Showing papers on "Geographic routing published in 1981"

Advances in Verifiable Fail-Safe Routing Procedures

Abstract: Two new versions of a distributed protocol for establishing and maintaining loop-free routing tables for communication networks with changing topology are presented. The protocols here possess significant advantages over previous versions in terms of complexity of the node algorithm and of the validation procedure, as well as the communication and storage needs. In addition, we present a procedure for establishing new and disrupted calls in a virtual or physical circuit-switched network, and for canceling existing calls, such that each call is loop-free and is established according to the routing tables provided by the protocol.

A Technique for Adaptive Routing in Networks

Abstract: A two-level adaptive routing scheme for packet-switched computer communication networks is proposed and investigated. The first level is quasi-static and based on the global network status. The second level is dynamic with decisions being made at each node in an attempt to obtain the savings in average delay predicted by a multiserver model of the node. Simulations confirm the predicted improvement.

Notes on Optimal Routing and Flow Control for Communication Networks.

Abstract: : The main purpose of routing and flow control in a communication network is, roughly speaking, to keep delay per message within an acceptable level while minimizing the amount of offered traffic that is rejected by the network due to its inability to handle it. These two objectives are clearly contradictory so a good routing and flow control scheme must strike a balance between the two. It should also take into account a number of other issues such as fairness for all users, the possibility that the network topology can be altered due to unexpected link or node failures, and the fact that the statistics of offered traffic change with time. In these notes we consider some aspects of routing and flow control for long-haul wire data networks in which the communication resource is scarce (as opposed to local networks such as Ethernet where it is not), and where there are no issues of contention resolution due to random access of a broadcast medium (as in some satellite, local, and packet radio networks). We place primary emphasis on optimal procedures since these offer a more sound philosophical basis than heuristic schemes and also provide a yardstick for measuring the effectiveness of other methods.

A distributed minimum hop routing algorithm

Abstract: A two-part distributed algorithm for minimum hop routing in message-switched networks subject to end-to-end average message delay constraints is developed. The first part of the algorithm provides for unconstrained minimum hop routing, while the second corrects this routing to satisfy the delay constraints. Both parts are implemented nodewise via low-order linear programs wherein the information exchange required for each node to carry out its computations involves only adjacent neighbor nodes. The algorithm is illustrated via an example of an 8- node, 14-link network with 7 commodities, and directions for future research to enhance present results are indicated.

Adaptive routing in large communication networks: Probabilistic study

Abstract: A network model is presented and conditions for stochastic stability of the network system are given. For adaptation algorithms which change the routing probabilities slowly (small stepsize), expressions for steady-state variances are derived; usimg these, guidelines for the selection of algorithm parameters are discussed.

Routing in Networks

Abstract: : This report is concerned with routing protocols in networks. The major result is a low bound for any oblivious routing strategy where the route of a packet depends only on the source and destination of the packet. We show that for any oblivious routing protocol for a network of n processors in which the maximum number of processors directly connected to any processor is d, there exists a permutation that requires time (sq. root of n) d (to the 3/2). For specific networks such as an n-cube we give an oblivious routing algorithm whose performance is close to this lower bound. (Author)