Showing papers on "Optimized Link State Routing Protocol published in 1989"
01 Aug 1989
TL;DR: A protocol that maintains the shortest-path routes in a dynamic topology, that is, in an environment where links and nodes can fail and recover at arbitrary times, and avoids the bouncing effect and the looping problem that occur in the previous approaches of the distributed implementation of Bellman-Ford algorithm.
Abstract: Distributed algorithms for shortest-path problems are important in the context of routing in computer communication networks. We present a protocol that maintains the shortest-path routes in a dynamic topology, that is, in an environment where links and nodes can fail and recover at arbitrary times. The novelty of this protocol is that it avoids the bouncing effect and the looping problem that occur in the previous approaches of the distributed implementation of Bellman-Ford algorithm. The bouncing effect refers to the very long duration for convergence when failures happen or weights increase, and the nonterminating exchanges of messages, or counting-to-infinity behavior, in disconnected components of the network resulting from failures. The looping problems cause data packets to circulate and, thus, waste bandwidth. These undesirable effects are avoided without any increase in the overall message complexity of previous approaches required in the connected part of the network. The time complexity is better than the distributed Bellman-Ford algorithm encountering failures. The key idea in the implementation is to maintain only loop-free paths, and search for the shortest path only from this set.
226 citations
TL;DR: An adaptive hierarchical routing protocol based on the extension of the new Arpanet scheme is proposed and its simulated performance is presented and the tradeoff between two conflicting performance criteria, response speed and communication overhead, is shown.
Abstract: An adaptive hierarchical routing protocol based on the extension of the new Arpanet scheme is proposed and its simulated performance is presented. The protocol can adapt to rapidly changing environments and works for arbitrarily large networks. A number of existing schemes as well as the proposed scheme are simulated under many different environments and clustering structures. The proposed protocol is found to be superior to the other protocols tested in many different types of network traffic and topological configurations. The results indicate that intercluster links must be reliable, because (1) the failure of these links can significantly degrade the routing performance, even though the protocol does not degrade as badly as the existing scheme and (2) hierarchical routing protocols usually prefer small clusters, which means that there will be many intercluster links. The tradeoff between two conflicting performance criteria, response speed and communication overhead, is shown. >
88 citations
15 Oct 1989
TL;DR: The results show that, when the rate of topological change becomes very high, flooding is preferable to the other alternatives, and for lower rate of change, the performance of the new algorithm is encouraging in that it has been generally superior to that of the alternative protocols.
Abstract: The authors present a distributed routing protocol intended for use in networks where the rate of topological change is not so fast as to make 'flooding' the only possible routing method but not so slow as to make one of the existing protocols for a static topology applicable. The routing algorithm adapts asynchronously in a distributed fashion to arbitrary changes in topology in the absence of global topological knowledge. The protocol maintains a set of loop-free routes to each destination from any node that desires a route. The protocol's performance, measured in terms of end-to-end packet delay and throughput, is compared with that of pure flooding and an alternative algorithm that is well suited to the medium-rate topological change environment envisioned here. The results show that, when the rate of topological change becomes very high, flooding is preferable to the other alternatives. For lower rate of change, it appears that, when the effects of channel access are accounted for, the performance of the new algorithm is encouraging in that it has been generally superior to that of the alternative protocols. >
32 citations
27 Nov 1989
TL;DR: The author describes a novel approach to the design of node-by-node routing virtual circuit data networks that explicitly integrates the loop-free alternate routing requirements into the network design process and produces loop- free cost optimized networks.
Abstract: The author describes a novel approach to the design of node-by-node routing virtual circuit data networks. A major challenge in the design of such networks is to ensure that the network has loop-free alternate routing. The approach explicitly integrates the loop-free alternate routing requirements into the network design process and produces loop-free cost optimized networks. This is achieved by identifying a topology which supports loop-free alternate routing. This topology is optimal in the sense of achieving a prescribed level of network connectivity with the fewest possible links. This topology have several desirable routing properties, based on which a simple loop-free alternate routing scheme has been developed. Further, by solving an optimization problem, it is possible to find the optimal connectivity between nodes that minimizes the total link length. This leads to a significant reduction in network cost. Two methods for solving this optimization problem have been developed. >
3 citations
15 Oct 1989
TL;DR: The authors present novel algorithms for adaptive routing and link assignment, which can be used in a large-scale network with dynamic topology and stress, and addresses the following key issues: maintenance of up-to-date routing information in the presence of dynamics, robustness to failures that can partition areas, and optimization of routing algorithm performance through multiple path routing.
Abstract: The authors present novel algorithms for adaptive routing and link assignment, which can be used in a large-scale network (1000-10000 nodes) with dynamic topology and stress. Special attention was given to performance (delay, throughput, and survivability) and implementation cost issues as the size of the network grows. These costs are controlled by a logical partitioning of the network into areas. The proposed class of algorithms addresses the following key issues: maintenance of up-to-date routing information in the presence of dynamics, robustness to failures that can partition areas, optimization of routing algorithm performance through multiple path routing, and optimization of network topology for performance metrics of delay, link performance, and connectivity. >
2 citations