Analyzing the state of the art in order to tackle a new problem is always a mandatory issue. Literature offers surveys based on summaries of previous works, often based on theoretical descriptions of the methods. An engineer however, requires some evidence from experimental evaluations in order to make the appropriate decision when selecting a technique for a problem. This is what we have done in this paper: experimentally analyze a set of representative techniques of the state of the art in the problem we are dealing with, namely the road passenger transportation problem. This is an optimization problem in which drivers should be assigned to transport services fulfilling some constraints and minimizing some function cost. The experimental results have provided us with a good knowledge of several properties of the methods, as modeling expressiveness, anytime behavior, computational time, memory requirements, parameters, and free downloadable tools. From our experience, we are able to choose a technique to deploy our problem. We hope that this analysis can be also helpful for other engineers facing a similar problem.

SUMMARYLabel space consumption has been studied in label-based forwarding architectures such as multi-protocol label switching (MPLS) to reduce forwarding table sizes and lookup complexity, to simplify network management, and to limit operational expenditures. On the other hand, nowadays label-based forwarding is also considered in the context of carrier class Ethernet architectures. Given that these architectures may use different label scopes (domain-wide vs. local) and size spaces (depending on their encoding), there is a need to analyse and compare the properties of their respective label spaces, particularly in terms of scalability. In this paper, the impact of topology characteristics on label space consumption is studied. The dependency on factors such as the number of nodes, the topology node degree and the network structure is determined (both analytically and via experimentation), allowing a detailed comparison between the properties of the evaluated label spaces. Proposed techniques that can be applied to improve label space usage for label-based Ethernet forwarding architectures are considered. The proposed methodology and results can serve as guidelines for the design of future label based forwarding architectures.

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Optical transport networks (OTN) should be prepared to jointly handle both multicast and unicast traffic. Both opaque and transparent architectures are available to handle these types of traffic. Light-trees have been proposed as a way to transport information in a transparent manner. The light-tree however, may route unwanted information through some links while performing grooming of unicast and multicast traffic. To solve this problem we propose S/G light-tree with the goal of optimising the resources from the point of view of the number of wavelengths and available capacity. S/G light-tree uses detection systems (DS) and splitter and amplifier banks (SABs) to determine when unicast traffic should not be routed jointly with a multicast one by eliminating it optically from the link. This article proposes an online heuristic with grooming policies which allows for the analysis of the effects of the number of SABs on the blocking probability in OTN with dynamic traffic. Impact of the number of SAB on architectures 91

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