Showing papers on "Hazy Sighted Link State Routing Protocol published in 1988"

Decentralized adaptive routing for virtual circuit networks using stochastic learning automata

Abstract: The problem of routing virtual circuits according to dynamical probabilities in virtual-circuit packet-switched networks is considered. Queueing network models are introduced and performance measures are defined. A decentralized asynchronous adaptive routing methodology based on learning automata theory is presented. Every node in the network has a stochastic learning automaton as a router for every destination node. The routing probabilities that are assigned to the network paths are updated asynchronously on the basis of current network conditions. A learning algorithm suitable for routing is used. Some initial simulation experiments, for a simple network, show convergence to optimal routing. >

Spatial reuse through dynamic power and routing control in common-channel random-access packet radio networks

Abstract: Topologies of common-channel packet radio networks (PRNETs) are difficult to optimize because some of the links between multiple pairs of packet radio units are not independent. Previous analysis has shown that designing the topology to provide spatial reuse of the common-channel will improve the network throughput and delay performance in general. Unfortunately, the complexity of the link interactions has impeded the design of protocols that can be implemented in operational networks. This dissertation discusses how to optimize the topologies of common-channel random-acess PRNETs through dynamic power control at the link layer and routing at the network layer. Methods of implementing dynamic power control at the link layer on an individual packet-by-packet transmission basis are presented. These methods should be implementable at the link layer of any packet radio with dynamic per-packet power control capability. A new routing protocol, called Least Interference Routing (LIR), is defined which is designed specifically to operate in common-channel random-access PRNETs. The goal of LIR is to minimize the destructive interference caused along each route within the network, thus improving the spatial reuse of the common-channel. The LIR protocol calculates the potential destructive interference along each link, creates the network routing tables that minimize the potential destructive interference along an entire route, and specifies the per-packet transmission power. The implementation flexibility of each of these operations allows LIR to be implemented in a variety of radios and radio networks. Myopic one-hop and network multiple-hop simulations indicate that dynamic power control and/or LIR improve end-to-end PRNET performance over no power control or other routing strategies, such as minimum hop routing.

Performance evaluation of a hierarchical hybrid adaptive routing algorithm for large scale computer communication networks

Abstract: A hierarchical hybrid adaptive routing algorithm (HHARA) is presented for dynamic large-scale computer communication networks (LSCCN). The performance of the proposed algorithm is evaluated and compared to that of nonhierarchical routing algorithms by simulation experiments on a 50-node network model. The major evaluation criteria are reliability, communication overhead, computation overhead, and average packet delay. A fixed routing algorithm, the most recent ARPANET routing algorithm, and HHARA are compared using simulation experiments. The simulation study indicates that HHARA makes a good balance between the reduction of routing database maintenance overhead, and the global routing capability as well as the local adaptivity to the network changes. >

Network Queueing System

Abstract: Program directs traffic in UNIX-based network. NQS provides facilities for remote queueing, request routing, remote status, queue-access controls, batch-request resource-quota limits, and remote output return. Written in C.

On routing and performance comparison of techniques for packet-switched networks using learning automata

Abstract: Distributed adaptive routing algorithms with the ability to adaptively proportion traffic over several paths is proposed for packet-switched data networks. A learning automaton is situated at each node of the network where a routing decision must be made and directs traffic entering the node onto one of the outgoing links. Using network feedback, and automaton modifies its routing strategy to improve its link selections. This approach has the advantage over existing routing schemes of offering a simple and extremely practical feedback and updating policy. >

NOM-a tool for optimal design and performance evaluation of routing strategies and its application to the Telenet network

Abstract: A network optimization model (NOM) that provides a tool for performance analysis and optimal design of a broad class of routing strategies is presented. It can evaluate and optimize both static and dynamic, local and global routing strategies. The tool is applicable to both packet-switched and circuit-switched networks. NOM software is based on original modeling methods and optimization algorithms. It is user-friendly and menu-driven, and has extensive 'what if' capabilities. NOM can be used for performance evaluation of existing routing strategy and for optimal routing design for a given performance criterion. As a performance evaluation tool, for a given network topology, link and node capacities, point-to-point demand matrix, and routing strategy, NOM models the routing and computes important characteristics of network performance. As a routing optimization tool, for a given network topology, link and node capacities, point-to-point demand matrix, and performance criterion, NOM generates the optimal routing, and computes important characteristics of network performance. The current Telenet local dynamic routing strategy is compared with a set of optimal routing strategies designed for various performance criteria. >

A distributed protocol for reducing neighborhood size in radio networks

Abstract: A distributed protocol which specifies how modes select at random a subset of their adjacent link is described. The protocol results in a routing topology with nodal degree that does not exceed a predetermined limit, and allows late entries to be incorporated into the network and partitioned networks to be reconstituted. Simulation of the protocol has demonstrated a threshold effect for global network connectivity with respect to the average nodal degree. Moreover, if nodes are allowed to operate with their degree above the threshold, the probability that the protocol results in a connected routing graph is very close to one. That probability decreases sharply to zero as the nodal maximum degree drops below the threshold. Specifically, the threshold has been found to be between 3 and 7 for a large variety of network configuration and protocol conditions. >

A fault-tolerant communication system for the B-Hive generalized hypercube multiprocessor

Abstract: We describe the implementation of a communication system on the B-HIVE generalized hypercube. B-HIVE has 24 nodes connected in a 2 x 3 x 4 structure. Each node consists of two processors: an application processor (AP) and a communication processor (CP). The communication system runs solely on the CP and presents a simple DMA-like interface to user programs.A fault-tolerant communication system was developed for these reasons: (1) We desired a way to transmit messages reliably over a potentially unreliable communication network, and (2) B-HIVE implements both packet-switched and circuit-switched communications in the same network. At any time many channels may be allocated to a circuit-switched transaction and therefore be unusable for packet-switched routing. Since these channels can be rapidly allocated and then deallocated, we wanted an automatic mechanism for discovering these “failed” routes rather than broadcasting to the entire network each time a link is removed.These requirements mandated a simple protocol for detecting failed links, and updating the necessary routing tables. An algorithm is described that routes messages efficiently in a network where large portions are not functioning, A related issue is broadcasting a message to all nodes in the network. Several different methods of broadcasting are considered, and the routing algorithm is adapted to perform a broadcast. Currently we have implemented a static routing network where routes are only changed in the case of a detected failure. Future research will be directed towards more dynamic routing with load balancing.