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Highly Dynamic DestinationSequenced DistanceVector Routing (DSDV) for Mobile Computers
, 1994
"... An adhoc network is the cooperative engagement of a collection of Mobile Hosts without the required intervention of any centralized Access Point. In this paper we present an innovative design for the operation of such adhoc networks. The basic idea of the design is to operate each Mobile Host as a ..."
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Cited by 1677 (8 self)
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An adhoc network is the cooperative engagement of a collection of Mobile Hosts without the required intervention of any centralized Access Point. In this paper we present an innovative design for the operation of such adhoc networks. The basic idea of the design is to operate each Mobile Host as a specialized router, which periodically advertises its view of the interconnection topology with other Mobile Hosts within the network. This amounts to a new sort of routing protocol. We have investigated modifications to the basic BellmanFord routing mechanisms, as specified by RIP [5], to make it suitable for a dynamic and selfstarting network mechanism as is required by users wishing to utilize adhoc networks. Our modifications address some of the previous objections to the use of BellmanFord, related to the poor looping properties of such algorithms in the face of broken links and the resulting time dependent nature of the interconnection topology describing the links between the Mobile Hosts. Finally, we describe the ways in which the basic networklayer routing can be modified to provide MAClayer support for adhoc networks.
EndtoEnd Routing Behavior in the Internet
, 1996
"... The largescale behavior of routing in the Internet has gone virtually without any formal study, the exceptions being Chinoy's analysis of the dynamics of Internet routing information [Ch93], and recent work, similar in spirit, by Labovitz, Malan and Jahanian [LMJ97]. We report on an analysis o ..."
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Cited by 603 (15 self)
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The largescale behavior of routing in the Internet has gone virtually without any formal study, the exceptions being Chinoy's analysis of the dynamics of Internet routing information [Ch93], and recent work, similar in spirit, by Labovitz, Malan and Jahanian [LMJ97]. We report on an analysis of 40,000 endtoend route measurements conducted using repeated “traceroutes ” between 37 Internet sites. We analyze the routing behavior for pathological conditions, routing stability, and routing symmetry. For pathologies, we characterize the prevalence of routing loops, erroneous routing, infrastructure failures, and temporary outages. We find that the likelihood of encountering a major routing pathology more than doubled between the end of 1994 and the end of 1995, rising from 1.5 % to 3.3%. For routing stability, we define two separate types of stability, “prevalence, ” meaning the overall likelihood that a particular route is encountered, and “persistence, ” the likelihood that a route remains unchanged over a long period of time. We find that Internet paths are heavily dominated by a single prevalent route, but that the time periods over which routes persist show wide variation, ranging from seconds up to days. About 2/3's of the Internet paths had routes persisting for either days or weeks. For routing symmetry, we look at the likelihood that a path through the Internet visits at least one different city in the two directions. At the end of 1995, this was the case half the time, and at least one different autonomous system was visited 30 % of the time.
Routing Highbandwidth Traffic in Maxmin Fair Share Networks
"... We study how to improve the throughput of highbandwidth traffic such as large file transfers in a network where resources are fairly shared among connections. While it is possible to devise priority or reservationbased schemes that give highbandwidth traffic preferential treatment at the expense ..."
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Cited by 66 (6 self)
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We study how to improve the throughput of highbandwidth traffic such as large file transfers in a network where resources are fairly shared among connections. While it is possible to devise priority or reservationbased schemes that give highbandwidth traffic preferential treatment at the expense of other connections, we focus on the use of routing algorithms that improve resource allocation while maintaining maxmin fair share semantics. In our approach, routing is closely coupled with congestion control in the sense that congestion information, such as the rates allocated to existing connections, is used by the routing algorithm. To reduce the amount of routing information that must be distributed, an abstraction of the congestion information is introduced. Using an extensive set of simulation, we identify a linkcost or cost metric for "shortestpath" routing that performs uniformly better than the minimalhop routing and shortestwidest path routing algorithms. To further improve throughput without reducing the fair share of singlepath connections, we propose a novel prioritized multipath routing algorithm in which low priority paths share the bandwidth left unused by higher priority paths. This leads to a conservative extension of maxmin fairness called prioritized multilevel maxmin fairness. Simulation results confirm the advantages of our multipath routing algorithm.
New Dynamic Algorithms for Shortest Path Tree Computation
 IEEE/ACM Transactions on Networking
, 2000
"... The OSPF and ISIS routing protocols widely used in today's Internet compute a shortest path tree (SPT) from each router to other routers in a routing area. Many existing commercial routers recompute an SPT from scratch following changes in the link states of the network. Such recomputation of ..."
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Cited by 61 (1 self)
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The OSPF and ISIS routing protocols widely used in today's Internet compute a shortest path tree (SPT) from each router to other routers in a routing area. Many existing commercial routers recompute an SPT from scratch following changes in the link states of the network. Such recomputation of an entire SPT is inecient and may consume a considerable amount of CPU time. Moreover, as there may coexist multiple SPTs in a network with a set of given link states, recomputation from scratch causes frequent unnecessary changes in the topology of an existing SPT and may lead to routing instability. In this paper, we present new dynamic SPT algorithms that make use of the structure of the previously computed SPT. Besides efficiency, our algorithm design objective is to achieve routing stability by making minimum changes to the topology of an existing SPT (while maintaining shortest path property) when some link states in the network have changed. We establish an algorithmic framework that allows ...
New Dynamic SPT Algorithm based on a BallandString Model
, 1999
"... A key functionality in today's widely used interior gateway routing protocols such as OSPF and ISIS involves the computation of a shortest path tree (SPT). In many existing commercial routers, the computation of an SPT is done from scratch following changes in the link states of the network. A ..."
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Cited by 27 (0 self)
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A key functionality in today's widely used interior gateway routing protocols such as OSPF and ISIS involves the computation of a shortest path tree (SPT). In many existing commercial routers, the computation of an SPT is done from scratch following changes in the link states of the network. As there may coexist multiple SPTs in a network with a set of given link states, such recomputation of an entire SPT not only is inefficient but also causes frequent unnecessary changes in the topology of an existing SPT and creates routing instability. This paper presents a new dynamic SPT algorithm that makes use of the structure of the previously computed SPT. Our algorithm is derived by recasting the SPT problem into an optimization problem in a dual linear programming framework, which can also be interpreted using a ballandstring model. In this model, the increase (or decrease) of an edge weight in the tree corresponds to the lengthening (or shortening) of a string. By stretching the strings...
Integrated routing algorithms for anycast messages
 IEEE COMMUNICATIONS MAGAZINE
, 2000
"... In this paper, we propose and analyze three routing algorithms for anycast packets: i) sourcedestination based routing with weighted random selection (SD/WRS), ii) destination based routing with weighted random selection (D/WRS), and iii) the shortest shortest path first (SSPF) algorithms. The SSPF ..."
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Cited by 24 (16 self)
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In this paper, we propose and analyze three routing algorithms for anycast packets: i) sourcedestination based routing with weighted random selection (SD/WRS), ii) destination based routing with weighted random selection (D/WRS), and iii) the shortest shortest path first (SSPF) algorithms. The SSPF algorithm is a simple extension to the traditional SPF algorithm for routing unicast packets. The SD/WRS and D/WRS algorithms explicitly take into account characteristics of anycast message traffic and its recipient group. As a result, our simulation study shows that both the SD/WRS and D/WRS algorithms perform much better than SSPF in terms of average endtoend packet delay. In particular, SD/WRS performs very close to a dynamic optimal algorithm in most cases. Our algorithms are simple, efficient, and compatible with the most of existing routing technologies. We also formally prove the loop free and correctness properties for our algorithms.
Increasing the Weight of Minimum Spanning Trees
, 1996
"... The problems of computing the maximum increase in the weight of the minimum spanning trees of a graph caused by the removal of a given number of edges, or by finite increases in the weights of the edges, are investigated. For the case of edge removals, the problem is shown to be NPhard and an \Omeg ..."
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Cited by 23 (1 self)
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The problems of computing the maximum increase in the weight of the minimum spanning trees of a graph caused by the removal of a given number of edges, or by finite increases in the weights of the edges, are investigated. For the case of edge removals, the problem is shown to be NPhard and an \Omega\Gamma/ = log k)approximation algorithm is presented for it, where k is the number of edges to be removed. The second problem is studied assuming that the increase in the weight of an edge has an associated cost proportional to the magnitude of the change. An O(n 3 m 2 log(n 2 =m)) time algorithm is presented to solve it. 1 Introduction Consider a communication network in which information is broadcast over a minimum spanning tree. There are applications for which it is important to determine the maximum degradation in the performance of the broadcasting protocol that can be expected as a result of traffic fluctuations and link failures [25]. Also, there are several combinatorial op...
A Survey of Algorithms for Convex Multicommodity Flow Problems
, 1997
"... There are many problems related to the design of networks. Among them, the message routing problem plays a determinant role in the optimization of network performance. Much of the motivation for this work comes from this problem which is shown to belong to the class of nonlinear convex multicommodit ..."
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Cited by 22 (3 self)
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There are many problems related to the design of networks. Among them, the message routing problem plays a determinant role in the optimization of network performance. Much of the motivation for this work comes from this problem which is shown to belong to the class of nonlinear convex multicommodity flow problems. This paper emphasizes the message routing problem in data networks, but it includes a broader literature overview of convex multicommodity flow problems. We present and discuss the main solution techniques proposed for solving this class of largescale convex optimization problems. We conduct some numerical experiments on the message routing problem with some different techniques. 1 Introduction The literature dealing with multicommodity flow problems is rich since the publication of the works of Ford and Fulkerson's [19] and T.C. Hu [30] in the beginning of the 1960s. These problems usually have a very large number of variables and constraints and arise in a great variety o...
Optimized kShortestPaths Algorithm for Facility Restoration
 SOFTWAREPRACTICE AND EXPERIENCE
, 1994
"... This paper presents experimental studies of several wellknown shortestpaths algorithms adapted to the task of finding the ksuccessivelyshortest linkdisjoint replacement paths for restoration in a telecommunications network with n nodes. The implementations range in complexity from O(kn ) when ..."
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Cited by 19 (9 self)
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This paper presents experimental studies of several wellknown shortestpaths algorithms adapted to the task of finding the ksuccessivelyshortest linkdisjoint replacement paths for restoration in a telecommunications network with n nodes. The implementations range in complexity from O(kn ) when based on Dijkstra's original method, through several improvements to an efficient implementation of O(kn[v+logn]) complexity, and finally to an O(kn) implementation for the special case of edgesparse graphs with small integer edge weights. Here n is the maximum degree of a node in the network. Several alternatives were tested during the course of these studies, particularly with a view to minimizing the number of heap updates. These alternatives are possible because we are searching for several paths between a given pair of nodes, rather than just one path between one or more pairs of nodes. Two fairly straightforward changes yield a decrease in execution time, whereas a more complex heap management strategy consumes as much time in the added code as it releases from the main routine. Experimental results confirm the theoretical complexity of O(kn log n) and demonstrate a speedup of nearly an order of magnitude over the simpler O(kn ) implementation in the largest networks tested. The optimized implementation is recommended for planning and operational applications of kshortest paths rerouting for telecommunications network restoration and restorable network design. If hop counts or small integer link weights can be used to measure distances, then the O(kn) implementation is recommended, as typical telecommunications networks are edgesparse