Showing papers on "Wireless Routing Protocol published in 1991"

Routing of multipoint connections

Abstract: The author addresses the problem of routing connections in a large-scale packet-switched network supporting multipoint communications. He gives a formal definition of several versions of the multipoint problem, including both static and dynamic versions. He looks at the Steiner tree problem as an example of the static problem and considers the experimental performance of two approximation algorithms for this problem. A weighted greedy algorithm is considered for a version of the dynamic problem which allows endpoints to come and go during the life of a connection. One of the static algorithms serves as a reference to measure the performance of the proposed weighted greedy algorithm in a series of experiments. >

Deadlock-free multicast wormhole routing in multicomputer networks

Abstract: Efficient routing of messages is the key to the performance of multicomputers. Multicast communication refers to the delivery of the same message from a source node to an arbitrary number of destination nodes. Wormhole routing is the most promising switching technique used in new generation multicomputers. In this paper, we present multicast wormhole routing methods for multicomputers adopting 2D-mesh and hypercube topologies. The dual-path routing algorithm requires less system resource, while the multipath routing algorithm creates less traffic. More import antly, both routing algorithms are deadlock-free, which is essential to wormhole networks.

Deadlock-free adaptive routing algorithms for multicomputers: evaluation of a new algorithm

Abstract: A new theory for the design of deadlock-free adaptive routing algorithms for wormhole and store-and-forward routing as well as two design methodologies have been proposed previously. In this paper, a new adaptive routing algorithm, obtained from the application of the former theory to the binary n-cube, is evaluated under different load conditions and compared with other algorithms. The results show that the new design methodology supplies faster routing algorithms, at least for those networks with a high connectivity. >

Connectivity database overhead for inter-domain policy routing

Abstract: Policy routing protocols incorporate policy related constraints into the route computation and packet forwarding functions for inter-administrative domain (AD) communication. However, this functionally exacerbates the already critical problem of routing information distribution and storage overhead in very large internets (e.g., 100000 ADs). The authors investigate the scalability of the inter-domain policy routing (IDPR) architecture. In particular, they present an informal analysis of connectivity database and update overhead. A model of the IDPR architecture is defined and tested by varying several parameters. The results obtained illustrate the scaling properties of the IDPR architecture and their dependencies upon internet configuration, connectivity among ADs, and number of policies. It is found that, under certain reasonable assumptions, global information for an internet of 5000 transit ADs (and 50000 stub ADs) will occupy on the order of 2.5 MB of storage in the route server. >

Team theory and backpropagation for dynamic routing in communication networks

Abstract: The dynamic routing problem in communication networks is considered. Traffic routing nodes are required to generate routing decisions on the basis of local information, and to compute or adapt their routing strategies online. The first requirement leads to regarding routing nodes as the cooperating decision makers of a team organization. The second requirement calls for a computationally distributed algorithm. This fact and the impossibility of solving, under general conditions, team functional optimization problems suggest that each routing node be assigned a set of multilayer feedforward neural networks able to generate routing decisions. The weights of such neural networks are then adjusted by means of an algorithm based on backpropagation. >

Multihour engineering and traffic routing optimization in hierarchical telephone networks

Abstract: Classical hierarchical routing in telephone networks is extended to a wider class called out-of-chain routing in such a way that some useful properties of hierarchical routing are retained. This new routing pattern offers more potential paths than the fixed hierarchical one and can be introduced as a dynamic routing where the fixed alternate sequences change at some predetermined instants during the day. The effect of this new routing pattern on the network performances is examined. The main topic of this paper is to present heuristic methods used to optimise such routings in large networks. We show on artificial networks that the throughput of a given network can be significantly improved by suitable routing choices. We demonstrate that the integration of routing changes within a multihour dimensioning process is possible but the lack of realistic data does not permit at this time to quantify the value of routing optimization on real networks.

Technology-trial of dynamic traffic routing with 5 minute updates

Abstract: DR5 (dynamic routing with 5-minute updates) is a routing scheme for telephone traffic in which traffic measurements provided by the switches at 5-min intervals are used to define the routing to be followed for the next 5 min. A successful technology-trial of DR5 was conducted in a five-node subnetwork of 1A-ESS switches. The authors describe the DR5 algorithm, the architecture used for its implementation in the technology trial, and the main results of the trial. They also provide the results of economic studies on the potential benefits of DR5 deployment, and they discuss the possible future implementation of dynamic routing as part of the advanced intelligent network (AIN) architecture. The work described considers dynamic routing in the circuit-switched voice network. >

An Expanded Spanning-tree Protocol For Home-oriented Network Management

Abstract: An expanded spanning-tree protocol capable to simultaneous configurations of plural logical spanning-trees is proposed. It configures a set of optimum spanning-trees and offers an optimal routing path to each packet. This protocol should be highly effective for minimizing the possible traffic increase caused by routing packets and for minimizing the transmission lag. Details of the operating algorithm of the bridge are described. Also proposed is a simplified version of this protocol, called the approximate protocol, which can be incorporated in a more compact form and is much easier to apply. The benefits of these proposed protocols are quantitatively evaluated in terms of the reduction of traffic and packet delay compared with the conventional protocol. >

A method and apparatus for providing an efficient and adaptive management of message routing in a multi-node communication system

Abstract: The method for providing an efficient and adaptive management of message routing in a multi-platform, communication system having dynamically changing platform populations and dynamically changing connectivities between platforms where each of the platforms are capable of performing the steps of recognizing at least certain ones of the platforms in the system, deriving from at least one of the recognized platforms the quality of interconnectivities of the recognized platforms and certain others of the platforms in the system; and employing the derived quality of interconnectivities to make connectivity-based routing decisions using a selective one of a point-to-point routing algorithm, a point-to-multipoint routing algorithm and a broadcast routing algorithm.

The metrobridge: a backbone network distributed switch

Abstract: This paper describes the Metrobridge project - a distributed switch for connecting PC cards via a high-speed ATM-style backbone network. Initially the system architecture is outlined, then certain aspects are examined in more detail. Topics discussed include learning and routing algorithms, access/routing control, management functions, and applications.

Multicast routing algorithms for 3-stage Clos ATM switching networks

Abstract: The author investigates the general problem of multicast routing in the three-stage Clos switching network, with point-to-point routing as a special case. An optimal and a heuristic algorithm have been designed and tested. The results show that the heuristic algorithm can find multicast routes that are close to optimal within a response time that is significantly lower than that of the optimal algorithm. Further analysis of the experimental data suggests a hybrid implementation in which the optimal and heuristic algorithms are run in parallel with a set time limit. The algorithms and the discussion provided also apply to other networks, including wide-area communication networks, with a two-hop structure. >

Intelligent routing in large-scale communications networks

Abstract: The authors consider a class of large-scale communication networks with both dynamic adaptive routing and deterministic routing mechanisms and devise efficient routing algorithms for network designs involving multiple types of traffic. Analytical approaches are combined with quasi-simulation methods to evaluate the performance measures for each given design. The design goal for the networks under study comprises multiple objectives and requirements. Modern expert system and artificial intelligence techniques are incorporated into the design methods to meet the objectives in efficient ways. The routing mechanisms will vary depending on the traffic types, and the affected network performance will be discussed. The study is also extended to integrated networks with voice and data traffic. >

Design and analysis of multiprotocol networks with IP routers

Abstract: The design and analysis of large-scale multiprotocol networks interconnected by IP (internet protocol) routers are discussed, and efficient methods for routine data traffic across heterogeneous networks are introduced. For the internet currently operated by Defense Communications Agency, the long-haul network uses dynamic adaptive routing, while other networks adopt different types of routing mechanisms, depending on their network protocols. A class of modern routing algorithms, such as deterministic routing and virtual circuit routing, are also studied to develop intelligent methods for computing the performance measures for the global internet and subnetworks. For each routing mechanism used in the internet, analytical and quasi-simulation methods for computing various network performance attributes have been devised for expert-system network design tools. The study is extended to the case where the performance attributes are evaluated for the global internet with combined routing algorithms. >

A hierarchical scheme for combined access control and routing of circuit-switched traffic in ISDN environments

Abstract: For integrated networks that support circuit-switched traffic classes with varying bandwidth requirements, an efficient integration of the access control and routing functions is important in realizing optimum network performance. A hierarchical scheme for combined access control and routing is presented for realizing the above objective. The hierarchy comprises two levels; at the lower level each network node implements a distributed call routing strategy, while at the higher level a network supervisor implements an access control policy for minimizing the overall blocking probability. The access control problem to be solved at the supervisor level is formulated in an integer programming framework by a partitioning approach which divides the overall network into several distinct subnets, one corresponding to each bandwidth class. For routing the admitted calls within each subnet in an optimal fashion, a distributed minimum loss routing scheme is developed for implementation at the network nodes. Performance evaluation studies showing the superiority of the various control functions developed are presented. >

Efficient randomized routing on Clos networks

Abstract: Clos networks are well-known universal multistage networks that realize all permutations. However, the routing algorithms to realize permutations on these networks are so slow that their usefulness is severely limited. This paper gives a simple, efficient randomized algorithm that routes any given permutation on Clos networks. Randomization takes place in the first column of the network, while self-routing is used in the remaining columns. Probabilistic analysis of the algorithm is conducted and the queueing delay of any permutation is shown to be bounded by a small constant ( >

Routing and bandwidth management options in high speed integrated services networks

Abstract: The authors present various options of routing architectures for asynchronous transfer mode (ATM) networks based on currently developed user-network interface (UNI) protocols. The bandwidth reallocation, routing updating, and call connection levels are distinguished. The functions of the corresponding procedures are defined with respect to the traffic performance requirements and are related to the ATM protocol layers. An architecture of the ATM node is briefly discussed. >

A parallel algorithm for global routing in sea-of-gates technology

Abstract: The author studies the global routing of multiterminal nets in the sea-of-gates technology. The author first presents an algorithm which achieves optimum global density in one direction and controls the global density in the other direction. He then presents a parallel algorithm which is suitable for the problems in which most nets are short. Most VLSI routing problems have this property since the placement algorithm tries to place the modules containing terminals of the same net close to each other. The key idea is to transform a global routing problem (GRP) into a channel routing problem (CRP) and to solve it by using channel routers which are available in the literature. >

Reduced broadcast algorithm for source routing

Abstract: Source routing is an effective method for routing frames through high speed bridged LANs. The major disadvantage of the method is the high overheads associated with the route discovery procedure. A method is described for finding optimum routes that has minimum overheads associated with it. This is achieved with a simple address comparison in each bridge that results in a reduced load on the network and processing overheads in end stations compared with the existing source routing method.

Integrated routing for multi-protocol TCP/IP-OSI environments

Abstract: This paper describes an Integrated Routing Protocol, based on the OSI IS-IS protocol, which may be used as an Interior Gateway Protocol (IGP) to support TCP/IP and well as OSI CLNP. This allows a single routing protocol to be used in pure IP environments, pure OSI CLNP environments, as well as multi-protocol environments.