Energy-aware routing in the Cognitive Packet Network

An energy aware routing protocol (EARP) is proposed to minimise a performance metric that combines the total consumed power in the network and the QoS that is specified for the flows. The algorithm uses source routing based on the functionalities provided by the Cognitive Packet Network (CPN), running autonomously at each input node to the network based on smart packets which gather relevant information throughout the network using reinforcement learning at each of the intermediate nodes. Measurements on an experimental test-bed that uses EARP are presented and they indicate that it offers a reduction in power consumption, as compared to a purely QoS driven approach, and also respects the requested QoS level.     

A competitive neural network algorithm for solving vehicle routing problem

This paper describes a self organization Neural Network algorithm for a class of Vehicle Routing Problems. Motivated by the outstanding performance of adaptive Neural Network approach in the Traveling Salesman Problem, we devised an algorithm to extend the domain of applicability of this approach to more complex problems. First, relevant adaptation is proposed to refine the model for the Multiple Traveling Salesman Problem. Then, an additional mechanism to satisfy further constraints are embodied into the algorithm. The effectiveness of the proposed algorithm is evaluated by considering a series of standard problems from the literature. The results show that the algorithm can yield solutions within a few percent of optimality.     

Algorithms for multicast connection under multi-path routing model

Given a source node and a set of destination nodes in a network, multicast routing problem is usually treated as Steiner tree problem. Unlike this well-known tree based routing model, multicast routing under multi-path model is to find a set of paths rooted at the source node such that in each path at most a fixed number of destination nodes can be designated to receive the data and every destination node must be designated in a path to receive the data. The cost of routing is the total costs of paths found. In this paper we study how to construct a multicast routing of minimal cost under multi-path model. We propose two approximation algorithms for this NP-complete problem with guaranteed performance ratios.     

Fat-tree routing and node ordering providing contention free traffic for MPI global collectives

As the size of High Performance Computing clusters grows, so does the probability of interconnect hot spots that degrade the latency and effective bandwidth the network provides. This paper presents a solution to this scalability problem for real life constant bisectional-bandwidth fat-tree topologies. It is shown that maximal bandwidth and cut-through latency can be achieved for MPI global collective traffic. To form such a congestion-free configuration, MPI programs should utilize collective communication, MPI-node-order should be topology aware, and the packet routing should match the MPI communication patterns. First, we show that MPI collectives can be classified into unidirectional and bidirectional shifts. Using this property, we propose a scheme for congestion-free routing of the global collectives in fully and partially populated fat trees running a single job. The no-contention result is then obtained for multiple jobs running on the same fat-tree by applying some job size and placement restrictions. Simulation results of the proposed routing, MPI-node-order and communication patterns show no contention which provides a 40% throughput improvement over previously published results for all-to-all collectives.     

Competitive routing over time

Congestion games are a fundamental and widely studied model for selfish allocation problems like routing and load balancing. An intrinsic property of these games is that players allocate resources simultaneously and instantly. This is particularly unrealistic for many network routing scenarios, which are one of the prominent application scenarios of congestion games. In many networks, load travels along routes over time and allocation of edges happens sequentially. In this paper, we consider two frameworks that enhance network congestion games with a notion of time. We introduce temporal network congestion games that are based on coordination mechanisms — local policies that allow to sequentialize traffic on the edges. In addition, we consider congestion games with time-dependent costs, in which travel times are fixed but quality of service of transmission varies with load over time. We study existence and complexity properties of pure Nash equilibria and best-response strategies in both frameworks for the special case of linear latency functions. In some cases our results can be used to characterize convergence properties of various improvement dynamics, by which the population of players can reach equilibrium in a distributed fashion.     

无线传感网协作能量感知路由方法*

将多跳分集引入无线传感网中以节能,提出协作能量感知路由方法（CEAR：Cooperative Energy Aware Routing）。协作能量感知路由方法利用多跳分集方法对无线传感网经典的能量感知路由（EAR: Energy Aware Routing）方法加以改进。分析了多跳分集方法中各跳的总能耗,并基于能耗分析结果设计协作能量感知路由方法。仿真结果表明,相比于能量感知路由方法,协作能量感知路由方法有更好的节能性能。     

Variable neighborhood descent with iterated local search for routing and wavelength assignment

In this work we treat the Routing and Wavelength Assignment (RWA) with focus on minimizing the number of wavelengths to route demand requests. Lightpaths are used to carry the traffic optically between origin-destination pairs. The RWA is subjected to wavelength continuity constraints, and a particular wavelength cannot be assigned to two different lightpaths sharing a common physical link. We develop a Variable Neighborhood Descent (VND) with Iterated Local Search (ILS) for the problem. In a VND phase we try to rearrange requests between subgraphs associated to subsets of a partition of the set of lightpath requests. In a feasible solution, lightpaths belonging to a subset can be routed with the same wavelength. Thus, the purpose is to eliminate one subset of the partition. When VND fails, we perform a ILS phase to disturb the requests distribution among the subsets of the partition. An iteration of the algorithm alternates between a VND phase and a ILS phase. We report computational experiments that show VND-ILS was able to improve results upon powerful methods proposed in the literature.     

一种采用按需路由策略的MPRN路由协议

提出了一种采用按需路由发现策略的移动分组无线网路由协议。协议采用按需路由发现过程,动态更新路由信息和建立路由转发组。数据包在转发组成员间进行有限泛洪,使协议能够降低对带宽的占用及减少可能的大量路由更新信息的传播。     

路由器软硬件转发表同步的设计与Linux实现

路由表的实现是路由器软件的核心，而硬件转发表的维护则是硬件高速转发的关键。在分析路由表与转发表同步模块接口与功能的基础上，充分利用Linux虚拟网络设备和BSD套接字扩展机制的优势与特点，提出了一种在Linux下完成两者同步的新思路。该总体方案及实现已应用于国际合作项目高速宽带路由器的研制与开发中。     

Dynamic Prediction based Multi Queue (DPMQ) drop policy for probabilistic routing protocols of delay tolerant network

Two most important issues should be considered to achieve data delivery in DTN networking: routing protocols for the network and intelligent buffer management policy for everyone node in the network. The routing scheme decides which messages should be forwarded when nodes meet, and the buffer management policy determines which message is purged when the buffer overflows in a node. This study proposes a buffer management policy named as Dynamic Prediction based Multi Queue (DPMQ) for probabilistic routing protocols. It works by classification of local buffer into three queues of messages, which are DCTL, HPTL and LPTL. The simulation results have proven that the DPMQ performs well as compared to DLA, DOA, MOFO, LIFO, LEPR and LIFO in terms of reducing the message relay, message drop, hop counts average and overhead while rising in the delivery probability.     

路由器软硬件转发表同步的设计与Linux实现*

路由表的实现是路由器软件的核心,而硬件转发表的维护则是硬件高速转发的关键。在分析路由表与转发表同步模块接口与功能的基础上,充分利用Linux虚拟网络设备和BSD套接字扩展机制的优势与特点,提出了一种在Linux下完成两者同步的新思路。该总体方案及实现已应用于国际合作项目高速宽带路由器的研制与开发中。     

On supporting high-throughput routing metrics in on-demand routing protocols for multi-hop wireless networks

Researchers have proposed routing metrics other than hop count, such as ETX (expected transmission count) and ETT (expected transmission time), to find routes with high throughput. These metrics are inherently suitable to be used in source routing protocols such as DSR, because link state information needs to be collected for the calculation of the shortest path. In this paper, we propose an efficient and generalized approach called accumulated path metric (APM) for supporting high-throughput metrics (HTMs) in on-demand routing protocols. One advantage of APM is that it is able to find the shortest path, in terms of a particular metric, without collecting topology information and without running a shortest-path algorithm. This will significantly simplify the existing design of supporting HTMs in DSR. We present a proof of the correctness of APM. Moreover, we address the problem of duplicate RREQ (route request) transmissions with existing HTM schemes and present a broadcast ordering (BO) technique to suppress unnecessary RREQ transmissions. We study the performance of APM and BO in both AODV and DSR, and the results verify the effectiveness of the proposed approaches.     

节点能量敏感的容迟/容断网络概率路由算法

针对容迟/容断网络(DTN)中节点能量受限的问题,提出一种节点能量敏感的概率路由算法。该算法将网络中的节点划分能量状态,针对不同能量状态的节点采取有区别的消息转发机制和节能的缓存管理策略,实现消息交付率与网络能耗之间的平衡。仿真结果表明,与其他几种算法相比,该算法能够在低能耗的基础上提高消息交付率并降低网络开销,具有较长的网络寿命。     

Energy efficient routing algorithm for fiber-wireless access networks: A network formation game approach

New multimedia services and ubiquitous networking pose great challenges on existing access network infrastructures. To cope with such requirements new access technologies, such as the fiber-wireless (FiWi), are being developed. Together with the emergence of new access networks, efforts are being made to reduce the amount of energy required to provide services. Indeed, this issue plays an increasingly important role. Here we propose an energy efficient routing algorithm for FiWi access networks. The main idea is to exploit the multipath capabilities of the wireless mesh front end of FiWi access networks to create energy efficient routes that optimize the sleeping and active periods of all ONUs and wireless nodes. To achieve this goal, an energy efficient network model based on network formation game theory is used. This model allows several network formation processes to be compared in regard to the energy efficiency of the routes they generate. Our results reveal that the farsighted network formation process establishes the most energy efficient routes, meaning that the choices done by this formation process were the best ones. However, this farsighted process is computationally expensive. For this reason a heuristic algorithm is developed, which explores the most energy efficient choices taken by the network formation processes, and farsighted process in particular. Results show that the proposed heuristic is able to obtain results close to the farsighted process.     

AODV和AOMDV路由协议性能分析与比较

移动无线自组网(MANET)作为一种典型的自组织网络,其路由协议一直是研究的重点。介绍了无线自组网按需平面距离矢量路由(AODV)协议和无线自组网按需多路径距离矢量路由(AOMDV)协议的特点,在NS2模拟软件中使用多种测试场景和不同的介质访问控制(MAC)层协议对这两种路由协议的性能进行了测试和分析。实验结果表明,AOMDV协议在平均延时和路由发现频率上优于AODV协议,在分组投递率和归一化路由开销方面的性能低于AODV协议。     

An economic analysis of routing conflict and its resolution

Thousands of competing autonomous systems (ASes) must cooperate with each other to provide global Internet connectivity. Each AS has independent economic objectives and retains autonomy in setting their routing policies independently to maximize its profit. However, such autonomy enables ASes to produce conflicting routing polices and thus raises route oscillations between them (i.e., routing divergence). This paper studies the basic problem of routing divergence by investigating real ISP pricing data. We first demonstrate that routing divergences occur under economic dependency cycles, i.e., provider–customer cycles, of different ASes which are raised by economic conflicts between themselves. We then propose a provable cycle-breaking routing mechanism to detect and solve economic conflicts and route divergence. We show that every cycle-breaking strategy allows ASes to maximize their own profits to converge to a Nash equilibrium with a profit-sharing mechanism derived from the coalition game concept of Shapley value. At the Nash equilibrium point, the cycle-breaking strategies maximize ASes’ profits and encourage ASes so as to ensure divergence-free routing.     

Classical and modern heuristics for the vehicle routing problem

This article is a survey of heuristics for the Vehicle Routing Problem . It is divided into two parts: classical and modern heuristics. The first part contains well-known schemes such as, the savings method, the sweep algorithm and various two-phase approaches. The second part is devoted to tabu search heuristics which have proved to be the most successful metaheuristic approach. Comparative computational results are presented.     

Group routing without group routing tables: an exercise in protocol design

We present a group routing protocol for a network of processes. The task of the protocol is to route data messages to each member of a process group. To this end, a tree of processes is constructed in the network, ensuring that each group member is included in the tree. To build this tree, the group routing protocol relies upon the local unicast routing tables of each process. Thus, group routing is accomplished by composing two protocols: an underlying unicast routing protocol, whose detailed behavior is unknown but its basic properties are given, and a protocol that builds a group tree based upon the unicast routing tables. The group routing protocol is developed in three steps. First, a simple protocol is obtained, and is proven correct. Then, the protocol is refined twice. Each refined protocol improves upon its predecessor by satisfying all of the predecessor's properties plus some additional stronger properties. The final protocol has the property of adapting the group tree to changes in the unicast routing tables without compromising the integrity of the group tree, even in the presence of unicast routing loops.     

Congestion estimation for hexagonal routing

Interconnect planning is an important issue in VLSI designs. Routing congestion is an important problem during placement. This paper presents a novel approach to estimating the routing congestion on the hexagonal model with bounded-length detours. It is the first probabilistic estimation work on hexagonal topologies. A combinatorial estimation algorithm is presented. The experimental results demonstrate the effectiveness of the method.     

Potential based routing as a secondary best-effort routing for Information Centric Networking (ICN)

One challenge to the retrieval process of ICN is to take advantage of largely distributed copies in in-network caches. This paper proposes Potential Based Routing (PBR) as a secondary best-effort routing mechanism to boost availability of copies in ICN architectures. The control overhead issue of the PBR is evaluated through both theoretical analysis and numerical simulation. In addition, the paper provides the PBR with a recovery mechanism from a failure, which can reduce the control overhead traffic by at least 40% in the simulation environment. Lastly, it is demonstrated how an ICN architecture can benefit from this PBR in terms of cache hit and delay reduction ratios.