In recent years, there has been a rapid growth in the need to support moving hosts and moving networks in IPv6-based mobile networks. As the number of such hosts and networks grows, so will the demand for delay sensitive real-time applications, such as voice over IP (VoIP), that require seamless handover. Two well-known approaches to reduce the handover latency have been proposed in the literature: proactive and reactive approaches. While proactive handover is known to generally outperform reactive handover, its reliability and practicality are still questionable since it basically depends on predictive information which may be unreliable in some cases. In this paper, based on the standard specification for IPv6 mobility support, we analyze the existing movement detection and address configuration procedures which are the main components of reactive handover approach. We also propose a novel reactive handover procedure which employs our optimized movement detection and address configuration schemes. The proposal is simple and robust because it does not need any predictive information and it requires a minimum number of signaling messages. The performance evaluation shows that the proposal substantially reduces the signaling load on wireless/wired networks and its handover latency is reduced enough to support seamless services

IETF mobile Internet protocol version 6 and its fast handover protocol are proposals for handling routing of IPv6 packets to mobile nodes that have moved away from their home network. To do this, each time a mobile node moves to a new location, iit configures and confirms it temporal IP address. In this paper, we study the impact of the address configuration and confirmation procedure on the their IP handover latency. We first argue that the current strategies for them are unnecessarily slow, hampering the use of current proposals for real-time traffic. We present a new scheme which can be a substitute of the current strategies. The underlying objective of our scheme is to completely eliminate the latency taken by the address configuration and confirmation from the whole handover latency. Further, a mathematical analysis is developed to show the benefits of our scheme. In this analysis, various parameters are discussed to analyze the existing proposals, while our approach focuses on the reduction of handover latency.

Abstract 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.

Many dynamic location update schemes such as time-based, movement-based, and distance-based; have been studied in the location management of mobile communication. Also there are many studies that improve these schemes adaptively using mobile nodes' call and mobility patterns. These schemes usually use the prediction-based algorithms for mobile nodes' mobility patterns. However those need complicated computation such as heuristic algorithm. Those schemes' management cost are various for mobile nodes' diverse mobility patterns. In this paper we propose a novel approach in which the location management costs are rarely affected by mobile nodes' mobility patterns. The basic idea is to use the velocity of a mobile node, which is represented by the combination of two thresholds: time threshold T and distance threshold D. The update process is triggered by the change of mobile nodes' velocity, that is two thresholds. These values are adjusted by simple algorithm whenever a location update occurs. Also, we use stepwise paging scheme using the mobile nodes' velocity in order to reduce the paging cost. We compare our scheme with the distance-based scheme through numerical analysis. Finally, we show that our proposed scheme is better than the distance-based scheme with an optimal distance threshold value for most mobility patterns.

Recently, hierarchical architecture for location databases has been proposed in order to accommodate the growing number of PCSs user. With the 3-level hierarchical database architecture, which is compatible with the current cellular mobile systems, newly developed additional databases, including the regional location database (RLR), are positioned between the HLR and the VLRs. We propose an efficient cache scheme, the Double T-thresholds Location Cache Scheme, could reduce the network and database costs to lookup a portable using the 3-level architecture. The idea behind our proposed scheme is to use two pieces of cache information, VLR and RLR, which are serving the called portables. These two pieces are required in order to exploit not only the locality of a registration area (RA) but also the locality of a regional registration area (RRA), a wide area covered by the RLR. We also use two threshold values in order to determine whether the two pieces are obsolete. The cost analysis presented in this paper shows that the double T-thresholds location cache scheme significantly reduces network and database costs for most patterns of portables.