In computer networks with decentralized control, it is necessary to provide a distributed query mechanism, whereby a node can dynamically discover the location of a remote resource. The authors propose a query mechanism based on flooding with feedback, which uses no more than two messages over any link. They examine the fault tolerant aspects of this distributed query mechanism, operating in a network where links and nodes may fail and show that, under certain conditions, the resource is indeed found. They then construct enhancements to this mechanism, where the conditions under which the resource is found are substantially relaxed, at the cost of some increase in message complexity.>

This paper introduces the notion of cost-sensitive communication complexity and exemplifies it on the following basic communication problems: computing a global function, network synchronization, clock synchronization, controlling protocols' worst-case execution, connected components, spanning tree, etc., constructing a minimum spanning tree, constructing a shortest path tree. IntroductionTraEic load is one of the major factors affecting the behavior of a communication network.This fact is well recognized, and is the reason why most

It is known that HDLC (high-level data link control) and other bit-oriented DLC procedures ensure data transmission reliability across noisy transmission media, provided that all frame errors are detected and the link processes are synchronized at initialization. It is shown that the HDLC initialization procedure does not ensure synchronization and allows inadvertent loss of data. Several link initialization procedures are proposed and it is proved that they do ensure synchronization.>

This paper discusses SNA/LEN, a possible extension of Systems Network Architecture intended to allow peer, dynamic, and easy to use networking functions for a variety of node sizes down to and including the new generation of personal computers. After reviewing the special requirements posed by small systems and the need for including them as equal partners in networks, the LEN architecture is described. This is done by following a sequence of steps that begin when a logical resource at some node that may not yet be part of the connectivity of an existing network requests a session with a remote logical resource of unknown location. After connectivity with the preexisiting network is established, directory services locates the remote object, route selection services determines the preferred path, a session is activated, and deadlock-free flow control assures a useful flow of data. Preliminary quantitative results from an LEN prototype are presented.