Multicasts on WDM all-optical multistage interconnection networks (original) (raw)
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Cost-effective implementation of multicasting in wavelength-routed networks
Journal of Lightwave Technology, 2000
Multicasting in the optical domain has been recently shown to provide substantial savings in terms of the network-wide average packet hop distance and the total number of transceivers in the network. Current proposed multicasting architectures [e.g., Splitter-and-Delivery (SaD)] employ power splitting mechanisms which have the side effect of high fabrication cost due to the large number of splitters and the need for optical amplifiers. We propose a low-cost novel architecture called Tap-and-Continue (TaC) for realizing multicasting. This architecture provides a natural evolution from current unicast cross-connects and is based on tapping devices. We prove that any multicasting session can be feasibly realized in networks employing only TaC cross-connects, and the problem of finding the optimal multiple-destination minimum cost trail in such networks is NP-complete. Therefore, we develop a 4-approximation algorithm for multiple-destination routing. Simulation results demonstrate that the TaC cross-connect provides a realistic, cost-effective approach for implementing multicasting with negligible blocking degradation especially in multifiber networks.
Multicast routing and wavelength assignment in multihop optical networks
IEEE/ACM Transactions on Networking, 2002
This paper addresses multicast routing in multi-hop optical networks employing wavelength-division multiplexing (WDM). We consider a model in which multicast communication requests are made and released dynamically over time. A multicast connection is realized by constructing a multicast tree which distributes the message from the source node to all destination nodes such that the wavelengths used on each link and the receivers and transmitters used at each node are not used by existing circuits. We show that although the routing and wavelength assignment in this model is NP-complete, the wavelength assignment problem can be solved in linear time.
Multicast routing and allocation of wavelengths in a WDM network with splitters and converters
International Journal of Internet Protocol Technology, 2021
This paper deals with the problem of multicast routing and the allocation of wavelengths in a WDM network with optical splitters and converters. We present an exact formulation in integer linear programming (ILP) to find a set of optical structures connecting a source to a set of destination nodes. We use a new optical structure called hierarchical. In hierarchical structure, an optical signal can pass more than once through the same optical node and an intermediate node can belong to the set of destinations; this is a generalization of "light trails"). The problem of multicast routing with sparse wavelength conversion and sparse splitting using the hierarchical structure has not yet been studied. So, our main contribution consists of introducing new optical constraints of wavelength converters with the hierarchical structure. The objective is to focus on the benefits and performances of using wavelength converters in a WDM network. Simulation results show that the hierarchical structure gets better results in terms of overall link cost and number of wavelengths in the case of WDM network sparse wavelength converters than the WDM network without converters.
Multicasting in Optical Transport Networks
Journal of Optical Communications, 1998
The introduction of multicasting in optical transport networks is analysed and discussed. Three different optical path realization techniques, involving the multicasting function, are examined: the Multicast Wavelength Path (MWP), the Multicast Virtual Wavelength Path (MVWP) and the Partial Multicast Virtual Wavelength Path (PVWP). A performance evaluation model is reported and results of the performance analysis are discussed. In addition several optical cross-connect architectures, allowing multicasting to be achieved, are investigated and compared. Three different types of optical switches are considered: space division, delivery and coupling, and wavelength switches. Crucial aspects as the modularity, the complexity, the costs and some transmission aspects are taken into account in the analysis.
Optimal wavelength-routed multicasting
Discrete Applied Mathematics, 1998
Motivated by wavelength division multiplexing in all-optical networks, we consider the problem of finding a set of paths from a fixed source to a multiset of destinations, which can be coloured by the fewest number of colours so that paths of the same colour do not share an arc. We prove that this minimum number of colours (wavelengths) is equal
Routing algorithm for multicast under multi-tree model in optical networks
To establish a multicast connection in a wavelength routed optical network, two steps are needed under the multi-tree model. One is to construct a set of light-trees rooted at the source node such that in each of them at most a speciÿed number of destination nodes are allowed to receive the data and every destination node must be designated in one of them to receive the data. The other is to assign a wavelength to each of the produced light-trees in such a way that two light-trees must be assigned two distinct wavelengths if they use a common link. In this paper we mainly study how to construct a multicast routing of minimal cost under the multi-tree model in optical networks, where the routing cost is total costs of the produced light-trees. We propose a 4-approximation algorithm for this NP-hard problem.
Routing and Wavelength Assignment in All-Optical Networks with Multihop Connections
AEU - International Journal of Electronics and Communications, 2001
Abstracf-This paper considers the problem of routing connections in a reeontigurable optical network using wavelength division multiplexing. Each connection between a pair of nodes in the network is assigned a path through the network and a wavelength on that path, such that connections whose paths share a common link in the network are assigned d]fferent wavelengths. We derive an upper bound on the carried traffic of connections (or equivalently, a lower bound on the blocking probability) for any routing and wavelength assignment (RWA) algorithm in such a network. The bound scales with the number of wavelengths and is achieved asymptotically (when a large number of wavelengths is available) by a fixed RWA algorithm. Although computationally intensive, our bound can be used as a metric against which the performance of different RWA algorithms can be compared for networks of moderate size. We illustrate thii by comparing the performance of a simple shortest-path RWA (SP-RWA) algorithm via simulation relative to our bound. We also derive a similar bound for optical networks using dynamic wavelength converters, which are equivalent to circuit-switched telephone networks, and compam the two cases for different examples. Finatly, we quantify the amount of wavelength reuse achievable in large networks using the SP-RWA via simulation as a function of the number of wavelengths, number of edges, and number of nodes for randomly constructed networks as well as deBruijn networks. We also quantify the difference in wavelength reuse between two different optical node architectures. The results show that it is feasible to provide several all-optical connections to each node in a large network using a limited number of wavelengths. For instance, using 32 wavelengths, it is possible to provide 10 full-duplex connections to each node in a 128-node random network with average degree 4, and 5 full-duplex connections per node in a 1000-node random network with average degree 4. The results also show that wavelength converters offer a 10-40% increase in the amount of reuse achievable for our sampling of 14 networks ranging from 16 to 1000 nodes when the number of wavelengths available is small (10 or 32).
Power-efficient design of multicast wavelength-routed networks
IEEE Journal on Selected Areas in Communications, 2000
In this paper, we introduce the power-efficient design space for multicast wavelength-routed networks. The power-efficient design space is based on the impact of power on the overall design of wavelength-routed networks. Two cross-connect architectures on this design concept are investigated. One is an existing architecture called splitter-and-delivery (SaD). The other is a new architecture called multicast-only splitter-and-delivery (MOSaD).
IEEE Communications Letters, 2007
We consider the multicast routing and wavelength assignment (MC-RWA) problem on WDM bidirectional ring networks without wavelength conversion. We give an integer programming formulation of the problem and propose an algorithm to solve it optimally. The algorithm is based on column generation and branch-and-price. We test the proposed algorithm on randomly generated data and the test results show that the algorithm gives optimal solutions to all of the test problems.
IEICE Transactions on Communications, 2010
We propose a scheme of MultiCast Routing and Wavelength Assignment (MC-RWA) to establish light-tree for dynamic multicast session for the Wavelength Division Multiplex (WDM) network by choosing the wavelength that leads to a reduction in blocking probabilities by using a parameter Δ. Δ is defined as the overall reduction of connectivity of the nodes in the network caused by a wavelength assignment process when using a particular wavelength, and we assign wavelength resources to the multicast session by choosing the Δ which leads to smallest reduction in connectivity. Through computer simulation, we show that the proposed scheme has lower blocking probabilities when compared with minimum cost scheme under the condition that wavelength conversion is not allowed.