Showing papers on "Routing protocol published in 1982"

Performance evaluation of data communication systems

Abstract: This paper is a tutorial and a survey of analytical methods in the evaluation of data communication networks. The major mathematical methods are Markov chains applied to discrete time systems and queueing theory. Emphasis is placed on the applications of the mathematical tools. The discussion follows the framework of the layered architecture. In the section on data link control, rigorous as well as "engineering" approaches are highlighted. In this area, models of great accuracy have been developed. In the path-control or routing layer, the major model is provided by Kleinrock's delay analysis of packet networks. Finite buffer pools still pose many problems. The method of the homogeneous network is introduced, a method which reduces complexity originating from the network topology in favor of more realistic protocol features. This thought is expanded into the layer of end-to-end protocols where the tandem-queue model is introduced and its application to the flow-control problem discussed.

A learning model for routing in telephone networks

Abstract: The aim of this paper is to develop a theory of adaptive routing in telephone networks using learning methods. A mathematical model of the network with slow-learning algorithms distributed at various nodes is presented. The algorithms update the routing probabilities on the basis of network feedback information (like call blocking or completion) only. Convergence of the routing strategies is established. Two linear updating algorithms, under certain conditions, are shown to have desirable equilibrium behavior like load equalization and minimum blocking probability for the entire network.

A Distributed Routing Design for a Broadcast Environment

Abstract: In this paper, we will present the need for distributed network control in a packet radio environment, the criteria used for its evaluation, and an overview of the network algorithms chosen to maintain routing information and to route user traffic The routing algorithm, known as tiered rings, functions by building a distributed tree of shortest path routes to each packet radio in the network The information kept by each node grows only linearly as the network expands The design uses the radio channel efficiently by providing shortest path routing and by taking advantage of the information available in a broadcast environment

A reliable broadcast protocol

Abstract: Broadcast in a communication network is the delivery of copies of messages to all nodes. A broadcast algorithm is reliable if all messages reach all nodes in finite time, in the correct order and with no duplication. The present paper presents an efficient, reliable broadcast algorithm.

Hardware Support for Automatic Routing

Abstract: A system for automatic routing based on an iterative application of Lee's algorithm is presented. An extended cell admissibility is defined for continuous design rules in coarse rectangular grids. Combined hardware and software design strategies are applied towards the definition of data structures and their kernel primitives for automatic routing. The hardware architecture and the implementation of specific structures are discussed. The resulting extended routing unit is used in a CAD system. Thus the throughput of the iterative router is improved by a factor of 5 compared to the equivalent software process. Finally the architecture of a high speed stand-alone routing processor is presented.

A Minimum-Impact Routing Algorithm

Abstract: A routing heuristic is presented that routes two-terminal nets one at a time, for each net choosing the path so as to avoid adversely impacting the nets not yet routed. An algorithm is presented and proved to correctly implement this heuristic; the computational complexity of that algorithm is shown to be polynomially bounded, but perhaps still too great to be of practical use. Another, speedier algorithm is presented that seems to approximate the heuristic rather closely. Strong evidence is given that the Lee routing algorithm is in some sense inadequate to implement this heuristic. The heuristic has been applied, with very encouraging results, to a specific routing problem: the routing of a channel in which all four sides of the channel may contain terminals. This problem arises in the layout of custom VLSI.

Two-Dimensional Channel Routing and Channel Intersection Problems

Abstract: A two-dimensional channel routing program for hierarchical IC layout with orthogonal building blocks of variable size and shape is presented. A two dimensional channel model and a one layer channel router are used. A detailed description of the routing scheme which avoids the generation of "switch box" problems is given. The behavior of the two-dimensional routing algorithm to single and coupled channel intersections is demonstrated.

Routing of telephone traffic to minimize network blocking

Abstract: The problem of optimum routing of telephone traffic to minimize network blocking is formulated for a class of routing schemes. The necessary conditions for minimum-blocking routing are shown to be analogous to conditions for minimum-delay routing in a store-and-forward data network. A method is described for calculating an optimum routing on the basis of centralized computational for the network. Owing to its computational complexity, however, the method is more useful for off-line studies than for real-time adaptive routing.

The design of a routing service for campus-wide internet transport

Abstract: A campus-wide network requires many subnetworks connected by gateways and it has a relatively loose administration. Modularization of network implementing is important in this environment to make efficient use of ever-improving technologies and protocols. The need for modularization makes it desirable to separate a routing and target identification scheme from gateway implementation - a facility that source routing provides. Moreover, removing routing and target identification responsibilities from the gateways leads to their simplicity and, therefore, a better chance that gateways will not be bottlenecks in the high-bandwidth network. This thesis focuses on the design of a Routing Service to support source routing in the campus environment. The Routing Service is designed to find paths from a requesters attachment point to a node specified by the requester. The Routing Service accepts hints from the requester about the destination node''s location in the network to limit the search involved. The Routing Service also provides user-control of paths and diagnosis for faulty paths. The design of the Routing Service places strong emphasis on scalability with respect to the size of the network. Reliability and simplicity are two other key features of the Routing Service.

A routing scheme for integrated networks

Abstract: A routing scheme using delay, bandwidth and reliability measures is presented, and flow control is partially included in the method. Decisions are distributed, and the routing tables at each node contain lists of non-dominated best paths to all other nodes. Two algorithms are presented for constructing the tables, and simulation results show that their overheads are comparable to those of existing algorithms. The routing scheme is suitable for integrated packet switched and circuit switched computer networks.

A distributed routing protocol for a packet radio network

Abstract: : Packet Radio is a digital communications concept which offers the user the capability to pass voice and other data in a radio network which may link high power computers with small mobile radios containing microprocessors. The technique of routing digital traffic from source to destination depends on the operational requirements of the network. Most routing concepts today centralize network control (in varying degrees) for normal operations.

Performance of SNA's LU-LU session protocols

Abstract: SNA is both an architecture and a set of products built in conformance with the architecture (1,2,3). The architecture is layered and precisely defined; it is both evolutionary and cost effective for implementing products. Perhaps the largest component of cost effectiveness is performance: transaction throughput and response times. For SNA, this involves data link control protocols (for SDLC and S/370 channel DLC's), routing algorithms, protocols used on the sessions that connect logical units (LU-LU session protocols), and interactions among them.SNA's DLC and routing protocols have been discussed elsewhere (4,5,6); this talk examines protocols on sessions between logical units (LU-LU session protocols) and illustrates the results of design choices by comparing the performance of various configurations.