High-throughput multicast routing metrics in wireless mesh networks

The stationary nature of nodes in a mesh network has shifted the main design goal of routing protocols from maintaining connectivity between source and destination nodes to finding high-throughput paths between them. Numerous link-quality-based routing metrics have been proposed for choosing high-throughput routing paths in recent years. In this paper, we study routing metrics for high-throughput tree or mesh construction in multicast protocols. We show that there is a fundamental difference between unicast and multicast routing in how data packets are transmitted at the link layer, and accordingly how the routing metrics for unicast routing should be adapted for high-throughput multicast routing. We propose a low-overhead adaptive online algorithm to incorporate link-quality metrics to a representative multicast routing protocol. We then study the performance improvement achieved by using different link-quality-based routing metrics via extensive simulation and experiments on a mesh-network testbed, using ODMRP as a representative multicast protocol.Our extensive simulation studies show that: (1) ODMRP equipped with any of the link-quality-based routing metrics can achieve higher throughput than the original ODMRP. In particular, under a tree topology, on average, ODMRP enhanced with link-quality routing metrics achieve up to 34% higher throughput than the original ODMRP under low multicast sending rate; (2) the improvement reduces to 21% under high multicast sending rate due to higher interference experienced by the data packets from the probe packets; (3) heavily penalizing lossy links is an effective way in the link-quality metric design to avoid low-throughput paths; and (4) the path redundancy from a mesh data dissemination topology in mesh-based multicast protocols provides another degree of robustness to link characteristics and reduces the additional throughput gain achieved by using link-quality-based routing metrics. Finally, our experiments on an eight-node testbed show that on average, ODMRP using SPP and PP achieves 14% and 17% higher throughput over ODMRP, respectively, validating the simulation results.     

On-demand loop-free routing with link vectors

We present the on-demand link vector (OLIVE) protocol, a routing protocol for ad hoc networks based on link-state information that is free of routing loops and supports destination-based packet forwarding. Routers exchange routing information reactively for each destination in the form of complete paths, and each node creates a labeled source graph based on the paths advertised by its neighbors. A node originates a broadcast route request (RREQ) to obtain a route for a destination for which a complete path does not exist in its source graph. When the original path breaks, a node can select an alternative path based on information reported by neighbors, and a node can send a unicast RREQ to verify that the route is still active. A node that cannot find any alternate path to a destination sends route errors reliably to those neighbors that were using it as next hop to the destination. Using simulation experiments in ns2, OLIVE is shown to outperform dynamic source routing, ad hoc on-demand distance vector, optimized link-state routing protocol, and topology broadcast based on reverse-path forwarding, in terms of control overhead, throughput, and average network delay, while maintaining loop-free routing with no need for source routes.     

Toward path reliability by using adaptive multi-path routing mechanism for multimedia service in mobile Ad-hoc network

Traditional multi-path routing mechanisms aim to establish complete node or link disjoint paths.However,under some circumstances if multiple paths cannot be established based on the current network topology,the traditional multi-path routing mechanism will degenerate into single path routing mechanism,thus the advantages of multi-path routing cannot be exhibited.To enhance the end-to-end path reliability,an adaptive multi-path routing mechanism with path segment is proposed,in which multi-path can be establ...     

Adhoc-like routing in wired networks with genetic algorithms

Routing of packets in networks requires that a path be selected either dynamically while the packets are being forwarded, or statically (in advance) as in source routing from a source node to a destination. Quality of service (QoS) driven routing has been proposed using a protocol called the “Cognitive Packet Network” (CPN) which dynamically selects paths through a store and forward packet network so as to provide best effort QoS to route peer-to-peer connections. CPN operates very much as an adhoc protocol within a wired setting, and uses smart packets to select routes based on QoS requirements. We extend the path discovery process in CPN to include a genetic algorithm which can help discover new paths that may not have been discovered by smart packets. We describe how possible routes can “evolve” from prior knowledge, and then be selected based on “fitness” with respect to QoS. We detail the design of the algorithm and of its implementation, and report on resulting QoS measurements.     

A fast and reliable routing technique for wireless mesh networks

In wireless mesh networks (WMNs), real time communications (e.g., Voice over IP (VoIP) and interactive video communications) may often be interrupted as packets are frequently lost or delayed excessively. This usually happens due to the unreliability of wireless links or buffer overflows along the routing paths. The mesh connectivity within the WMN enables the capability to enhance reliability and reduce delay for such applications by using multiple paths for routing their packets. The vital components in multi‐path routing for achieving this are the pre‐determined formation of paths and the technique that the paths are deployed for packet traversal. Therefore, we propose a novel multi‐path routing protocol by introducing a new multi‐path organization and a traffic assignment technique. The designed technique dubbed as FLASH (Fast and reLiAble meSH routing protocol) discovers one primary path between a pair of source and destination based on a new proposed metric, and thereafter selects mini‐paths, which connect pairs of intermediate nodes along the primary path. The primary path and mini‐paths are concurrently deployed, as multiple copies of packets are routed through. This technique compensates for possible outage at intermediate wireless nodes or their corresponding wireless links along the primary path. Routing along mini‐paths is performed in such a way that redundant copies do not cause an excessive congestion on the network. The effectiveness of the proposed scheme is evaluated analytically and through extensive simulations under various load conditions. The results demonstrate the superiority of the proposed multi‐path organization in terms of reliability and satisfactory achievements of the protocol in enhancing delay and throughput compared to the existing routing protocols, especially for long distances and in congested conditions. Copyright © 2010 John Wiley & Sons, Ltd.     

Routing for cognitive radio networks consisting of opportunistic links

Cognitive radio (CR) has been considered a key technology to enhance overall spectrum utilization by opportunistic transmissions in CR transmitter–receiver link(s). However, CRs must form a cognitive radio network (CRN) so that the messages can be forwarded from source to destination, on top of a number of opportunistic links from co‐existing multi‐radio systems. Unfortunately, appropriate routing in CRN of coexisting multi‐radio systems remains an open problem. We explore the fundamental behaviors of CR links to conclude three major challenges, and thus decompose general CRN into cognitive radio relay network (CRRN), CR uplink relay network, CR downlink relay network, and tunneling (or core) network. Due to extremely dynamic nature of CR links, traditional routing to maintain end‐to‐end routing table for ad hoc networks is not feasible. We locally build up one‐step forward table at each CR to proceed based on spectrum sensing to determine trend of paths from source to destination, while primary systems (PSs) follow original ways to forward packets like tunneling. From simulations over ad hoc with infrastructure network topology and random network topology, we demonstrate such simple routing concept known as CRN local on‐demand (CLOD) routing to be realistic at reasonable routing delay to route packets through. Copyright © 2009 John Wiley & Sons, Ltd.     

Improving path duration in high mobility vehicular ad hoc networks

In this paper, we consider a high-speed highway mobility scenario, where the available knowledge about the network’s topology is used to improve the routing path duration. The improvement is mainly due to the use of a topology control algorithm, which increases the path duration by decreasing the probability of path breaks. For network regions having an enough density of vehicles, the packets are preferentially routed over the oldest links created by the vehicles moving in the same direction. For smaller values of vehicles’ density, the routing preferentially uses the most recent links created in both moving directions. This choice is shown to increase the routing path duration.The topology control scheme here proposed can be easily integrated in the existing routing protocols: we describe how to integrate it in the Optimized Link-State Routing Protocol (OLSR).¹ We compare the performance of our approach with other routing protocols for different values of vehicles’ density. The comparison includes end-to-end path delay, path availability and path length (in number of hops). Finally, we evaluate the path duration achieved with our approach, concluding that it exhibits a significant improvement over the most relevant topology and position-based routing protocols.     

Algebra and algorithms for QoS path computation and hop-by-hop routing in the Internet

Prompted by the advent of quality-of-service routing in the Internet, we investigate the properties that path weight functions must have so that hop-by-hop routing is possible and optimal paths can be computed with a generalization of E.W. Dijkstra's algorithm (see Numer. Math., vol.1, p.269-71, 1959). We define an algebra of weights which contains a binary operation, for the composition of link weights into path weights, and an order relation. Isotonicity is the key property of the algebra. It states that the order relation between the weights of any two paths is preserved if both of them are either prefixed or appended by a common, third, path. We show that isotonicity is both necessary and sufficient for a generalized Dijkstra's algorithm to yield optimal paths. Likewise, isotonicity is also both necessary and sufficient for hop-by-hop routing. However, without strict isotonicity, hop-by-hop routing based on optimal paths may produce routing loops. They are prevented if every node computes what we call lexicographic-optimal paths. These paths can be computed with an enhanced Dijkstra's algorithm that has the same complexity as the standard one. Our findings are extended to multipath routing as well. As special cases of the general approach, we conclude that shortest-widest paths can neither be computed with a generalized Dijkstra's algorithm nor can packets be routed hop-by-hop over those paths. In addition, loop-free hop-by-hop routing over widest and widest-shortest paths requires each node to compute lexicographic-optimal paths, in general.     

Sink location privacy protection under direction attack in wireless sensor networks

Wireless Sensor Networks have been widely deployed in military and civilian applications. Due to the nature of the sensor network, it is easy for an adversary to trace the movement of packets and get the sink location. Many ways have been proposed to deal with this problem, most of them provide path diversity. But these techniques always expose direction information. Once adversaries have got the direction information, they can launch a direction attack by deducing the direction of the sink and choosing right paths to trace. To cope with the direction attack, we present an improved scheme based on injecting fake packets and random walk of real packets. In this scheme, real packets do a random walk to hide direction information at a special phase, fake packets are injected in intersection nodes of two or more shortest paths, which can lead adversaries to fake paths. Privacy analysis shows that our scheme has a good performance on protecting sink location. We also examine the delivery time, energy consumption and safe time by simulations.     

Ad Hoc网带预测后备路由算法研究

网络拓扑的动态变化是AdHoc网络的主要特点,也是影响通信性能的主要因素。DSR协议是一种按需式路由协议,当发现1个链路断开的时候,就要重新建立1个新的路径,在路径重建的过程中会使包丢失,并且会造成重要的吞吐量的降低。鉴此,提出一种高效的路由协议。在移动预测的机制下,该协议能够选取另外一条后备路径来实现,减少包的丢失。     

Integrated routing algorithms for anycast messages

The use of anycast service can considerably simplify many communication applications. Two approaches can be used for routing anycast packets. Single-path routing always uses the same path for anycast packets from a source, while multipath routing splits anycast traffic into several different paths. The former is simple and easy to implement, while the latter may potentially reduce congestion, improving delay and throughput performance. However, multipath routing may require additional cost to maintain multipath information. To take advantage of both approaches and overcome their shortcomings, we develop a set of integrated routing algorithms that can adaptively select a subset of routers in the network to carry out multipath routing for anycast messages. We demonstrate that systems using our integrated routing algorithms perform substantially better than those where either the single-path or multipath approach is used alone     

软件定义网络一致性协同更新算法

为实现软件定义网络的一致性更新,本文提出一种协同利用分段路由、顺序更新、两步复制三种机制的更新算法.算法首先启用分段路由机制,尝试用现有路径规则拼接待更新数据流的最终路径,并根据最终路径是否能由现有规则拼接,将数据流分为可拼接与不可拼接两种.对于可拼接流,分段路由可将最终路径信息封装入数据包包头,使得数据包能立即沿最终路径转发.对于不可拼接流,算法计算最长一致性更新序列,并按照此序列依次更新节点,最后利用两步复制机制来完成剩余未更新节点的更新.并且经实验验证,算法比之前研究提出的算法不仅消耗更少的三态内容寻址存储器的空间资源,并且有更好的适用性与稳定性.     

A practical network coding and routing scheme based on maximum flow combination

Network coding is a novel field of information theory and coding theory. It is a breakthrough over the traditional store‐and‐forward routing methods by allowing coding of two or more packets together. From an information flow aspect, multiple flows could be overlapped in a routing scheme. Hence the theoretical upper bound of multicast capacity could be achieved by network coding. In this project, a complete routing and coding scheme is constructed to realize the maximum multicast transportation task. In order to implement the scheme, the paths of multiple max‐flows are determined. Edges are divided into overlapped and normal type based on the merged max‐flows. The transmitting data are represented using packets in a specific format. Multicast, forward and coding operations are defined to transmit data at the nodes. The nodes are classified according to the type of operation. A dynamic coding and routing algorithm is proposed to route packets gradually from source node to destinations in topological sorting order by the three operations on the path of merged max‐flows. We show that the use of simple XOR operations can satisfy most of the network topologies. The running time of the algorithm presented here is less than 1 second for most of the benchmark and random datasets. Copyright © 2012 John Wiley & Sons, Ltd.     

A protocol for scalable loop-free multicast routing

In network multimedia applications such as multiparty teleconferencing, users often need to send the same information to several (but not necessarily all) other users. To manage such one-to-many or many-to-many communication efficiently in wide-area internetworks, it is imperative to support and perform multicast routing. Multicast routing sends a single copy of a message from a source to multiple receivers over a communication link that is shared by the paths to the receivers. Loop-freedom is an especially important consideration in multicasting because applications using multicasting tend to be multimedia and bandwidth intensive, and loops in multicast routing duplicate looping packets. We present and verify a new multicast routing protocol, called multicast Internet protocol (MIP), which offers a simple and flexible approach to constructing both group-shared and shortest-paths multicast trees. MIP can be sender-initiated or receiver-initiated or both; therefore, it can be tailored to the particular nature of an application's group dynamics and size. MIP is independent of the underlying unicast routing algorithms used. MIP is robust and adapts under dynamic network conditions (topology or link cost changes) to maintain loop-free multicast routing. Under stable network conditions, MIP has no maintenance or control message overhead. We prove that MIP is loop-free at every instant, and that it is deadlock-free and obtains multicast routing trees within a finite time after the occurrence of an arbitrary sequence of topology or unicast changes     

无线传感网络中基于探测包的多径路由

多径路由是应对无线传感网络(WSNs)的链路质量差的重要技术。现存的构建多径路由依赖集中运算或迭代的分布式运算,消耗大量的运行时间。为此,提出基于探测包的多径路由(EPMR)。EPMR路由先利用探测包的传输,收集局部拓扑信息。依据接收探测包的到达时间,设置端口优先级,优先考虑端口优先级的节点参与路由。一旦参与了一条路径,节点不再参与源节点与目的节点间的其他路径,进而保证多径间的不相交性。仿真结果表明,提出的EPMR提升了数据包传输成功率,缩短了运行时间。     

QoS-aware multi-path video streaming for urban VANETs using ACO algorithm

Drivers can be provided with several beneficial services associated with video streaming in a vehicular ad-hoc network (VANET). Given the dynamic topology and high mobility of VANETs, a single path cannot support the required quality of service (QoS). To maximize global QoS metrics, a two-path model is proposed based on a disjoint algorithm to forward sub-streams over diverse paths from the transmitter to the receiver vehicle. In this solution, the video information spread in separate paths is categorized based on their priority. For this purpose, the protocol for transmitting each kind of video data should be selected cautiously. The present study aims to propose an ant colony optimization-based technique to establish the primary and secondary paths and enhance the QoS of routing paths. To achieve this goal, the QoS routing issue is formulated mathematically as a problem of constrained optimization. Moreover, to achieve high-quality video streaming, inter-frames are transmitted over the user datagram protocol and intra-frames are transmitted over the transmission control protocol (TCP). TCP transmission delays are also minimized using a TCP-ETX algorithm for selecting appropriate paths. According to the simulation results, the proposed two-path solution can be used to improve the quality of video streaming and to enhance the performance in terms of end-to-end delay, packet delivery ratio, and overhead. In this way, the proposed method can outperform several prominent routing algorithms such as adaptive QoS-based routing for VANETs, geographic source routing (GSR), intersection-based geographical routing protocol, and efficient GSR.

     

A novel approach to source routing for multi-hop ad hoc networks

The popularity of wireless ad hoc networks has significantly increased over the past years. As a result, a great scientific effort has been made to develop and implement efficient routing protocols, able to cope with the stochastically varying topology of such networks. We present an efficient routing protocol that combines source routing, caching of routes, and the use of sequence numbers to alleviate the routing load and at the same time increase the successful delivery of data packets.     

Secure and Policy-Compliant Source Routing

In today's Internet, inter-domain route control remains elusive; nevertheless, such control could improve the performance, reliability, and utility of the network for end users and ISPs alike. While researchers have proposed a number of source routing techniques to combat this limitation, there has thus far been no way for independent ASes to ensure that such traffic does not circumvent local traffic policies, nor to accurately determine the correct party to charge for forwarding the traffic. We present Platypus, an authenticated source routing system built around the concept of network capabilities, which allow for accountable, fine-grained path selection by cryptographically attesting to policy compliance at each hop along a source route. Capabilities can be composed to construct routes through multiple ASes and can be delegated to third parties. Platypus caters to the needs of both end users and ISPs: users gain the ability to pool their resources and select routes other than the default, while ISPs maintain control over where, when, and whose packets traverse their networks. We describe the design and implementation of an extensive Platypus policy framework that can be used to address several issues in wide-area routing at both the edge and the core, and evaluate its performance and security. Our results show that incremental deployment of Platypus can achieve immediate gains.     

Queue‐based multiple path load balancing routing protocol for MANETs

Congestion in the network is the main cause for packet drop and increased end‐to‐end transmission delay of packet between source and destination nodes. Congestion occurs because of the simultaneous contention for network resources. It is very important to efficiently utilize the available resources so that a load can be distributed efficiently throughout the network. Otherwise, the resources of heavily loaded nodes may be depleted very soon, which ultimately affects network performances. In this paper, we have proposed a new routing protocol named queue‐based multiple path load balancing routing protocol. This protocol discovers several node‐disjoint paths from source to destination nodes. It also finds minimum queue length with respect to individual paths, sorts the node‐disjoint paths based on queue length, and distributes the packets through these paths based on the minimum queue length. Simulation results show that the proposed routing protocol distributes the load efficiently and achieves better network performances in terms of packet delivery ratio, end‐to‐end delay, and routing overhead. Copyright © 2016 John Wiley & Sons, Ltd.     

Contrôle de puissance dans les réseaux ad-hoc

In an ad-hoc network, mobile stations communicate with each other using multi-hop wireless links. There is no stationary infrastructure such as base stations. Each node in the network also acts as a router, forwarding data packets for other nodes. In this architecture, mobile stations have a multi-hop path, via other mobile stations acting as intermediaries or relays, to indirectly forward packets from source to destination. Adjusting the transmitted power is extremely important in ad-hoc networks due to at least the following reasons. The transmitted power of the radio terminals determines the network topology. The network topology in turn has considerable impact on the throughput (fraction of packets, sent by a source, and successfully received at the receiver) performance of the network. The need for power efficiency must be balanced against the lifetime of each individual node and the overall life of the network. Power control problem can be classified in one of three categories. The first class comprises of strategies to find an optimal transmitted power to control the connectivity properties of the network. The second class of approaches could be called power aware routing. Most schemes use some shortest path algorithm with a power based metric, rather than a hop count based metric. The third class of approaches aim at modifying the mac layer. We use distributed power control algorithms initially proposed for cellular networks. We establish a classification of power control algorithms for wireless ad-hoc networks. We evaluate these algorithms in anIeee 802.11b multi-hop wireless ad-hoc LAN environment. Results show the advantage of power control in maximizing signal-to-interference ratio and minimizing transmitted power.