Two snap-stabilizing point-to-point communication protocols in message-switched networks

A snap-stabilizing protocol, starting from any configuration, always behaves according to its specification. In this paper, we present a snap-stabilizing protocol to solve the message forwarding problem in a message-switched network. In this problem, we must manage resources of the system to deliver messages to any processor of the network. In this purpose, we use information given by a routing algorithm. By the context of stabilization (in particular, the system starts in an arbitrary configuration), this information can be corrupted. So, the existence of a snap-stabilizing protocol for the message forwarding problem implies that we can ask the system to begin forwarding messages even if routing information are initially corrupted. In this paper, we propose two snap-stabilizing algorithms (in the state model) for the following specification of the problem: - Any message can be generated in a finite time. - Any emitted message is delivered to its destination once and only once in a finite time. This implies that our protocol can deliver any emitted message regardless of the state of routing tables in the initial configuration. These two algorithms are based on the previous work of [MS78]. Each algorithm needs a particular method to be transform into a snap-stabilizing one but both of them do not introduce a significant overcost in memory or in time with respect to algorithms of [MS78]

A survey of routing techniques in store-and-forward and wormhole interconnects.

This paper presents an overview of algorithms for directing messages through networks of varying topology. These are commonly referred to as routing algorithms in the literature that is presented. In addition to providing background on networking terminology and router basics, the paper explains the issues of deadlock and livelock as they apply to routing. After this, there is a discussion of routing algorithms for both store-and-forward and wormhole-switched networks. The paper covers both algorithms that do and do not adapt to conditions in the network. Techniques targeting structured as well as irregular topologies are discussed. Following this, strategies for routing in the presence of faulty nodes and links in the network are described

A Universal Proof Technique for Deadlock-Free Routing in Interconnection Networks

An important open problem in interconnection network routing has been to characterize the conditions under which routing algorithms are deadlock-free. Although this problem has been resolved for restricted classes of routing algorithms, no general solution has been found. In this paper, we solve this problem by proving a necessary and sufficient condition that can be used for any interconnection network routing algorithm, as long as only local information is required for routing. Our proof technique is universal: it can be used with any switching technique that is not inherently deadlock-free. This includes switching techniques such as wormhole routing, store-and-forward routing, and virtual cut-through. The proof technique for the necessary and sufficient condition introduces a new type of dependency graph, the buffer waiting graph, which omits most dependencies that cannot be used to create a deadlock configuration. Our methodology is illustrated by proving deadlock freedom for a sto..