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Showing papers on "Destination-Sequenced Distance Vector routing published in 1996"


Journal ArticleDOI
TL;DR: This paper first examines the basic problem of QoS routing, namely, finding a path that satisfies multiple constraints, and its implications on routing metric selection, and presents three path computation algorithms for source routing and for hop-by-hop routing.
Abstract: Several new architectures have been developed for supporting multimedia applications such as digital video and audio. However, quality-of-service (QoS) routing is an important element that is still missing from these architectures. In this paper, we consider a number of issues in QoS routing. We first examine the basic problem of QoS routing, namely, finding a path that satisfies multiple constraints, and its implications on routing metric selection, and then present three path computation algorithms for source routing and for hop-by-hop routing.

1,769 citations


Journal ArticleDOI
TL;DR: WRP reduces the number of cases in which a temporary routing loop can occur, which accounts for its fast convergence properties and its performance is compared by simulation with the performance of the distributed Bellman-Ford Algorithm, DUAL, and an Ideal Link-state Algorithm.
Abstract: We present the Wireless Routing Protocol (WRP). In WRP, routing nodes communicate the distance and second-to-last hop for each destination. WRP reduces the number of cases in which a temporary routing loop can occur, which accounts for its fast convergence properties. A detailed proof of correctness is presented and its performance is compared by simulation with the performance of the distributed Bellman-Ford Algorithm (DBF), DUAL (a loop-free distance-vector algorithm) and an Ideal Link-state Algorithm (ILS), which represent the state of the art of internet routing. The simulation results indicate that WRP is the most efficient of the alternatives analyzed.

1,452 citations


Journal ArticleDOI
TL;DR: This paper is the second part of a work on the application of new search techniques for the vehicle routing problem with time windows and describes GENEROUS, the GENEtic ROUting System, which is based on the natural evolution paradigm.
Abstract: This paper is the second part of a work on the application of new search techniques for the vehicle routing problem with time windows. It describes GENEROUS, the GENEtic ROUting System, which is based on the natural evolution paradigm. Under this paradigm, a population of solutions evolves from one generation to the next by “mating” parent solutions to form new offspring solutions that exhibit characteristics inherited from their parents. For this vehicle routing application, a specialized methodology is devised for merging two vehicle routing solutions into a single solution that is likely to be feasible with respect to the time window constraints. Computational results on a standard set of test problems are reported, and comparisons are provided with other heuristics.

419 citations


Journal ArticleDOI
28 Aug 1996
TL;DR: It is found 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.
Abstract: The large-scale behavior of routing in the Internet has gone virtually without any formal study, the exception being Chinoy's analysis of the dynamics of Internet routing information [Ch93]. We report on an analysis of 40,000 end-to-end 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 3.4%. 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.

371 citations


Proceedings ArticleDOI
28 Aug 1996
TL;DR: This work identifies a link-cost or cost metric for "shortest-path" routing that performs uniformly better than the minimal-hop routing and shortest-widest path routing algorithms and proposes a novel prioritized multi-path routing algorithm in which low priority paths share the bandwidth left unused by higher priority paths.
Abstract: We study how to improve the throughput of high-bandwidth traffic such as large file transfers in a network where resources are fairly shared among connections. While it is possible to devise priority or reservation-based schemes that give high-bandwidth traffic preferential treatment at the expense of other connections, we focus on the use of routing algorithms that improve resource allocation while maintaining max-min 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 link-cost or cost metric for "shortest-path" routing that performs uniformly better than the minimal-hop routing and shortest-widest path routing algorithms. To further improve throughput without reducing the fair share of single-path connections, we propose a novel prioritized multi-path routing algorithm in which low priority paths share the bandwidth left unused by higher priority paths. This leads to a conservative extension of max-min fairness called prioritized multi-level max-min fairness. Simulation results confirm the advantages of our multi-path routing algorithm.

146 citations


Journal ArticleDOI
TL;DR: The theoretical background for the design of deadlock-free adaptive routing algorithms for virtual cut-through and store-and-forward switching is developed and a design methodology is proposed, which automatically supplies fully adaptive, minimal and non-minimal routing algorithms.
Abstract: This paper develops the theoretical background for the design of deadlock-free adaptive routing algorithms for virtual cut-through and store-and-forward switching. This theory is valid for networks using either central buffers or edge buffers. Some basic definitions and three theorems are proposed, developing conditions to verify that an adaptive algorithm is deadlock-free, even when there are cyclic dependencies between routing resources. Moreover, we propose a necessary and sufficient condition for deadlock-free routing. Also, a design methodology is proposed. It supplies fully adaptive, minimal and non-minimal routing algorithms, guaranteeing that they are deadlock-free. The theory proposed in this paper extends the necessary and sufficient condition for wormhole switching previously proposed by us. The resulting routing algorithms are more flexible than the ones for wormhole switching. Also, the design methodology is much easier to apply because it automatically supplies deadlock-free routing algorithms.

145 citations


Journal ArticleDOI
TL;DR: Simulations of the one-fault-tolerant routing algorithm and other minimal and nonminimal routing algorithms in a two-dimensional mesh indicate that misrouting increases communication latencies significantly at high throughputs, so it is concluded thatMisrouting should be used only for increasing the degree of fault tolerance, never for just increasing adaptiveness.
Abstract: Previous methods of making wormhole-routed meshes fault tolerant have been based on adding virtual channels to the networks. This paper proposes an alternative method, one based on the turn model for designing wormhole routing algorithms. The turn model produces routing algorithms that are deadlock free, very adaptive, minimal or nonminimal, and livelock free for direct networks--whether or not they contain virtual channels. This paper illustrates how to modify the routing algorithms produced by the turn model to handle dynamic faults. This paper first describes how to modify the negative-first routing algorithm, which the turn model produces for n-dimensional meshes without virtual channels, to make it one-fault tolerant. Simulations of the one-fault-tolerant routing algorithm and other minimal and nonminimal routing algorithms in a two-dimensional mesh indicate that misrouting increases communication latencies significantly at high throughputs. The conclusion is that misrouting should be used only for increasing the degree of fault tolerance, never for just increasing adaptiveness. Finally , the paper describes how to modify the negative-first routing algorithm to make it (n - 1)-fault tolerant for n-dimensional meshes without virtual channels.

132 citations


Journal ArticleDOI
TL;DR: A model to design vehicle routing when demand at the nodes is uncertain is developed, based on the heuristic “sweeping” algorithm, the rules of fuzzy arithmetic and fuzzy logic.

113 citations


Proceedings ArticleDOI
12 Aug 1996
TL;DR: A novel deadlock-free adaptive routing algorithm is proposed to allow irregular interconnection of cut-through switches and some heuristics are suggested in terms of the selection of Eulerian trails, the avoidance of long routing paths, and the degree of adaptivity.
Abstract: Many cut-through switches, which can greatly reduce network latency, are commercially available for the construction of high-speed local area networks. The interconnection of cut-through switches provides an excellent network platform for high-performance workstation clusters. A novel deadlock-free adaptive routing algorithm is proposed to allow irregular interconnection of cut-through switches. The adaptive routing algorithm is based on two unidirectional adaptive trails constructed from two opposite unidirectional Eulerian trails. Some heuristics are suggested in terms of the selection of Eulerian trails, the avoidance of long routing paths, and the degree of adaptivity. Extensive simulation experiments based on a more realistic finite input source model are conducted to evaluate the network performance under different network parameters and traffic conditions. Both bimodal and bursty messages are considered. Such switch-based irregular networks are truly incrementally scalable and have potential to be reconfigured to adapt to the dynamics of network traffic conditions.

100 citations


Journal ArticleDOI
TL;DR: This paper considers optical networks with and without switches, and different types of routing in these networks, and presents optimal or near-optimal constructions of optical networks in these cases and algorithms for routing connections, specifically permutation routing for the networks constructed here.
Abstract: This paper studies the problem of dedicating routes to connections in optical networks. In optical networks, the vast bandwidth available in an optical fiber is utilized by partitioning it into several channels, each at a different optical wavelength. A connection between two nodes is assigned a specific wavelength, with the constraint that no two connections sharing a link in the network can be assigned the same wavelength. This paper considers optical networks with and without switches, and different types of routing in these networks. It presents optimal or near-optimal constructions of optical networks in these cases and algorithms for routing connections, specifically permutation routing for the networks constructed here.

96 citations


Journal ArticleDOI
TL;DR: In this article, an extension to ACVRP of the two well-known Clarke-Wright and Fisher-Jaikumar heuristic algorithms is proposed, which, starting with an initial infeasible solution, determines the final set of vehicle routes through an insertion procedure as well as intea-route and inter-route arc exchanges.

Proceedings ArticleDOI
24 Mar 1996
TL;DR: A framework for the modeling of multipath routing in connectionless networks that dynamically adapt to network congestion is presented, which regulates the parameters of the destination-oriented permit buckets and guarantees that all portions of a multipath are loop free.
Abstract: We present a framework for the modeling of multipath routing in connectionless networks that dynamically adapt to network congestion. The basic routing protocol uses a short-term metric based on hop-by-hop credits to reduce congestion over a given link, and a long-term metric based on end-to-end path delay to reduce delays from a source to a given destination. A worst-case bound on the end-to-end path delay is derived under three architectural assumptions: each router adopts weighted fair queueing (or packetized generalized processor sharing) service discipline on a per destination basis, a permit-bucket filter is used at each router to regulate traffic flow on a per destination basis, and all paths are loop free. The shortest multipath routing protocol regulates the parameters of the destination-oriented permit buckets and guarantees that all portions of a multipath are loop free.

Journal ArticleDOI
TL;DR: The nucleolus is formed, which minimizes maximum discontent among the players in a co-operative game in characteristic function form and gives conditions for when the core of the vehicle routing game is nonempty.
Abstract: In the vehicle routing cost allocation problem the aim is to find a good cost allocation method, i.e., a method that according to specified criteria allocates the cost of an optimal route configuration among the customers. We formulate this problem as a co-operative game in characteristic function form and give conditions for when the core of the vehicle routing game is nonempty. One specific solution concept to the cost allocation problem is the nucleolus, which minimizes maximum discontent among the players in a co-operative game. The class of games we study is such that the values of the characteristic function are obtained from the solution of a set of mathematical programming problems. We do not require an explicit description of the characteristic function for all coalitions. Instead, by applying a constraint generation approach, we evaluate information about the function only when it is needed for the computation of the nucleolus.

Journal ArticleDOI
TL;DR: Another fault-tolerant routing algorithm, which requires only a constant of five virtual networks in wormhole routing to ensure the property of deadlock freeness for a hypercube of any size, is presented in this research.
Abstract: We investigate fault-tolerant routing which aims at finding feasible minimum paths in a faulty hypercube. The concept of unsafe node and its extension are used in our scheme. A set of stringent criteria is proposed to identify the possibly bad candidates for forwarding a message. As a result, the number of such undesirable nodes is reduced without sacrificing the functionality of the mechanism. Furthermore, the notion of degree of unsafeness for classifying the unsafe nodes is introduced to facilitate the design of efficient routing algorithms which rely on having each node keep the states of its nearest neighbors. We show that a feasible path of length no more than the Hamming distance between the source and the destination plus four can always be established by the routing algorithm as long as the hypercube is not fully unsafe. The issue of deadlock freeness is also addressed in this research. More importantly, another fault-tolerant routing algorithm, which requires only a constant of five virtual networks in wormhole routing to ensure the property of deadlock freeness for a hypercube of any size, is presented in this paper.

Proceedings ArticleDOI
01 May 1996
TL;DR: It is proved that for every shortest path routing scheme, for any constant e, O < c < 1, and for every integer d such that 3 ~ d < En, there exists a n-node network of maximum degree d that locally requires @(n log d) bits of memory on El(n) nodes.
Abstract: In this paper, we deal with the compact routing problem on distributed networks, that is implementing routing schemes that use a minimum memory size on each node. We prove that for every shortest path routing scheme, for any constant e, O < c < 1, and for every integer d such that 3 ~ d < En, there exists a n-node network of maximum degree d that locally requires @(n log d) bits of memory on El(n) nodes. This optimal lower bound means that whatever you choose the routing scheme (interval routing, boolean routing, prefix routing, . ..). there exists a network on which one can not do better than routing tables.

Proceedings ArticleDOI
10 Nov 1996
TL;DR: A polynomial time algorithm is given to decide whether there is a feasible river routing solution and produce one with minimum crosstalk whenever the problem is feasible and given the positions of the pins in a single-layer routing channel and the maximum tolerable crosStalk between each pair of nets.
Abstract: With the increasing density of VLSI circuits, the interconnection wires are getting packed even closer. This has increased the effect of interaction between these wires on circuit performance and hence, the importance of controlling crosstalk. In this paper, we consider river routing with crosstalk constraints. Given the positions of the pins in a single-layer routing channel and the maximum tolerable crosstalk between each pair of nets, we give a polynomial time algorithm to decide whether there is a feasible river routing solution and produce one with minimum crosstalk whenever the problem is feasible.

Patent
11 Jun 1996
TL;DR: In this paper, a remote access call forwarding method and system adapted for an Advanced Intelligent Network to forward a call incoming to a subscriber's telephone number in response to a routing destination number if the routing destination numbers does not correspond to a blocked destination identifier retrieved from a database.
Abstract: A remote access call forwarding method and system adapted for an Advanced Intelligent Network to forward a call incoming to a subscriber's telephone number in response to a routing destination number if the routing destination number does not correspond to a blocked destination identifier retrieved from a database. Further, a search to a subscriber profile unique to each subscriber is provided, the subscriber profile containing valid routing destination numbers previously validated to which the calls incoming to the subscriber have previously been forwarded. Thus, calls are forwarded in response to the routing destination number when the routing destination number matches a valid destination number found in the subscriber profile.

Journal ArticleDOI
TL;DR: A competitive neural network model and a genetic algorithm are used to improve the initialization and construction phase of a parallel insertion heuristic for the vehicle routing problem with time windows.
Abstract: A competitive neural network model and a genetic algorithm are used to improve the initialization and construction phase of a parallel insertion heuristic for the vehicle routing problem with time windows. The neural network identifies seed customers that are distributed over the entire geographic area during the initialization phase, while the genetic algorithm finds good parameter settings in the route construction phase that follows. Computational results on a standard set of problems are also reported.

Journal ArticleDOI
TL;DR: A necessary and sufficient condition is proposed that can be used for any adaptive or nonadaptive routing algorithm for wormhole routing, as long as only local information is required for routing, and which omits most channel dependencies that cannot be used to create a deadlock configuration.

Proceedings ArticleDOI
18 Nov 1996
TL;DR: The work reports on a modification of the algorithm embracing both static and dynamic heuristic components and multiple source nodes and the modified algorithm is applied in a 3D spatial information system (SIS) for routing emergency service vehicles.
Abstract: This paper discusses the implementation of Dijkstra's (1959) classic double bucket algorithm for path finding in connected networks. The work reports on a modification of the algorithm embracing both static and dynamic heuristic components and multiple source nodes. The modified algorithm is applied in a 3D spatial information system (SIS) for routing emergency service vehicles. The algorithm has been implemented as a suite of modules and integrated into a commercial SIS software environment. Genuine 3D spatial data is used to test the algorithm on the problem of vehicle routing and rerouting under simulated earthquake conditions in the Japanese city of Okayama. Coverage graphs were also produced giving contour lines joining points with identical travel times.

Patent
Yoshiyuki Kawakami1
15 May 1996
TL;DR: In this paper, a constraint graph is generated by representing plural nets by using vertices and correlation in the horizontal and vertical directions among the nets using edges, and clustering is conducted so that each of the vertices of the constraint graph are assigned to any one of plural layers in view of a channel height and so as to minimize the number of stacked vias.
Abstract: A constraint graph is generated by representing plural nets by using vertices and correlation in the horizontal and vertical directions among the nets by using edges. Then, clustering is conducted so that each of the vertices of the constraint graph is assigned to any one of plural layers in view of a channel height and so as to minimize the number of stacked vias. Next, routing topology is obtained on the basis of obtained clusters of the respective layers and the constraint graph, and routing patterns satisfying a design rule are obtained on the basis of the routing topology. In the clustering, the number of the stacked vias is minimized while retaining the minimum channel height in view of the final routing patterns. Accordingly, the routing patterns satisfying a desired design rule can realize a high density, resulting in a compact semiconductor integrated circuit.

Journal ArticleDOI
TL;DR: This paper studies the two-dimensional FPGA, Xilinx-like routing architectures and presents the first known computational complexity results for them, and proves that there is no constant bound on the mapping ratio of a track number required by a detailed routing to a global routing channel density.
Abstract: In this paper, we study the two-dimensional FPGA, Xilinx-like routing architectures and present the first known computational complexity results for them. The routing problem is formulated as a two-dimensional interval packing problem and is proved to be NP-complete with or without doglegs. Next, we consider other routing structures obtained from the industrial one by arbitrarily changing switch box connection topology while maintaining the same connection flexibility. There is an exponentially large number of such routing structures. We further prove that there does not exist a better routing architecture among the members of this large domain. In addition, we prove that there is no constant bound on the mapping ratio of a track number required by a detailed routing to a global routing channel density for the studied architectures. Finally, we show two directions of changing the routing architectures which yield polynomial time mapping solutions and constant bounded mapping ratios. Our theoretical analysis is intended to give some insight to, and understanding of this new routing problem's fundamental properties.

Patent
01 Jul 1996
TL;DR: In this article, a routing approach is selected in a conversational mode while routing efficiency is consulted to compose routing processing procedure so as to generate a routing program, and a component placement processing procedure designated according to placement control information are combined to generate the placement program.
Abstract: This invention is directed to a method and apparatus to find out an optimum solution in automatic routing or automatic placement with certainty and at a high-speed to improve a routing rate, and to realize automatic routing in a high-density. To these end, a routing approach is selected in a conversational mode while routing efficiency is consulted to compose routing processing procedure so as to generate a routing program. Besides, component placement processing procedures designated according to placement control information are combined to generate the placement program. A straight line between component pins adjacent to each other is defined as a chord, a wave for maze method routing is generated from a start point toward an end point of a routing path and propagated between the chords adjacent to each other. Positions of the chords through which the wave has passed until reaching the end point from the start point are successively stored and the positions through which the wave has passed is traced back to the start point from the end point when the wave reaches the end point to decide a routing path of the routing pattern. The method and apparatus of this invention are applicable to routing design or component placement design of LSIs, multichip modules, printed circuit boards, etc.

Proceedings ArticleDOI
15 Apr 1996
TL;DR: The adaptive source routing (ASR) method is described which is a first attempt to combine adaptive routing and source routing methods and a route generation algorithm that determines maximally adaptive routes in multistage networks is described.
Abstract: We describe the adaptive source routing (ASR) method which is a first attempt to combine adaptive routing and source routing methods. In ASR, the adaptivity of each packet is determined at the source processor. Every packet can be routed in a fully adaptive or partially adaptive or non-adaptive manner, all within the same network at the same time. We evaluate and compare performance of the proposed adaptive source routing networks and oblivious routing networks by simulations. We also describe a route generation algorithm that determines maximally adaptive routes in multistage networks.

Journal ArticleDOI
TL;DR: This paper develops an exact algorithm based on a new subtour elimination constraint for solving Vehicle Routing Problems characterized by fixed or variable number of vehicles, common vehicle capacity, distance restrictions, and minimization of total distance travelled by all vehicles.

Proceedings ArticleDOI
28 Apr 1996
TL;DR: The results show that the static routing gives lower ongoing call blocking probabilities than the dynamic counterpart since the former's pre-computed routing table is less susceptible to the abrupt topological change during a state transition.
Abstract: We compare the performance of two routing schemes for LEO satellite networks through simulation. The two routing schemes represent static and dynamic routing for the case where the LEO satellite network is modeled as a finite state automaton (FSA). Each state in this FSA modeling corresponds to an equal-length interval within the period of the LEO satellite network. Modeling the LEO satellite network in this way allows us to consider the LEO satellite network as if it is a fixed topology network within each state. The routing table for the static routing is fixed within each state whereas that for the dynamic routing is updated continuously according to the shortest-path algorithm. The simulation results show that the static routing performs better in terms of newly initiated call blocking than the dynamic one. The results also show that the static routing gives lower ongoing call blocking probabilities than the dynamic counterpart since the former's pre-computed routing table is less susceptible to the abrupt topological change during a state transition.

Proceedings ArticleDOI
14 Oct 1996
TL;DR: This work proves a sufficient condition for the stability of dynamic packet routing algorithms, and gives the first dynamic algorithm for routing on a butterfly with bounded buffers, which is also applicable to the recently introduced adversarial input model.
Abstract: We prove a sufficient condition for the stability of dynamic packet routing algorithms. Our approach reduces the problem of steady state analysis to the easier and better understood question of static routing. We show that certain high probability and worst case bounds on the quasistatic (finite past) performance of a routing algorithm imply bounds on the performance of the dynamic version of that algorithm. Our technique is particularly useful in analyzing routing on networks with bounded buffers where complicated dependencies make standard queuing techniques inapplicable. We present several applications of our approach. In all cases we start from a known static algorithm, and modify it to fit our framework. In particular we give the first dynamic algorithm for routing on a butterfly with bounded buffers. Both the injection rate for which the algorithm is stable, and the expected time a packet spends in the system are optimal up to constant factors. Our approach is also applicable to the recently introduced adversarial input model.

Journal ArticleDOI
TL;DR: This paper gives theoretical analyses of simple wormhole routing algorithms, showing them to be nearly optimal for butterfly and mesh connected networks, and reports simulation results suggesting that the idea of random initial delays may have an impact beyond theoretical analysis.
Abstract: Virtually all theoretical work on message routing in parallel computers has dwelt on packet routing: messages are conveyed as packets, an entire packet can reside at a node of the network, and a packet is sent from the queue of one node to the queue of another node until its reaches its destination. A trend in multicomputer architecture, however, is to use wormhole routing. In wormhole routing a message is transmitted as a contiguous stream of bits, physically occupying a sequence of nodes/edges in the network. Thus, a message resembles a worm burrowing through the network. In this paper we give theoretical analyses of simple wormhole routing algorithms, showing them to be nearly optimal for butterfly and mesh connected networks. Our analysis requires initial random delays in injecting messages to the network. We report simulation results suggesting that the idea of random initial delays may have an impact beyond theoretical analysis.

Proceedings ArticleDOI
18 Nov 1996
TL;DR: A new RAW scheme is developed which unifies the routing and wavelength assignment subproblems and is found to yield significantly better solutions to the RAW problem than the earlier ones.
Abstract: We consider the problem of routing and assignment of wavelength (RAW) in wavelength-routed optical networks. Given a set of requests for all-optical connections (or lightpaths), the problem is to find wavelength-continuous routes from the source nodes to their respective destination nodes. Since the number of wavelengths available per link is limited, lightpaths cannot be established between every source-destination node pairs. Moreover, a common wavelength might not be available on all the segments of a chosen route. Thus, routing and wavelength assignment are to be considered concurrently for the best possible performance. Several heuristic algorithms have already been proposed for the RAW problem, however, most of these algorithms are based on the traditional model of circuit-switched networks where the routing and wavelength assignment steps are decoupled. A new RAW scheme is developed which unifies the routing and wavelength assignment subproblems. This unified approach is found to yield significantly better solutions to the RAW problem than the earlier ones. The paper also introduces an analytical model for predicting the average number of lightpaths requests a given physical network can support.