排序方式： 共有57条查询结果，搜索用时 15 毫秒
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Guido Maier Mauro Scappini Mario Martinelli Achille Pattavina 《Transactions on Emerging Telecommunications Technologies》2000,11(1):91-98
Dynamic wavelength assignment in a WDM all‐optical network with partial and sparse wavelength conversion is discussed in this paper. The performance of unidirectional and bidirectional ring networks in terms of blocking probability, conversion gain and fairness is evaluated under various types of offered traffic patterns. Smooth and peaked patterns have been considered in addition to the classical Poisson traffic type. We show how the partial use of wavelength converters having a limited conversion capability affects the blocking performance of connections and, more importantly in terms of network fairness, its dependence on the source‐destination distance. 相似文献
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Achille Pattavina 《Transactions on Emerging Telecommunications Technologies》1999,10(6):571-583
ATM switch architectures based on deflection routing are here examined, described in terms of a general switch model and compared with regards to their internal operations. Their common feature is the availability of multiple I/O paths through a multistage unbuffered interconnection network where conflicts for the same interstage link are dealt with by deflecting packets onto the wrong path. The main engineering parameter of the architecture, that is the number of network stages that provides a given packet loss performance is studied in depth. In particular it is found that basically all the examined architectures have a complexity on the order of N log2 N in the range of switch size of usual interest. Furthermore it has been possible to rank the architectures with comparable complexity based on the loss performance they provide. The Shuffleout switch turns out to behave better than other architectures previously known as providing an optimal performance. 相似文献
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Francesco Masetti Achille Pattavina Cesare Sironi 《Transactions on Emerging Telecommunications Technologies》1992,3(2):157-166
This paper describes the design and implementation aspects of the Shuffleout switch, a new class of switching fabric architectures. The key points of this structure are the adoption of a memoryless multistage interconnection network and a new packet routing strategy. Compared to the basic multistage shuffle interconnection network of Shuffleout, adopting 2×4 switching elements, three other architectures of the interconnection network are described, which use larger switching elements, that is 4×6, 3×5 and 4×8. Adopting these upgraded structures aims not only at decreasing the number of interconnection network stages that provide a given cell loss probability, thus reducing the switching fabric complexity, but also at improving fairness in the network. The VLSI hardware design of a switching element and of a chip is then described with reference to the basic Shuffleout structure, with design and implementation details on their major functional blocks. Finally a complexity comparison of the different enhanced architectures is assessed. 相似文献
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In order to model and verify systems of concurrent processes (such as those involved in communication protocols), finite-state machines and Petri nets can be used as local and global models, respectively. The problem of composing a set of communicating finite-state machines into a single global Petri net is considered in the letter with special attention to the case of more than two processes. 相似文献
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Massimo Tornatore Diego Lucerna Biswanath Mukherjee Achille Pattavina 《Journal of Network and Systems Management》2012,20(1):34-55
Survivability is a key concern in modern network design. This paper investigates the problem of survivable dynamic connection provisioning in general telecom backbone networks, that are mesh structured. We assume differentiated services where connections may have different availability requirements, so they may be provisioned differently with protection (if needed) based on their availability requirements and current network state. The problem of effectively provisioning differentiated-service requests, that has been widely investigated for connections routed at the physical layer, assumes peculiar features if we consider sub-wavelength requests at the logical layer that have to be protected (or more generically, whose availability target has to be guaranteed), but also have to be groomed for an efficient use of network resources. An integrated multilayer approach is necessary that considers requirements and grooming of connections at the logical layer as well as their routing and availability at the physical layer. Joint availability-guaranteed routing and traffic grooming may lead to a negative interaction, since the objective of the first problem (guaranteeing a given level of availability to the connections) clashes with the objective of the other problem (minimizing resource consumption). For a multilayer WDM mesh network, we propose new multilayer routing strategies that perform effective availability-guaranteed grooming of sub-wavelength connections. These strategies jointly considers connection availability satisfaction and resource optimization and are developed under two different practical hypotheses: guaranteed target, i.e., a connection is routed only if its availability target is satisfied, and best-effort target, a connection is always routed and, when the availability target cannot be guaranteed, the path with the best possible availability is provisioned. Numerical results are reported and discussed for the two approaches mentioned above. In both cases, the results show high effectiveness of our provisioning strategy. 相似文献
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Bregni S. Pattavina A. Vegetti G. 《Selected Areas in Communications, IEEE Journal on》2003,21(7):1113-1121
In order to support the continuous growth of transmission capacity demand, optical packet switching technology is emerging as a strong candidate, promising to allow fast dynamic allocation of wavelength-division multiplexing (channels, combined with a high degree of statistical resource sharing). This work addresses the design of optical switch architectures, based on previous proposals available in the technical literature that use an arrayed waveguide grating (AWG) device to route packets. Since the port number of currently available AWGs is a limiting factor, we propose two new modified structures which better exploit the switching capability of this component in the wavelength domain. Since a limited hardware complexity is a key requirement for all-optical switches, due to the high cost of optical components, these different node configurations are compared in terms of complexity. Traffic performance of these new structures in a full optical packet switching scenario is also examined. 相似文献
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A. Stavdas A. BiancoA. Pattavina C. RaffaelliC. Matrakidis C. Piglione C. Politi M. SaviR. Zanzottera 《Optical Switching and Networking》2012,9(1):13-24
In this work, two bufferless high capacity broadcast-and-select optical switching node architectures are presented and their performance is evaluated. The architectures are modular permitting the expansion from basic to complex structures by adding new blocks/components in a gradual way, enhancing at the same time the corresponding network functionality. The blocking performance is assessed and scheduling algorithms are proposed to solve contention for a single node. Finally, physical layer modeling is carried out in order to investigate node scalability and node cascadeability. Overall, the proposed solutions are offering modularity, transparency to switching technology, graceful evolution and high performance at an affordable cost. 相似文献