Tiago Condeixa

A characterization of mobility management in user-centric networks

Mobility management is a key aspect to consider in future Internet architectures, as these architectures include a highly nomadic end-user which often relies on services provided by multi-access networks. In contrast, todays mobility management solutions were designed having in mind simpler scenarios and requirements from the network and where roaming could often be taken care of with previously established agreements.With a more dynamic behavior in the network, and also with a more prominent role from the end-user, mobility management has to deal with additional requirements derived from new Internet paradigms. To assist in understanding such requirements and also how to deal with them, this paper proposes a starting point to dismantle current mobility management notions. Our contribution is an initial proposal on defining mobility management in concrete functional blocks, their interaction, as well as a potential grouping which later can assist in deriving novel and more flexible mobility management architectures.

Dynamic mobile IP anchoring

The increase of mobile traffic and the new role of the users as active elements in the network require a new approach for network architectures to adopt more flatten models. However, current mobile IP approaches were developed assuming static and centralized models: a single entity is responsible for the mobile traffic, the signaling and the context information of a large amount of Mobile Nodes. We propose a new host-based mobility approach denoted as Dynamic Mobile IP Anchoring (DMIPA) that distributes mobility management functionalities among Access Routers (ARs) and MNs, and provides dynamic sessions anchoring. DMIPA is envisioned to support these novel flat network architectures, and it is able to provide global IP mobility to the users, independently of the access network, technology and Internet provider. Through an analytical model, we compare DMIPA against Mobile IPv6, which is the standard host-based mobility model for IPv6 networks. The evaluation shows that DMIPA achieves better results regarding the handover delay and the data delivery cost, while the signaling cost can also be reduced in networks with low loss probability.

Multiparty Seamless Transport

The demanding requirements of new real-time and mobile multimedia group-based applications (e.g. IPTV and video-conferencing) motivates the research for novel and efficient network architectures, able to fulfil service requirements and increase user experience. Multicast, despite its scalability issues, is the most suitable network technology for the delivery of multiparty content. Context-awareness is taken as a key feature in Next Generation Networks, enabling a management framework with a more comprehensive knowledge of the network, application and user. The challenge is how to use the available knowledge towards service personalization and network efficiency. This paper presents and evaluates an architecture that aims to provide personalized session content delivery to multiple mobile users, integrating different access and transport technologies. The architecture relies on an end-to-end context-aware communication framework able to dynamically react and adapt to context changes, through session and network reconfiguration. Our focus is on the transport network part, addressing a new level of scalable multiparty content delivery through the concepts of abstract multiparty trees and overlay nodes. The results show that the concept of abstract trees reduces the network reconfiguration complexity while still guaranteeing end-to-end QoS.

A Decoupling Approach for Distributed Mobility Management

This paper addresses the problematic of mobility management decomposition, as a first step towards the development of decentralized mobility management architectures. We propose and evaluate an IP mobility management solution based on the decoupling of data and control plane. We have carried out simulations, showing that the proposed approach can significantly reduce packet loss and reachability time for mobile nodes.

Lessons learned from a real vehicular network deployment of delay-tolerant networking

Vehicular networks are inherently unstable networks with high mobility and intermittent connectivity. These networks can greatly benefit from Delay Tolerant Networking (DTN) solutions for opportunistic connectivity in the transmission of delay-tolerant data. In this paper, we evaluate the performance of different DTN routing protocols in real world vehicular networks with different degrees of connectivity in order to understand their feasibility in real vehicular environments. Our case-study application is the upload of delay-tolerant sensing data from vehicular nodes to a server on the Internet. We deploy DTN in 3 vehicular testbeds: a heterogeneous lab testbed with controlled mobility, a low-mobility high-connectivity network of harbor trucks, and a high-mobility low-connectivity city bus network. We compare 3 routing protocols: epidemic, static and PRoPHET, for which we measure delivery ratio, average delay, path length, as well as transmission and storage overhead. We analyze the results for experimental insight, and extract lessons for DTN routing protocol design.

Mobility Estimation in the Context of Distributed Mobility Management

This paper addresses mobility management in the context of user-centri networking, alerting to the need to consider new paradigms to adapt mobility management solutions to future Internet architectures. The paper provides notions concerning distributed mobility management aspects, as well as what is mobility estimation and how it can be applied to current or to future mobility management solutions, based on an existing proof-of-concept.

Centralized, Distributed or Replicated IP Mobility?

This letter studies a network-based IPv6 mobility model based on Proxy Mobile IP, called Multiple Local Mobility Anchors. It replicates the Local Mobility Anchors of Proxy Mobile IP through access routers and gateways of the network. The Local Mobility Anchors maintain the binding between the well-known IPv6 address of the mobile node and its current access router, in order to achieve an optimized routing path to data sessions that require mobility support. Multiple Local Mobility Anchors approach is compared with Proxy Mobile IP and Distributed Mobility Anchoring through analytical models. The outcome demonstrates that it significantly improves the data cost at the expense of a slight increase in the signaling cost.

Context-aware adaptive IP mobility anchoring

The novel distributed mobility management trend is a promising direction to cope with the increasing mobile data traffic and flatten network architectures. Most of the novel mobility approaches distribute the mobility anchors through the access level, as opposed to the centralized mobility anchoring model. Other recent approaches argue that mobility anchors closer to the content servers may be the solution to optimize the mobility performance. However, none of the mobility anchoring models is ideal for all scenarios, since it depends on the user, the session and the network. Hence, we propose an IP mobility approach driven by the context of the user, sessions and the network, where the mobility anchors for IP address allocation and for routing/forwarding are distributed through the network nodes, while the mobility context is managed by the mobile devices. Although each session is properly anchored in the establishment phase, the routing/forwarding is adapted over time, according to the user, the session and the network context: the proposed approach is able to signal different mobility anchors to optimize the routing path to new and ongoing sessions of the user. The outcome of the evaluation shows that the proposed approach overall reduces the data cost, the data delay, the tunneled packets and the tunnel length, when compared with other anchoring models.

Decoupling and distribution of mobility management

Current mobility management approaches deploy heavy centralized models that are not prepared to deal with the requirements of growing mobile environments, leading to suboptimal routing and scalability problems. As a first step towards a decoupled and distributed mobility management architecture, we propose and evaluate different approaches for the distribution of the mobility management functionalities. We initiate our mobility decoupling from the most common split into data and control planes. We go further in splitting the control plane of mobility management into location and handover management. We evaluate the distributed approaches, based on the proposed decoupling, and we compare them with the most adopted fully-centralized approaches. The results of the evaluation demonstrate that the distribution of mobility management functionalities through elements closer to the end-user improve both user and network performance, even in a hierarchical network topology.

Context-aware selection in multicast environments

Personalization and group communications have always been conflicting approaches. From one side, the user wants to get the services with their specific characteristics. From the other side, group communications imply the support of the same service, with the same characteristics, by a group of users. To simultaneously enable personalization and profit from the resources improvements provided by group-based communications, these groups need to be defined based on the users requirements, services and network information, which we denote as “context”. Based on this context for group definition, it is possible to adapt the content to the groups of users or even re-group them according to common features. This paper addresses the network part of the problem: based on the context information, we define an intelligent network selection, both for the access and core, respectively to efficiently choose the attachment points and the multicast trees for groups of users. This selection approach will improve the efficiency of the architecture in delivering the multiparty services. The simulation results of the proposed approach show that performing a wise network selection based on context increases overall network efficiency while still providing a personalized multiparty content delivery.