Mobile Networking

We point out the different performance problems that need to be addressed when considering mobility in IP networks. We also define the reference architecture and present a framework to classify the different solutions for mobility management in IP networks. The performance of the major candidate micro-mobility solutions is evaluated for both real-time (UDP) and data (TCP) traffic through simulation and by means of an analytical model. Using these models we compare the performance of different mobility management schemes for different data and real-time services and the network resources that are needed for it. We point out the problems of TCP in wireless environments and review some proposed enhancements to TCP that aim at improving TCP performance. We make a detailed study of how some of micro-mobility protocols namely Cellular IP, Hawaii and Hierarchical Mobile IP affect the behavior of TCP and their interaction with the MAC layer. We investigate the impact of handoffs on TCP by means of simulation traces that show the evolution of segments and acknowledgments during handoffs.Publicad

Generic Models for Mobility Management in Next Generation Networks

In the network community different mobility management techniques have been proposed over the years. However, many of these techniques share a surprisingly high number of similarities. In this technical report we analyze and evaluate the most relevant mobility management techniques, pointing out differences and similarities. For macro-mobility we consider Mobile IP (MIP), the Session Initiation Protocol (SIP) and mobility management techniques typical of a GSM network; for micro-mobility we describe and analyze several protocols such as: Hierarchical MIP, TeleMIP, IDMP, Cellular IP and HAWAII

Intra-domain mobility management

Mobility supporting protocols are designed to provide connectivity of mobile nodes from any point of attachment to the Internet. Fast handoff, low signaling overhead and packet loss are the key factors to be addressed in designing a mobility management protocol. This work proposes Intra Domain Mobility Management (IDMM) protocol, based on micro-mobility concept. The protocol implements an efficient tracking mechanism for locating the mobile nodes and ensures that their movements remain transparent to communicating nodes. The protocol is designed with the hierarchical tree topology in mind that allows for low cost solution and efficient management. The optimized routing enables fast delivery of packets to the mobile node in the micro-mobility domain. IDMM is implemented using Network Simulator (ns2) tools. Packet loss, throughput, delay in the network and traffic overhead due to location management are studied. The comparison with major mobility protocols such as Mobile IP and Cellular IP is done to demonstrate the performance of IDMM under high frequency of roaming

Load Balancing in Tree-based IP Micro-Mobility Domains

Nowadays the penetration of wireless access is continuously increasing. Additionally, the mobile users become more and more dependent on data. The IP-based (Internet Protocol) Internet was designed for data transmission and has become the most ubiquitous wired internetwork. According to these trends the next generation networks (and already 3G networks also include IP-based parts) are designed as a combination of these two types of networks (mobile and IP-based). The Mobile IP protocol handles mobility in the IP layer globally, but it is not well-adopted to local coverage areas. Within such access networks the micro-mobility proposals enhance the performance of Mobile IP. In this paper we propose a solution for improving the performance of tree-based micro-mobility protocols by rearranging their capacity using additional links. Based on analytical considerations we obtain a formula to determine the optimal link size in particular cases. The method is also examined with our simulation testbed, the results show improvement in the performance of the domain

MOBILITY SUPPORT ARCHITECTURES FOR NEXT-GENERATION WIRELESS NETWORKS

With the convergence of the wireless networks and the Internet and the booming demand for multimedia applications, the next-generation (beyond the third generation, or B3G) wireless systems are expected to be all IP-based and provide real-time and non-real-time mobile services anywhere and anytime. Powerful and efficient mobility support is thus the key enabler to fulfil such an attractive vision by supporting various mobility scenarios. This thesis contributes to this interesting while challenging topic. After a literature review on mobility support architectures and protocols, the thesis starts presenting our contributions with a generic multi-layer mobility support framework, which provides a general approach to meet the challenges of handling comprehensive mobility issues. The cross-layer design methodology is introduced to coordinate the protocol layers for optimised system design. Particularly, a flexible and efficient cross-layer signalling scheme is proposed for interlayer interactions. The proposed generic framework is then narrowed down with several fundamental building blocks identified to be focused on as follows. As widely adopted, we assume that the IP-based access networks are organised into administrative domains, which are inter-connected through a global IP-based wired core network. For a mobile user who roams from one domain to another, macro (inter-domain) mobility management should be in place for global location tracking and effective handoff support for both real-time and non-real-lime applications. Mobile IP (MIP) and the Session Initiation Protocol (SIP) are being adopted as the two dominant standard-based macro-mobility architectures, each of which has mobility entities and messages in its own right. The work explores the joint optimisations and interactions of MIP and SIP when utilising the complementary power of both protocols. Two distinctive integrated MIP-SIP architectures are designed and evaluated, compared with their hybrid alternatives and other approaches. The overall analytical and simulation results shown significant performance improvements in terms of cost-efficiency, among other metrics. Subsequently, for the micro (intra-domain) mobility scenario where a mobile user moves across IP subnets within a domain, a micro mobility management architecture is needed to support fast handoffs and constrain signalling messaging loads incurred by intra-domain movements within the domain. The Hierarchical MIPv6 (HMIPv6) and the Fast Handovers for MIPv6 (FMIPv6) protocols are selected to fulfil the design requirements. The work proposes enhancements to these protocols and combines them in an optimised way. resulting in notably improved performances in contrast to a number of alternative approaches

Investigating the Applicability of Mobile IP and Cellular IP for Roaming in Smart Environments

Increased research and development in the field of ubiquitous computing, and in particular smart spaces, has heightened the need for a comprehensive mobility solution. Existing mobility protocols are often categorised as either macro or micro mobility but few, if any, bridge the divide between the two. Mobile IP is at present the IETF proposed standard for delivery of IP packets to mobile devices. However, as a macro mobility protocol, it does not adequately support data delivery to mobile devices that regularly roam within local networks. Cellular IP, a more recent development in mobility, falls under the banner of micro mobility and as such delivers a number of benefits that a macro mobility protocol alone could not. This paper describes a complete mobility architecture accomplished by integrating Mobile IP with Cellular IP and continues by addressing the suitability of this integration for supporting roaming in smart environments

Efficient Micro-Mobility using Intra-domain Multicast-based Mechanisms (M&M)

One of the most important metrics in the design of IP mobility protocols is the handover performance. The current Mobile IP (MIP) standard has been shown to exhibit poor handover performance. Most other work attempts to modify MIP to slightly improve its efficiency, while others propose complex techniques to replace MIP. Rather than taking these approaches, we instead propose a new architecture for providing efficient and smooth handover, while being able to co-exist and inter-operate with other technologies. Specifically, we propose an intra-domain multicast-based mobility architecture, where a visiting mobile is assigned a multicast address to use while moving within a domain. Efficient handover is achieved using standard multicast join/prune mechanisms. Two approaches are proposed and contrasted. The first introduces the concept proxy-based mobility, while the other uses algorithmic mapping to obtain the multicast address of visiting mobiles. We show that the algorithmic mapping approach has several advantages over the proxy approach, and provide mechanisms to support it. Network simulation (using NS-2) is used to evaluate our scheme and compare it to other routing-based micro-mobility schemes - CIP and HAWAII. The proactive handover results show that both M&M and CIP shows low handoff delay and packet reordering depth as compared to HAWAII. The reason for M&M's comparable performance with CIP is that both use bi-cast in proactive handover. The M&M, however, handles multiple border routers in a domain, where CIP fails. We also provide a handover algorithm leveraging the proactive path setup capability of M&M, which is expected to outperform CIP in case of reactive handover.Comment: 12 pages, 11 figure

Taxonomy and analysis of IP micro-mobility protocols in single and simultaneous movements scenarios

The micro-mobility is an important aspect in mobile communications, where the applications are anywhere and used anytime. One of the problems of micro-mobility is the hand-off latency. In this paper, we analyse two solutions for IP micro-mobility by means of a general taxonomy. The first one is based on the Stream Control Transmission Protocol (SCTP), which allows the dynamic address configuration of an association. The second one is based on the Session Initiation Protocol (SIP), which is the most popular protocol for multimedia communications over IP networks. We show that for the SCTP solution, there is room for further optimisations of the hand-off latency by adding slight changes to the protocol. However, as full end-to-end solution, SCTP is not able to handle simultaneous movement of hosts, whose probability in general cannot be neglected. On the other hand, the SIP can handle both single and simultaneous movements cases, although the hand-off latency can increase with respect to the SCTP solution. We show that for a correct and fast hand-off, the SIP server should be statefull