End-to-end internet quality of service with intserv/diffserv, mobile IPv6 and IEEE802.11e

Master'sMASTER OF ENGINEERIN

QoS Abstraction Layer in 4G Access Networks

Tese de Mestrado. Redes e Serviços de Comunicação. Faculdade de Engenharia. Universidade do Porto. 200

Actas da 10ª Conferência sobre Redes de Computadores

Universidade do MinhoCCTCCentro AlgoritmiCisco SystemsIEEE Portugal Sectio

Context transfer support for mobility management in all-IP networks.

This thesis is a description of the research undertaken in the course of the PhD and evolves around a context transfer protocol which aims to complement and support mobility management in next generation mobile networks. Based on the literature review, it was identified that there is more to mobility management than handover management and the successful change of routing paths. Supportive mechanisms like fast handover, candidate access router discovery and context transfer can significantly contribute towards achieving seamless handover which is especially important in the case of real time services. The work focused on context transfer motivated by the fact that it could offer great benefits to session re-establishment during the handover operation of a mobile user and preliminary testbed observations illustrated the need for achieving this. Context transfer aims to minimize the impact of certain transport, routing, security-related services on the handover performance. When a mobile node (MN) moves to a new subnet it needs to continue such services that have already been established at the previous subnet. Examples of such services include AAA profile, IPsec state, header compression, QoS policy etc. Re-establishing these services at the new subnet will require a considerable amount of time for the protocol exchanges and as a result time- sensitive real-time traffic will suffer during this time. By transferring state to the new domain candidate services will be quickly re-established. This would also contribute to the seamless operation of application streams and could reduce susceptibility to errors. Furthermore, re-initiation to and from the mobile node will be avoided hence wireless bandwidth efficiency will be conserved. In this research an extension to mobility protocols was proposed for supporting state forwarding capabilities. The idea of forwarding states was also explored for remotely reconfiguring middleboxes to avoid any interruption of a mobile users' sessions or services. Finally a context transfer module was proposed to facilitate the integration of such a mechanism in next generation architectures. The proposals were evaluated analytically, via simulations or via testbed implementation depending on the scenario investigated. The results demonstrated that the proposed solutions can minimize the impact of security services like authentication, authorization and firewalls on a mobile user's multimedia sessions and thus improving the overall handover performance

Pro-collaborative mobile systems in next generation IP networks

Computing system designs of today take on either the interactive or the proactive form. Motivated by the user’s desire to make his/her computing experience more intelligent and personalised, the progression from interactive (human-centred) to proactive (human-supervised) is evident. It can be observed that current research mainly emphasises the user as the dominant focus of a user-system interaction. Consider a model that we called the opponent-process model. It contains two processes, one representing the user and the other the system, where both processes are capable of dominating each other, though working collaboratively towards a predefined task. We argue the necessity to design computing systems which are balanced in this model, such that the system process, at times, becomes the dominant process. We refer to this as the pro-collaborative design form. We dissect mobility into the notion of a nomadic user and the notion of a nomadic system. The examination into the nomadic user problem space reveals the potential for applying the pro-collaborative approach in optimising handoff management. Significant performance advantages can be obtained with our proposed S-MIP framework, based on the pro-collaborative design, when compared with established handoff latency optimisation schemes. The key differentiator lies in its indicative approach in addressing handoff ambiguity. Instead of passively anticipating through prediction as to when a mobile user might cross network boundaries (user-dominant), the system actively indicates to the user when, where and how to handoff (system-dominant). This eliminates the handoff ambiguity. Regarding the notion of a nomadic system, that is, the ability to move services offered by computing systems to arbitrary points in the Internet, we explore the idea of the dynamic extension of network services to a mobile user on-demand. Based on the pro-collaborative form, we develop the METAMORPHOSE architecture which facilitates such a dynamic service extension. By assuming the proliferation of programmable network switches and computational resources within the Internet, we re-examine how ‘loose’ service agreements between network services providers can be, to achieve such borderless moving-service offerings. The viability of the pro-collaborative form is reflected through our design and implementation of protocols and architectures which address the notion of nomadic user and nomadic system