Dynamic hierarchical mobility management strategy for mobile IP networks

One of the major challenges for the wireless network design is the efficient mobility management, which can be addressed globally (macromobility) and locally (micromobility). Mobile Internet protocol (IP) is a commonly accepted standard to address global mobility of mobile hosts (MHs). It requires the MHs to register with the home agents (HAs) whenever their care-of addresses change. However, such registrations may cause excessive signaling traffic and long service delay. To solve this problem, the hierarchical mobile IP (HMIP) protocol was proposed to employ the hierarchy of foreign agents (FAs) and the gateway FAs (GFAs) to localize registration operations. However, the system performance is critically affected by the selection of GFAs and their reliability. In this paper, we introduce a novel dynamic hierarchical mobility management strategy for mobile IP networks, in which different hierarchies are dynamically set up for different users and the signaling burden is evenly distributed among the network. To justify the effectiveness of our proposed scheme, we develop an analytical model to evaluate the signaling cost. Our performance analysis shows that the proposed dynamic hierarchical mobility management strategy can significantly reduce the system signaling cost under various scenarios and the system robustness is greatly enhanced. Our analysis also shows that the new scheme can outperform the Internet Engineering Task Force mobile IP hierarchical registration scheme in terms of the overall signaling cost. The more important contribution is the novel analytical approach in evaluating the performance of mobile IP networks.     

Dynamic multi-step paging scheme in PMIPv6-based wireless networks

In Proxy Mobile IP (PMIPv6) networks, proxy-registrations are performed even for idle MNs, resulting in unnecessary signaling traffic. Although there have been many IP paging techniques aimed at reducing the unnecessary location update, they focus only on Mobile IP (MIP) since they had been developed before PMIPv6 was proposed. Thus, adopting existing IP paging support is not sufficient to support mobility in PMIPv6 networks. For more efficient support, we propose a dynamic multi-step paging scheme that pages an MN in multiple incremental steps instead of flooding paging messages to a whole paging area to significantly reduce the signaling traffic caused by the proxy location updates in the PMIPv6 networks. In addition, to improve the paging delay performance that may be deteriorated by the multi-step paging, the proposed scheme configures paging area dynamically to raise the efficiency of locating MNs. The size of a paging area is designed to be determined based on the speed of an MN. We also develop a thorough analytical model for evaluating the performance of the proposed scheme compared with a static paging scheme in terms of the signaling cost and the paging delay. Thorough analysis and simulation demonstrate that in the PMIPv6 network, our paging scheme can significantly reduce the signaling cost for IP paging, achieving a shorter paging delay, compared to that of a paging scheme with a fixed paging area.     

区域注册移动IP中的分布式位置管理方案

提出了一种区域注册移动IP的分布式位置管理方案。该方案基于区域网络逻辑上分层的结构特点,提出了在流量负载不超出一定流量门限的前提下,为移动节点选取不同层次上的外地代理FA作为网关外地代理GFA。通过对一种区域网络模型的研究,分析了不同层次上的FA作为GFA时的信令开销。最后通过仿真计算得出了采用分布式位置管理方案时区域注册移动IP信令开销的数值结果。通过分析比较说明该方案相比于区域注册移动IP而言,可以节约10％以上的信令开销,并将有效流量分配山多个GFA承担,当某个GFA失效时将不会影响其它GFA工作,提高了网络的稳健性。     

A Comprehensive Analysis of Mobility Management in MPLS-Based Wireless Access Networks

Efficient mobility management is one of the major challenges for next-generation mobile systems. Indeed, a mobile node (MN) within an access network may cause excessive signaling traffic and service disruption due to frequent handoffs. The two latter effects need to be minimized to support quality-of-service (QoS) requirements of emerging multimedia applications. In this perspective, we propose in this paper a new mobility management scheme designed to track host mobility efficiently so as to minimize both handoff latency and signaling cost. Building on and enhancing Mobile IP and taking advantage of MPLS traffic engineering capability, three mechanisms (FH-, FC- and MFC-Micro Mobile MPLS) are introduced. In order to assess the efficiency of our proposals, all protocols are compared. To achieve this, we develop analytical models to evaluate the signaling cost and link usage for both two-dimensional and one-dimensional mobility models. Additional mathematical models are also provided to derive handoff latency and packet loss rate. Numerical and simulation results show that the proposed mechanisms can significantly reduce the registration updates cost and provide low handoff latency and packet loss rate under various scenarios.      

A Distributed and Adaptive Location Management Scheme for Hierarchical Mobility Management

1IntroductionThe IETF Mobile IPstandards[1~2]were proposedtosolve the general problemof host mobility in the inter-net.However,whenthe number of Mobile Node(MN)grows rapidly and the MNare far away fromhome andwith micro mobility,this basic mechanism will …     

在基于MPLS的层次化移动IP网络中支持DiffServ的研究

MPLS支持DiffServ、流量工程,能为网络提供较好的QoS保证,而移动IP(MIP)能为移动设备提供较好的移动性支持。文章探讨了在无线接入网中MPLS和MIP结合实现DiffServ的方案,并给出了一种在基于MPLS的层次化MIP网络结构中支持DiffServ的体系结构,设计了其节点功能模型和关键协议。方案中利用了层次化结构的区域注册和重路由机制,减少了切换时延和网络的信令负荷。     

Integrated Mobility Management Methods for Mobile IP and SIP in IP based Wireless Data Networks

With developments in voice over IP (VoIP), IP-based wireless data networks and their application services have received increased attention. While multimedia applications of mobile nodes are served by Session Initiation Protocol (SIP) as a signaling protocol, the mobility of mobile nodes may be supported via Mobile IP protocol. For a mobile node that uses both Mobile IP and SIP, there is a severe redundant registration overhead because the mobile node has to make location registration separately to a home agent for Mobile IP and to a home registrar for SIP, respectively. Therefore, we propose two new schemes that integrate mobility management functionality in Mobile IP and SIP. We show performance comparisons among the previous method, which makes separate registration for Mobile IP and SIP without integration, and our two integrated methods. Numerical results show that the proposed methods efficiently reduce the amount of signaling messages and delay time related to the idle handoff and the active handoff.     

Two-level pointer forwarding strategy for location management in PCS networks

For a IPCS network to effectively deliver services to its mobile users, it must have an efficient way to keep track of the mobile users. The location management fulfills this task through location registration and paging. To reduce the signaling traffic, many schemes such as a local anchor (LA) scheme, per-user caching scheme and pointer forwarding scheme have been proposed in the past. In this paper, we present a new location management scheme which intends to mitigate the signaling traffic as well as reduce the tracking delay in the PCS systems. In this strategy, we choose a set of visitor location registers (VLRs) traversed by users as the mobility agents (MA), which form another level of management in order to make some registration signaling traffic localized. The idea is as follows: instead of always updating to the home location register (HLR), which would become the bottleneck otherwise, many location updates are carried out in the mobility agents. Thus, the two-level pointer forwarding scheme is designed to reduce the signaling traffic: pointers can be set up between VLRs as the traditional pointer forwarding scheme and can also be set up between MAs. The numerical results show that this strategy can significantly reduce the network signaling traffic for users with low CMR without increasing much of the call setup delay.     

Mobility Management in Identifier/Locator Split Networks

In the traditional Transmission Control Protocol/Internet Protocol (TCP/IP) stack, IP address represents not only the identifier but also the location of a node so that it can not provide global roaming seamless. To address this problem, MIP (Mobile IP) uses dynamical care-of-address to indicate the location of a mobile node (MN) and stable home address to indicate its identifier. However, such a separation of MIP can not support routing scalability, location privacy, and manageability. In this paper, we propose an identifier/locator split architecture which contains an overlay mapping system to store identifier-to-locator mappings and manage mobile nodes?? behavior. In addition, we design a novel mobility management scheme based on the identifier/locator split architecture (MMILS) which can address the above issues of MIP. To reduce the amount of signaling and enhance the performance, we distinguish micro-mobility and macro-mobility by introducing an Agent Tunnel Router (ATR). For micro-mobility, the ATR keeps the MN??s identifier-to-locator mapping invariable, so it avoids the mapping update in the mapping system and the Tunnel Route (TR) of each correspondent node. For macro-mobility, to support fast update and handover, we design a united mapping table in the ATR. And then, we estimate the number of entries and the required storage space to validate it feasible. To evaluate the efficiency of MMILS, we analyze the signaling cost by establishing an analytical model and implement it in our test-bed. The results demonstrate that the proposed scheme can effectively reduce signaling traffic and has a low handover delay compared to MIP and HMIP (Hierarchical Mobile IP).     

移动IP与SIP集成应用中优化的AAA过程

在移动IP和SIP分别实现网络层和应用层移动性管理的多层多协议移动性管理方案中,当两种协议独立进行AAA操作时,存在缺乏效率的问题。为解决该问题,提出优化方案——“移动IP与SIP集成应用中优化的AAA过程”(OAPIMS)。在新一代AAA协议Diameter环境下,通过移动注册时,对两种协议的操作信令进行优化,减少了信令交互次数,达到提高效率的目的。分析表明,该方法可以明显降低信令开销,减少时延,提高系统性能。     

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.     

Fast and reliable handoff for vehicular networks

A layer-3 mobility management scheme for an all-IP Wireless Access Network (WAN), and in particular for vehicular networks, is developed in this paper. The proposed method enables fast and reliable handoff. This feature is extremely important for high speed vehicular networks. Since vehicles are characterized by likely-predictable path, as well as very high speed, handoff events can and should be predicted in order to achieve fast and reliable handoff. As it is shown in this study, the proposed scheme can significantly reduce the packet loss ratio caused by frequent handoff events experienced by high speed vehicles. This scheme is topology-independent in the sense that it does not assume any network topology. The key idea is to use a topology-learning algorithm that enables to perform localized mobility management, by efficiently re-selecting a Mobility Anchor Point (MAP) node. The goal of the proposed scheme is to maintain a continues connection subject to user-dependent delay constraints, while minimizing the signaling cost and packet loss ratio associated with handoff events. This scheme is consistent with the existing mobility management schemes currently used in Mobile IP (MIP) and cellular networks, and it fits into the Hierarchical Mobile IPv6 (HMIPv6) scheme defined in Mobile IPv6 (MIPv6) for integrating mobile terminals with the Internet wired backbone.     

Seamless Handoff Scheme Based on Pre-registration and Pre-authentication for UMTS–WLAN Interworking

Interworking issues between Universal Mobile Telecommunication System (UMTS) and Wireless Local Area Network (WLAN) have become a great matter of interest as an increasing number of mobile internet users require broadband wireless access to IP services in the wide area. In this paper, we present a practical UMTS–WLAN interworking architecture based on 3GPP standards and propose a seamless handoff scheme that guarantees low delay and low packet loss during UMTS–WLAN handoff. For low handoff delay, the proposed handoff scheme performs pre-registration and pre-authentication processes before layer 2 handoff. Moreover, it uses packet buffering and forwarding functions in order to reduce packet loss during the handoff period. On the above basis, detailed signaling procedures are presented, together with system requirements when a mobile terminal moves from UMTS to WLAN and vice-versa. Numerical results show that the proposed scheme performs well with respect to signaling cost, handoff delay, and packet loss compared with conventional schemes.     

A cost effective distributed location management strategy for wireless networks

The mobility feature of mobile stations (MSs) imposes a large burden on network traffic control as a result of location management. Design issues of location management include MS registration (updating) and call setup (paging). Previous approaches introduced several network topologies for updating and paging procedures, but most of them focused on a single problem: either updating optimization or paging optimization. In this paper, we design and integrate two mechanisms, distributed temporary location caches (TLCs) and distributed home location registers (HLRs), to reduce database access delay and to decrease network signaling traffic in both updating and paging for low power, low tier micro cellular systems. By using TLCs, our approach can improve the performance of updating and paging in comparison with previous approaches. Experimental results based on our analytic model show that our location management procedures have lower HLR access rate, lower registration cost, and lower call setup cost than other approaches.     

基于动态层次位置管理的HIP移动性支持机制

针对现有HIP机制不支持节点微移动的问题,该文提出了基于动态层次位置管理的HIP移动性支持机制。在该机制中,网络划分成多个自治域,每个自治域划分成多个注册域。当节点在同一个注册域内移动时,在管理该注册域的本地集合服务点中进行位置更新;当节点在同一个自治域内移动时,在管理该自治域的网关集合服务点中进行位置更新。节点根据自己的移动速率以及呼叫到达率选取本地集合服务点并计算注册域的最佳范围。仿真结果表明,该机制能较好地降低节点移动时的信令开销,支持节点微移动。     

A survey and comparative study of QoS aware broadcasting techniques in VANET

Mobile operators currently encounter numerous challenges caused by the centralized architecture of mobile networks. A single mobility anchor placed at the network core maintains the entire mobility and data traffic forwarding in the existing centralized mobility management (CMM) solutions. The CMM approach confronts several issues in scalability, reliability, signaling overhead, and non-optimal routing due to the increasing number of mobile devices and the volume of data traffic. To overcome these issues, a new architectural paradigm called distributed mobility management (DMM) is proposed to flatten the network architecture by moving mobility anchors closer to users and separating the control and data planes at the network edge. Two DMM solutions are developed: partially distributed mobility management (partial-DMM) in which only the data plane is distributed and fully distributed mobility management (full-DMM) where both control and data planes are distributed, which can be potentially applied for future mobile networks. This paper presents a network-based full-DMM scheme that was developed and implemented using NS2 network simulator by removing any dedicated centralized mobility anchor from the architecture. Extensive simulations were conducted to evaluate and compare the performance of the full-DMM model with that of the traditional CMM model. The simulation results show that the full-DMM provides lower end-to-end delay performance than CMM. However, the full-DMM generates higher handover latency and packet loss than CMM at high MN speeds. Moreover, simulation results clearly show the benefits of dynamic mobility activation in the full-DMM model.     

Mobility Management Approaches for Mobile IP Networks: Performance Comparison and Use Recommendations

In wireless networks, efficient management of mobility is a crucial issue to support mobile users. The Mobile Internet Protocol (MIP) has been proposed to support global mobility in IP networks. Several mobility management strategies have been proposed which aim reducing the signaling traffic related to the Mobile Terminals (MTs) registration with the Home Agents (HAs) whenever their Care-of-Addresses (CoAs) change. They use different Foreign Agents (FAs) and Gateway FAs (GFAs) hierarchies to concentrate the registration processes. For high-mobility MTs, the Hierarchical MIP (HMIP) and Dynamic HMIP (DHMIP) strategies localize the registration in FAs and GFAs, yielding to high-mobility signaling. The Multicast HMIP strategy limits the registration processes in the GFAs. For high-mobility MTs, it provides lowest mobility signaling delay compared to the HMIP and DHMIP approaches. However, it is resource consuming strategy unless for frequent MT mobility. Hence, we propose an analytic model to evaluate the mean signaling delay and the mean bandwidth per call according to the type of MT mobility. In our analysis, the MHMIP outperforms the DHMIP and MIP strategies in almost all the studied cases. The main contribution of this paper is the analytic model that allows the mobility management approaches performance evaluation.     

改进的移动IP的注册性能分析

根据现有的IETF移动IP规范，当移动节点驻留在远离归属网络的外地网络时，将会产生严重的注册延迟，从而引起严重的包丢失和通信吞吐量的下降。本文利用改进后的移动IP网络结构，引入routing agent，使得大量的当地注册报文只需要在RA上处理即可，从而减少了注册延迟，改善了移动IP的性能。本文对其中的注册代价进行了深入的分析，并与标准移动IP中的注册代价进行了对比。     

IP Flow Mobility in PMIPv6 Based Networks: Solution Design and Experimental Evaluation

The ability of offloading selected IP data traffic from 3G to WLAN access networks is considered a key feature in the upcoming 3GPP specifications, being the main goal to alleviate data congestion in cellular networks while delivering a positive user experience. Lately, the 3GPP has adopted solutions that enable mobility of IP-based wireless devices relocating mobility functions from the terminal to the network. To this end, the IETF has standardized Proxy Mobile IPv6 (PMIPv6), a protocol capable to hide often complex mobility procedures from the mobile devices. This paper, in line with the mentioned offload requirement, further extends PMIPv6 to support dynamic IP flow mobility management across access wireless networks according to operator policies. Considering energy consumption as a critical aspect for hand-held devices and smart-phones, we assess the feasibility of the proposed solution and provide an experimental analysis showing the cost (in terms of energy consumption) of simultaneous packet transmission/reception using multiple network interfaces. The end-to-end system design has been implemented and validated by means of an experimental network setup.