Showing papers on "Equal-cost multi-path routing published in 2008"

The vehicle routing problem : latest advances and new challenges

Abstract: Overviews and Surveys- Routing a Heterogeneous Fleet of Vehicles- A Decade of Capacitated Arc Routing- Inventory Routing- The Period Vehicle Routing Problem and its Extensions- The Split Delivery Vehicle Routing Problem: A Survey- Challenges and Advances in A Priori Routing- Metaheuristics for the Vehicle Routing Problem and Its Extensions: A Categorized Bibliography- Parallel Solution Methods for Vehicle Routing Problems- Recent Developments in Dynamic Vehicle Routing Systems- New Directions in Modeling and Algorithms- Online Vehicle Routing Problems: A Survey- Modeling and Solving the Capacitated Vehicle Routing Problem on Trees- Using a Genetic Algorithm to Solve the Generalized Orienteering Problem- An Integer Linear Programming Local Search for Capacitated Vehicle Routing Problems- Robust Branch-Cut-and-Price Algorithms for Vehicle Routing Problems- Recent Models and Algorithms for One-to-One Pickup and Delivery Problems- One-to-Many-to-One Single Vehicle Pickup and Delivery Problems- Challenges and Opportunities in Attended Home Delivery- Chvatal-Gomory Rank-1 Cuts Used in a Dantzig-Wolfe Decomposition of the Vehicle Routing Problem with Time Windows- Vehicle Routing Problems with Inter-Tour Resource Constraints- From Single-Objective to Multi-Objective Vehicle Routing Problems: Motivations, Case Studies, and Methods- Practical Applications- Vehicle Routing for Small Package Delivery and Pickup Services- Advances in Meter Reading: Heuristic Solution of the Close Enough Traveling Salesman Problem over a Street Network- Multiperiod Planning and Routing on a Rolling Horizon for Field Force Optimization Logistics- Health Care Logistics, Emergency Preparedness, and Disaster Relief: New Challenges for Routing Problems with a Focus on the Austrian Situation- Vehicle Routing Problems and Container Terminal Operations - An Update of Research

Streamlined packet forwarding using dynamic filters for routing and security in a shared forwarding plane

Abstract: A network router includes a plurality of interfaces configured to send and receive packets, and a routing component comprising: (i) a routing engine that includes a control unit that executes a routing protocol to maintain routing information specifying routes through a network, and (ii) a forwarding plane configured by the routing engine to select next hops for the packets in accordance with the routing information. The forwarding plane comprises a switch fabric to forward the packets to the interfaces based on the selected next hops. The network router also includes a security plane configured to apply security functions to the packets. The security plane is integrated within the network router to share a streamlined forwarding plane of the routing component.

Methods and apparatus for routing between virtual resources based on a routing location policy

Abstract: In one embodiment, a method includes performing, at a host device on a first side of a single-hop link, packet classification associated with hairpin routing of a first data packet between a first virtual resource and a second virtual resource that are logically defined at the host device. The first virtual resource can be different than the second virtual resource. The also includes transmitting a second data packet to a network device on a second side of the single-hop link so that packet classification associated with hairpin routing of the second data packet between at least two virtual resources logically defined at the host device is performed at the network device.

Implementation and Analysis of a New Selection Strategy for Adaptive Routing in Networks-on-Chip

Abstract: Efficient and deadlock-free routing is critical to the performance of networks-on-chip. The effectiveness of any adaptive routing algorithm strongly depends on the underlying selection strategy. A selection function is used to select the output channel where the packet will be forwarded on. In this paper we present a novel selection strategy that can be coupled with any adaptive routing algorithm. The proposed selection strategy is based on the concept of Neighbors-on-Path the aims of which is to exploit the situations of indecision occurring when the routing function returns several admissible output channels. The overall objective is to choose the channel that will allow the packet to be routed to its destination along a path that is as free as possible of congested nodes. Performance evaluation is carried out by using a flit-accurate simulator under traffic scenarios generated by both synthetic and real applications. Results obtained show how the proposed selection strategy applied to the Odd-Even routing algorithm yields an improvement in both average delay and saturation point up to 20% and 30% on average respectively, with a minimal overhead in terms of area occupation. In addition, a positive effect on total energy consumption is also observed under near-congestion packet injection rates.

Toward internet-wide multipath routing

Abstract: The Internet would be more efficient and robust if routers could flexibly divide traffic over multiple paths. Often, having one or two extra paths is sufficient for customizing paths for different applications, improving security, reacting to failures, and balancing load. However, support for Internet-wide multipath routing faces two significant barriers. First, multipath routing could impose significant computational and storage overhead in a network the size of the Internet. Second, the independent networks that comprise the Internet will not relinquish control over the flow of traffic without appropriate incentives. In this article, we survey flexible multipath routing techniques that are both scalable and incentive compatible. Techniques covered include: multihoming, tagging, tunneling, and extensions to existing Internet routing protocols.

Path splicing

Abstract: We present path splicing, a new routing primitive that allows network paths to be constructed by combining multiple routing trees ("slices") to each destination over a single network topology. Path splicing allows traffic to switch trees at any hop en route to the destination. End systems can change the path on which traffic is forwarded by changing a small number of additional bits in the packet header. We evaluate path splicing for intradomain routing using slices generated from perturbed link weights and find that splicing achieves reliability that approaches the best possible using a small number of slices, for only a small increase in latency and no adverse effects on traffic in the network. In the case of interdomain routing, where splicing derives multiple trees from edges in alternate backup routes, path splicing achieves near-optimal reliability and can provide significant benefits even when only a fraction of ASes deploy it. We also describe several other applications of path splicing, as well as various possible deployment paths.

Distributed energy-efficient cooperative routing in wireless networks

Abstract: Recently, the merits of cooperative communication in the physical layer have been explored. However, the impact of cooperative communication on the design of the higher layers has not been well-understood yet. Cooperative routing in wireless networks has gained much interest due to its ability to exploit the broadcast nature of the wireless medium in designing power efficient routing algorithms. Most of the existing cooperation based routing algorithms are implemented by finding a shortest path route first and then improving the route using cooperative communication. As such, these routing algorithms do not fully exploit the merits of cooperative communications, since the optimal cooperative route might not be similar to the shortest path route. In this paper, we propose a cooperation-based routing algorithm, namely, the minimum power cooperative routing (MPCR) algorithm, which makes full use of the cooperative communications while constructing the minimum-power route. The MPCR algorithm constructs the minimum-power route, which guarantees certain throughput, as a cascade of the minimum-power single-relay building blocks from the source to the destination. Thus, any distributed shortest path algorithm can be utilized to find the optimal cooperative route with polynomial complexity. Using analysis, we show that the MPCR algorithm can achieve power saving of 65.61% in regular linear networks and 29.8% in regular grid networks compared to the existing cooperation-based routing algorithms, where the cooperative routes are constructed based on the shortest-path routes. From simulation results, MPCR algorithm can have 37.64% power saving in random networks compared to those cooperation-based routing algorithms.

Controlling the spread of interests and content in a content centric network

Abstract: One embodiment of the present invention provides a system for controlling the spread of interests and content in a content centric network (CCN). During operation, the system maintains a routing policy for content data. The system also receives a packet associated with a piece of content or an interest for the content. Next, the system determines that the structured name included in the packet is within the namespace specified in the routing policy. The system further determines that the packet satisfies the condition in the routing policy. Subsequently, the system routes the packet based on in part the action corresponding to the condition as specified in the routing policy.

Ad hoc networks beyond unit disk graphs

Abstract: In this paper, we study an algorithmic model for wireless ad hoc and sensor networks that aims to be sufficiently close to reality as to represent practical real-world networks while at the same time being concise enough to promote strong theoretical results The quasi unit disk graph model contains all edges shorter than a parameter d between 0 and 1 and no edges longer than 1 We show that--in comparison to the cost known for unit disk graphs--the complexity results of geographic routing in this model contain the additional factor 1/d2 We prove that in quasi unit disk graphs flooding is an asymptotically message-optimal routing technique, we provide a geographic routing algorithm being most efficient in dense networks, and we show that classic geographic routing is possible with the same asymptotic performance guarantees as for unit disk graphs if d ≥ 1/√2

Design Guidelines for Routing Metrics in Multihop Wireless Networks

Abstract: The design of a routing protocol must be based on the characteristics of its target networks. The diversity of wireless networks motivates the design of different routing metrics, capturing different aspects of wireless communications. The design of routing metrics, however, is not arbitrary since it has a great impact on the proper operation of routing protocols. Combining a wrong type of routing metrics with a routing protocol may result in routing loops and suboptimal paths. In this paper, we thoroughly study the relationship between routing metrics and routing protocols. Our work provides important guidelines for designing routing metrics and identifies the specific properties that a routing metric must have in order to be combined with certain type of routing protocols.

Consensus routing: the internet as a distributed system

Abstract: Internet routing protocols (BGP, OSPF, RIP) have traditionally favored responsiveness over consistency. A router applies a received update immediately to its forwarding table before propagating the update to other routers, including those that potentially depend upon the outcome of the update. Responsiveness comes at the cost of routing loops and blackholes--a router A thinks its route to a destination is via B but B disagrees. By favoring responsiveness (a liveness property) over consistency (a safety property), Internet routing has lost both. Our position is that consistent state in a distributed system makes its behavior more predictable and securable. To this end, we present consensus routing, a consistency-first approach that cleanly separates safety and liveness using two logically distinct modes of packet delivery: a stable mode where a route is adopted only after all dependent routers have agreed upon it, and a transient mode that heuristically forwards the small fraction of packets that encounter failed links. Somewhat surprisingly, we find that consensus routing improves overall availability when used in conjunction with existing transient mode heuristics such as backup paths, deflections, or detouring. Experiments on the Internet's AS-level topology show that consensus routing eliminates nearly all transient disconnectivity in BGP.

Systems and methods for adaptive routing in mobile ad-hoc networks and disruption tolerant networks

Abstract: The systems and methods described herein include adaptive routing processes for packet-based wireless communication networks. This routing approach works both in MANETs (when a contemporaneous end-to-end path is available) and in DTNs (when a contemporaneous end to end path is not available, but one of formed over space and time). In particular, the methods include adaptively selecting a routing process for transmitting a packet through a node in the network based on available information on the network topology and/or the contents of the packet.

Remote Message Routing Device and Methods Thereof

Abstract: A message routing method includes receiving a plurality of messages at a routing node. The routing node is configured to receive instructions indicating an offset, criteria associated with the offset, and a group of interested nodes. The routing node examines a portion of a data payload of a received message based on the offset. If the information at the offset matches the criteria, the routing node routes the message to each of the group of interested nodes. Thus, the routing node can route messages to different groups of destination nodes depending on information in the data payload of received messages, thereby providing a flexible way to route messages over a network.

A tabu search algorithm for the periodic vehicle routing problem with multiple vehicle trips and accessibility restrictions

Abstract: In this paper, we consider a periodic vehicle routing problem that includes, in addition to the classical constraints, the possibility of a vehicle doing more than one route per day, as long as the maximum daily operation time for the vehicle is not exceeded. In addition, some constraints relating to accessibility of the vehicles to the customers, in the sense that not every vehicle can visit every customer, must be observed. We refer to the problem we consider here as the site-dependent multi-trip periodic vehicle routing problem. An algorithm based on tabu search is presented for the problem and computational results presented on randomly generated test problems that are made publicly available. Our algorithm is also tested on a number of routing problems from the literature that constitute particular cases of the proposed problem. Specifically we consider the periodic vehicle routing problem; the site-dependent vehicle routing problem; the multi-trip vehicle routing problem; and the classical vehicle routing problem. Computational results for our tabu search algorithm on test problems taken from the literature for all of these problems are presented.

Randomized 3D Geographic Routing

Abstract: We reconsider the problem of geographic routing in wireless ad hoc networks. We are interested in local, memoryless routing algorithms, i.e. each network node bases its routing decision solely on its local view of the network, nodes do not store any message state, and the message itself can only carry information about O(1) nodes. In geographic routing schemes, each network node is assumed to know the coordinates of itself and all adjacent nodes, and each message carries the coordinates of its target. Whereas many of the aspects of geographic routing have already been solved for 2D networks, little is known about higher-dimensional networks. It has been shown only recently that there is in fact no local memoryless routing algorithm for 3D networks that delivers messages deterministically. In this paper, we show that a cubic routing stretch constitutes a lower bound for any local memoryless routing algorithm, and propose and analyze several randomized geographic routing algorithms which work well for 3D network topologies. For unit ball graphs, we present a technique to locally capture the surface of holes in the network, which leads to 3D routing algorithms similar to the greedy-face-greedy approach for 2D networks.

(p,q)-Epidemic routing for sparsely populated mobile ad hoc networks

Abstract: This paper considers (p, q )-Epidemic Routing, a class of store-carry-forward routing schemes, for sparsely populated mobile ad hoc networks. Our forwarding scheme includes Two-Hop Forwarding and the conventional Epidemic Routing as special cases. In such forwarding schemes, the original packet is copied many times and its packet copies spread over the network. Therefore those packet copies should be deleted after a packet reaches the destination. We analyze the performance of (p, q)-Epidemic Routing with VACCINE recovery scheme. Unlike most of the existing studies, we discuss the performance of (p, q)-Epidemic Routing in depth, taking account of the recovery process that deletes unnecessary packets from the network.

System and method for dynamically routing communications

Abstract: A system and method for routing an incoming call to a subscriber-selected destination number in accordance with dynamic data concerning the subscriber provided by an address book, a calendar and a presence server. A routing system routes the incoming call in accordance with a subscriber-defined routing rule associated with the originating number of the incoming call, as determined from the address book. The routing rule may specify that the incoming call be routed to a destination number associated with the current date and time, as indicated by the calendar. The routing rule may specify, alternatively or in addition thereto, that the incoming call be routed to a destination number associated with a presence-enabled service on which the subscriber is currently active. The subscriber or caller may also be alternatively notified of the routing of the incoming call.

An algorithmic approach to geographic routing in ad hoc and sensor networks

Abstract: The one type of routing in ad hoc and sensor networks that currently appears to be most amenable to algorithmic analysis is geographic routing. This paper contains an introduction to the problem field of geographic routing, presents a specific routing algorithm based on a synthesis of the greedy forwarding and face routing approaches, and provides an algorithmic analysis of the presented algorithm from both a worst-case and an average-case perspective.

Survey on routing protocols for wireless sensor networks

Abstract: This paper presented the problems and challenges of routing protocols by the analysis and comparison of typical flat and hierarchical routing protocols.Finally,summaried the important features that ideal routing protocols possess as well as its future research strategies and trends.

A Decade of Capacitated Arc Routing

Abstract: Summary. Arc Routing is the arc counterpart to node routing in the sense that focus regarding service and resource constraints are on the arcs and not on the nodes. The key problem within this area is the Capacitated Arc Routing Problem (CARP), which is the arc routing counterpart to the vehicle routing problem. During the last decade, arc routing has been a relatively active research area with respect to lower bounding procedures, solution approaches and modeling. Furthermore, several interesting variations of the problem have been studied. We survey the latest research within the area of arc routing focusing mainly on the CARP and its variants.

MaizeRouter : Engineering an Effective Global Router

Abstract: In this paper, we present the complete design and architectural details of MaizeRouter. MaizeRouter reflects a significant leap in progress over existing publicly available routing tools yet relies upon relatively simple operations, including extreme edge shifting, a technique aimed primarily at the efficient reduction of routing congestion, and edge retraction, a counterpart to extreme edge shifting that serves to reduce unnecessary wirelength. We present enhanced variations of these operations to enable the rapid exploration of candidate paths, along with a form of dynamic cost deflation that provides our various path computation procedures with progressively more accurate (and less optimistic) cost information as search continues. These algorithmic contributions are built upon a framework of interdependent net decomposition, a representation that improves upon traditional two-pin net decomposition by preventing duplication of routing resources while enabling cheap and incremental topological reconstruction. Collectively, these operations permit a broad search space that previous algorithms have been unable to achieve, resulting in solutions of considerably higher quality than those of well-established routers.

BioRoute: A Network-Flow-Based Routing Algorithm for the Synthesis of Digital Microfluidic Biochips

Abstract: Due to recent advances in microfluidics, digital microfluidic biochips are expected to revolutionize laboratory procedures. One critical problem for biochip synthesis is the droplet routing problem. Unlike traditional very large scale integration routing problems, in addition to routing path selection, the biochip routing problem needs to address the issue of scheduling droplets under practical constraints imposed by the fluidic property and timing restriction of synthesis results. In this paper, we present the first network-flow-based routing algorithm that can concurrently route a set of noninterfering nets for the droplet routing problem on biochips. We adopt a two-stage technique of global routing followed by detailed routing. In global routing, we first identify a set of noninterfering nets and then adopt the network-flow approach to generate optimal global-routing paths for nets. In detailed routing, we present the first polynomial-time algorithm for simultaneous routing and scheduling using the global-routing paths with a negotiation-based routing scheme. Our algorithm targets at both the minimization of cells used for routing for better fault tolerance and minimization of droplet transportation time for better reliability and faster bioassay execution. Experimental results show the robustness and efficiency of our algorithm.

Robust cooperative routing protocol in mobile wireless sensor networks

Abstract: In wireless sensor networks, path breakage occurs frequently due to node mobility, node failure, and channel impairments It is challenging to combat path breakage with minimal control overhead, while adapting to rapid topological changes Due to the Wireless Broadcast Advantage (WBA), all nodes inside the transmission range of a single transmitting node may receive the packet, hence naturally they can serve as cooperative caching and backup nodes if the intended receiver fails to receive the packet In this paper, we present a distributed robust routing protocol in which nodes work cooperatively to enhance the robustness of routing against path breakage We compare the energy efficiency of cooperative routing with noncooperative routing and show that our robust routing protocol can significantly improve robustness while achieving considerable energy efficiency

Maximally radio-disjoint multipath routing for wireless multimedia sensor networks

Abstract: In wireless sensor networks, bandwidth is one of precious resources to multimedia applications. To get more bandwidth, multipath routing is one appropriate solution provided that inter-path interferences are minimized. In this paper, we address the problem of interfering paths in the context of wireless multimedia sensor networks and consider both intra-session as well as inter-session interferences. Our main objective is to provide necessary bandwidth to multimedia applications through non-interfering paths while increasing the network lifetime. To do so, we adopt an incremental approach where for a given session, only one path is built at once. Additional paths are built when requi red, typically in case of congestion or bandwidth shortage. Interference awareness and energy saving are achieved by switching a subset of sensor nodes in a passive state in which they do not take part in the routing process. Despite the routing overhead introduced by the incremental approach we adopt, our simulations show that this can be compensated by the overall achieved throughput and the amount of consumed energy per correctly received packet especially for relatively long sessions such as multimedia ones. This is mainly due to the fact that a small number of non-interfering paths allows for better performances than a large number of interfering ones.

Cooperative Routing in Multi-Source Multi-Destination Multi-Hop Wireless Networks

Abstract: In a network supporting cooperative communication, the sender of a transmission is no longer a single node, which causes the concept of a traditional link to be reinvestigated. Thus, the routing scheme basing on the link concept should also be reconsidered to ";truly"; exploit the potential performance gain introduced by cooperative communication. In this paper, we investigate the joint problem of routing selection in network layer and contention avoidance among multiple links in MAC layer for multi-hop wireless networks in a cooperative communication aware network. To the best of our knowledge, it is the first work to investigate the problem of cooperative communication aware routing in multi-source multi-destination multi-hop wireless networks. Several important concepts, including virtual node, virtual link and virtual link based contention graph are introduced. Basing on those concepts, an optimal cooperative routing is achieved and a distributed routing scheme is proposed after some practical approximations. The simulation results show that our scheme reduces the total transmission power comparing with non-cooperative routing and greatly increases the network throughput comparing with single flow cooperative routings.

Some Applications of the Generalized Vehicle Routing Problem

Abstract: The Generalized Vehicle Routing Problem (GVRP) is an extension of the classical Vehicle Routing Problem (VRP) in which the vertex set is partitioned into clusters and vehicles must visit exactly one (or at least one) vertex per cluster. The GVRP provides a useful modelling framework for a wide variety of applications. The purpose of this paper is to provide such examples of applications and models. These include the Travelling Salesman with Profits, several VRP extensions, the Windy Routing Problem, and the design of tandem configurations for automated guided vehicles.

Utility-Based Opportunistic Routing in Multi-Hop Wireless Networks

Abstract: Recently, opportunistic routing (OR) has been widely used to compensate for the low packet delivery ratio of multi-hop wireless networks. Previous works either provide heuristic solutions without optimality analysis, or assume that unlimited retransmission is available for delivering a data packet. In this paper, we apply OR to a utility-based routing where the successful delivery of a data packet generates benefit. The objective is to maximize utility, defined as a function of benefit and cost of transmission. As the link reliability of each relay determines eventual packet delivery and hence utility, OR offers the ability to increase reliability through opportunistic relays. We explore the optimality of utility-based routing through OR without allowing retransmission, and observe that the optimal scheme requires exhaustive searching of all paths from source to destination. We then propose a heuristic solution to select relays and determine priorities among them. Finally, we provide distributed implementations for both schemes. Simulations on NS-2 and our customized simulator are conducted to verify the effectiveness of the heuristic compared with the optimal.

An Optimization Framework for Opportunistic Multipath Routing in Wireless Mesh Networks

Abstract: We consider wireless mesh networks, and exploit the inherent broadcast nature of wireless by making use of multipath routing. We present an optimization framework that enables us to derive optimal flow control, routing, scheduling, and rate adaptation schemes, where we use network coding to ease the routing problem. We prove optimality and derive a primal-dual algorithm that lays the basis for a practical protocol. We use simulation to show on realistic topologies that we can achieve 20-200% throughput improvement compared to single path routing, and several times compared to a recent related opportunistic protocol (MORE).