Shared restoration is key to realizing the bandwidth savings offered by meshnetworking. To be viable, restoration has to be effected very quickly—typically,within 50 ms after failure. However, all the known schemes i...
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Shared restoration is key to realizing the bandwidth savings offered by meshnetworking. To be viable, restoration has to be effected very quickly—typically,within 50 ms after failure. However, all the known schemes involve signaling andcross-connect setups and require excessive duration times. We describe a novelrestoration scheme called FASTeR that dramatically reduces restoration times byeliminating these operations. It involves a novel select-multicast feature of thecross connects and can be applied to all-optical or electrical networks. We extendthe generalized multiprotocol label-switching (GMPLS) standard to support thisscheme and present simulation results to evaluate the scheme and show that a smallmulticasting degree is sufficient in practice to achieve the bandwidth savingsgained in traditional restoration schemes.
A bottleneck arises in backbone electronic Internet Protocol (IP) routersbecause the lookup in a routing table is performed according to the longest prefixmatch. To resolve this problem, a versatile optical-code- (OC-...
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A bottleneck arises in backbone electronic Internet Protocol (IP) routersbecause the lookup in a routing table is performed according to the longest prefixmatch. To resolve this problem, a versatile optical-code- (OC-) based longest prefixmatch that uses variable-length optical gates for photonic IP packet routing hasbeen developed. The developed OC-based IP routing with the longest prefix match willreduce the number of routing entries so that the matching entry can be found morequickly. Moreover, the new routing procedure will help make photonic routers morecompact and cost effective.
This paper designs and analyzes the performance and scalability of a source-based interdomain provisioning (SIP) solution for multidomain software-defined optical transport networking (SDOTN). The challenge of this pa...
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This paper designs and analyzes the performance and scalability of a source-based interdomain provisioning (SIP) solution for multidomain software-defined optical transport networking (SDOTN). The challenge of this paper is to design SIP to solve the processing complexity of distributed per-domain provisioning (DPP) while eliminating the traffic and processing concentration of hierarchical interdomain provisioning (HIP). By using mathematical models, the throughput and latency of the proposed solution were evaluated. The numerical results prove that the proposed SIP improves the scalability more than ten times compared with DPP and around twice that of HIP.
We describe a general construction for space–wavelength log2(FW;m; p) networkscapable of wave-mixing conversion, including previous designs proposed in theliterature, where F is the number of fibers and W is the numb...
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We describe a general construction for space–wavelength log2(FW;m; p) networkscapable of wave-mixing conversion, including previous designs proposed in theliterature, where F is the number of fibers and W is the number of wavelengths perfiber. In these networks, a lightpath is converted through at most f log2W +min(m;log2 W)g cascaded conversions, with O(pF log2 W) converters. Therefore the newconstruction enables the design of rearrangeably and strictly nonblockinglog2(FW;m;p) wavelength interchanging cross connects, respectively, with O[F log2W(FW)1=2=2m=2] and O[F log2 Wf(FW)1=2=2m=2+mg] wave-mixing converters. It alsoprovides a trade-off between transmission impairments and converterrequirements.
This paper proposed FC-Switch, which is a nova combined switch, defined its switch-level connection pattern and primarily analyzed its performance. Moreover, four routing algorithms for the FC-Switch were discussed, a...
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This paper proposed FC-Switch, which is a nova combined switch, defined its switch-level connection pattern and primarily analyzed its performance. Moreover, four routing algorithms for the FC-Switch were discussed, and the experiments on TH-1A network testing platform was carried out. Experiments result shows that the FC-Switch can achieve a good performance by correctly choosing switch-level connection pattern and the routing algorithm.
An effective algorithm DMEO applying the deferred-merge embedding (DME) algorithm is presented for clock tree construction in the presence of obstacles. During the clock routing, a track graph is constructed in order ...
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An effective algorithm DMEO applying the deferred-merge embedding (DME) algorithm is presented for clock tree construction in the presence of obstacles. During the clock routing, a track graph is constructed in order to guarantee the obstacle-avoidance. By considering obstruction as routing constraint, the method is composed of a bottom-up phase computing possible loci of nodes and a top-down step to determine the exact placement of each node in the clock topology tree. Experimental results show that the algorithm is promising with more than 7% wirelength reduction.
This paper describes the basic construction of the objective functions of the transit network design problem and proposes a new approach taking account of both passenger and operator interests. The approach presented ...
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This paper describes the basic construction of the objective functions of the transit network design problem and proposes a new approach taking account of both passenger and operator interests. The approach presented combines the philosophy of the mathematical programming approaches with decision-making techniques, so as to allow the user to select from a number of alternatives. The nature of the overall formulation is nonlinear and mixed integer programming.
Traffic grooming, which can efficiently multiplex many low-rate traffic streams into one lightpath, has been a hot topic in the research community. Here adaptive routing and wavelength assignment (RWA) is studied for ...
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Traffic grooming, which can efficiently multiplex many low-rate traffic streams into one lightpath, has been a hot topic in the research community. Here adaptive routing and wavelength assignment (RWA) is studied for WDM grooming mesh networks with constraints on the number of transceivers and wavelength continuity. Three adaptive traffic-grooming algorithms are proposed, and a dynamic path-protection traffic-grooming algorithm is also proposed to provide the survivable optical network. The performance of these algorithms is assessed through simulations.
The problem of finding the best path trajectory in a graph is highly complex due to its combinatorial nature, making it difficult to solve. Standard search algorithms focus on selecting the best path trajectory by int...
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The problem of finding the best path trajectory in a graph is highly complex due to its combinatorial nature, making it difficult to solve. Standard search algorithms focus on selecting the best path trajectory by introducing constraints to estimate a suitable solution, but this approach may overlook potentially better alternatives. Despite the number of restrictions and variables in path planning, no solution minimizes the computational resources used to reach the goal. To address this issue, a framework is proposed to compute the best trajectory in a graph by introducing the mathematical morphology concept. The framework builds a lattice over the graph space using mathematical morphology operators. The searching algorithm creates a metric space by applying the morphological covering operator to the graph and weighing the cost of traveling across the lattice. Ultimately, the cumulative traveling criterion creates the optimal path trajectory by selecting the minima/maxima cost. A test is introduced to validate the framework's functionality, and a sample application is presented to validate its usefulness. The application uses the structure of the avenues as a graph. It proposes a computable approach to find the most suitable paths from a given start and destination reference. The results confirm that this is a generalized graph search framework based on morphological operators that can be compared to the Dijkstra approach.
With flexibility in optical layer, elastic optical network (EON) has been considered as a competitive candidate to architect next-generation backbone networks. routing and spectrum assignment (RSA) is a key problem fo...
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With flexibility in optical layer, elastic optical network (EON) has been considered as a competitive candidate to architect next-generation backbone networks. routing and spectrum assignment (RSA) is a key problem for the service provisioning in EONs. The RSA problem is $\mathcal {NP}$ -hard even in elastic optical rings. Numerous heuristics have been proposed, and they can generally be categorized into two types: Route-First (RF) and Spectrum-First (SF). Although most previous work demonstrated by numerical simulations that the SF algorithms always outperform the RF ones, there is a lack of theoretical analysis on the reasons causing the performance difference between the two types of RSA algorithms. In this paper, we aim at proposing a unified theoretical framework for the performance analysis of RSA algorithms by leveraging conflict graphs, which offers a new perception on the optimality of RSA algorithms. To validate the proposed framework, we apply it in elastic optical rings (with cycle topology), and theoretically analyze the number of edges of the conflict graphs for RF and SF algorithms. Different from the literature, we obtain an interesting observation that neither the RF nor the SF can surpass the other in elastic optical rings under different traffic distributions, and their performances have a strong correlation to the edge count of their conflict graph. This observation provides a new perspective, i.e., conflict graph, to explore the property of RSA algorithms.
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