Providing unperturbed Internet connectivity to mobile hosts has been studied in the IETF for some years now, and protocols such as Mobile IP and Mobile IPv6 have been developed. We are now witnessing the emergence of mobile networks, namely a set of hosts that move collectively as a unit, such as on ships and aircrafts. The protocols for mobility support therefore need to be extended from supporting an individual mobile device to supporting an entire mobile network. In this paper we examine the state-of-the-art in network mobility support. We first motivate the problem by considering typical network mobility scenarios and identify the characteristics that require new solutions. We then study the design requirements of the protocols that support network mobility. Thereafter, we review some of the current approaches for network mobility support, and discuss their strengths and weaknesses in addressing the design requirements. We conclude by identifying some open research issues in the realization of mobile networks.

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Background:Suicidal behaviour among youth is a major public health concern in Sri Lanka. Prevention of youth suicides using effective, feasible and culturally acceptable methods is invaluable in this regard, however research in this area is grossly lacking.Objective:This study aimed at determining the effectiveness of problem solving counselling as a therapeutic intervention in prevention of youth suicidal behaviour in Sri Lanka.Setting and design:This control trial study was based on hospital admissions with suicidal attempts in a sub-urban hospital in Sri Lanka. The study was carried out at Base Hospital Homagama.Materials and Methods:A sample of 124 was recruited using convenience sampling method and divided into two groups, experimental and control. Control group was offered routine care and experimental group received four sessions of problem solving counselling over one month. Outcome of both groups was measured, six months after the initial screening, using the visual analogue scale.Results:Individualized outcome measures on problem solving counselling showed that problem solving ability among the subjects in the experimental group had improved after four counselling sessions and suicidal behaviour has been reduced. The results are statistically significant.Conclusion:This Study confirms that problem solving counselling is an effective therapeutic tool in management of youth suicidal behaviour in hospital setting in a developing country.

In the future, mobility support will require handling roaming in heterogeneous access networks. In order to enable seamless roaming it is necessary to minimize the impact of the vertical handoffs. Localized mobility management schemes such as Fast Handovers for Mobile IPv6 (FMIPv6) and Hierarchical Mobile IPv6 do not provide sufficient handoff performance, since they have been designed for horizontal handoffs. In this paper, we propose the SafetyNet protocol, which allows a Mobile Node to perform seamless vertical handoffs. Further, we propose the SafetyNet handoff timing algorithm, to enable a Mobile Node to delay or even completely avoid upward vertical handoffs. We implement the SafetyNet protocol and compare its performance with the FMIPv6 protocol in our wireless test bed and analyze the results. The experimental results indicate that the proposed SafetyNet protocol can provide an improvement of up to 95% for TCP performance in vertical handoffs, when compared with FMIPv6 and an improvement of 64% over FMIPv6 with bicasting. We use numerical analysis of the protocol to show that its over the air signaling and data transmission overhead is comparable to FMIPv6 and significantly smaller than that of FMIPv6 with bicasting.