On MPR-OSPF Specification and Implementation in Quagga/GTNetS

This document analyses the MPR-OSPF current specification and compares it with the implemented version for the Quagga / Zebra routing suite, adapted for the GTNetS network simulator. It presents the relationship between Quagga/Zebra core and the GTNetS simulation framework, describes the inner architecture of the MPR-OSPF extension in the OSPF Quagga general implementation and identifies the different protocol main elements in the implemented code

THE CONVERGENCE OF THE OSPF ROUTING PROTOCOL

In this paper an OSPF convergence time prediction model is introduced. It is based on examining the behaviour OSPF and on the analysis of the generated data by OSPF flooding. The model was validated and refined by tests and experiments on a test network built for this work. The resultant model can be used to predict the effect and convergence of a change in an OSPF network. This feature is very usable for pre-emptive network management and network planning

Design and Development of the Reactive BGP peering in Software-Defined Routing Exchanges

The Software-Defined Networking (SDN) is considered to be an improved solution for applying flexible control and operation recently in the network. Its characteristics include centralized management, global view, as well as fast adjustment and adaptation. Many experimental and research networks have already migrated to the SDN-enabled architecture. As the global network continues to grow in a fast pace, how to use SDN to improve the networking fields becomes a popular topic in research. One of the interesting topics is to enable routing exchanges among the SDN-enabled network and production networks. However, considering that many production networks are still operated on legacy architecture, the enabled SDN routing functionalities have to support hybrid mode in operation. In this paper, we propose a routing exchange mechanism by enabling reactive BGP peering actions among the SDN and legacy network components. The results of experiments show that our SDN controller is able to mask as an Autonomous System (AS) to exchange routing information with other BGP routers

MPR-based Pruning Techniques for Shortest Path Tree Computation

Multi-Point Relaying (MPR) is a well-known relay pruning algorithm that has proved to be useful for efficient dissemination in Mobile Ad hoc Networks (MANETs). But this technique may be useful for other tasks in MANET link-state routing as well. In particular, the approach is attractive for the selection of topology information to be flooded across the network. Requirements for such topology selection are however different from those applying for efficient dissemination, so approaches in such direction need to address these requirements and adapt or complement the MPR mechanism accordingly. This paper analyzes the main asymptotic properties of MPR and MPR-based topology selection algorithms, and provides sufficient conditions for the correctness of MPR-based topology selection. It examines as well in detail the MPR-based topology selection algorithm of MPR-OSPF, Path MPR, and shows that this algorithm may be unable, in certain conditions, to preserve optimal routes in its topology selection. The paper concludes by proposing and validating a modification of the Path MPR algorithm to overcome this sub-optimal performance

Average Size of Unstretched Remote-Spanners

International audienceMotivated by the optimization of link state routing in ad hoc networks, and the concept of multipoint relays, we introduce the notion of remote-spanner. Given an unweighted graph $G$, a remote spanner is a set of links $H$ such that for any pair of nodes $(u,v)$ there exists a shortest path in $G$ for which all links in the path that are not adjacent to $u$ belong to $H$. The remote spanner is a kind of minimal topology information beyond its neighborhood that any node would need in order to compute its shortest paths in a distributed way. This can be extended to $k$-connected graphs by considering minimum length sum over $k$ disjoint paths as distance. In this paper, we give distributed algorithms for computing remote-spanners in order to obtain sparse remote-spanners with various properties. We provide a polynomial distributed algorithm that computes a $k$-connecting unstretched remote-spanner whose number of edges is at a factor $2(1+\log \Delta)$ from optimal where $\Delta$ is the maximum degree of a node. Interestingly, its expected compression ratio in number of edges is O(\frackn\log n) in Erdös-Rényi graph model and O((\frackn)^\frac23) in the unit disk graph model with a uniform Poisson distribution of nodes

A flexible routing scheme for patients with topographical disorientation

<p>Abstract</p> <p>Background</p> <p>Individuals with topographical disorientation have difficulty navigating through indoor environments. Recent literature has suggested that ambient intelligence technologies may provide patients with navigational assistance through auditory or graphical instructions delivered via embedded devices.</p> <p>Method</p> <p>We describe an automatic routing engine for such an ambient intelligence system. The method routes patients with topographical disorientation through indoor environments by repeatedly computing the route of minimal cost from the current location of the patient to a specified destination. The cost of a given path not only reflects the physical distance between end points, but also incorporates individual patient abilities, the presence of mobility-impeding physical barriers within a building and the dynamic nature of the indoor environment. We demonstrate the method by routing simulated patients with either topographical disorientation or physical disabilities. Additionally, we exemplify the ability to route a patient from source to destination while taking into account changes to the building interior.</p> <p>Results</p> <p>When compared to a random walk, the proposed routing scheme offers potential cost-savings even when the patient follows only a subset of instructions.</p> <p>Conclusion</p> <p>The routing method presented reduces the navigational effort for patients with topographical disorientation in indoor environments, accounting for physical abilities of the patient, environmental barriers and dynamic building changes. The routing algorithm and database proposed could be integrated into wearable and mobile platforms within the context of an ambient intelligence solution.</p