Buffering in proxy mobile IPv6: implementation and analysis

Proxy mobile IPv6 (PMIPv6) is a network-based mobility management protocol that improves performance in terms of handover latency, signaling cost, and packet loss compared to host-based mobility management protocols. However, still packet loss occurs during the handover of the mobile node (MN). Several attempts have been made to improve the reliability of PMIPv6 service by proposing schemes in which packets are buffered in network entities during the handover of the MN to prevent packet loss, and performance improvement has been demonstrated via simulations. So far, there have been no implementations of buffering functions in the literature. This paper addresses design of buffering function and its implementation to prevent packet loss, and demonstrates the results. We have implemented a PMIPv6 testbed based on open source resources. We discuss the functional and performance enhancements, comparing PMIPv6 with the buffering implemented and standard PMIPv6. We also propose an improved buffering function where the packet forwarding rate of the buffer is adjusted. The results through the testbed show that the buffering function in PMIPv6 effectively prevents packet loss during the handover of the MN. We have found out that we can manage the amount of packets in the buffer without further increment by adjusting the packet forwarding rate of the buffer as well.     

基于IPv6的城市车载网移动协议

提出了一种基于IPv6的城市车载网移动切换协议。本协议提出了城市车载网络体系结构, 车辆节点在移动过程中由家乡地址唯一标志, 无须转交地址, 因此节省了转交地址配置时间和代价, 从而缩短了移动切换时间, 降低了移动切换代价。车辆节点无须参与移动切换过程, 从而避免了由于车辆节点高速行驶引起丢包而增加移动切换代价和延迟的情况。仿真数据结果表明该方案的性能更好。     

一种6LoWPAN无线传感器网络移动协议

提出了一种6LoWPAN无线传感器网络移动协议。此协议提出了6LoWPAN网络体系结构,以及6LoWPAN网络地址分层结构及地址配置算法。基于提出的6LoWPAN网络体系结构,提出了6LoWPAN网络内与网络之间的移动切换协议。在移动过程中,移动节点无须转交地址,即移动切换过程无须为移动节点配置转交地址,也无须进行转交地址注册,因此降低了移动切换代价和延迟。从理论和仿真两个角度对MIPv6、Inter-MARIO及本协议的移动切换代价、移动切换延迟、丢包率等性能参数进行了分析比较,分析结果表明本协议的移动切换代价更小、移动切换延迟更短、丢包率更低。     

Handoff performance analysis of PMIPv6-based distributed mobility management protocol-urban scenario

Mobility management allows the networks to track down a mobile user's location for sending datagrams and to retain the connection when the user changes its location points repeatedly. Whenever a node switches between one base station and another, the connectivity is maintained through a process called handoff management. For real-time traffic implementations in wireless network communications, handover performance is essential. A mobile node is blocked from transmitting and receiving a datagram for a longer time as the handover delay increases. Unacceptable handover delays are common in real-time communication services. To guarantee smooth connectivity and continuous provision of services, effective handoff methods are required. The handoff efficiency of network-based distributed mobility management (DMM) is studied extensively in this article, along with a comparison to PMIPv6. We specifically investigate how handover delay, session recovery, and packet loss are influenced by cell radius. From the analytical and simulation findings this paper concludes that network-based DMM performs better than PMIPv6.     

Design,implementation and experimental evaluation of an end-to-end vertical handover scheme on NCTUns simulator

This paper presents the simulation study of “Host based autonomous Mobile Address Translation” using NCTUns simulator. It is a network layer, end-to-end vertical handover solution, based upon modification of “Mobile IP with address Translation”. Vertical handover approaches generally require new network elements, a new layer in TCP/IP stack, or fixing a protocol at a particular layer. To enhance handover experience, recent approaches focus on reducing signalling, localizing the registration, creating hierarchies, using proxy, preparing handover in advance, predicting target network, or exploiting multicasting and path extension techniques. These approaches, however, demand change in the network infrastructure to support mobility and limit the scope of mobility. Despite end-to-end signalling, the Host based autonomous Mobile Address Translation scheme ensures minimum service disruption and distinctly allows global mobility of the mobile node without requiring any modification in the network. We have simulated the mobility of a multi-interface mobile node in a heterogeneous network environment composed of WiFi (IEEE802.11a, IEEE802.11b) and WiMAX (IEEE802.16e) access networks. Performance of the scheme is evaluated taking into account wide range of end-to-end delays between mobile node and the correspondent node, various speeds of the mobile node and different packet loss rates of the network. Based on our detailed simulation study, it has been observed that this scheme offers reduced service disruption time, packet loss and packet latency. The service disruption time is found to be significantly low (typically in the range of 10 ms) compared to that of Mobile IP (which is in the order of 100 ms); this makes this new scheme perfectly suitable for real time applications. Low service disruption time consequently reduces the packet loss by manyfold and the packet latency remains unaffected during and after handover due to translation of address at the source. The results suggest that this protocol is a viable vertical handover solution due to its simplicity, scalability, low overhead and ready deployability.     

Analytical study of intradomain handover in multiple-mobile-routers-based multihomed NEMO networks

The need to stay connected to the Internet “anytime” and “anywhere” is becoming more and more required in the recent years with the development of wireless networks. The NEMO basic support protocol was developed to grant the Internet connection for an entire mobile network, like vehicle or aircraft network. In NEMO a Mobile Router manages the mobility of the entire network on behalf of the other nodes in order to reduce the overhead of signaling messages. The critical part of mobility support is to reduce the handover latency, particularly when a Mobile Router is not reachable. This handover period degrades the performance of most delay sensitive applications. Referring to our proposition for NEMO handover improvement which is conceived for multiple-mobile-routers-based multihomed NEMO network, we find out a mathematical model to study the intradomain handover performance. We derive the mathematical model to analyze interruption interval (the time interval during which none of mobile routers can transport packets) during the intradomain handover. We study the impact of varying critical parameters, like vehicle speed, overlapping coverage distance, distance between mobile routers, and scanning frequency. The obtained results reveal that the seamless handover can be achieved if network configuration parameters are correctly chosen.     

Experimentation and performance analysis of multi-interfaced mobile router scheme

Network mobility (NEMO) aims providing seamless Internet connectivity of the whole mobile network that consists of mobile routers (MRs) and mobile network nodes (MNNs). The network moves around along with vehicles as a whole. According to NEMO basic support protocol (NEMO BSP), only one primary care of address (CoA) of MR can be registered with home agent, which will affect the handover performance. As an extension of NEMO BSP, multiple care of addresses (MCoA) registration scheme was proposed as Internet-draft and has received extensive researches.This paper studies the Internet connectivity of mobile router (MR) on the basis stated above; MR is equipped with WLAN, CDMA and GPRS interfaces simultaneously. Concretely, a smooth handover algorithm is proposed and experimented on our platform successfully; round trip time (RTT) of each link and the handover process between different interfaces are analyzed, respectively. Furthermore, the service disruption time and packet loss ratio performances are also compared between uni-interfaced MR scheme of NEMO BSP and scheme proposed in this paper, and the results indicate that multi-interfaced scheme not only supports large area movement across heterogeneous networks of MR, it also provides a seamless handover with no packet loss and little service disruption time.     

Fuzzy based multi-criteria vertical handover decision modeling in heterogeneous wireless networks

Vertical handover gain significant importance due to the enhancements in mobility models by the Fourth Generation (4G) technologies. However, these enhancements are limited to specific scenarios and hence do not provide support for generic mobility. Similarly, various schemes are proposed based on these mobility models but most of them are suffered from the high packet loss, frequent handovers, too early and late handovers, inappropriate network selection, etc. To address these challenges, a generic vertical handover management scheme for heterogeneous wireless networks is proposed in this article. The proposed scheme works in three phases. In the first phase, a handover triggering approach is designed to identify the appropriate place for initiating handover based on the estimated coverage area of a WLAN access point or cellular base station. In the second phase, fuzzy rule based system is designed to eliminate the inappropriate networks before deciding an optimal network for handover. In the third phase, a network selection scheme is developed based on the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) decision mechanism. Various parameters such as delay, jitter, Bit Error Rate (BER), packet loss, communication cost, response time, and network load are considered for selecting an optimal network. The proposed scheme is tested in a mobility scenario with different speeds of a mobile node ranging from very low to very high. The simulation results are compared with the existing decision models used for network selection and handover triggering approaches. The proposed scheme outperforms these schemes in terms of energy consumption, handover delay and time, packet loss, good put, etc.     

一种基于HIP的移动性管理机制

主机标识协议（Host Identity Protocol,HIP）是一种综合解决主机移动、多宿主及安全问题的有效方案,为了解决现有HIP机制在处理主机移动时存在切换延迟大、丢包率高等问题,提出了一种高效的基于HIP的移动性管理机制。该机制在基于HIP的层次化设计模型基础上,采用FMIPv6中的快速切换思想,引入了链路层触发机制、预先绑定更新机制和分组缓存转发机制。有效解决了移动主机在不同区域范围内的切换问题,降低了切换延迟和丢包率,改善了移动主机的切换性能,实现了透明、平滑、快速的网络切换。     

Optimized fast handover scheme in Mobile IPv6 networks to support mobile users for cloud computing

In the future cloud computing, users will heavily use mobile devices. Mobile networks for cloud computing should be managed efficiently as well as support seamless services to mobile users regardless of their locations and movements. Hence, in mobile networks for cloud computing, it is important to support seamless mobility management to mobile users who request real-time services such as VoIP, streaming, and interactive game playing. To support seamless mobility management for various wireless technologies in cloud computing, Mobile IPv6 (MIPv6) and fast handovers for MIPv6 (FMIPv6) have been studied. FMIPv6 has been emerged to reduce long handover latency and packet loss in MIPv6. FMIPv6 may provide seamless handover by minimizing the handover latency, and prevent packet loss through buffering and tunneling. FMIPv6 uses anticipation based on layer 2 trigger information, and consists of two operation modes such as the predictive mode and the reactive mode. Several works have been done to evaluate the performance of FMIPv6 in different network environments. However, the previous works did not consider the probability of predictive mode failure (PPMF) that distinguishes two operation modes. Even in the most previous work, two operation modes of FMIPv6 are evaluated separately. However, to accurately analyze the overall performance of FMIPv6, two operation modes should be analyzed altogether. In this paper, FMIPv6 combining two operation modes is analyzed considering the PPMF that is affected by the radius of a cell, velocity of mobile nodes, and the layer 2 triggering time. The effect of system parameters, such as the PPMF, the time required to process additional layer 3 signaling, and the layer 2 trigger time, is analytically investigated with respect to the signaling cost and the packet delivery cost. Analytical results show a trade-off between performance and system parameters. Then we show methods to optimize overhead of FMIPv6. Finally, mobile networks for cloud computing can be efficiently managed through the optimized FMIPv6.     

一种基于标地分离的卫星网络移动切换管理技术

移动卫星网络因具有覆盖区域广、通信延时低等优势受到广泛关注,当前有大量研究旨在开发IP协议的组网技术,并将其与地面IP网络融合。融合网络的挑战之一,即为卫星移动性,用户在卫星网络中的接入点频繁切换导致移动管理问题,而现有的移动IP技术不能高效支持卫星网络移动切换。为了高效支持移动切换,在卫星网络中应用标地分离思想,在标地分离的架构下研究切换管理问题;用映射服务系统对终端进行位置管理,在移动切换中由新接入卫星网关和终端的标志为主要信息在原卫星中形成通告转发表。仿真结果表明,相对移动IP技术,该方法有明显优势。将其应用于卫星网络时可以降低切换延时,减少大量的绑定更新开销或是次优路由,提升系统的性能和可扩展性。     

A mobility management model based on users’ mobility profiles for IPv6 networks

Fourth-generation (4G) mobile systems provide access to a wide range of services and enable mobile users to communicate regardless of their geographical location and their roaming characteristics. Due to the growing number of mobile users, global connectivity, and the small size of cells, one of the most critical issues pertaining to these networks is location management. In recent years, several strategies have been proposed to improve the performance of the location management procedure in 3G and 4G mobile networks. In this paper, we propose a new model called Seamless Mobile IPv6 (SMIPv6) to improve the performance of the handover component in location management schemes. This model improves handover by predicting user location based on Users’ Mobility Profiles. The overall goals of SMIPv6 are to reduce both handover latency and signaling loads generated during the location update process. Simulation results show that the use of SMIPv6 produces a handover with low delay, as well as a significant drop of signaling overhead. Better results have been obtained by our protocol in all cases studied when compared to Mobile IPv6 (MIPv6) and Fast Handovers for MIPv6 (FMIPv6).     

命名数据网络中面向移动用户的内容预取方法*

针对命名数据网络(Named Data Networking, NDN)移动性增强支持不足的问题,基于城区移动场景提出了一种基于移动预测的内容预取方法(Mobility-aware Prediction Approach for Content Prefetching, MAP-CP)及扩展方案(extended MAP-CP, eMAP-CP)。MAP-CP和eMAP-CP通过预测移动用户的下一接入点(Access Point, AP),预取在当前AP下因切换AP不能获取到的Data并缓存到所预测的下一AP相关联的NDN节点中,为切换AP后的移动用户就近服务,达到降低内容获取延迟和提高响应率的目的。eMAP-CP在MAP-CP的基础上,可预取切换AP过程中请求的Data,能够进一步提高性能。基于ndnSIM的仿真实验表明,和NDN本身相比,MAP-CP和eMAP-CP具有更低的平均内容获取延迟和更高的响应率,而且eMAP-CP更优。在移动速度为20m/s,发包速率为200pps时,MAP-CP和eMAP-CP的平均内容获取延迟可分别降低约4.0%和38.7%,响应率可分别提高约1.2%和4.9%。     

A mobility management scheme for wireless mesh networks based on a hybrid routing protocol

Recent advances in wireless mesh networks (WMNs) have overcome the drawbacks of traditional wired networks and wireless ad hoc networks. WMNs will play a leading role in the next generation of networks, and the question of how to provide seamless mobility management for WMNs is the driving force behind the research. The inherent characteristics of WMNs, such as relatively static backbones and highly mobile clients, require new mobility management solutions to be designed and implemented.In this paper, a hybrid routing protocol for forwarding packets is proposed: this involves both link layer routing and network layer routing. Based on the hybrid routing protocol, a mobility management scheme for WMNs is presented. Both intra-domain and inter-domain mobility management have been designed to support seamless roaming in WiFi-based WMNs. During intra-domain handoff, gratuitous ARP messages are used to provide new routing information, thus avoiding re-routing and location update. For inter-domain handoff, redundant tunnels are removed in order to minimize forwarding latency. Comprehensive simulation results illustrate that our scheme has low packet latency, low packet loss ratio and short handoff latency. As a result, real-time applications over 802.11 WMNs such as VoIP can be supported.     

An efficient design and validation technique for secure handover between 3GPP LTE and WLANs systems

Future generations wireless systems, which integrate different wireless access networks together, will support a secured seamless mobility and a wide variety of applications and services with different quality of service (QoS) requirements. Most of the existing re-authentication protocols during vertical handover still have certain limitations such as man in the middle, eavesdropping and session hijacking attacks, and unacceptable delay for real time applications. In this article, we propose two re-authentication schemes to secure handover between 3GPP LTE and WLANs systems: Initial Handover Re-authentication Protocol, and Local Re-authentication Protocol. The second proposed protocol is executed locally in a WLAN network without contacting the authentication server of the home network for credentials verification. In fact, after a successful execution of the Initial Handover Re-authentication Protocol, the local key (LK) is shared between USIM and the authentication server of the WLAN. It is then used for securing handover and traffic in WLAN networks. Performance evaluation results obtained using simulation analysis show that the proposed re-authentication protocol enhances handover parameters such as handover latency, handover blocking rate and packet loss rate. Additionally, the proposed enhanced fast re-authentication protocol has been modeled and verified using the software AVISPA and is found to be safe.     

A network-based mobility management scheme for future Internet

The current Internet was originally designed for “fixed” terminals and can hardly support mobility. It is necessary to develop new mobility management schemes for the future Internet. This paper proposes an Identifiers Separating and Mapping Scheme (ISMS), which is a candidate for the future Internet mobility management, and discusses the basic principles and detailed message flow. ISMS is a network-based mobility management scheme that takes advantage of the identity and location separation. The mobility entities in the core network are responsible for the location management. ISMS is designed to satisfy the requirements of faster handover, route optimism, advanced management, location privacy and security. The average handover delay of ISMS is on the order of milliseconds only, which is far smaller than that of Mobile IPv6. Analyses show that ISMS can reduce packet overhead on wireless channels. We build a prototype and perform some experiments. Results verify the feasibility of ISMS.     

6LoWPAN无线传感器网络移动管理方案

提出了一种跨层的6LoWPAN无线传感器网络移动管理方案。首先提出了6LoWPAN网络体系结构, 基于该体系结构, 提出了一种跨层的移动切换算法。在此算法中, 网络层移动切换与链路层移动切换同时进行, 在三层切换过程中, 移动节点无须转交地址配置, 也无须参与网络层的移动切换过程, 且无须参与移动切换过程, 在二层切换过程中, 移动节点无须扫描所有信道, 通过获取的信道信息直接进行二层切换, 因此降低了切换延迟、丢包率和切换代价。     

层次移动IPv6宏切换的优化方案

针对层次移动IPv6宏切换中丢包率高、切换延迟大的问题,提出一种将隧道机制应用于层次移动IPv6的优化方案（TBFMH）。TBFMH根据切换信息提前获得转交地址,进行重复地址检测,并在建立隧道的同时完成本地绑定更新。仿真实验表明,TBFMH比层次移动IPv6至少减少50%的切换延迟,同时降低了丢包率,有效提高了移动节点进行宏切换的性能。     

A high performance link layer mobility management strategy for professional private broadband networks

In this paper, we present an innovative approach to solving the mobility management problem in the context of professional private broadband networks in the vehicular scenario. These heterogeneous communication networks are commonly deployed and managed by mission-critical organisations with the aim of supporting their specific and highly demanding services. Taking advantage of the specific characteristics of these networks, we propose to solve the mobility problem at Layer 2. This way, the mobility management overhead is reduced compared to solutions that operate at Layer 3 or above and therefore, shorter handover delays and better end-to-end application performances are achieved. The core element of our proposal is an intelligent mobile switch that makes use of the services provided by the IEEE 802.21 protocol to enhance vertical or heterogeneous handover performance. To validate our approach, we have developed a prototype implementation of the designed mobile switch with IEEE 802.11 and IEEE 802.16 support. Using this mobile switch implementation, we have carried out a set of experiments over a real testbed and measured some key indicators to assess the mobility management process. The obtained results show that our handover strategy comfortably meets the requirements of the ITU-T Y.1541 recommendation for highly demanding applications and ITU-R report M.2134 for high-speed handover. To the best of our knowledge, our contribution is the first proposal that solves the mobility management problem at Layer 2 while addressing the multi-access technology context in the vehicular professional private network scenario.