problem, and then formulate the problem by a mixed integer linear programming (MILP)
It is beneficial, for both customers and carriers, to provide optical virtual private network for... more It is beneficial, for both customers and carriers, to provide optical virtual private network for workflow-based distributed computing applications. We formulate the schedule system and also propose a rescheduling scheme under dynamic shared OVPN scenario.
This paper presents a reconfigurable Photonic Network on Chip architecture and evaluates its ultr... more This paper presents a reconfigurable Photonic Network on Chip architecture and evaluates its ultra-low latency potential. The latency performance simulation shows a 50% decrease compared to static photonic network on chip.
We propose a novel separated unicast/multicast splitter-and-delivery (SUM-SaD) switch for mixed u... more We propose a novel separated unicast/multicast splitter-and-delivery (SUM-SaD) switch for mixed unicast and multicast traffic. Only multicast connections undergo extra splitting loss but are compensated by incorporated optical amplifiers. A typical multicasting-capable optical cross-connect is constructed by using the proposed SUM-SaDs. Theoretically, we prove that it is strictly nonblocking for both unicast and multicast connections if = 2, where and are the dimension of SUM-SaD and the number of SaD input ports, respectively. Therefore, means the maximum accommodated trees in the SUM-SaD. To save cost, can be less than 2, and the throughput performance is investigated by simulation. The results show that the throughput is improved when increases. In the experiment, we construct a 4 4 SUM-SaD prototype and measure the bit-error rate (BER) of unicast connection, multicast connection with or without optical amplifier. There is no clear BER difference between them for the small dimensional SUM-SaD switch.
IEEE Journal on Selected Areas in Communications, 2004
This paper focuses on dynamic integrated routing in multifiber Internet protocol/wavelength-divis... more This paper focuses on dynamic integrated routing in multifiber Internet protocol/wavelength-division multiplexing (IP/WDM) networks, which can be implemented through either one-step routing (OSR) or two-step routing (TSR) approach. Based on an extended layered-graph, two resource assignment strategies, termed channel-level balance (CLB) and link-level balance (LLB), are proposed to balance the traffic in the network at different levels. To further improve the performance, a parameter is introduced to make a dynamic tradeoff between the logical-layer links and the optical-layer links. Simulation studies are carried out for various topologies. The results show that LLB is better than CLB in most cases, and LLB combined with OSR has the optimal performance. Also, we find that the routing approach and the resource assignment strategy individually play different roles with different values of that is introduced to indicate the resource richness of the network.
The optical network based distributed computing system has been thought as a promising technology... more The optical network based distributed computing system has been thought as a promising technology to support large-scale data-intensive distributed applications. For such a system with so many heterogeneous resources and middlewares involved, faults seem to be inevitable. However, for those applications that need to be finished before the given deadline, a fault in the system will lead to the failure of the application. Therefore, fault-tolerant policy is necessary to improve the performance of the system when faults could happen. In this paper, we address to the fault-tolerant problem for the optical network based distributed computing system. We first propose an overlay approach which applies the existing fault-tolerant policies for distributed computing and optical network. Then we present a joint fault-tolerant policy which takes into account the fault tolerance for computing resource and network resource in the same time. We compare the performances of different polices by simulation. The simulation results show that the joint fault-tolerant policy achieves much better performances compared to overlay approaches.
A field trial of dynamic P2MP connections across two domains was successfully achieved in the ASO... more A field trial of dynamic P2MP connections across two domains was successfully achieved in the ASON layer of the 3TNet testbed in Yangtze River Delta, China for the first time using web service mechanism.
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Papers by Yaohui Jin