分级移动IPv6中一种新的自适应MAP选择算法*

分级移动IPv6中存在单点故障和负荷集中问题。提出一种基于分布式MAP结构的自适应MAP选择算法,综合考虑移动节点的当前速度、会话到达率、MAP负荷及距离等因素,以MN注册后将产生的移动性管理信令开销最小为依据进行选择。仿真结果表明,自适应MAP选择算法能够根据移动节点和网络的当前特性优化地选择不同的MAP进行注册,使移动性管理信令开销最小,具有较好的负荷分担效果,并一定程度上增强了分级结构的鲁棒性。与最远/近MAP选择方案相比,自适应MAP选择算法能够提高网络的吞吐量及减少平均切换时延。     

On a moving direction pattern based MAP selection model for HMIPv6 networks

In a large-scale mobile IPv6 network, usually there are several coexisting mobility anchor points (MAPs) for networking robustness and traffic sharing. Therefore, it is a challenging issue for an arriving mobile node to choose the most appropriate MAP to bind. This task must be carried out by considering the issues of load balancing, binding update and packet delivery cost minimization. This paper proposes a novel MAP selection scheme for hierarchical mobile IPv6 networks to allow a mobile node to discover the most appropriate MAP when there are multiple coexisting MAPs. This scheme is an enhancement to the adaptive MAP selection scheme. The proposed scheme improve the overall performance due to the consideration of the movement (direction) pattern of mobile nodes. Simulation results show that this scheme outperforms the existing cost models in terms of total binding update and packet delivery costs, ensuring a level of load balance similar to adaptive MAP selection scheme.     

Dynamic partitioning of IP-based wireless access networks

In HMIPv6-based network architecture, Mobile Nodes (MNs) generate excessive signalling overhead, where they move at borders of different Mobility Anchor Point (MAP) domains. Furthermore all the traffic originated or destined to MNs must traverse through the MAPs. Thus, MAPs are potential points of bottlenecks in the network, as the traffic load grows. To mitigate these drawbacks, division of the access network domain into overlapping partitions (MAP domains) is proposed in order to provide more scalable and robust mobile services. Partitioning problem is an NP-hard problem. In this paper, we propose three, heuristic, Kernighan–Lin based partitioning algorithms to minimise the total inter-area handover rate as well as bottleneck effect of MAPs. Our proposed algorithms adopt the proposed scheme of multiple MAP deployment per domain, where each AR can be assigned to more than one MAP in the same level of hierarchy. The proposed algorithms dynamically adapt to traffic and mobility changes. We devise a cost function for each algorithm and formulate optimisation problems, accordingly. Then we evaluate the performance of the algorithms in terms of dynamic adaptation to mobility and load changes, and also to the degree of load-balance, and mean amount of bandwidth blocking and dropping rates. A simulation evaluation and comparison study with Sanchis algorithm, demonstrates that the proposed overlapping scheme outperforms the conventional non-overlapping scheme. Furthermore, all proposed algorithms obtain improved performance implementation of Sanchis algorithm.     

Dynamic load balancing in IP-over-WDM optical burst switching networks

In this paper, we consider the problem of dynamic load balancing in wavelength division multiplexing (WDM)-based optical burst switching (OBS) networks. We propose a load balancing scheme based on adaptive alternate routing aimed at reducing burst loss. The key idea of adaptive alternate routing is to reduce network congestion by adaptively distributing the load between two pre-determined link-disjoint alternative paths based on the measurement of the impact of traffic load on each of them. We develop two alternative-path selection schemes to select link-disjoint alternative paths to be used by adaptive alternate routing. The path selection schemes differ in the way the cost of a path is defined and in the assumption made about the knowledge of the traffic demands. Through extensive simulation experiments for different traffic scenarios, we show that the proposed dynamic load balancing algorithm outperforms the shortest path routing and static alternate routing algorithms.     

一种新的基于分级移动IPv6的移动性管理方案*

提出了一种基于分级移动IPv6 的自适应移动性管理方案,该方案重点研究切换过程中的MN和MAP的操作。当MN进入一个新的子网内时,它可以利用这种自适应MAP选择算法来选择一个合适的MAP进行注册,同时,MAP可以综合考虑当时的业务情况和其他相关信息自适应地改变它在分级结构中的位置。这就使得MAP可以自适应地改变它的管理域,使得分级移动IP的体系结构是可伸缩的。     

分层移动IP网络的自适应移动性管理

移动IP(mobile IP,MIP)使主机在移动过程中不需改变IP地址便可连续访问Internet,其主要缺点是主机在移动过程中需要频繁地进行绑定更新,产生的信令开销较大。为降低移动IPv6的信令开销,IETF(Internet engineering task force)提出了分层移动IPv6(hierarchical mobile IPv6,HMIPv6)协议。基于HMIPv6,提出了一种自适应的分层移动性管理方案。这种方案采用模糊逻辑,根据移动主机的移动次数及移动性管理代价,动态选取MAP(mobility anchor point)并调整MAP区域所管辖的接入路由器个数。仿真分析表明,所提出的方案的代价优于固定MAP区域的移动性管理方案。     

HMIPv6中的自适应MAP选择算法

HMIPv6是一种有效的微移动管理协议。当移动节点进入一个域时,它会选择一个MAP进行注册。针对HMIPv6的特点,提出了一种支持负载分担的MAP选择算法。该算法利用MAP的优先级值来表征其负载情况,并根据MAP负载的变化,动态调整其优先级值。此外,还将速度因素引入了MAP协议开销的计算。模拟结果表明,该算法实现简单,开销管理和负载分担效果好。     

An adaptive learning scheme for load balancing with zone partition in multi-sink wireless sensor network

In many researches on load balancing in multi-sink WSN, sensors usually choose the nearest sink as destination for sending data. However, in WSN, events often occur in specific area. If all sensors in this area all follow the nearest-sink strategy, sensors around nearest sink called hotspot will exhaust energy early. It means that this sink is isolated from network early and numbers of routing paths are broken. In this paper, we propose an adaptive learning scheme for load balancing scheme in multi-sink WSN. The agent in a centralized mobile anchor with directional antenna is introduced to adaptively partition the network into several zones according to the residual energy of hotspots around sink nodes. In addition, machine learning is applied to the mobile anchor to make it adaptable to any traffic pattern. Through interactions with the environment, the agent can discovery a near-optimal control policy for movement of mobile anchor. The policy can achieve minimization of residual energy’s variance among sinks, which prevent the early isolation of sink and prolong the network lifetime.     

QoS-aware dynamic MAP selection schemes in HMIPv6 networks

We consider a dynamic Mobile Anchor Point (MAP) selection problem when there are both real-time and non-real time sessions in a Hierarchical Mobile IPv6 (HMIPv6) network. We propose schemes in which Mobile Nodes (MNs) holding real-time sessions register with the root MAP in a hierarchy of MAPs to reduce the inter-domain handovers while those with non-real time sessions select one either to balance the load or to reduce handover frequencies.     

Autonomous mobile agent routing for efficient server resource allocation

Mobile agents are becoming increasingly important in the highly distributed applications frameworks seen today. Their routing/dispatching from node to node is a very important issue as we need to safeguard application efficiency, achieve better load balancing and resource utilization throughout the underlying network. Selecting the best target server for dispatching a mobile agent is, therefore, a multi-faceted problem that needs to be carefully tackled. In this paper we propose distributed, adaptive routing schemes (next node selection) for mobile agents. The proposed schemes overcome risks like load oscillations, i.e., agents simultaneously abandoning a congested node in search for other, less saturated node. We try to induce different routing decisions taken by agents to achieve load balancing and better utilization of network resources. We consider five different algorithms and evaluate them through simulations. Our findings are quite promising both from the user/application and the network/infrastructure perspective.     

Immune optimization algorithm for solving joint call admission control problem in next-generation wireless network

The integration of radio access networks with different radio access technologies (RATs) is one of the remarkable characteristics of the next-generation wireless networks (NGWNs). In NGWN, the users with multi-network interface terminals should be able to select independently radio access network to obtain the best service. Therefore, joint call admission control (JCAC) schemes are required to select the most appropriate radio access network (RAN) for incoming calls. We propose an immune algorithm-based JCAC (IA-JCAC) scheme with users centric in order to enhance user's satisfaction. However, JCAC algorithms with users centric can lead to highly unbalanced traffic load among the available RANs in NGWN because users act independently, and most of them may prefer to be connected through a particular RAN. Highly unbalanced traffic load in NGWN will result in high overall call blocking/dropping probability and poor radio result utilization. To solve this problem, we employ dynamic pricing for balancing traffic load among available RANs in heterogeneous wireless networks where users' preferences are considered in decision-making on RAT selection. The proposed IA-based JCAC scheme is compared with another scheme that does not use the dynamic pricing on the performance. The simulation result shows the effectiveness of the proposed IA-JCAC scheme is improved significantly.     

Modeling of Adaptive Load Balancing with Hybrid F/CDMA and Sectorization Schemes in Mobile Communication Networks

In this paper, we investigate the load balancing problem in mobile communications by considering sectorization and a hybrid F/CDMA scheme (HFCS) jointly in the scenario of uneven traffic distributions. The problem is formulated as a combinatorial optimization model, subject to quality of service (QoS) requirements, and solved by the Lagrangean relaxation approach. In addition, Lagrangean multipliers are used to conduct sensitivity analysis. The model’s objective is to minimize the weighted call blocking rate in terms of the distribution diversity. The model’s performance is evaluated by the proposed HFCS, which is an adaptive scheme (AS). We compare the performance of AS with that of a non-adaptive (NA) scheme, which is a common power control method. Experiment results show that combining sectorization with the bandwidth segmentation scheme provides effective adaptive load balancing (ALB). The performance improvement achieved by the proposed adaptive scheme over the common power control scheme is as high as 68%. Moreover, under the scheme, the performance improves as the traffic load increases. Load balancing improves even further when AS is combined with the sectorization.     

Performance analysis of an adaptive dynamic grid-based approach to data distribution management

Data distribution management (DDM) plays a key role in traffic control for large-scale distributed simulations. In recent years, several solutions have been devised to make DDM more efficient and adaptive to different traffic conditions. Examples of such systems include the region-based, fixed grid-based, and dynamic grid-based (DGB) schemes, as well as grid-filtered region-based and agent-based DDM schemes. However, less effort has been directed toward improving the processing performance of DDM techniques. This paper presents a novel DDM scheme called the adaptive dynamic grid-based (ADGB) scheme that optimizes DDM time through the analysis of matching performance. ADGB uses an advertising scheme in which information about the target cell involved in the process of matching subscribers to publishers is known in advance. An important concept known as the distribution rate (DR) is devised. The DR represents the relative processing load and communication load generated at each federate. The DR and the matching performance are used as part of the ADGB method to select, throughout the simulation, the devised advertisement scheme that achieves the maximum gain with acceptable network traffic overhead. If we assume the same worst case propagation delays, when the matching probability is high, the performance estimation of ADGB has shown that a maximum efficiency gain of 66% can be achieved over the DGB scheme. The novelty of the ADGB scheme is its focus on improving performance, an important (and often forgotten) goal of DDM strategies.     

Dynamic storage and access load balancing for answering range queries in peer-to-peer networks

Recently, many applications have used Peer-to-Peer (P2P) systems to overcome the current problems with client/server systems such as non-scalability, high bandwidth requirement and single point of failure. In this paper, we propose an efficient scheme to support efficient range query processing over structured P2P systems, while balancing both the storage load and access load. The paper proposes a rotating token scheme to balance the storage load by placing joining nodes in appropriate locations in the identifier space to share loads with already overloaded nodes. Then, to support range queries, we utilize an order-preserving mapping function to map keys to nodes in order preserving way and without hashing. This may result in an access load imbalance due to non-uniform distribution of keys in the identifier space. Thus, we propose an adaptive replication scheme to relieve overloaded nodes by shedding some load on other nodes to balance the access load. We derive a formula for estimating the overhead of the proposed adaptive replication scheme. In this study, we carry simulation experiments with synthetic data to measure the performance of the proposed schemes. Our simulation experiments show significant gains in both storage load balancing and access load balancing.     

Joint coverage and link utilization for fast IP local protection

To mitigate the impact of failures, many IP Fast Local Recovery (IPFLR) schemes have been proposed to reroute traffic in the events of failures. However, the existing IPFLR schemes either aimed to find the alternate backup routes to protect failures, or focused on balancing the traffic load routed on the backup routes. Furthermore, in Internet, flows are often managed by shortest path routing, and therefore purely determining the backup routing paths is not sufficient in protecting the error-prone networks. In this paper, we propose a Simulated Annealing based Load balancing and Protection (SALP) scheme to determine link weights for balancing link utilization in the non-failure state and simultaneously construct backup routing tables for protecting any single link failure in IP networks. In our proposed scheme, the two most significant issues, (1) load balancing and (2) coverage, are jointly considered to recover the network operation from single link failures. In the proposed scheme, upon a failure, only the nodes adjacent to a failure are activated to divert affected traffic to backup paths without disturbing regular traffic. Numerical results delineate that the proposed scheme achieves high coverage rate and load balancing at the expense of slightly increasing the entries of backup routing table.     

MF-DLB: Multimetric forwarding and directed acyclic graph-based load balancing for geographic routing in FANETs

Flying ad hoc network (FANET) comprising unmanned aerial vehicles (UAVs) emerges as a promising solution for numerous military and civil applications. Transferring data collected from the environment to the ground station (GS) is a primary concern for meeting the communication demands of most of these applications. However, the highly mobile UAVs with limited communication range, resulting in frequent topology change and intermittent connectivity, make data routing challenging. In such scenarios, geographic routing is a viable solution due to its scalability and robustness. However, the basic forwarding mechanism of geographic routing favors the neighboring UAV nearest to the destination, impacted substantially by link failures and routing holes in a dynamic environment. Additionally, routing decisions ignoring the current load over UAVs contribute to performance degradation due to the high concentration of data traffic near the GS. Thus, to address these issues, a geographic routing protocol named MF-DLB comprising multimetric forwarding (MF) and a directed acyclic graph-based load balancing (DLB) scheme is proposed to enhance packet forwarding in FANETs. MF takes account of multiple metrics related to connectivity, geographic progress, link lifetime, and residual energy to select the next hop with a stable communication link while effectively bypassing the routing holes. The second scheme, DLB, focuses on proactively maintaining routing paths near GS for load distribution among underutilized nodes to address the congestion problem. Simulations performed in network simulator ns-3 confirm the outperformance of MF-DLB over other related routing schemes in terms of different performance metrics.     

移动IPv6移动性能的改进

主要问题是移动IPv6协议中移动主机移动性能的改进。通过对现有方案的研究和分析，提出了一种新的多层次移动IPv6方案。新方案中采用了新的方法计算主机的移动速度以便移动主机选择合适的MAP，同时还提出了新的缓存机制来减少转交过程中数据包的丢失。还利用了NS2对新方案进行了模拟仿真。新方案可以适应移动主机的快速移动，并能够减少绑定更新报文和数据包的丢失。     

基于最小通信开销的动态负载均衡策略

针对动态负载均衡过程产生额外通信开销的问题,建立了一种基于最小通信开销的数学模型。在此基础上,提出一种利用遗传算法解决该问题的新策略。该策略可减少负载迁移次数,降低动态负载均衡过程中的网络流量。仿真实验表明,该策略可获得比贪心策略具有更小通信开销的分配方案。     

Strategy and Simulation of Adaptive RID for Distributed Dynamic Load Balancing in Parallel Systems

Dynamic load balancing schemes are significant for efficiently executing nonuniform problems in highly parallel multicomputer systems.The objective is to minimize the total exectuion time of single applications.This paper has proposed an ARID strategy for distributed dynamic load balancing.Its principle and control protocol are described,and te communication overhead,the effect on system stability and the performance efficiency are analyzed.Finally,simulation experiments are carried out to compare the adaptive strategy with other dynamic load balancing schemes.     

Mobility-Aware Mobile Router Selection and Address Management for IPv6 Network Mobility

Network mobility (NEMO) extends IP mobility to moving networks, which are groups of nodes that often constitute a subnet of a mobile router (MR). To realize this collective mobility, there are a number of important issues such as addressing and multihoming. With the proliferation of mobile nodes connected to the Internet, the efficient allocation/deallocation of addresses is becoming a vital requirement. We propose a collaborative address management scheme for network mobility, where the home DHCPv6 agent of a mobile network performs prefix delegation, while the mobile DHCPv6 agent (in the mobile network) allocates the IPv6 address to each mobile node. Also, network mobility with multiple MRs is taken into consideration. To provide a mobile network that has multiple MRs with robust Internet connectivity, we propose mobility-aware mobile router selection schemes. The concept of mobility awareness refers to the capability of a moving network in a vehicle (e.g., a train) to pinpoint the most stable Internet connectivity, by choosing the mobile router based on the vehicles movement pattern. The simulation shows that the proposed scheme outperforms a round-robin mobile router selection scheme in terms of the amount of carried traffic.