Showing papers on "Hazy Sighted Link State Routing Protocol published in 1993"

Dynamics of internet routing information

Abstract: The Internet is a complex mesh of networks that use a common suite (TCP/IP) of networking protocols. A key feature of the Internet is that all of these constituent networks are interconnected, thereby providing system wide communication. The magnitude and pattern of the flow of routing information directly represents the connectivity stability of the Internet. The NSFNET backbone network provides transit services to a large portion of the global Internet and maintains routing tables reflecting this current connectivity. These routing tables are constantly updated based on information received by the attached networks. This paper investigates the dynamics of routing information flow as presented to the NSFNET backbone network.

Mesh Connected Computers with Fixed and Reconfigurable Buses: Packet Routing, Sorting, and Selection

Abstract: Mesh connected computers have become attractive models of computing because of their varied special features. In this paper we consider two variations of the mesh model: 1) a mesh with fixed buses, and 2) a mesh with reconfigurable buses. Both these models have been the subject matter of extensive previous research. We solve numerous important problems related to packet routing, sorting, and selection on these models. In particular, we provide lower bounds and very nearly matching upper bounds for the following problems on both these models: 1) Routing on a linear array; and 2) k-k routing, k-k sorting, and cut through routing on a 2D mesh for any k≥12. In addition we present greedy algorithms for 1-1 routing, k-k routing, cut through routing, and k-k sorting that are better on average and supply matching lower bounds. We also show that sorting can be performed in logarithmic time on a mesh with fixed buses. As a consequence we present an optimal randomized selection algorithm. Further, we provide a selection algorithm for the mesh with reconfigurable buses whose time bound is significantly better than the existing ones. Most of our algorithms have considerably better time bounds than known algorithms for the same problems.

Dynamic routing in multiparented networks

Abstract: The authors investigate some of the consequences for dynamic routing schemes of dual- and multiparented networks, in which a call can enter (or leave) the network at two or more points. In particular, they compare bounds on the performance of optimal dynamic routing strategies which respectively ignore and utilize the multiparented structure, and show that simple schemes, easily implemented and analyzed, are able to achieve most of the additional advantages allowed to dynamic routing schemes by multiparenting. The robust behavior of these schemes under traffic mismatches as well as multiple link or node failure events is illustrated. >

SDH management network: architecture, routing and addressing

Abstract: CCITT recommendation G.784 provides several options for the implementation of routing and addressing schemes within the synchronous digital hierarchy (SDH) management network (SMN). In addition, equipment manufacturers and network operators have identified a hierarchical topology for the SDH network. Based on these routing and addressing options and network topologies, the network operators need to implement an efficient, robust and cost effective management structure. Two alternatives have been identified as possible implementation strategies for the SMN. The first option makes use of an X.25 packet switched network, as well as the SDH data communications channels (DCCs). Here the complexities of implementing a wide area packet switched network are alleviated by making use of the X.25 network with a static routing scheme. The protocol specified in Annex C of G.784 can be used for this implementation, but the authors identify serious deficiencies in the standards. Hence, its use would require a proprietary solution or considerable effort in the CCITT standardisation arena. The second option uses the DCC exclusively to provide the communications network. The standard protocol stack as specified in CCITT recommendation G.784 is used. Dynamic routing is provided by the intermediate system to intermediate system (IS-IS) routing protocol. The first option may be implemented in the initial stages. A gradual migration path can be adopted to take advantage of the second option with the advance of SDH equipment and its management capabilities. >

HF radio network simulation based on automatic link establishment (ALE) and distributed routing policies

Abstract: The application of the automatic link establishment (ALE) procedures of MIL-STD-188-141A, combined with improved signal processing technology found in advanced modems, provides the basic elements to create adaptive high frequency (HF) radio networks. Dynamic changes in ionospheric conditions and noise fluctuations make the HF network a hostile one, where links between nodes are subject to frequent failure. The addition of adaptive routing and information management enhances network robustness in this environment. This suggests the use of a distributed routing algorithm in which convergence to the shortest path is of primary concern. However, routing decisions derived from such distributed processes exhibit an inherent uncertainty due to the randomness of link failures and the latency of network performance information. The authors describe predictions of a computer simulation of a wide area HF radio network that invokes ALE procedures, adaptive routing, and information management protocols. Aspects include the impact of modem interleaver delay time, encryption synchronization delay, management overhead, and message handling on throughput and network latency. Recommendations are presented with respect to the application of statistical neural processing to improve network management in this environment. >

Application of neural networks for routing in telecommunications networks

Abstract: Discusses the application of neural networks to routing in telecommunications networks under normal and abnormal conditions. Concepts related to optimal routing are discussed from the theoretical and telecommunications networks perspective to define a translation to the neural network paradigm. A sample network is then used to determine optimal neural network parameters, which are then tested to determine routing accuracy and performance under normal and abnormal routing conditions. Following the analysis of the results, conclusions and recommendations on the results are provided. >

Performance analysis of random routing algorithm for n-D connected networks

Abstract: An n-D connected network is a kind of networks which have n input links to each node and n output links from each node It is designed for packet communications in a local or metropolitan area Two examples of n-D connected networks are Manhattan Street Network (MSN) and Chordal Ring Network In this paper, the random routing algorithm is used for n-D connected networks For the random routing algorithm we give the theoretical steady state delay and throughput analysis for n-D connected networks by a single node approximate Markov Chain model A simple iterative formula used for calculating the related distributions is derived, and its accuracy is verified by simulations >

A comparison of meshes with static buses and half-duplex wrap-arounds

Abstract: We investigate the relative computational powers of a mesh with static buses and a mesh with half-duplex wrap-arounds. The latter model is like a torus, except that any wrap-around link of the architecture can only transmit data in one of the two directions at any clock tick. We show that the permutation routing problem can be solved as efficiently on a linear array augmented with a half-duplex wrap-around link, as on a linear array with an augmented broadcast bus. We also present a routing algorithm for a two-dimensional (2D) mesh with half-duplex wrap-around links whose run time is close to that of the best known algorithm for routing on a 2D mesh with broadcast buses in each dimension. In addition, we show that on an n×n 2D mesh with broadcast buses, randomized sorting of n2 elements can be accomplished in time that is only o(n) more, with high probability, than the time needed for permutation routing.

A routing algorithm for Multihop Packet Radio Networks with uni- and bi-directional links

Abstract: Multihop Packet Radio Networks require routing algorithms which are distributed in nature and have the ability to timely detect changes in the network topology. These changes are mostly changes in connectivity caused by link or node failures and by the relative motion of the nodes. This paper describes and analyzes an adaptive decentralized routing algorithm for Frequency-Hopping Spread-Spectrum Packet Radio Networks. Unlike most of the algorithms found in the open literature the one proposed here can deal with networks having both uni- and bi-directional radio links. A detailed software simulation model has been built to investigate the performance of the algorithm. Examples are shown to illustrate the methodology. >

Connectivity properties of radio telephone network

Abstract: Pure connectivity and routing-algorithm-based connectivity of randomly distributed radio network are studied. The 'magic number' of average neighbours of each station from the connectivity point of view is obtained. >

The Calculus of Self-Modifiable Algorithm Based Evolutionary Computer Network Routing

Abstract: The Calculus of Self-Modifiable Algorithms (CSA) is a universal approach to parallel and intelligent system. Its aim is to integrate different styles of programming and is applied to different areas of future generation computers. Potential applications of CSA include expert systems, machine learning, adaptive systems and many others. The problem of route optimization in computer networks is identified as a task that requires some sort of cost-driven solution that allows for the computation of paths in a network based on experience and inference. The Calculus of Self-Modifiable Algorithm is used to do the specification of this problem by modeling a system of machine learning algorithms that learn proper routing techniques for a particular computer network by incorporating an apportionment of credit system and various rule discovery concepts similar to the learning techniques used in evolutionary computing and symbolic learning.

A cost-effective self-routing permutation network

Abstract: A cost-effective self routing permutation network that is able to connect any input set of permutations assuming one-to-one connection is discussed The network resembles the baseline network topology, and thus has log N stages However, a re-circulation scheme is adopted in each stage of the network as in a single-stage shuffle-exchange (S/E) network The inputs are re-circulated in each stage of the network before they are passed to the subsequent stage The routing scheme is a binary radix routing The hardware complexity of the network is O(N log N) The complexity is much less than O(N log/sup 2/ N) of the Batcher network which can be used as a self-routing permutation network when a banyan network is attached to it The propagation delay of the network is O(log/sup 2/ N) stages The hardware overhead to implement the self-routing is small, and the implementation has a good regularity >

Experiments with randomized and deterministic routing algorithms on transputer networks

Abstract: An interprocessor communication scheme is a key to exploit parallel computers effectively. One of the efficient communication schemes on hypercubes is the two-phased randomized routing algorithm. In this paper, the performance of this randomized routing algorithm is studied. In addition, the performance of a deterministic routing algorithm, the greedy routing algorithm is evaluated.