Eranga Perera

Survey on network mobility support

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.

Measuring and Improving the Performance of Network Mobility Management in IPv6 Networks

Measuring the performance of an implementation of a set of protocols and analyzing the results is crucial to understanding the performance and limitations of the protocols in a real network environment. Based on this information, the protocols and their interactions can be improved to enhance the performance of the whole system. To this end, we have developed a network mobility testbed and implemented the network mobility (NEMO) basic support protocol and have identified problems in the architecture which affect the handoff and routing performance. To address the identified handoff performance issues, we have proposed the use of make-before-break handoffs with two network interfaces for NEMO. We have carried out a comparison study of handoffs with NEMO and have shown that the proposed scheme provides near-optimal performance. Further, we have extended a previously proposed route optimization (RO) scheme, OptiNets. We have compared the routing and header overheads using experiments and analysis and shown that the use of the extended OptiNets scheme reduces these overheads of NEMO to a level comparable with Mobile IPv6 RO. Finally, this paper shows that the proposed handoff and RO schemes enable NEMO protocol to be used in applications sensitive to delay and packet loss

OptiNets: an architecture to enable optimal routing for network mobility

More and more people want to access the Internet and virtual private networks from anywhere at anytime. This has given rise to providing connectivity capabilities to commuters of public transportation systems. Internet access from moving vehicles has necessitated an architecture which relies upon a special entity, namely a mobile router to support the mobility of the entire network. This paper presents an optimal routing architecture for devices accessing the Internet through a mobile router deployed in such a mobile network. Our scheme takes into consideration all entities involved in a network mobility scenario and attempts to diffuse the mobility management load without burdening a single entity of the architecture. Our architecture has three main benefits. Firstly, it provides mechanisms for any type of mobile network node present in the network - mobility aware or mobility unaware - to communicate using optimal routes with their correspondent nodes. Secondly added functionality to the MIPv6 operation is neither required at the correspondent nodes nor at the mobile network nodes. Thirdly, our architecture reduces and diffuses the processing burden at the mobile routers and their home agents.

MOBNET: the design and implementation of a network mobility testbed for NEMO protocol

The inherent difficulty in faithfully modeling wireless channel characteristics in simulators has prompted researchers to build wireless network testbeds for realistic testing of protocols. While previous testbeds are mostly designed to provide a research environment of static wireless networks, our work is aimed to assess protocols used for mobile wireless networks (such as an on-board network on public transport vehicles). In this work, we describe our on-going efforts in designing and implementing a network mobility testbed for network mobility (NEMO) protocol. This paper attempts to provide an initial reference to identify the feature set necessary for a network mobility testbed. We first describe the architecture of our testbed. Next, we present some preliminary results to demonstrate the use of our testbed in evaluating the performance of NEMO protocol under different scenarios

A mobility toolbox architecture for all-IP networks: an ambient networks approach

The future Internet will need to cater to an increasing number of mobile devices and mobile networks, roaming across different access networks and trust domains. In addition, various limitations imposed by the end user, service provider, or network operator agreements and preferences will need to be considered. A plethora of mobility management protocols have been proposed to handle different and mostly limited sets of these mobility requirements. In this article we make the case for coexistence of mobility protocols in order to support the large range of mobility scenarios possible in future all-IP networks. This coexistence takes the form of a mobility toolbox that enables mobility handling mechanisms to be selected according to the context. We then present a design for the mobility toolbox as a component of the ambient networks architecture, including a simplified mobility tool interface toward protocol modules, and show how it meets the requirements of future all-IP networks. We further demonstrate the feasibility and performance gains of the mobility toolbox architecture with a prototype implementation based on network mobility.

Multicasting with selective delivery: a SafetyNet for vertical handoffs

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.

Bandwidth fuelling for network mobility

The deployment of mobile networks in automobiles, trains, ships, planes buses etc. would undoubtedly change the way we travel. More and more people would be inclined towards taking public transportation systems if they would get the opportunity to utilize their commuting time in a constructive manner. In order for on board Internet connectivity to be appealing for the public the cost and the performance of the service should be reasonable. However providing continuous high-performance service over wireless networks at a reasonable cost is still a challenge. Use of caching allows more efficient usage of the potentially scarce bandwidth of the wireless resources. In this paper we utilize the idea of caching and present a bandwidth fueling architecture for network mobility. We analyze the feasibility of the architecture by measuring the performance of our prototype implementation

An Experimental Evaluation of Mobile Node based versus Infrastructure based Handoff Schemes

The rate at which the Internet is becoming mobile is unprecedented. This has increased the demand for continuous connectivity even while moving from one network to another at very high speeds. Moving from one network to another gives rise to a handoff process which often incurs packet losses and severe end to end transport protocol performance degradations for the Mobile Node. Most research on IP mobility has focused on minimizing the delays of the handoff process with network infrastructure based approaches. A different way of minimizing the impact of the handoff is to enable the Mobile Node to connect to multiple access networks simultaneously, allowing it to perform Make-Before-Break handoffs. In this paper, we compare the performance of these two alternatives, focusing on the use of Fast Handovers for Mobile IPv6 framework on the infrastructure side and on the other hand Make-Before-Break handoffs using two network interfaces. Both of these schemes require proactive handoffs for optimal performance. The results show that the use of two interfaces for Make-Before-Break handoffs provides increased handoff performance over Fast Handovers for Mobile IPv6.

Failover for mobile routers: a vision of resilient ambience

The ambient networking approach includes the flexibility of every end system to be not just a node but also an entire network. The end user entities are, in the majority of use cases, mobile and they operate in a highly dynamic environment. The exponential growth of wireless devices and services contributes to the increasing number of these dynamic mobile networks, whose changeable characteristics in turn contribute to the high probability of failures. To maintain the high level of connectivity required for the overall ambient networks environment, it is imperative to maintain the same level of connectivity in various network parts. In this paper we consider the Mobile Router related failures that could occur in todays mobile networks and describe how the ambient networking environment with its in-built enhanced failover management functionality has a potential to create resilient networks.

Ongoing efforts on performance comparison of mobile routers

The growth of wireless networks is inevitable. The Mobile Router is an inherent part of wireless networks and provides mobility management of an entire network. A Mobile Router implementation has been successfully completed on our network mobility test bed and is currently being employed to test various mobility scenarios. The performance of such an integral component of a system would undoubtedly come under close scrutiny. One of the methods to establish the quality of the implementation is to compare it to an industry standard implementation. This paper presents the on going work that is being done to evaluate the performance of the lab implemented Mobile Router by comparing it to a router available commercially.