The disjoint multipath challenge: multiple disjoint paths guaranteeing scalability

The multipath challenge is a research line in continuous development because of its multiple benefits, however, these benefits are overshadowed by scalability, which goes down considerably when the paths are multiple and disjoint. The disjointness aggregates an extra value to the multiple paths, but it also implies more complex mathematical operations that increase the computational cost. In fact, diverse proposals exist that try to increase scalability by limiting the number of paths obtained to the minimum possible (two-disjoint paths), which is enough for backup applications but not for other purposes. This paper presents an algorithm that solves these drawbacks by discovering multiple disjoint paths among multiple nodes in an efficient way, while keeping bounded the computational cost and ensuring scalability. The proposed algorithm has been validated thoroughly by performing a theoretical analysis, bolstered afterwards by an exhaustive experimental evaluation. The collected results are promising, our algorithm reduces the time spent to obtain the disjoint paths regarding its competitors between one and three orders of magnitude, at the cost of a slight decrease in the number of paths discovered.Comunidad de MadridJunta de Comunidades de Castilla-La Manch

Modified Dijkstra Shortest Path Algorithm for SD Networks

This paper uses a modified Dijkstra shortest path method for considering cumulative delays rather than bandwidth in software-defined networks. To implement the proposed method, an open-source Ryu controller is used, and a Mininet tool is used to emulate the topology. The proposed method is compared with the traditional Dijkstra’s algorithm to demonstrate its performance. This comparison shows that the modified Dijkstra’s algorithm provides higher performance of the different cumulative delays. Several experiments were conducted to evaluate the performance of the proposed method using three parameters (bandwidth, transfer rate and jitter). In addition, the cumulative distribution function is calculated using the parameters to show its distribution through the experiment period

Loop detection and prevention mechanism in multiprotocol label switching

The extended color thread algorithm is based on running a thread hop by hop before the labels are distributed inside a MPLS Cloud Since the path for the data packets is set beforehand, the loop formation occurs at the control path. The shortest paths between selected source and destination have been calculated using Dijkstra\u27s shortest path algorithm and threads are allowed to extend through the routers. With the passage of each next hop, a distributed procedure is executed within the thread, generating a unique color at nodes. This keeps a track on router\u27s control path and at the same time ensures that no loop formation occurs. In loop prevention mode, a router transmits a label mapping, when it rewinds the thread for that particular LSP. Likewise, if a router operates in loop detection mode, it returns a label-mapping message without a thread object, after receiving a colored thread. The scheme is a loop prevention scheme, thus, ensuring loop detection and loop mitigation. The same algorithm is then extended to a proposed MPLS environment with global label space. (Abstract shortened by UMI.)

Performance Analysis of Optimal Path Finding Algorithm In Wireless Mesh Network

Wireless Mesh Network has emerged as a key technology for next generation wireless networking because of its advantage over other wireless technologies. Wireless Mesh Network has been widely accepted as a replacement for areas of ad-hoc network or MANET. Multi hop wireless mesh technology has become a new paradigm for communication. Wireless Mesh Network is an attractive solution for providing last-mile connectivity. ...

Path Planning and Control of an Autonomous Quadrotor Testbed in a Cluttered Environment

A classical problem for robotic navigation is how to efficiently navigate from one point to another and what to do if obstacles are encountered along the way. Many map based path planning algorithms attempt to solve this problem, all with varying levels of optimality and complexity. This work shows a review of selected algorithms, and two of these are selected for simulation and testing using a quadrotor unmanned aerial vehicle (UAV) in a dynamic indoor environment which requires replanning capabilities. The Dynamic A* algorithm, or simply D*, and the Probabilistic Roadmap method (PRM) are used in a scenario designed to test their respective functionality and usefulness with the goal of determining the better algorithm for flight testing given a partially known or changing environment.;The development of the quadrotor platform hardware is discussed as well as the associated software and capabilities. Both algorithms are redesigned to fit this specific application and display their respective planned and replanned paths in an intuitive and comparable manner. Simulation is performed and an obstacle is added to the map during the quadrotor motion, requiring a replanned path. Results are compared for both computed path length and computational intensity. Flight testing is performed in an indoor environment, and during the flight an obstacle is inserted into the flight path, requiring detection and replanning. Results are compared for computed path length and intuitively analyzed to compare optimality and complexity

Implementasi Multipath Routing Berbasis Algoritme DFS yang dimodifikasi

Multipath routing merupakan metode routing dengan menggunakan beberapa jalur yang tersedia. Dengan multipath routing diharapkan dapat mengurangi kemacetan pada jaringan dengan melakukan load-balancing sehingga traffic jaringan dapat didistribusikan ke beberapa jalur. Multipath routing dapat diterapkan dengan konsep Software-Defined Networking (SDN) yang memisahkan control plane dan data plane sehingga dapat mempermudah pengembangan aplikasi jaringan. Untuk itu, penulis melakukan implementasi multipath routing pada jaringan OpenFlow SDN berbasis algoritma DFS yang dimodifikasi dan algoritma Dijkstra yang dimodifikasi sebagai referensi pembanding. Hasil simulasi menunjukkan sistem dapat melakukan pencarian beberapa jalur pada suatu topologi dengan response time rata-rata algoritme DFS adalah 612,7 ms. Rata-rata response time algoritme DFS yang dimodifikasi adalah 632,6 ms dan Dijkstra 325,6 ms. Jumlah iterasi Algoritme DFS memerlukan 12694 iterasi, modified-DFS sebanyak 12860 iterasi, dan Dijkstra sebanyak 800 iterasi. Rata-rata execution time algoritme DFS adalah 0,0185 ms, modified DFS adalah 0,0258 ms, dan modified Dijkstra 0,0005 ms. Hasil pengujian throughput menunjukan sebanyak 50% dari client mendapat throughput 20 Mbps atau kurang pada algoritme modified-DFS. Sedangkan pada Dijkstra, sebanyak 50% dari client mendapat throughput 23 Mbps atau kurang. Hasil pengujian multipath menunjukkan mekanisme load-balancing dengan group table masih terdapat flow yang tidak terdistribusi seimbang

Social Graphs and Their Applications to Robotics

In this thesis, we propose a new method to design a roadmap-based path planning algorithm in a 2D static environment, which assumes a-priori knowledge of robots’ positions, their goals’ positions, and surrounding obstacles. The new algorithm, called Multi-Robot Path Planning Algorithm (MRPPA), combines Visibility graph VG method with the algebraic connectivity