L2 Handover Research Articles

Extension of MIH for FPMIPv6 (EMIH-FPMIPv6) to support optimized heterogeneous handover

Fast handover for Proxy Mobile IPv6 (FPMIPv6) can optimize the handover performance compared with PMIPv6 in terms of handover delay and packet loss. However, FPMIPv6 cannot handle heterogeneous handovers due to the lack of unified Layer 2 triggering mechanism. While Media Independent Handover (MIH) can provide heterogeneous handover support, and a lot of MIH-based integration solutions have been proposed. However, most of these solutions are based on the integration of MIH and PMIPv6, and require additional mechanisms such as L2 scanning, handover coordinator or neighbor discovery, which are out of the scope of MIH and difficult to be standardized. Furthermore, the direct integration of MIH and FPMIPv6 will cause redundant signaling cost due to the similar functions such as MIH handover commit procedure in MIH and inter-MAG (Mobility Access Gateway) tunnel setup in FPMIPv6. This paper provides a comprehensive survey on these solutions and compares each solution’s functionality and characteristic, and then proposes an integration scheme based on Extension of MIH for FPMIPv6 (EMIH-FPMIPv6) to support optimized heterogeneous handover, which extends the existing MIH standard and reduces the redundant messages interaction caused by FPMIPv6 and MIH. This paper adopts the city section mobility model and heterogeneous networks model to analyze and compare the performance of EMIH-FPMIPv6 under different heterogeneous handover scenarios. The analytical results show that EMIH-FPMIPv6 is capable of reducing the handover delay and the signaling cost compared to the solution specified in MIH standard (noted as standard handover solution) and FPMIPv6.

A Network-Based Seamless Handover Scheme for VANETs

Vehicular ad hoc network (VANET) standards, including IEEE 1609 WAVE and ETSI C-ITS, use IPv6 to interconnect VANET with the Internet. Considering the high vehicle speeds and short communication ranges of road side units (RSUs), such vehicles may suffer from frequent service interruptions. Several VANET IP mobility schemes have been proposed in order to mitigate this problem. However, these only support L3 handover, as the RSUs act as IPv6 access routers (ARs) for vehicles. Some VANET IP mobility schemes reduce the handover latency of the L3 handover but do not fundamentally mitigate the frequency of the L3 handover. As L3 handover indicates that the default router of the vehicle is changing, the vehicle must perform IPv6 configuration, including router discovery and neighbor unreachability detection. Since most L3 handover latency is caused by this IPv6 configuration, the L3 handover involves a higher signaling cost and longer handover latency than the L2 handover. We propose a network-based L2 extension handover scheme for VANET. It decouples the AR functions from the RSU. An AR connects several RSUs via L2 links within its coverage. In this configuration, most inter-AR handovers are replaced with intra-AR handovers, so that the frequency of the L3 handover is decreased substantially. Therefore, the service disruption time caused by default router switching is also reduced, and the deployment of VANET can be made more flexible by decoupling the RSU and the AR. Proxy Mobile IPv6 is adopted in order to support inter-AR handover in the proposed scheme. Furthermore, the scheme supports seamlessness in both the intra-AR and inter-AR handovers with buffering at the AR. The performance analysis and the simulation result reveal that the proposed scheme reduces the signaling cost and handover latency and also shows seamless packet delivery for vehicles.

Mobility management for 6LoWPAN WSN

When a wireless node moves across different IP domains, it needs to perform both the handover in the link layer (L2) and the handover in the network layer (L3). The L2 handover is responsible for the channel switch, and the L3 handover takes charge of the IP address change to ensure the communication correctness. The L2 handover and the L3 handover are two independent processes which are performed in series, so the total handover delay is equal to the sum of the L2 handover delay which is mainly caused by channel scanning and the L3 handover delay which is primarily incurred by care-of address (CoA) configuration. This considerable total handover latency causes severe packet loss, so it is significant to reduce the total handover latency. This paper proposes a cross-layering mobility management scheme to reduce the total handover delay and it has the following contributions: (1) This scheme combines the L3 handover with the L2 one so that they can be performed in parallel. (2) A CoA is pre-configured and the channel information is acquired in advance so that the L3 handover can be achieved without CoA configuration and the L2 handover can be performed without channel scanning. The performance of this scheme is evaluated, and the results show that this scheme effectively reduces the total handover latency.

A cross-layer mobility handover scheme for IPv6-based vehicular networks

This paper proposes a cross-layer mobility handover scheme for IPv6-based vehicular networks. In this scheme, the architecture for vehicular networks is proposed and it is made up of three hierarchies including road domains, road segments and clusters. A vehicular network is made up of multiple road domains, a road domain consists of multiple road segments, and a road segment includes multiple clusters. Based on this architecture, the cluster generation algorithm based on the link duration time is proposed, and the cross-layer mobility handover algorithm is presented. In the handover algorithm, the handover in the network layer (L3) is launched before the one in the link layer (L2). Through the L3 handover process the information on the L2 handover can be acquired in order to achieve the fast L2 handover. Moreover, during the L3 handover process, a vehicle does not need to be configured with a care-of address, so the L3 handover delay and packet loss are reduced. The performance of the proposed scheme is evaluated, and the data results show that this scheme shortens the handover delay and lowers the packet loss rate.

A cross-layer mobility support protocol for wireless sensor networks

This paper proposes a cross-layer mobility support scheme for the IPv6 over low-power wireless personal area network (6LoWPAN) wireless sensor network (WSN). This scheme combines the handover in the network layer (L3) with the handover in the link layer (L2) so that the L3 handover and the L2 one can be performed simultaneously. During the L3 handover process, a sensor node neither needs a care-of address nor participates in the handover process. During the L2 handover process, a node uses the channel information to directly achieve the L2 handover without scanning all channels. Finally, this paper analyzes and evaluates the performance of this protocol, and the data results show that this protocol improves the mobility handover performance.

An IPv6‐based mobility framework for urban vehicular networks

SummaryThis paper proposes an IPv6‐based mobility framework for urban vehicular networks. In this framework, the architecture for urban vehicular networks is presented, and based on this architecture, the IPv6 address structure for urban vehicular networks is proposed. In this framework, a vehicle is always identified by its home address and does not need to be configured with a care‐of address. Based on this architecture, the pre‐handover algorithm is presented. In this algorithm, the third‐layer (L3) mobility handover is performed before the second‐layer (L2) one. When a vehicle finishes the L3 handover but does not perform the L2 handover, the corresponding access router or border router reserves the messages destined for the vehicle. After the vehicle completes the L2 handover, the access router or border router transmits the reserved messages to the vehicle. The performance of this framework is evaluated, and the results show that this framework reduces the handover cost and delay and lowers the packet loss. Copyright © 2015 John Wiley & Sons, Ltd.

Performance improvement of handover integration of FMIPv6 in HMIPv6

Fast handover for Hierarchical Mobile IPv6 (F-HMIPv6) is scheme that integrates Fast handovers for Mobile IPv6 (FMIPv6) in Hierarchical Mobile IPv6 (HMIPv6). F-HMIPv6 has some limitations, such as circle routing problem occurs within the handover process, packets to the destination can wrong order, the handover latency is quite high when MN moves inter-domain. We propose improved F-HMIPv6 scheme (called I-FHMIPv6) - an improvements in binding update to HA/CN when MN moves inter-domain. When a MN receives an FBAck message with the new LCoA and RCoA acceptance, it will send a Binding Update message to the HA/CN to update the MN’s new RCoA before the L2 handover occurs. So it helps avoiding circle routing problem within the handover process, can wrong order of packets at the destination and handover latency can be reduce.

Dynamic host configuration protocol for IPv6 improvements for mobile nodes

In wireless networks mobile clients change their physical location, which results in changing point of attachment to the network. Such handovers introduce unwanted periods, when node does not have communication capabilities. Depending on many conditions, such events may require reconfiguration of layer 2 (e.g. IEEE 802.16) or both 2 and 3 layers (IPv6). This paper investigates delays introduced in the latter type of handover. IPv6 protocol family supports two automatic configuration modes: stateless (SLAAC) and stateful (DHCPv6). Both modes may be used in wireless networks. Once the L2 handover procedure is completed, the mobile node (MN) starts its IPv6 configuration process, using stateless (router advertisements) or stateful (DHCPv6) mode. When care-of address (CoA) is assigned, its uniqueness has to be verified, using Duplicate Address Detection (DAD) procedure. Depending on a network type, this procedure may even take more than 1000 ms. The obtained CoA can be used only when configuration and DAD procedures are completed for informing corresponding nodes about new MN location. Such delay introduces unacceptable gaps in communication capability. This paper proposes several new mechanisms that enable faster IPv6 reconfiguration. First proposal allow MN to obtain its IPv6 address and other configuration options in advance, before completing actual handover. Such a priori knowledge about configuration available at destination locations may be exploited to speed up configuration process itself and also allow initiating Mobile IPv6 operations earlier, thus further shortening delays. Another proposal includes new way of delivering routing information to MN, using DHCPv6. Mechanism itself and its verification techniques are discussed. Results of extensive simulations, statistical analysis as well as areas of further study conclude this paper.

무선랜 환경에서 서비스 연속성 지원을 위한 IMS 기반 핸드오버 지원 방안

본 논문은 단일 무선랜 인터페이스를 갖는 IMS 단말에서 서비스 연속성을 지원하기 위해 패킷 손실을 최소화하는 L3 핸드오버 지원방안을 제안한다. 기존 IMS 서비스 연속성 지원 방안은 하나의 단말 내에 존재하는 다수의 인터페이스를 통해 서로 다른 접속망을 경유하여 IMS 코어 네트워크와의 통신이 가능한 상태에서 이동성 제공이 가능하다. 하지만, 단일 인터페이스를 갖는 무선랜 단말은 동시에 하나 이상의 접속망을 통해 IMS 코어 네트워크와 통신을 할 수 없다. 제안 방안은 Candidate Access Router Discovery(CARD) 매커니즘을 이용하여 타겟 WLAN 영역에서 단말이 사용할 IP를 미리 구성하고, 서비스 연속성 서버가 단말을 대신하여 타겟 WLAN 영역에서의 L3 연결 과정 및 IMS 서버로의 등록절차를 수행한다. 이후 서비스 연속성 제공을 위해 SIP 기반의 세션 제어 메커니즘을 수행한다. 제안된 핸드오버 제공 방안의 성능 검증을 위해 기존 서비스 연속성 제공 방안과 제안 방안에 대한 핸드오버 지연(latency), 시그널링 비용(cost)을 비교 분석하였다. This paper proposes a L3 handover method to minimize packet loss for supporting service continuity to IMS Terminal which has a single WLAN interface. The existing IMS based handover solution is able to support handover between different access networks in case that a terminal has multiple interfaces. That is, WLAN terminals need multiple interfaces to connect with one or more access networks. This proposed method configures IP address for the terminal in target WLAN previously by using Candidate Access Router Discovery(CARD) mechanism. Also, in the proposed method, service continuity server performs L3 connection establishment in target WLAN and registration to IMS server instead of the terminal. And then session control mechanism based on SIP is performed to support service continuity. We analyzed handover latency and signaling cost in the proposed method and existing method to show the improved performance by the proposed method.

Inter‐domain handover scheme using an intermediate mobile access gateway for seamless service in vehicular networks

AbstractCurrent IP‐level mobility management protocols are unable to satisfy the stringent handover latency requirements for supporting real‐time multimedia services between different domains in a high‐speed vehicular environment. This paper proposes an inter‐domain handover scheme for Proxy Mobile IPv6 (PMIPv6) with a new network entity, called intermediate‐mobile access gateway (iMAG). The iMAG is located between the home and the foreign domains and is connected to both domains. The proposed scheme is a proactive handover approach that performs the inter‐domain L3 handover in advance before the inter‐domain L2 handover while the Mobile Node (MN) is still connected to the iMAG in the home domain. Therefore, the proposed scheme enables the inter‐domain handover latency to reduce as low as the intra‐domain handover latency. Numerical analysis and simulation results demonstrate that the proposed scheme is able to support seamless service continuity in inter‐domain handovers. Copyright © 2009 John Wiley & Sons, Ltd.

M-FHMIP mechanism for mobile multicasting in IP networks

Fast handover is essential to support seamless multicast service in MIPv6. To reduce handover latency of multicast, there are two handover mechanisms, one is M-FMIP that prepares fast L3 handover before L2 handover and the other is M-HMIP that performs local area mobile multicast management. This paper proposes M-FHMIP that integrates an advantage of M-FMIP and M-HMIP, and analyzes the multicast handover latency.

Seamless handover support over heterogeneous networks using FMIPv6 with definitive L2 triggers

Various wireless communication systems have been developed and will be integrated into an IP-based network to offer end users the Internet access anytime and anywhere. In heterogeneous multi-access networks, one of main issues is to manage nodes' mobility with session continuity and minimal handover latency. In order to support the mobility of mobile nodes, MIPv6 has been proposed by IETF. Even though MIPv6 provides a solution to handling nodes' mobility in IPv6 networks, there is a significant problem due to its inability to support a seamless handover caused by long latency and high packet losses during a handover. FMIPv6 has been proposed to reduce MIPv6 handover latency by using an address pre- configuration method with the aid of L2 triggers. Current research defines a general L2 trigger model for seamless handover operation, but it does not address the exact timing and definitive criteria of L2 triggers which causes a significant effect on the handover performance of FMIPv6. This paper considers the available timing and accurate criteria of L2 triggers. With the definitive L2 triggers, we present a practical handover scenario to integrate L2 and L3 layers for low handover latency and low number of packet losses during a handover. We also study the impact of definitive L2 triggers on the handover performance of the FMIPv6 protocol in real testbeds and prove that the FMIPv6 protocol performs its handover operation prior to the L2 handover and obtains a seamless handover.

Analysis and evaluation of mobile IPv6 handovers over wireless LAN

In this paper, we analyze the IPv6 handover over wireless LANs. Mobile IPv6 is designed to manage mobile nodes movements between wireless IPv6 networks. Nevertheless, a mobile node cannot receive IP packets on its new point of attachment until the handover completes. Therefore, a number of extensions to Mobile IPv6 have been proposed to reduce the handover latency and the number of lost packets. We focus on Fast Mobile IPv6 which is an extension of Mobile IPv6 that allows the use of L2 triggers to anticipate the handover. We compare the handover latency in four specific cases: basic Mobile IPv6, the forwarding method of Mobile IPv6, the Anticipated method, and the Tunnel-Based Handover. The results of the handover latency are calculated with the L2 properties of IEEE 802.11b. In particular, we take into account the L2 handover for different configurations of the wireless network.