共查询到20条相似文献,搜索用时 31 毫秒
1.
A. Teixeira L. Costa G. Franzl S. Azodolmolky I. Tomkos K. Vlachos S. Zsigmond T. Cinkler G. Tosi-Beleffi P. Gravey T. Loukina J. A. Lázaro C. Vazquez J. Montalvo E. Le Rouzic 《Photonic Network Communications》2009,18(2):191-210
A vertical perspective, ranging from management and routing to physical layer options, concerning dynamic network monitoring
and compensation of impairments (M&C), is given. Feasibility, reliability, and performance improvements on reconfigurable
transparent networks are expected to arise from the consolidated assessment of network management and control specifications,
as a more accurate evaluation of available M&C techniques. In the network layer, physical parameters aware algorithms are
foreseen to pursue reliable network performance. In the physical layer, some new M&C methods were developed and rating of
the state-of-the-art reported in literature is given. Optical monitoring implementation and viability is discussed.
相似文献
E. Le RouzicEmail: |
2.
Routing on pre-configured topology for dynamic optical networks 总被引:1,自引:0,他引:1
Yongli Zhao Jie Zhang Dahai Han Lei Wang Wanyi Gu Yuefeng Ji 《Photonic Network Communications》2009,17(3):299-310
3.
The serial-mode multicasting scheme (SM), which can achieve duplication, buffering, and serial export of optical multicast
packets in Optical Packet Switched (OPS) networks, is experimentally studied in this paper. Based on the experimental results,
several limitations of this scheme, such as the multicast latency and signal impairment, are discussed. In addition, its performance
in OPS networks is investigated by computer simulations. From the simulation results, a conclusion can be drawn that compared
with the parallel-mode multicasting scheme (PM) producing multiple simultaneous copies of the optical packets by an optical
power splitter or other devices, the SM scheme can increase the multicast success ratio and reduce the multicast retransmission
times at the costs of some signal impairments and some extra transmission latency.
相似文献
Yuefeng Ji (Corresponding author)Email: |
4.
In optical wavelength-division multiplexing (WDM) networks, traffic can be unevenly distributed across the network causing
inefficient utilization of resources. To solve this problem, an improved soft preemptive (SP) scheme is proposed by considering
dynamic resource distribution to deal with the uneven network utilization. A novel unevenly distributed traffic model in cross-time-zone
networks is also presented to evaluate the efficiency of the new scheme. Compared with other schemes such as normal shortest
path first (SPF) routing and wavelength conversion (WC), the new proposed scheme results demonstrate significantly better
performance with respect to the network utilization and overall network blocking probability.
相似文献
Nan HuaEmail: |
5.
This article proposes a new approach for routing and wavelength assignment (RWA) for permanent and reliable wavelength paths
(WP) in wide all-optical WDM networks with wavelength continuity constraint. Given a number of available wavelengths on each
optical fiber, for each simple link failure of the network, we seek to maximize the number of satisfied requests for connections.
This is known as RWAP problem. In our algorithm, called RWA with Minimum Loaded Link for Permanent and Reliable wavelength
paths (MLL-PR), routing is based on the search for the optimal path while trying to minimize the maximum load on the links of the network
in order to minimize the maximum link capacity and then minimize the number of dropped lightpaths after any link failure.
The wavelength assignment is based on a graph coloring method using tabu-search. A series of experiments using two well-known
networks (ARPANET and NSFNET) have been carried out in order to evaluate the performance of our approach, in terms of the
number of blocked demands, for different failure scenarios. Generally, our results are better than those provided by the current
solving approaches taken as reference.
相似文献
Zouhair GuennounEmail: |
6.
In this article, we find that the limiting hop count in a lightpath impacts on the performance of optical networks. Based
on this observation, we propose a dynamic hop count shifting (DYHOS) algorithm that limits the hop count of lightpaths dynamically,
depending on the traffic load. The proposed algorithm searches an available route, while minimizing the waste of network resources
and limiting excessive traffic on the network. Hence, the proposed algorithm increases the network throughput and reduces
the blocking probability. Comparing with shortest path routing and adaptive path routing algorithms, we show the performance
of the proposed algorithm has the lowest blocking probability influenced by the hop count of lightpaths for a given routing
algorithm.
相似文献
Jeonghoon MoEmail: |
7.
Optical burst switching (OBS) networks have been receiving much attention as a promising approach to build the next generation
optical Internet. In the bufferless DWDM switching technology, burst loss that should be minimized is the key design parameter.
One of the critical design issues in OBS network is how to plan the optimal routing path in order to minimize burst dropping
due to network resource contention. This study proposes the burst frequent-pattern tree (BFP-Tree) approach to pre-determine
a suitable routing path in the OBS network. The BFP-Tree approach essentially is a learning-based mechanism that is able to
determine a suitable transmission path from the historical network transaction data. The experiment results show that the
successful rates of routing paths obtained by the BFP-Tree approach are able to converge to those of the optimal results.
相似文献
Zen-Der ShyuEmail: |
8.
The negative impact of cascaded wavelength conversions has been largely ignored in optical burst switching performance evaluations.
When optical bursts are transmitted all optically from source to destination, each wavelength conversion performed along the
lightpath may cause some signal-to-noise deterioration. If the distortion of the signal quality becomes significant enough,
the receiver would not be able to recover the original data. In this paper we examine the performance degradation when an
upper bound on the number of wavelength conversions that a signal can go through is enforced. We refer to this constraint
as conversion cascading constraint. We propose a novel proactive routing scheme under this constraint that considers the instantaneous link congestion at the
moment when the bursts arrive. It has three major advantages: (1) utilize the same offset times for the same node pairs while
providing dynamic routing without using any fiber delay lines (FDL); (2) decrease burst loss probability to a great extent;
(3) mitigate unfairness among the bursts with different hop counts, which is even worse under the conversion cascading constraint
if without any special treatment. We also extend the proposed mechanism to embrace a variant of regulated deflection routing
which can further improve network performance.
相似文献
Guifang LiEmail: |
9.
Qing Liu Chongyang Xie Tannous Frangieh Nasir Ghani Ashwin Gumaste Nageswara S. V. Rao 《Photonic Network Communications》2009,17(1):63-74
This paper studies routing scalability in multi-domain DWDM networks. Although inter-domain provisioning has been well studied
for packet/cell-switching networks, the wavelength dimension (along with wavelength conversion) poses many challenges in multi-domain
DWDM settings. To address these concerns a detailed GMPLS-based hierarchical routing framework is proposed for multi-domain
DWDM networks with wavelength conversion. This solution uses mesh topology abstraction schemes to hide domain-internal state.
However related inter-domain routing loads can be significant here, growing by the square of the number of border nodes. To
address these scalability limitations, improved inter-domain routing update strategies are also proposed and the associated
performance of inter-domain lightpath RWA and signaling schemes studied.
相似文献
Nasir GhaniEmail: |
10.
Haitham S. Hamza 《Photonic Network Communications》2009,17(3):277-291
In this paper, we propose a new Benes-type wavelength division multiplexing (WDM) optical network with space-wavelength switching
capability. Intuitively, adding wavelength switching capability to space Benes networks requires the use of additional hardware
components (i.e., wavelength converters). However, in this paper, we show that a Benes network with full-permutation capability
in both space and wavelength domains can be designed using a smaller number of hardware components but the same number of
stages as that in a space-only Benes network. In addition, wavelength conversion in the proposed network occurs only between
two pre-defined wavelengths, eliminating the need for any expensive wide-range wavelength converters. The proposed Benes network is based
on the newly proposed concept of wavelength-exchangeable permutation networks. Wavelength-exchangeable networks implement
single-step space and wavelength switching and hence reduces the number of hardware components. We show that, such wavelength-exchangeable
networks possess some interesting properties that can be used for designing routing algorithms to improve signal quality.
相似文献
Haitham S. HamzaEmail: |
11.
Ruth Van Caenegem Didier Colle Mario Pickavet Piet Demeester 《Photonic Network Communications》2009,17(1):75-91
All-Optical Label Swapping (AOLS) nodes are believed to be part of the future networks. The original node designs, however,
are very hard scalable. This article presents three alternatives that swap labels analogous to the original design. Two of
the proposed new switches use the same all-optical technology to parallelly compare labels but, they divide fibres in data
wavelengths that only transport payloads and label wavelengths that only transport labels. The third design sequentially compares
the incoming label with addresses in the node available in order to make the routing decision. All three architectures are
compared in terms of hardware necessary to perform routing.
相似文献
Piet DemeesterEmail: |
12.
Optical burst switching (OBS) presents itself as a promising technology for bridging the gap between optical wavelength switching
and optical packet switching. Increasingly, researchers attempt to incorporate more realistic constraints into the design
of OBS networks. Optical signal transmission quality is subject to various types of physical impairment introduced by optical
fibers, switching equipment, or other network components. The signal degradation due to physical impairments may be significant
enough such that the bit-error rate of received signals is unacceptably high at the destination, rendering the signal not
usable. In this paper, based on earlier work, we study the burst scheduling problem in OBS networks, taking into account physical
impairment effects. We propose three effective burst scheduling algorithms: (1) a JET based Physical Impairment Constrained
Algorithm (JETPIC), (2) an Integrated Physical Impairment Constrained Algorithm (IPIC), and (3) an Enhanced Integrated Physical
Impairment Constrained Algorithm (EIPIC). At an OBS node, the proposed algorithms schedule bursts for transmission by searching
for available resources as well as verifying signal quality. Our simulation results show that the proposed algorithms are
effective in terms of reducing the burst blocking probability. In general, algorithm JETPIC outperforms algorithms IPIC and
EIPIC in burst blocking probability and average end-to-end delay performance.
相似文献
Bin WangEmail: |
13.
An efficient dynamic distributed optical link establish method in intelligent all-optical networks 总被引:1,自引:0,他引:1
In this article, an efficient, fast, and dynamic distributed optical link setup method is proposed. Two kinds of novel optical
fast link release mechanisms (Ahead and Timeout Release) are presented for an optical-link establishment. They can dramatically
reduce the blocking probability. For dynamic routing detection, a new kind of dynamic weighted Dijkstra algorithm (DW-DA)
along with dynamic optical link load balancing is described. A variable mutation and crossover rates of a genetic algorithm
(VMCR-GA) is used for fast wavelength assignment with two-novel-wavelength assignment rules in a wavelength relationship graph,
which can reduce the necessary wavelengths and link establishment time. Through simulation giving the blocking probability
and the time for link establishment on several well-known networks, the effectiveness of this method has been verified. The
blocking probability of the network can be reduced significantly below that of normal routing and wavelength assignment (RWA).
Furthermore, the calculating time for reaching the minimum blocking probability can be reduced dramatically.
相似文献
Jun HeEmail: |
14.
Igor M. Moraes Rafael P. Laufer Daniel de O. Cunha Otto Carlos M. B. Duarte 《Photonic Network Communications》2009,18(1):65-76
This article proposes the load-level-based admission control (LLAC) mechanism in order to provide service differentiation
for optical burst-switched networks. The LLAC mechanism admits bursts of a given service class according to the network load
and a class-associated parameter. Based on this parameter, called load level, the proposed mechanism differentiates the burst blocking probability experienced by each service class. We develop an analytical
model for the proposed mechanism and evaluate its performance for different configurations through mathematical analysis.
The results show that the load-level-based mechanism reduces the blocking probability of high-priority bursts by two orders
of magnitude or more depending on the analyzed scenario. In addition, compared to other similar mechanisms, the load-level-based
mechanism effectively differentiates the services in all analyzed configurations, requires less states in optical burst switching
(OBS) nodes, and does not suffer from priority inversion.
相似文献
Otto Carlos M. B. DuarteEmail: |
15.
Based on the important role of optical switching in all-optical communications, a novel 3 × 3 optical switch is proposed using
Phase Spatial Light Modulators (PSLM), Polarizing Beam-Splitters (PBS), mirrors, and Quarter-Wave Plates (QWP). This new configuration
of optical switch has the advantages of being compact in structure, efficient in performance, and insensitive to polarization
of the signal beam. Moreover, the functions of the 3 × 3 optical switch have been implemented bidirectionally in free-space.
According to the routing-state table of the polarization-independent 3 × 3 optical switch, its operational processes are analyzed,
and the results show that the experimental module of the 3 × 3 optical switch can connect an arbitrary output port to any
input port beams. Simultaneously, the module is scalable to large array sizes and has the capability of reconfiguration. Therefore,
it should be helpful in the design of a large-scale switching matrix.
相似文献
Jun-Bo YangEmail: |
16.
Daniel Morató Javier Aracil Juan Pedro Fernández-Palacios Óscar González de Dios Jesús-Felipe Lobo Poyo 《Photonic Network Communications》2008,15(2):159-169
This article presents capacity planning rules for the control plane of all-optical networks featuring GMPLS and RSVP-TE as
a connection setup protocol. As per RSVP standard, a refresh message mechanism is incorporated to RSVP such that the state
is periodically refreshed on a link per link basis. We provide analytical expressions for the bandwidth and buffer sizes to
be provided such that no flows are torn down due to lack of refresh messages. Our findings show that small buffers (several
KBytes) suffice to sustain the signaling load for as much as 400 RSVP flows per link, with the simplest RSVP refresh mechanism
(neither using link bundling nor acknowledgments). On the other hand, we also find the packet drop probability per link for
a given network topology for the case that the flow survival probability is larger than a given threshold. We provide numerical
examples based on the COST 239 european network topology and real RSVP traffic traces from early-commercial switching equipment.
相似文献
Jesús-Felipe Lobo PoyoEmail: |
17.
A novel optical buffering architecture for Optical Packet Switching (OPS) networks is proposed in this article. The architecture
which adopts a fiber-sharing mechanism aims at solving the problem of using a large number of fiber delay lines that are used
to solve resource contention in the core node in OPS networks. The new architecture employs fewer fiber delay lines compared
to other simple architectures, but can achieve the same performance. Simulation results and analysis show that the new architecture
can decrease packet loss probability effectively and achieve reasonable performance in average packet delay.
相似文献
Fang GuoEmail: |
18.
Xianwei Zhou Lin Lin Jianping Wang Xuesong Zhang 《Wireless Personal Communications》2009,49(1):123-131
In this paper, the cross-layer design routing in cognitive radio(CR) networks is studied. We propose a colored multigraph
based model for the temporarily available spectrum bands, called spectrum holes in this paper. Based on this colored multigraph
model, a polynomial time algorithm with complexity O(n
2) is also proposed to develop a routing and interface assignment, where n is the number of nodes in a CR network. Our algorithm optimizes the hop number of routing, meanwhile, the adjacent hop interference
(AHI) is also optimized locally.
相似文献
Lin Lin (Corresponding author)Email: |
19.
Jean-Marc Hyppolite Philippe Galinier Samuel Pierre 《Photonic Network Communications》2008,15(2):123-130
This paper proposes a tabu search heuristic for solving the routing and wavelength assignment problem in multigranular optical
networks, considering the wavelength-continuity constraint and a set of connections to satisfy. For a number of fibers per
link, a number of wavebands per fiber, and a number of wavelengths per waveband, this algorithm attempts to minimize the total
number of ports used in the network by efficiently grouping lightpaths into bands and fibers, and switching the whole bands
and fibers. The algorithm has been implemented and tested on the NSFNET network, and comparisons have been made with the Balanced
Path Routing and Heavy Traffic First (BPHT) algorithm in terms of number of ports. Generally, the results obtained with our
tabu search heuristic are better than those provided by this algorithm.
相似文献
Samuel PierreEmail: |
20.
A dynamic routing and wavelength allocation technique with an interplay between physical and network layer parameters encompassing
Four-wave mixing (FWM) awareness and teletraffic performance of wavelength-routed optical networks has previously been proposed
for a distributed approach. In this article, we present a fast computational algorithm for our routing and wavelength assignment
(RWA) encompassing FWM-induced crosstalk. The objective is to minimize the time of establishing a dynamic lightpath. For this
purpose, a precomputed matrix of FWM crosstalk products is used in an adapted version of the FWM-aware dynamic RWA algorithm.
The approach is validated through simulations showing improvement up to 30–50% on the provisioning time of lightpaths for
different network topologies compared to an online full computational scheme.
相似文献
Ken-ichi KitayamaEmail: |