Showing papers on "Overlay network published in 1985"

Reliable Loop Topologies for Large Local Computer Networks

Abstract: Single-loop networks tend to become unreliable when the number of nodes in the network becomes large. Reliability can be improved using double loops. In this paper a highly reliable and efficient double-loop network architecture is proposed and analyzed. This network is based on forward loop backward hop topology, with a loop in the forward direction connecting all the neighboring nodes, and a backward loop connecting nodes that are separated by a distance ⌊√N⌋where N is the number of nodes in the network. It is shown that this topology is optimal, among this class of double-loop networks, in terms of diameter, average hop distance, processing overhead, delay, throughput, and reliability. The paper includes derivation of closed form expressions for diameter and average hop distance, throughput, and number of distinct routes between two farthest nodes. For fault-tolerance study, the effect of node and link failures on the performance of the network is analyzed. A simple distributed routing algorithm for reliable loop network operation is also presented.

Topologies and access methods

Abstract: This chapter discusses topologies and access methods. In a local area network, the relatively short distance spanned, the high bandwidth provided, and the low-cost media used create an operating environment in which bandwidth is cheap, a substantial contrast to the traditional common carrier environment. An important consequence of these differing environments is that there are radical differences between the network topology for a telephone network and that for a local area network. Whereas a telephone network generally has a hierarchical form, with links placed between nodes according to traffic and cost, a local area network usually has a regular form that is a star, a ring, or a bus. Further, the nodes of a telephone network route traffic according to complex rules, but the nodes of a local area network do little routing. The chapter explains that each topology is best suited to particular media types, has an optimum routing strategy, and has identifiable reliability characteristics. Circuit switching is an appropriate method for handling voice calls, as it provides the instantaneous, interactive, two-way communications so important to human interaction.