Home Agent Research Articles

Performance Analysis of a Network-Layer Soft Vertical Handoff Scheme Without Packet Reordering

With the integration of heterogeneous wireless technologies and the popularization of all-IP networks,network-layer soft handoff approaches have gradually evolved to improve the performance of vertical handoffs(VHOs).Unfortunately,the existing soft handoff approaches lead to plenty of out-of-order packets during downward VHOs.In this paper,the authors present a new network-layer soft vertical handoff scheme,called SHORDER.In the scheme,the mobile node(MN)starts or stops buffering packets from its new network based on a few interactive messages with its home agent(HA).With the buffering technique,the scheme can prevent mobile terminals from receiving reordered packets caused by downward VHOs,and is compatible with various transport-layer protocols and their variants due to its independence.Then,the authors theoretically analyze the influence of the proposed scheme on the handoff latency,the goodput and the congestion window of the TCP in comparison with a typical existing network-layer soft VHO method.Additionally,the authors also derive the applicable condition of the SHORDER scheme.Experiments show that the deployment of the proposed scheme is easy and the scheme has better performance under its applicable condition,further,experimental and analytical results are consistent with each other.Finally,based on the applicable condition of the SHORDER scheme,the scheme further is improved.

Global gateway-based UMTS/WLAN integration for improved delay performance

This paper proposes a loose coupling-based integration between universal mobile telecommunication system (UMTS) and wireless local area networks (WLANs) using mobile Internet protocol (MIP)-based vertical handoff between the two networks. In loose coupling, an integrated network must provide home agent (HA) functionality when a UMTS subscriber moves to WLAN. The position of HA effects the performance of an integrated network. If HA is deployed at gateway GPRS (general packet radio service) support node (GGSN), delay for data as well as control packets increases when both receiving and transmitting mobile stations (MSs) reside in WLAN. Because each packet travels to GGSN through Gi interface, and routed back to WLAN through the same interface. HA can also be deployed in WLAN Internet protocol (IP) network. This improves delay for data packets, but handoff delay from WLAN to UMTS increases because an MS cannot send MIP registration request to HA before the establishment of packet data protocol context in UMTS network. We propose an efficient integration by fixing the position of HA in a global gateway router which is deployed in WLAN IP network. The proposed interworking technique reduces packet delay when both sending and receiving MSs are in WLANs. The methods also update location of a user in UMTS as well as WLAN so that he/she is always reachable from each network irrespective of current position. ns-2-Based simulation results show that our new handoff methods reduce handoff delay from UMTS to WLAN by 10% and that from WLAN to UMTS by 18%.

Extended Mobile IPv6 Route Optimization for Mobile Networks in Local and Global Mobility Domain

Network mobility (NEMO) route optimization support is strongly demanded in next generation networks; without route optimization the mobile network (e.g., a vehicle) tunnels all traffic to its Home Agent (HA). The mobility may cause the HA to be geographically distant from the mobile network, and the tunneling causes increased delay and overhead in the network. It becomes peculiar in the event of nesting of mobile networks due to pinball routing, for example, a Personal Area Network (PAN) inside a vehicle. The authors propose an Extended Mobile IPv6 route optimization (EMIP) scheme to enhance the performance of nested mobile networks in local and global mobility domain. The EMIP scheme is based on MIPv6 route optimization and the root Mobile Router (MR) performs all the route optimization tasks on behalf of all active Mobile Network Nodes (MNNs). Thus, the network movement remains transparent to sub MRs and MNNs and modifies only MRs and MNNs leaving other entities untouched and is more efficient than the Network Mobility Basic Support protocol (NEMO BS). The authors carried out an extensive simulation study to evaluate the performance of EMIP.

A strong user authentication scheme with smart cards for wireless communications

Seamless roaming over wireless network is highly desirable to mobile users, and security such as authentication of mobile users is challenging. Recently, due to tamper-resistance and convenience in managing a password file, some smart card based secure authentication schemes have been proposed. This paper shows some security weaknesses in those schemes. As the main contribution of this paper, a secure and light-weight authentication scheme with user anonymity is presented. It is simple to implement for mobile user since it only performs a symmetric encryption/decryption operation. Having this feature, it is more suitable for the low-power and resource-limited mobile devices. In addition, it requires four message exchanges between mobile user, foreign agent and home agent. Thus, this protocol enjoys both computation and communication efficiency as compared to the well-known authentication schemes. As a special case, we consider the authentication protocol when a user is located in his/her home network. Also, the session key will be used only once between the mobile user and the visited network. Besides, security analysis demonstrates that our scheme enjoys important security attributes such as preventing the various kinds of attacks, single registration, user anonymity, no password/verifier table, and high efficiency in password authentication, etc. Moreover, one of the new features in our proposal is: it is secure in the case that the information stored in the smart card is disclosed but the user password of the smart card owner is unknown to the attacker. To the best of our knowledge, until now no user authentication scheme for wireless communications has been proposed to prevent from smart card breach. Finally, performance analysis shows that compared with known smart card based authentication protocols, our proposed scheme is more simple, secure and efficient.

Proof of certificateless MIP registration protocol based on PCL

Security protocols are the basis of many mobile communication systems, thus it is important to ensure protocol property correct. Using Protocol Composition Logic (PCL), this paper proves a Mobile IP (MIP) registration protocol that is based on certificateless public key signature without pairing between home agent and foreign agent, which minimizes the registration time and cost as well as improves the security compared with the identity-based and certificate-based registration protocol. Analysis and proof shows that the proposed protocol provides users security and authentications, moreover, the anonymity property is proved correct.

ROAD+: Route Optimization with Additional Destination-Information and Its Mobility Management in Mobile Networks

In the NEtwork MObility (NEMO) environment, mobile networks can form a nested structure. In nested mobile networks that use the NEMO Basic Support (NBS) protocol, pinball routing problems occur because packets are routed to all the home agents of the mobile routers using nested tunneling. In addition, the nodes in the same mobile networks can communicate with each other regardless of Internet connectivity. However, the nodes in some mobile networks that are based on NBS cannot communicate when the network is disconnected from the Internet. In this paper, we propose a route optimization scheme to solve these problems. We introduce a new IPv6 routing header named “destination-information header” (DH), which uses DH instead of routing header type 2 to optimize the route in the nested mobile network. The proposed scheme shows at least 30% better performance than ROTIO and similar performance improvement as DBU in inter-route optimization. With respect to intra-route optimization, the proposed scheme always uses the optimal routing path. In addition, the handover mechanism in ROAD+ outperforms existing schemes and is less sensitive to network size than other existing schemes.

Home Agent placement and assignment in WLAN with Cellular Networks

Home Agent placement and assignment in WLAN with Cellular Networks

WiBro에서 마코프 체인을 이용한 성능분석

WiBro의 ACR(Access Control Router)은 ACR간을 움직일 때만 홈 에이전트와 상대 노드에게 위치등록을 하므로, 위치등록비용은 MIPv6에 비해 적지만, 이동 노드의 송수신되는 모든 패킷들은 ACR을 통해 전달되기 때문에 ACR이 관리하는 이동노드의 수가 많아지면 ACR의 패킷처리비용은 증가한다. 따라서 ACR도메인 내에 있는 이동 노드들을 관리하는 ACR이 잘 작동한다면 ACR도메인 내의 통신상태는 원활하다. 그러나 ACR이 잘 작동하지 않으면 네트워크의 delay가 발생하므로 ACR의 역할은 중요하다. 본 논문에서는 WiBro의 효율적인 작동을 위해 ACR의 성능을 측정한다. 이를 위해, 성능평가 요소로서 이동노드의 거부확률(deny probability)와 ACR 성능의 총이익을 사용한다. 그리고 이동모델로서 랜덤워크 모델을 이용한다. The ACR (Access Control Router) of WiBro processes location registration of the Correspondent Node and Home Agent as the Correspondent Node moves between ACRs. Therefore, the location update cost is low compared with MIPv6. However, all packets which are sent and received are sent through the ACR, so as the number of mobile nodes that are managed by the ACR increases, the cost of packet delivery also increases. Therefore, the communication state of the ACR domain remains smooth when the ACR which manages the mobile node in the ACR domain has good performance. However, network delays occur unless the ACR performs well, so the role of the ACR is important. In this paper, we analysis performance of the ACR for efficient realization of the WiBro standard. By using the Deny Probability and the Total Profit of ACR performance and apply it to the Random Walk Mobility model as the mobility model.

The Effect of Bleaching Agents on the Surface Topography of Ceramometal Dental Alloys

To study the effect of bleaching agents on the surface topography of ceramometal alloys. Three types of ceramometal alloys were used (gold, Ni-Cr, Co-Cr-Ti), and two types of bleaching agents (an agent intended for home use, one intended for use in the dental office) were studied. Forty-five specimens were constructed and divided according to the alloy type into three main groups, 15 specimens per group. Each group was further subdivided into three subgroups according to the type of bleaching agent used. The first subgroup (five specimens) was not subjected to any bleaching agent. The second and third subgroups were subjected to home and in-office bleaching agents, respectively. Au alloy showed the least surface roughness when subjected to either of the two bleaching agents. Ni-Cr alloys showed the highest surface roughness for both the control and home bleached subgroups, and Co-Cr-Ti alloy showed the highest surface roughness in the in-office bleached subgroup. No statistically significant difference was found between the control subgroup and the home-bleached subgroup for either the Au alloy or the Co-Cr-Ti alloy. For the two alloys, both the control and home-bleached subgroups were statistically different from the in-office bleached subgroups. There was a statistically significant difference between the Ni-Cr control subgroup and the other two bleached subgroups, while there was no difference between the two bleached subgroups. Results also showed that increasing the concentration of bleaching agents increased the surface roughness of all the tested alloys. There was a statistical difference between the Ni-Cr alloy and the other two alloys in all tested subgroups except the in-office bleached subgroup, for which no difference between the surface roughness of the Ni-Cr alloy and the Co-Cr-Ti alloy was found. Scanning electron microscopic examination revealed surface deteriorations in the two bleached subgroups for all tested ceramometallic alloys. Surface topographic alterations occurred as a result of the application of bleaching agents. These alterations increased with the increase of the carbamide peroxide concentration.

Load Balancing for Home Agents in MIPv6 Based on Active Overload Prevention

In order to enhance service availability and improve system performance,it is necessary to configure multiple HAs on the home link and efficiently balance load among these HAs.This paper proposes the Home Agent Load balancing method based on Active Overload Prevention(HALAOP).HALAOP actively selects optimal HA for each registration request to prevent HA's overload in advance,rather than just passively switching load between HAs like previous methods.HALAOP introduces a dynamic load evaluate algorithm to provide the basis for optimal load balancing decision.In addition,the load slicing mechanism is introduced to eliminate unnecessary additional overhead.The results of numeric analysis show that HALAOP can be more efficient in reducing probability of registration failure due to HA's overload and registration delay at lower additional cost than previous methods.

Route Optimization in Nested NEMO: Classification, Evaluation, and Analysis from NEMO Fringe Stub Perspective

Mobile IP is the basic solution to providing host mobility, whereas network mobility (NEMO) refers to the concept of the collective mobility of a set of nodes. The NEMO basic support protocol has been proposed in IETF as a first solution to the problem of network mobility. The main limitation of this basic solution is that it forces triangular routing, i.e., packets are always forwarded through the home agent (HA), following a suboptimal path. This is because each sub-NEMO obtains a care of address (CoA) that belongs to the home prefix of its parent mobile router. Such a CoA is not topologically meaningful in the current location, since the parent mobile router could also be away from home, and hence, packets addressed to the CoA are forwarded through the HA of the parent NEMO. To solve this problem, various extended proposals, with differing approaches and goals, exist for route optimization (RO) in NEMO applications. Their influences on the RO performance have been evaluated by classifying the detailed operations performed within the nested NEMO network, and then each category is analyzed in detail. The modeling of the detailed RO operation is intended to quantify the tradeoffs between the different approaches in order to provide a basis for the selection decision. In particular, the proposed grouping of the different proposals, based on their address configuration strategy, clarifies their similarities and differences, and provides some useful insights into the various methods that have been developed. In conclusion, it is suggested that, when choosing a solution for deploying NEMO, the designer has to balance his choices between the different pros and cons, and the different cases of application that are derived in this paper.

Design and analysis of SIP-based mobile VPN for real-time applications

Mobile virtual private network (MVPN) has been developed to secure mobile user's communication between untrusted external networks and protected private internal network. The IETF's solution, however, leads to some problems: where should we put the external home agent (HA), how could we trust the external HA, and overhead of three tunnels. In this paper, we propose an alternative SIP-based MVPN. Because the proposed architecture is based on SIP, the problems inherited from mobile IP are not problems in our architecture. In addition, there is no need to tunnel a packet three times as that in IETF MVPN. In this paper, we also propose analytical models to evaluate and compare the performance of the proposed SIP-based MVPN with the IETF MVPN. The results show that the proposed SIP-based MVPN can reduce packet delivery cost significantly. It is especially suitable for real-time applications.

A wireless access network based on WDM-PON for HMIPv6 mobility support

In this paper, an IP-based wireless access network is proposed, which is designed to support the hierarchical MIPv6 standard on the wavelength division multiplexed passive optical network access network in order to provide a fast and seamless handoff support. Two schemes for enhancing the mobility management are included in the proposed network's infrastructure support. Firstly, the local-link channels between sub-networks are provided to improve the mobility management efficiency for the mobile nodes roaming between neighboring sub-networks. Secondly, the early route optimization scheme has been applied, which optimizes the mobility management process between the corresponding node and the home agent (HA), resulting in reduced bandwidth waste and long end-to-end packet delays, as well as lowering the heavy burden on the HA. The performance of the proposed mobility management scheme has been evaluated in terms of handoff delays, packet losses and transmission costs. The superior performance of the proposed scheme has been verified and compared to other schemes.

A cross‐layer partner‐based fast handoff mechanism for IEEE 802.11 wireless networks

AbstractIn wireless/mobile networks, users freely and frequently change their access points (APs) while they are communicating with other users. To support the mobility of mobile nodes (MNs), Mobile IPv6 (MIPv6) is used to inform the information of MN's home address and current care‐of‐address (CoA) to its home agent. MIPv6 suffers from a long delay latency and high packet losses (PLs) because MIPv6 does not support micromobility. A Hierarchical Mobile IPv6 (HMIPv6) is proposed which provides micromobility and macromobility to reduce handoff latency (HL) by employing a hierarchical network structure. In this paper, we propose a cross‐layer partner‐based fast handoff mechanism based on HMIPv6, called the PHMIPv6 protocol. Our PHMIPv6 protocol is a cross‐layer, layer‐2 + layer‐3, and cooperative approach. A cooperative node, called a partner node (PN), is adopted in the PHMIPv6 protocol. A new layer‐2 trigger scheme used in the PHMIPv6 protocol accurately predicts the next AP and then invites a cooperative PN in the area of the next AP. With the cooperation of the PN, the CoA can be pre‐acquired and duplicate address detection operation can be pre‐executed by the PN before the MN initializes the handoff request. The PHMIPv6 protocol significantly reduces the handoff delay time and PLs. In the mathematical analysis, we verified that our PHMIPv6 protocol offers a better HL than the MIPv6, HMIPv6, and SHMIPv6 protocols. Finally, the experimental results also illustrate that the PHMIPv6 protocol actually achieves performance improvements in the handoff delay time, PL rate, and handoff delay jitter. Copyright © 2009 John Wiley & Sons, Ltd.

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.

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.

An Adaptive Network Mobility Support Protocol in Hierarchical Mobile IPv6 Networks

The network mobility (NEMO) basic support protocol provides collective mobility for a group of nodes in vehicular area networks. Since the NEMO basic support protocol always performs the same operations, regardless of a mobile network's characteristics, it cannot achieve optimal performance. We propose an adaptive NEMO support protocol based on hierarchical mobile IPv6. The proposed protocol jointly optimizes binding update (BU) traffic and tunneling overhead by employing the adaptive BU strategy, depending on the session-to-mobility ratio (SMR). Specifically, both the mobile router (MR) and the visiting mobile nodes (VMNs) configure two care-of-addresses: 1) on-link care-of-address (LCoA) and 2) regional care-of-address (RCoA). If the SMR is lower than a predefined threshold, the MR and VMNs perform RCoA and LCoA BU procedures to their home agents (HAs), respectively. Otherwise, LCoA and RCoA BU procedures are conducted by the MR and VMNs, respectively. Via analytical models, we evaluate the performance of the adaptive NEMO support protocol against other NEMO support protocols and derive the optimal SMR threshold. Numerical results demonstrate that the adaptive NEMO support protocol is a valuable solution for promising NEMO applications.

A terminal-assisted route optimized NEMO management

The NEMO basic support protocol enhances mobile IPv6 (MIPv6) to enable mobile router (MR) to move together with mobile network node (MNN) as a unit. This protocol suffers from pinball routing effect which has triggered research works to enable direct routing between MNNs in the presence of network mobility. Instead of relying on MIPv6, this paper describes network mobility using a novel terminal-assisted IP mobility protocol on MNNs that work cooperatively with MRs and access routers to provide seamless connectivity. This protocol is superior as it neither suffers from pinball routing effect nor requires dedicated infrastructure support such as home agent. It also eliminates the need to dynamically increase the size of IP header in IP tunneling. Through quantitative comparisons with existing protocol, we show that this protocol performs better than existing protocols in terms of average packet delivery overhead and packet generation.

Mobile IPv6 deployments: Graph-based analysis and practical guidelines

The Mobile IPv6 protocol is a major solution to supply mobility services on the Internet. Many networking vendors have already implemented it in their operating systems and equipments. Moreover, it was recently selected to provide permanent IP addresses to end-users of WiMAX and 3GPP2. Mobile IPv6 relies on a specific router called the home agent that hides location changes of the mobile nodes from the rest of the Internet. To do so, the mobile nodes’ traffic must flow through the home agent. This mandatory deviation produces longer paths and higher communication delays. In order to solve these problems, we describe a new approach to address deployments of Mobile IPv6 based on graph theory and could be applied to any operator’s network. In particular, we use notions of centrality in graphs to quantify increases of communication distances induced by dogleg routing and identify relevant home agents locations. We evaluate this approach using real-world network topologies and show that the obtained Mobile IPv6 performance could be close to direct paths ones. The proposed algorithm is generic and can be used to achieve efficient deployments of Mobile IPv6 as well as Home Agent Migration: a new Mobile IPv6 architecture using several distributed home agents.

Improving Mobile IPv6 handover and authentication in wireless network with E‐HCF

AbstractMobile IP allows a mobile node to maintain a continuous connectivity to the Internet when moving from one access point to another. However, due to the link switching delay and to Mobile IP handover operations, packets designated to mobile nodes can be delayed or lost during the handover period. Moreover, every time a new attach point is confirmed, the mobile node, its home agent and its corresponding node must be authenticated mutually. This paper presents a new control function called Extended Handover Control Function (E‐HCF) in order to improve handover performance and authentication in the context of Mobile IPv6 over wireless networks. With an analytical model and some OPNET simulations, we show in this paper that our solution allows provision of low latency, low packet loss and mutual authentication to the standard handover of Mobile IPv6. Copyright © 2009 John Wiley & Sons, Ltd.