An improved multicast routing algorithm in sparse splitting WDM networks (original) (raw)
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Is Light-Tree Structure Optimal for Multicast Routing in Sparse Light Splitting WDM Networks
2009
To minimize the number of wavelengths required by a multicast session in sparse light splitting Wavelength Division Multiplexing (WDM) networks, a light-hierarchy structure, which occupies the same wavelength on all links, is proposed to span as many destinations as possible. Different from a lighttree, a light-hierarchy accepts cycles, which are used to traverse crosswise a 4-degree (or above) multicast incapable (MI) node twice (or above) and switch two light signals on the same wavelengths to two destinations in the same multicast session.
Distance priority based multicast routing in WDM networks considering sparse light splitting
2009
As we know, the Member-Only algorithm in [1] provides the best links stress and wavelength usage for the construction of multicast light-trees in WDM networks with sparse splitting. However, the diameter of tree is too big and the average delay is also too large, which are intolerant for QoS required multimedia applications. In this paper, a distance priority based algorithm is proposed to build light-trees for multicast routing, where the Candidate Destinations and the Candidate Connectors are introduced. Simulations show the proposed algorithm is able to greatly reduce the diameter and average delay of the multicast tree (up to 51% and 50% respectively), while keep the same or get a slightly better link stress as well as the wavelength usage than the famous Member-Only algorithm.
Computer Communications, 2006
Because optical WDM networks will be realized as network backbone in the near future, multicasting in WDM networks needs to be supported for various network applications. In this paper, we propose a new dynamic multicast routing problem under delay constraints (DMR-DC) for finding an optimal light-forest with the minimum multicast cost from these links with available wavelengths for routing a multicast request that arrives in random with a given delay bound in a WDM network with heterogeneous light splitting capabilities, where a light-forest is a set of lighttrees used to set up switches to route the request. Multicast cost is defined by communication cost ratio and wavelength consumption ratio. The problem is to determine a light-forest with less wavelength consumption and less communication cost. This problem is NP-hard because it can be reduced from the minimum Steiner tree problem. In this paper, we propose an efficient three-phase (generation, refinement, and conversion) solution model to find approximate solutions in a reasonable time.
Cost bounds of multicast light-trees in WDM networks
2010
The construction of light-trees is one principal subproblem for multicast routing in sparse splitting Wavelength Division Multiplexing (WDM) networks. Due to the light splitting constraint and the absence of wavelength converters, several light-trees may be required to establish a multicast session. However, the computation of optimal multicast light-trees is NP-hard. In this paper, we study the wavelength channel cost (i.e., total cost) of the light-trees built for a multicast session. An equal cost of 1 unit hop-count cost is assumed over all the fiber links in the network. We prove that the total cost of a multicast session is tightly lower limited to K and upper bounded to
Cost bounds and approximation ratios of multicast light-trees in WDM networks
2011
The construction of light-trees is one of the principal subproblems for all-optical multicast routing (AOMR) in sparse splitting Wavelength Division Multiplexing (WDM) networks. Due to the light splitting constraint and the absence of wavelength converters, several light-trees may be required to establish a multicast session. However, the computation of the cost-optimal multicast light-trees is NPhard. In this paper, first we study the cost bounds of the lighttrees built for a multicast session in unweighted WDM networks. Then, partially based on this result, the approximation ratios of some classical multicast light-tree computation algorithms, i.e., Reroute-to-Source (R2S) and Member-Only (MO) algorithms are derived in both unweighted and nonequally weighted WDM networks. Moreover, integer linear programming (ILP) formulations are introduced and carried out to search the optimal light-trees for multicast routing. The cost bounds and approximation ratios of R2S and MO algorithms in some candidate WDM backbone networks are examined through simulations.
Avoidance of multicast incapable branching nodes for multicast routing in WDM networks
Photonic Network Communication
In this articlewestudy themulticast routing problem in all-opticalWDMnetworks under the spare light splitting constraint. To implement a multicast session, several light-trees may have to be used due to the limited fanouts of network nodes. Although many multicast routing algorithms have been proposed in order to reduce the total number of wavelength channels used (total cost) for a multicast session, the maximum number of wavelengths required in one fiber link (link stress) and the end-to-end delay are two parameters which are not always taken into consideration. It is known that the shortest path tree (SPT) results in the optimal end-to-end delay, but it can not be employed directly for multicast routing in sparse light splitting WDM networks. Hence, we propose a novel wavelength routing algorithm which tries to avoid the multicast incapable branching nodes (MIBs, branching nodes without splitting capability) in the shortest-path-based multicast tree to diminish the link stress. G...
Multicast routing in WDM networks without splitters
IEEE Communications Magazine, 2014
Multicasting in WDM core networks is an efficient way to economize network resources for several multimedia applications. Due to their complexity and cost, multicast capable switches are rare in the proposed architectures. The paper investigates the multicast routing without splitters in directed (asymmetric) graphs. The objective is to minimize the number of used wavelengths and if there are several solutions, choose the lowest cost one. We show that the optimal solution is a set of light-trails. An efficient heuristic is proposed to minimize conflicts between the light-trails, and so to minimize the number of used wavelengths. The performance is compared to existing light-trail based heuristics. Our algorithm provides a good solution with a few wavelengths required and a low cost.
Construction of light-trees for WDM multicasting under splitting capability constraints
10th International Conference on Telecommunications, 2003. ICT 2003., 2003
m i k l o s. m o l n a r @ i r i s a. f r Absfmct-Communication systems with all-opticaf multi-demonstrated [l]. This capacity was obtained using carting h e bctterpe%fo"ce those mi% opdcdelec-273 wavelengths, and each wavelength had 40 Chps tricaVoptical conversion Multicast pmtacols assume that all mte, ~~~~~d~ many WM transmission nodes in the network can fonvard the signal m m one input to several outputs, Since to fabricate an optical switch with splhting c&jiity tech[ogy. :here fOu Multicast communication is becoming increasingly swirches that are multicast c d k. The heurisrics desirned imDortant in the recent vears. due to more efficient systems are availab1e ' Om different pmvidm' for ail-opticaf nenvorh have rb this limitation In-this paper; we intmduce a Shonest Path Based FOZSI algorithmfor all-optical rrerworkc We pmpose a post-processing algorithm to reduce the number of wavelength needed The effect of this post-processing algorithm is also m ' n e d in a well-known
Routing in sparse splitting optical networks with multicast traffic
Computer Networks, 2003
In this paper, we investigate the problem of Multicast Routing in Sparse Splitting Networks (MR-SSN). Given a network topology with the multicast capable nodes distributed uniformly throughout the network, and a multicast session, the MR-SSN problem is to find a route from the source node of the multicast session to all destinations of the multicast session such that the total number of fibers used in establishing the session is minimized. In this paper, we develop a rerouting algorithm for a given Steiner tree, which makes it feasible to route a multicast session using a treebased solution in sparse light splitting optical networks. In addition, we present a heuristic based on Tabu Search (TS) that requires only one transmitter for the source node and one wavelength for each multicast session. To evaluate the performance of heuristics, we formulate the MR-SSP problem as an integer linear program (ILP), and optimally solve small instances using the commercially available linear solver, CPLEX. We test our heuristic on a wide range of network topologies. Our experimental results show that: (1) The difference between our solution and ILP optimal solution, in terms of the number of fibers used for establishing a multicast session, is within 10% in almost all the instances and within 5% in about half of the instances. (2) The average delay, taken over all destination nodes, falls within three times the optimal value. (3) A sparse light splitting all-optical network with 30% of multicast capable cross-connects has an acceptable low cost and relatively good performance. (4) The improvement achieved by TS heuristic increases considerably when the session size is large, the number of Splitter-and-Delivery cross-connects is small, and the network connectivity is dense.
Virtual-node-based multicast routing and wavelength assignment in sparse-splitting optical networks
Photonic Network Communications, 2010
This paper investigates several problems associated with optical multicast routing and wavelength assignment in sparse-splitting optical networks for interactive real-time media distribution. Unfortunately, the constrained multicast routing with optimized wavelength assignment leads to NP-complete condition. Thus, in this paper, a virtual-node-based multicast routing algorithm is first proposed to satisfy the requirements of interactive real-time multicasting as well as the constraints from underlying optical networks. For the constructed multicast tree, we then associate an effective wavelength assignment algorithm. The experimental results show that the proposed algorithm combination performs well in terms of (1) the wavelength channel cost, (2) the maximum variation of inter-destination node delays, (3) the signal quality, and (4) the number of wavelength conversions.