Signaling cost and performance of SIGMA: A seamless handover scheme for data networks

Mobile IP has been developed to handle mobility of Internet hosts at the network layer. Mobile IP (MIP), however, suffers from a number of drawbacks such as requirement of infrastructure change, high handover latency, high packet loss rate, and conflict with network security solutions. In this paper, we describe and evaluate the performance of SIGMA, a Seamless IP diversity‐based Generalized Mobility Architecture. SIGMA utilizes multihoming to achieve seamless handover of mobile hosts, and is designed to solve many of the drawbacks of MIP, including requirement for changes in infrastructure. We first evaluate the signaling cost of SIGMA and compare with that of hierarchical Mobile IPv6 (an enhancement of Mobile IP) by analytical modeling, followed by comparison of handover performance of SIGMA and Mobile IPv6 enhancements. Criteria for performance evaluation include handover latency, packet loss, throughput, and network friendliness. Our results indicate that in most cases SIGMA has a lower signaling cost than Hierarchical Mobile IPv6. Moreover, for a typical network configuration, SIGMA has a higher handover performance over Mobile IP. Copyright © 2005 John Wiley & Sons, Ltd.     

Multilayer Hierarchical Model for Mobility Management in IPv6: A Mathematical Exploration

The mobility solution provided by Mobile IPv6 (MIPv6) imposes too much signaling load to the network and enforces large handoff latency to end user. Hierarchical MIPv6 (HMIPv6) on the other hand, is designed by organizing MIPv6 in layered architecture and performs better than MIPv6 in terms of handoff latency and signaling load. Observation shows that, there is still possibility to shrink the handoff latency and the signaling load by further extending HMIPv6 into multiple layers. To explore this possibility of enhanced performance through layered architecture, this paper aimed at mathematical exploration of an N-layered MIPv6 network architecture in order to figure out the optimal levels of hierarchy for mobility management. A widespread analysis is carried out on various parameters such as location update frequency and cost, handoff latency and packet delivery cost. Influence of queuing delay on handoff latency is examined by modeling M/M/1/K queue in the architecture and user mobility is modeled using Markov chain. Analytical investigation reveals that three levels of hierarchy in MIPv6 architecture provide an optimal solution for mobility management.     

Low-cost binding update scheme based on pointer forwarding in HMIPv6 network

By introducing a mobility anchor point(MAP),hierarchical mobile IPv6(HMIPv6)reduces the binding update signaling cost associated with mobile IPv6,but there still exist deficiencies.For instance,a mobile node(MN)needs to orderly accomplish two binding updates with the MAP and home agent(HA)when the MN performs inter-MAP mobility.This results in a high signaling cost,thus affecting network performance.To reduce the inter-MAP binding update cost of idle MN in HMIPv6,an optimization scheme based on pointer forwarding with a threshold is proposed.The scheme can reduces the binding update cost of idle MN by using the binding update between MAP to replace several home binding updates.The signaling cost difference is derived by analyzing the cost of the basic scheme and the optimization scheme between two successive sessions.Simulation results show that,the optimization scheme can reduce the binding update signaling cost and improve the network performance as long as a suitable threshold is chosen.The discussions on the sensitivity of tele-parameters are also given.     

基于不同移动模型的移动自组网多播路由协议性能研究

为了研究移动自组网中多播路由协议在不同移动模型下的性能,选取随机路点移动模型、高斯马尔科夫移动模型和参考点组移动模型,将三种移动模型的移动场景加入到NS2中,对基于部分网络编码的实时多播协议PNCRM进行仿真.结果表明,PNCRM协议在随机路点移动模型和高斯马尔科夫移动模型中的数据包投递率明显高于参考点组移动模型,但是参考点组移动模型的总开销和端到端延时是最优的.这样我们就可以根据不同的性能指标要求选择合适的移动模型.     

Smart Routers for Cross-Layer Integrated Mobility and Service Management in Mobile IPv6 Systems

We propose and analyze a cross-layer integrated mobility and service management scheme called DMAPwSR in Mobile IPv6 environments with the goal to minimize the overall mobility and service management cost for serving mobile users with diverse mobility and service characteristics. The basic idea of DMAPwSR is that each mobile node (MN) can utilize its cross-layer knowledge to choose smart routers to be its dynamic mobility anchor points (DMAPs) to balance the cost associated with mobility services versus packet delivery services. These smart routers are just access routers for MIPv6 systems except that they are capable of processing binding messages from the MN and storing the current location of the MN in the routing table for forwarding service packets destined to the MN. The MN’s DMAP changes dynamically as the MN roams across the MIPv6 network. Furthermore the DMAP service area also changes dynamically reflecting the MN’s mobility and service behaviors dynamically. Unlike previous mobility management protocols such as HMIPv6 that focus only on mobility management, DMAPwSR considers integrated mobility and service management. We develop an analytical model based on stochastic Petri nets to analyze DMAPwSR and compare its performance against MIPv6 and HMIPv6. We validate analytical solutions obtained through extensive simulation including sensitivity analysis of simulation results with respect to the network coverage model, the MN’s residence time distribution and the DMAP service area definition.     

The node distribution of the random waypoint mobility model for wireless ad hoc networks

The random waypoint model is a commonly used mobility model in the simulation of ad hoc networks. It is known that the spatial distribution of network nodes moving according to this model is, in general, nonuniform. However, a closed-form expression of this distribution and an in-depth investigation is still missing. This fact impairs the accuracy of the current simulation methodology of ad hoc networks and makes it impossible to relate simulation-based performance results to corresponding analytical results. To overcome these problems, we present a detailed analytical study of the spatial node distribution generated by random waypoint mobility. More specifically, we consider a generalization of the model in which the pause time of the mobile nodes is chosen arbitrarily in each waypoint and a fraction of nodes may remain static for the entire simulation time. We show that the structure of the resulting distribution is the weighted sum of three independent components: the static, pause, and mobility component. This division enables us to understand how the model's parameters influence the distribution. We derive an exact equation of the asymptotically stationary distribution for movement on a line segment and an accurate approximation for a square area. The good quality of this approximation is validated through simulations using various settings of the mobility parameters. In summary, this article gives a fundamental understanding of the behavior of the random waypoint model.     

A New Enhanced Fast Handover Algorithm in Hierarchical Mobile IPv6 Network

1　Introduction　MobileIPv6requirestheMobileNode (MN)toregisterwiththeHomeAgent (HA)andtheCorre spondentNode (CN)whenitchangesitspointofattachmentintheInternet[1～ 3] .Therefore ,thiscauseMobileIPv6toincurlongdelayintheregis tration process,andaddsignalingtraffictothebackbonenetworkespeciallywhentheHAandCNarefarawayfromtheMN .Inordertominimizethisdelay ,andthesignalingoverhead presentinMobileIPv6,literatures[4～7] proposeHierarchicalMobileIPv6(HMIPv6)architectureandafasthan dover…     

DMAP: integrated mobility and service management in mobile IPv6 systems

Mobile IPv6 (MIPv6) is a work in progress IETF standard for enabling mobility in IPv6 networks and is expected to have wide deployment. We investigate an integrated mobility and service management scheme based on MIPv6 with the goal to minimize the overall network signaling cost in MIPv6 systems for serving mobility and service management related operations. Our design extends IETF work-in-progress Hierarchical Mobile IPv6 (HMIPv6) with the notion of dynamic mobility anchor points (DMAPs) for each mobile node (MN) instead of static ones for all MNs. These DMAPs are access routers chosen by individual MNs to act as a regional router to reduce the signaling overhead for intra-regional movements. The DMAP domain size, i.e., the number of subnets covered by a DMAP, is based on the MN’s mobility and service characteristics. Under our DMAP protocol, a MN interacts with its home agent and application servers as in the MIPv6 protocol, but optimally determines when and where to launch a DMAP to minimize the network cost in serving the user’s mobility and service management operations. We demonstrate that our DMAP protocol for integrated mobility and service management yields significantly improved performance over basic MIPv6 and HMIPv6.     

移动IPv6分层管理费用的分析与自适应优化

为综合优化分层域内外以网络传输花费和带宽占用为代表的通信管理费用,论文对实施分层移动IPv6前后的费用变化进行了理论分析,得出了判决是否适宜使用分层移动管理的准则,并在此基础上提出一种允许移动节点动态地根据切换频度和流量强度等参数选择适宜的移动管理机制的自适应优化方案.仿真结果表明该方案能获得比静止使用某种移动管理机制更好的资源使用效率,可望具有较好的实际应用价值.     

Ensuring strong data guarantees in highly mobile ad hoc networks via quorum systems

Ensuring the consistency and the availability of replicated data in highly mobile ad hoc networks is a challenging task because of the lack of a backbone infrastructure. Previous work provides strong data guarantees by limiting the motion and the speed of the mobile nodes during the entire system lifetime, and by relying on assumptions that are not realistic for most mobile applications. We provide a small set of mobility constraints that are sufficient to ensure strong data guarantees and that can be applied when nodes move along unknown paths and speed, and are sparsely distributed.

In the second part of the paper, we analyze the problem of conserving energy while ensuring strong data guarantees, using quorum system techniques. We devise a condition necessary for a quorum system to guarantee data consistency and data availability under our mobility model. This condition shows the unsuitability of previous quorum systems and is the basis for a novel class of quorum systems suitable for highly mobile networks, called mobile dissemination quorum (MDQ) systems. We also show a MDQ system that is provably optimal in terms of communication cost by proposing an efficient implementation of a read/write atomic shared memory.

The suitability of our mobility model and MDQ systems is validated through simulations using the random waypoint model and the restricted random waypoint on a city section. Finally, we apply our results to assist routing and coordinate the low duty cycle of mobile nodes while maintaining network connectivity.     

Integrating Mobile Ad Hoc Network to the Internet

A novel scheme is presented to integrate mobile ad hoc networks （MANETs） with the lnternet and support mobility across wireless local area networks （WLANs） and MANETs. The mobile nodes, connected as a MANET, employ the optimize d link state routing （OLSR） protocol for routing within the MANET. Mobility management across WLANs and MANETs is achieved through the hierarchical mobile IPv6 （HMIPv6） protocol. The performance is evaluated on a HMIPv6 based test-bed composed of WLANs and MANETs. The efficiency gain obtained from using HMIPv6 in such a hybrid network is investigated. The investigation result shows that the use of HMIPv6 can achieve up to 27% gain on reducing the handoff latency when a mobile roams within a domain. Concerning the reduction of the signaling load on the lnternet, the use of HMIPv6 can achieve at least a 54% gain and converges to 69%.     

An adaptive hierarchical mobile IPv6 using mobility profile

The Hierarchical Mobile IPv6 (HMIPv6), which is based on the Mobile IPv6 (MIPv6), has been proposed by IETF to reduce registration control signaling. It separates micro‐mobility from macro‐mobility with the help of an intermediate mobility agent, called the mobility anchor point (MAP), and exploits a Mobile Node's (MN's) spatial locality. However, all packets from a Correspondent Node (CN) to an MN are delivered through the MAP. That causes delay in packets delivery and the congestion of packets in the MAP so that it results in deterioration of network capability. To alleviate these problems, we propose a Hierarchical Mobile IPv6 protocol using not only spatial locality but also temporal locality. We introduce a profile for management of these locality information. According to the information in the profile, some packets are directly delivered to an MN, if MN seems to reside for a long time in the current subnet. Also, we introduce a handover scheme with the help of an L2 trigger, so that the proposed scheme takes nearly the same handover delay time as HMIPv6. The other contribution of this paper is to suggest a mathematical modeling and analysis of network traffic costs, MAP processing costs and handover latency for both HMIPv6 and the proposed scheme. Copyright © 2004 John Wiley & Sons, Ltd.     

On the performance of underlay cognitive radio system with random mobility under imperfect channel state information

In this paper, the performance of an underlay cognitive radio system with random mobility and imperfect channel state information (CSI) is investigated. The mobile user (MU) utilises maximum ratio combining (MRC) and selection combining (SC) diversity techniques as signal reception to improve the quality of received signal‐to‐noise ratio (SNR). Under the Rayleigh fading, random waypoint mobility model is employed to characterised the effect of the MU random mobility on the system performance. Thus, novel probability density function (PDF) and cumulative distribution function (CDF) for the two considered diversity techniques are derived. Through these, the outage probability and average bit error rate (ABER) closed‐form analytical expressions are then obtained to quantify the system performance under the MRC and SC schemes. The results illustrate the effect of imperfect CSI, user mobility which is characterised by pathloss and the network topology on the system performance. Also, the results depict that MRC offers the system better performance compared with SC under the same system conditions. The accuracy of the derived analytical expressions is verified through Monte‐Carlo simulations.     

Analysis of link lifetime in wireless mobile networks

Link lifetime (LL) analysis is crucially important in designing and evaluating wireless mobile network protocols. Although a considerable amount of research has been conducted on this issue, the current paper studies several aspects of link lifetime for the first time, e.g. a closed form expression for the probability distribution of the residual link lifetime (RLL) for the constant velocity mobility model is obtained, which facilitates marginal studies on the behavior of link lifetime. As a case, using a tail analysis of LL and RLL distributions, we analytically prove that they are heavy-tailed. Using this outcome, a self-similar behavior in the traffic pattern of a sample delay tolerant network is justified analytically. To extend the model, the effect of stationary nodes, the effect of buffer zone, and the effect of link establishment policies between different node categories on the link lifetime are investigated. Extensive simulation experiments are performed to validate the obtained analytical results and derivations precisely. Moreover, simulation results confirm that the analytic results can also be used for two well known mobility models (random waypoint and random direction) with a negligible error.     

Two-Dimensional Modeling and Analysis of Generalized Random Mobility Models for Wireless Ad Hoc Networks

Most important characteristics of wireless ad hoc networks, such as link distance distribution, connectivity, and network capacity are dependent on the long-run properties of the mobility profiles of communicating terminals. Therefore, the analysis of the mobility models proposed for these networks becomes crucial. The contribution of this paper is to provide an analytical framework that is generalized enough to perform the analysis of realistic random movement models over two-dimensional regions. The synthetic scenarios that can be captured include hotspots where mobiles accumulate with higher probability and spend more time, and take into consideration location and displacement dependent speed distributions. By the utilization of the framework to the random waypoint mobility model, we derive an approximation to the spatial distribution of terminals over rectangular regions. We validate the accuracy of this approximation via simulation, and by comparing the marginals with proven results for one-dimensional regions, we find out that the quality of the approximation is insensitive to the proportion between dimensions of the terrain.     

Predictability of Aggregated Traffic of Gateways in Wireless Mesh Network with AODV and DSDV Routing Protocols and RWP Mobility Model

When evaluating the performance of routing protocols in wireless mesh network (WMN), we need deeper analysis from the aspect of network traffic complexity to show how traffic characteristics are influenced by routing protocols and node mobility. The predictability of network traffic can be used as one metric of complexity and can be analyzed by multi-scale entropy (MSE) method. With 20 different random waypoint (RWP) mobility scenarios and with destination sequenced distance vector (DSDV), a typical proactive protocol, and Ad hoc on-demand distance vector (AODV), a typical reactive protocol, the predictabilities of aggregated traffic of gateway in WMN are analyzed using MSE method to show how different routing protocols bear different mobility scenarios. The MSE results show that the aggregated traffic of gateway with DSDV is more difficult to be predicted than that with AODV for different mobility scenarios. The maxspeed parameter of RWP dominates the traffic predictability for AODV. Both of the pause time and the maxspeed parameters, have great influence on the traffic predictability for DSDV. The reasons lie in the behaviors of routing protocols, i.e., AODV has up-to-date paths while DSDV does not.     

A Comprehensive Framework for Evaluating IPv6 Based Mobility Management Protocols

Seamless mobility in future generation networks, which are envisioned to be heterogeneous in nature, is an important issue. While Internet Engineering Task Force (IETF) work groups have standardized various mobility management protocols, such as Mobile IPv6 and Proxy Mobile IPv6, a comprehensive study of these protocols in terms of various performance characteristics is a challenging issue. Moreover, this study also considers the recent proposals from IETF in distributed mobility management (DMM) protocols. In this paper, a novel analytical model is developed for comparison of various mobility management protocols in terms of handover latency, as well as packet density, and packet arrival rate during the handover time by applying transport engineering principles in the field of telecommunication. The signaling cost analysis using signaling overhead incurred during protocol operations is given for each of these protocols. The number of packets that can be lost during the handover operation is also obtained using this model. Moreover, it presents a unified framework using which one can assess the performance characteristics of both host based and network based mobile IP protocols. One can also assess the performance of centralized and DMM approaches. The correctness of the proposed model is established by the fact that it leads to results similar to those obtained by applying some of the existing models. At the same time, the model allows one to obtain additional results showing the effect of packet density and packet arrival rate on the handover latency.     

基于DNS的代理移动IPv6位置管理机制

Proxy Mobile IPv6 (PMIPv6) is designed to provide a network-based localized mobility management protocol, but it does not handle the global mobility of hosts. In this paper, we propose a location management scheme based on Domain Name System (DNS) for PMIPv6 which can support global mobility by using DNS as a location manager. In addition, to support large numbers of mobile terminals and enhance network scalability a paging extension scheme is introduced to PMIPv6.To evaluate the proposed location management scheme, we establish an analytical model, formulate the location update cost and the paging cost,and analyze the influence of the different factors on the total signaling cost. The performance results show that our proposed scheme outperforms the basic PMIPv6 under various parameters in terms of reducing the signaling overhead and the proposed scheme reduces signaling overhead compared to the basic PMIPv6.     

Random waypoint mobility model in cellular networks

In this paper we study the so-called random waypoint (RWP) mobility model in the context of cellular networks. In the RWP model the nodes, i.e., mobile users, move along a zigzag path consisting of straight legs from one waypoint to the next. Each waypoint is assumed to be drawn from the uniform distribution over the given convex domain. In this paper we characterise the key performance measures, mean handover rate and mean sojourn time from the point of view of an arbitrary cell, as well as the mean handover rate in the network. To this end, we present an exact analytical formula for the mean arrival rate across an arbitrary curve. This result together with the pdf of the node location, allows us to compute all other interesting measures. The results are illustrated by several numerical examples. For instance, as a straightforward application of these results one can easily adjust the model parameters in a simulation so that the scenario matches well with, e.g., the measured sojourn times in a cell.     

A Proxy Mobile IPv6 Based Global Mobility Management Architecture and Protocol

This paper specifies a global mobility management architecture and protocol procedure called GPMIP, which is based on Proxy Mobile IPv6. In GPMIP, mobility management is performed by the network entity rather than individual mobile nodes. The benefit is the elimination of the wireless link data delivery tunnel overhead between a mobile node and the access router. To compare with the well known Hierarchical Mobile IPv6 mobility management protocol, the location update, packet delivery, and total cost functions generated by a mobile node during its average domain residence time are formulated for each protocol based on fluid flow mobility model. Then, the impacts of various system parameters on the cost functions are analyzed. The analytical results indicate that the proposed global mobility management protocol can guarantee lower total costs. Furthermore, a qualitative comparison between GPMIP and some other global management protocols is also investigated.