Miguel Camelo

QoS routing algorithm based on multi-objective optimization for Wireless Mesh Networks

In this paper we present a new alternative for the routing problem in Wireless Mesh Networks (WMN) taking into account the quality of service (QoS). The actual problem includes multiple objectives with conflicts among them. Classical approximations optimize a single objective or QoS parameter, however they do not not take into account the conflicting nature of these parameters leading to suboptimal solutions. We take a new approach trying to improve the routing solutions and propose the use of a multi-objective evolutionary algorithms (MOEA), specifically the NSGA II algorithm. A mathematical model is introduced for this problem, which includes QoS parameters such as bandwidth, packet loss rates, delay and power consumption.

Efficient Routing in Data Center with Underlying Cayley Graph

Nowadays data centers are becoming huge facilities with hundreds of thousands of nodes, connected through a network. The design of such interconnection networks involves finding graph models that have good topological properties and that allow the use of efficient routing algorithms. Cayley Graphs, a kind of graphs that represents an algebraic group, meet these properties and therefore have been proposed as a model for these networks. In this paper we present a routing algorithm based on Shortlex Automatic Structure, which can be used on any interconnection network with an underlying Cayley Graph (of some finite group). We show that our proposal computes the shortest path between any two vertices with low time and space complexity in comparison with traditional routing algorithms.

Geometric Routing With Word-Metric Spaces

As a potential solution to the compact routing problem, geometric routing has been proven to be both simple and heuristically effective. These routing schemes assign some (virtual) coordinates in a metric space to each network vertex through the process called embedding. By forwarding packets to the closest neighbor to the destination, they ensure a completely local process with the routing table bounded in size by the maximum vertex degree. In this letter, we present an embedding of any finite connected graph into a metric space generated by algebraic groups, and we prove that it is greedy (guaranteed packet delivery). Then, we present a specialized compact routing scheme relying on this embedding for scale-free graphs. Evaluation through simulation on several Internet topologies shows that the resulting stretch remains below the theoretical upper bounds.

A Multi-objective Routing Algorithm for Wireless Mesh Network in a Smart Cities Environment

Wireless Mesh Networks (WMN) is one of the most common network infrastructure that provides the technical characteristics to fulfill the requirements proposed by the Smart Cities. In order to obtain an efficient allocation and use of resources in such kind of infrastructures, the design of routing protocols that support Quality of Service (QoS) is fundamental. In this paper we propose a routing algorithm based on the Strength Pareto Evolutionary Algorithm (SPEA). This algorithm intends to build the most efficient routes by considering the shortest path, the energy consumption, the free space lost and QoS restrictions (delay and bandwidth) at the same time. As result, the designed routing protocol could be used in unicast or multicast transmission schemes, with or without restrictions and into centralized or decentralized environments.

Cayley-Graph-Based Data Centers and Space Requirements of a Routing Scheme Using Automata

Modern data centers connect tens of thousands of computers by an interconnection network. The design of such networks implies the selection of an appropriate routing scheme for them. Those schemes need to be efficient with respect to time and space requirements. Cayley Graphs (CG) has been proposed as models for large-scale interconnection networks with excellent properties and very efficient routing schemes. In a previous work, we presented a fast general-purpose shortest path routing scheme for CG with compact routing tables. The scheme uses the concept the Automatic Structures (AS) of a group. However, the size of such structures was not considered into the complexity analysis. Therefore, this paper evaluates the required space to keep such structures and the several intermediate finite state automata that arise during the process of constructing such AS. We perform the evaluation on six well-known families of CG. The results show which structures are space-efficient to implement the scheme, and how the size of such structures depends on the so-called k-fellow traveler property.

Routing at Large Scale: Advances and Challenges for Complex Networks

A wide range of social, technological and communication systems can be described as complex networks. Scale-free networks are one of the well known classes of complex networks in which nodes� degrees follow a power-law distribution. The design of scalable, adaptive and resilient routing schemes in such networks is very challenging. In this article we present an overview of required routing functionality, categorize the potential design dimensions of routing protocols among existing routing schemes, and analyze experimental results and analytical studies performed so far to identify the main trends/trade-offs and draw main conclusions. Besides traditional schemes such as hierarchical/shortest-path path-vector routing, the article pays attention to advances in compact routing and geometric routing since they are known to significantly improve scalability in terms of memory space. The identified trade-offs and the outcomes of this overview enable more careful conclusions regarding the (un-)suitability of different routing schemes to large-scale complex networks and provide a guideline for future routing research.

WMGR: A Generic and Compact Routing Scheme for Data Center Networks

Data center networks (DCNs) connect hundreds and thousands of computers and, as a result of the exponential growth in their number of nodes, the design of scalable (compact) routing schemes plays a pivotal role in the optimal operation of the DCN. Traditional trends in the design of DCN architectures have led to solutions, where routing schemes and network topologies are interdependent, i.e., specialized routing schemes. Unlike these, we propose a routing scheme that is compact and generic, i.e., independent of the DCN topology, the word-metric-based greedy routing. In this scheme, each node is assigned to a coordinate (or label) in the word-metric space (WMS) of an algebraic group and then nodes forward packets to the closest neighbor to the destination in this WMS. We evaluate our scheme and compare it with other routing schemes in several topologies. We prove that the memory space requirements in nodes and the forwarding decision time grow sub-linearly (with respect to

A scalable parallel Q-Learning algorithm for resource constrained decentralized computing environments

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QoS Routing Algorithms based on Multi-Objective Optimization for Mesh Networks

, the number of nodes) in all of these topologies. The scheme finds the shortest paths in topologies based on Cayley graphs and trees (e.g. Fat tree), while in the rest of topologies, the length of any path is stretched by a factor that grows logarithmically (with respect to

MAGS - An Approach Using Multi-Objective Evolutionary Algorithms for Grid Task Scheduling

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