Results 1  10
of
35
Distributed Reset
 IEEE Transactions on Computers
, 1990
"... We design a reset subsystem that can be embedded in an arbitrary distributed system in order to allow the system processes to reset the system when necessary. Our design is layered, and comprises three main components: a leader election, a spanning tree construction, and a diffusing computation. Eac ..."
Abstract

Cited by 149 (24 self)
 Add to MetaCart
We design a reset subsystem that can be embedded in an arbitrary distributed system in order to allow the system processes to reset the system when necessary. Our design is layered, and comprises three main components: a leader election, a spanning tree construction, and a diffusing computation. Each of these components is selfstabilizing in the following sense. If the coordination between the up processes in the system is ever lost (due to failures or repairs of processes and channels) then each component eventually reaches a state where coordination is regained. This capability makes our reset subsystem very robust: it can tolerate failstop failures and repairs of processes and channels even when a reset is in progress. Categories and Subject Descriptors: C.2.4 [Computer Communication Systems]: Distributed Systemsdistributed applications, network operating systems ; D.1.3 [Programming Techniques]: Concurrent Programming ; D.4.5 [Operating Systems]: Reliabilityverification, fa...
Persistent route oscillations in interdomain routing
 Computer Networks
, 1996
"... Hopbyhop interdomain routing protocols, such as BGP and IDRP, use independent route selection to realize domains ’ local policies. A domain chooses its routes based on path attributes present in a route. It is widely believed that these interdomain routing protocols always converge. We show that ..."
Abstract

Cited by 133 (4 self)
 Add to MetaCart
Hopbyhop interdomain routing protocols, such as BGP and IDRP, use independent route selection to realize domains ’ local policies. A domain chooses its routes based on path attributes present in a route. It is widely believed that these interdomain routing protocols always converge. We show that there exist domain policies that cause BGP/IDRP to exhibit persistent oscillations. In these oscillations, each domain repeatedly chooses a sequence of routes to a destination. Complex oscillation patterns can occur even in very simple topologies. We analyze the conditions for persistent route oscillations in a simple class of interdomain topologies and policies. Using this analysis, we evaluate ways to prevent or avoid persistent oscillations in general topologies. We conclude that if a hopbyhop interdomain routing protocol allows unconstrained route selection at a domain, the protocol may be susceptible to route oscillations. Constraining route selection to a provably “safe ” procedure (such as shortest path) can reduce the number of realizable policies. Alternatively, a routing policy registry can help detect unsafe policies.
Functionally accurate, cooperative distributed systems
 IEEE Transactions on Systems, Man, and Cybernetics
, 1981
"... A new approach for structuring distributed processing systems, called functionally accurate, cooperative (FA/C), is proposed. The approach differs from conventional ones in its emphasis on handling distributioncaused uncertainty and errors as an integral part of the network problemsolving process. ..."
Abstract

Cited by 92 (18 self)
 Add to MetaCart
A new approach for structuring distributed processing systems, called functionally accurate, cooperative (FA/C), is proposed. The approach differs from conventional ones in its emphasis on handling distributioncaused uncertainty and errors as an integral part of the network problemsolving process. In this approach nodes cooperatively problem solve by exchanging partial tentative results (at various levels of abstraction) within the context of common goals. The approach is especially suited to applications in which the data necessary to achieve a solution cannot be partitioned in such a way that a node can complete a task without seeing the intermediate state of task processing at other nodes. Much of the inspiration for the FA/C approach comes from the mechanisms used in knowledgebased artificial intelligence (AI) systems for resolving uncertainty caused by noisy input data and the use of approximate knowledge. The appropriateness of the FA/C approach is explored in three application domains: distributed interpretation, distributed network trafficlight control, and distributed planning. Additionally, the relationship between the approach and the structure of management organizations is developed. Finally, a number of current research directions necessary to more fully develop the FA/C approach are outlined. These research directions include distributed search, the integration of implicit and explicit forms of control, and distributed planning and organizational selfdesign. I.
A responsive distributed routing algorithm for computer networks
 Communications, IEEE Transactions on
, 1982
"... AbsrrucrA new distributed algorithm is presented for dynamically determining weighted shortest paths used for message routing in computer networks. The major features of the algorithm are that the paths.defined do not form transient loops when weights change and the number of steps required to find ..."
Abstract

Cited by 66 (1 self)
 Add to MetaCart
AbsrrucrA new distributed algorithm is presented for dynamically determining weighted shortest paths used for message routing in computer networks. The major features of the algorithm are that the paths.defined do not form transient loops when weights change and the number of steps required to find new shortest paths when network links fail is less than for previous algorithms. Specifically, the worst case recovery time is proportional to the largest number of hops h in any of the weighted shortest paths. For previous loopfree distributed algorithms this recovery time is proportional to h2. I.
Error Recovery in Multicomputers Using Global Checkpoints
 In 1984 International Conference on Parallel Processing
, 1984
"... Abstract — Periodic checkpointing of the entire system state and rolling back to the last checkpoint when an error is detected is proposed as a basis for error recovery on a VLSI multicomputer executing noninteractive applications. Detailed algorithms for saving the checkpoints, distributing diagno ..."
Abstract

Cited by 51 (0 self)
 Add to MetaCart
Abstract — Periodic checkpointing of the entire system state and rolling back to the last checkpoint when an error is detected is proposed as a basis for error recovery on a VLSI multicomputer executing noninteractive applications. Detailed algorithms for saving the checkpoints, distributing diagnostic information, and restoring a valid system state are presented. This approach places no restrictions on the actions of the application tasks, and, during normal computation, does not require the complex communication protocols that are part of most other schemes. Estimates of the overhead of the proposed scheme are presented and extensions for efficient handling of transient faults, input/output operations, and disk failures are discussed.
Another Adaptive Distributed Shortest Path Algorithm
 IEEE Transactions on Communications
, 1991
"... We give a distributed algorithm to compute shortest paths in a network with changing topology. It does not suffer from the routing table looping behavior associated with the FordBellman distributed shortest path algorithm although it uses truly distributed processing. Its time and message complexiti ..."
Abstract

Cited by 42 (0 self)
 Add to MetaCart
We give a distributed algorithm to compute shortest paths in a network with changing topology. It does not suffer from the routing table looping behavior associated with the FordBellman distributed shortest path algorithm although it uses truly distributed processing. Its time and message complexities are evaluated. Pierre Humblet is with the Laboratory for Information and Decision Systems, Massachusetts Institute of Technology, Cambridge MA 02139. This research was supported in part by Codex Corporation and in part by the Army Research Office under Grant No. DAAL0386K0171. 2 1) INTRODUCTION One of the oldest and best known problems in the field of distributed algorithms is to compute shortest paths between nodes in a network. This problem arises in the following context. We have a network of links and nodes (processors). Each link (I,J) is characterized by a direction dependent length LEN(I,J) that can change with time and can only be observed at node I. The nodes execute a distr...
Analysis of ShortestPath Routing Algorithms in a Dynamic Network Environment
 ACM Computer Communication Review
, 1992
"... In a dynamic network environment under heavy traffic load, shortestpath routing algorithms, particularly those that attempt to adapt to traffic changes, frequently exhibit oscillatory behaviors and cause performance degradation. In this paper we first examine the problems from the perspective of co ..."
Abstract

Cited by 42 (1 self)
 Add to MetaCart
In a dynamic network environment under heavy traffic load, shortestpath routing algorithms, particularly those that attempt to adapt to traffic changes, frequently exhibit oscillatory behaviors and cause performance degradation. In this paper we first examine the problems from the perspective of control theory and decision making, and then analyze the behaviors of the shortestpath routing algorithms in details. 1. INTRODUCTION Shortestpath routing algorithms have been widely used in today's computer networks. In such algorithms, each node attempts to route packets to their destinations over paths of minimum distance and updates the distances periodically to adapt topological and traffic changes. There are two main classes of algorithms: distancevector algorithm and linkstate algorithm. In a distancevector algorithm, each node maintains a routing table containing the distance of the shortest path to every destination in the network. A node only informs its immediate neighbors of...
SelfStabilizing Unidirectional Network Algorithms by PowerSupply
 Chicago Journal of Theoretical Computer Science
, 1997
"... Powersupply, a surprisingly simple and new general paradigm for the development of selfstabilizing algorithms in different models, is introduced. The paradigm is exemplified by developing simple and efficient selfstabilizing algorithms for leader election and either BFS or DFS spanning tree co ..."
Abstract

Cited by 27 (0 self)
 Add to MetaCart
Powersupply, a surprisingly simple and new general paradigm for the development of selfstabilizing algorithms in different models, is introduced. The paradigm is exemplified by developing simple and efficient selfstabilizing algorithms for leader election and either BFS or DFS spanning tree constructions, in stronglyconnected unidirectional and bidirectional dynamic networks (synchronous and asynchronous). The different algorithms stabilize in O(n) time in both synchronous and asynchronous networks without assuming any knowledge about the network topology or size, where n is the total number of nodes. Following the leader election algorithms we present a generic selfstabilizing spanning tree and/or leader election algorithm that produces a whole spectrum of new and efficient algorithms for these problems. Two variations that produce either a rooted Depth First Search tree or a rooted Breadth First Search tree are presented. 1 Introduction A distributed system is selfs...
Systematic Testing of Multicast Routing Protocols: Analysis of Forward and Backward Search Techniques
 Analysis of Forward and Backward Search Techniques.” IEEE ICCCN
, 2000
"... In this paper, we present a new methodology for developing systematic and automatic test generation algorithms for multipoint protocols. These algorithms attempt to synthesize network topologies and sequences of events that stress the protocol’s correstness or performance. This problem can be viewed ..."
Abstract

Cited by 12 (6 self)
 Add to MetaCart
In this paper, we present a new methodology for developing systematic and automatic test generation algorithms for multipoint protocols. These algorithms attempt to synthesize network topologies and sequences of events that stress the protocol’s correstness or performance. This problem can be viewed as a domainspecific search problem that suffen from the state space explosion problem. One goal of this work is to circumvent the state space explosion problem utilizing knowledge of network and fault modeling, and multipoint protocols. The two approaches investigated in this study are based on forward and backward search techniques. We use an extended finite state machine (FSM) model of the protocol. The fint algorithm uses forward search to perform reduced reachability analysis. Using domainspecific information for multicast routing over LANs, the algorithm complexity is reduced from exponential to polynomial in the number of routers. This approach, however, does not fully automate topology synthesis. The second algorithm, the faultoriented test generation, uses backward search for topology synthesis and uses backtracking to generate event sequences instead of searching forward from initial states. Using these algorithms, we have conducted studies for correctness of the multicast routing protocol PIM. I.