Asanga Udugama

Managing Heterogeneous Access Networks Coordinated policy based decision engines for mobility management

Underwater sensor networks are typically distributed in nature and the nodes communicate using acoustic waves over a wireless medium. Such networks are characterized by long and variable propagation delays, intermittent connectivity, limited bandwidth and low bit rates. Due to the wireless mode of communication between the sensor nodes, a medium access control (MAC) protocol is required to coordinate access to the shared channel and enable efficient data communication. However, conventional terrestrial wireless network protocols that are based on RF technologies cannot be used underwater. In this paper, we propose PLAN - a MAC Protocol for Long-latency Access Networks that is designed for use in half-duplex underwater acoustic sensor networks. We utilize CDMA as the underlying multiple access technique, due to its resilience to multi-path and Dopplers effects prevalent in underwater environments, coupled with an RTS-CTS handshaking procedure prior to the actual data transmission. Using simulations, we study the performance and efficiency of the proposed MAC protocol in underwater acoustic networks.

NetCAPE: Enabling Seamless IMS Service Delivery across Heterogeneous Mobile Networks

An evolving wireless world is constantly providing users with a wider set of access technologies to choose from, each with different capabilities and properties. In this world, IMS as defined by 3GPP provides an enabling, standardized multimedia architecture that is access independent, hence, providing service convergence. This trend is accompanied by an increasing number of multimode terminals so that inter-access- system-service continuity gains relevance. This article presents the architectural framework of NetCAPE (networking context aware policy environment), which addresses the optimization of mobility management in such a heterogeneous environment while interacting with IMS applications to enable seamless service delivery across heterogeneous mobile networks; even as the mobility offered by the underlying network remains transparent to IMS applications. Although the focus is on 3GPP-based mobile networks, the framework also incorporates wired access technologies, hence, taking a further step toward fixed mobile convergence (FMC). First results are presented highlighting the improvements gained by applying NetCAPE concepts.

An On-demand Multi-Path Interest Forwarding strategy for content retrievals in CCN

Content Centric Networking (CCN) is a new paradigm in networking and a future Internet architecture. Performance evaluations show that conventional CCN forwarding strategies which use replication of Interests (standard) or the shortest path (best-face) do not perform well under high bandwidth requirements and loaded networks. We have designed and evaluated the performance of an On-demand Multi-Path Interest Forwarding (OMP-IF) strategy which identifies a set of paths based on the disjointness of paths to content locations. Then, the discovered paths are used simultaneously to distribute (split) Interests based on the characteristics of the paths. We have evaluated OMP-IF strategy using a simulator with a large scale network scenario and a realistic traffic generation model. The results show improved performance in CCN networks considering download time, load balancing, content hit ratios, and others.

Evaluation of a Network Based Mobility Management Protocol: PMIPv6

The Proxy Mobile IPv6 (PMIPv6) is a network based mobility management protocol standard that was ratified recently by the Network-based Localized Mobility Management (NetLMM) working group of the Internet Engineering Task Force (IETF). PMIPv6 is a protocol that uses the same concepts as used in Mobile IPv6 (MIPv6), but modified to operate in the network part only instead of involving the Mobile Node (MN) as well. PMPv6 is claimed to posses a number of advantages over the host based mobility management protocols in use today, above all MIPv6. The main advantage of using PMIPv6 is the freeing up of the mobile host in doing any mobility related activities and thereby saving its resources. The saving of resources may result in their usage for other purposes or even enable otherwise capabilities restricted devices to operate in the PMIPv6 domains. Other advantages include reduced signaling traffic volume and no tunneled packets in the access network. These aspects become very important since the access networks in mobile networks usually are air interfaces. Further, PMIPv6 is also becoming a very attractive mobility management protocol for mobile network operators as seen by its inclusion in current 3 rd Generation Partnership Project (3GPP) standardization as a possible alternative mobility management protocol for the Long Term Evolution (LTE) technologies. In addition to qualitative analyses and comparisons, the work attempts to quantify these advantages to show the achieved benefits. The quantifications are done through measurements in a real test-bed which is installed with a PMIPv6 implementation developed as part of this work.

Analytical characterisation of multi-path content delivery in Content Centric Networks

Content Centric Networking (CCN) is an evolving paradigm in networking where communications are based on named content rather than the named hosts model of todays networks. Though CCN is capable of multi-path communications by design, no work has been done to characterise multi-path content transfers in CCN with an analytical model. In this work, we have developed an analytical model to evaluate the performance of multi-path content transfers in CCN. The performance of this model is then compared against a packet level CCN simulator built in OPNET. Round trip times, throughput and download times are obtained for both multi-path and single path to make comparisons of performances. The comparisons indicate that the results obtained from the simulator are in agreement with the results of the analytical model.

Realization of multiple access interface management and flow mobility in IPv6

Internet capable mobile or portable devices are already a modern commodity while it is becoming more and more common that such devices are hosts to more than one wireless network interface. The aim of this work is to show from a users perspective how such a portable device may make best use of this property by using multiple wireless and wired network interfaces simultaneously. This would incline that the intelligent control logic can distribute active flows across the available network interfaces and that it is also able to seamlessly transfer them between the network interfaces in mid-session without interruption. Focus of this work is on the inclusion of user preferences in the decision process, recognizing that future telecommunication systems may include also network conditions and operator preferences.

A Novel Data Dissemination Model for Organic Data Flows

The number of computing devices of the IoT are expected to grow exponentially. To address the communication needs of the IoT, research is being done to develop new networking architectures and to extend existing architectures. An area that lacks attention in these efforts is the emphasis on utilisation of omnipresent local data. There are a number of issues (e.g., underutilisation of local resources and dependence on cloud based data) that need to be addressed to exploit the benefits of utilising local data. We present a novel data dissemination model, called the Organic Data Dissemination (ODD) model to utilise the omni-present data around us, where devices deployed with the ODD model are able to operate even without the existence of networking infrastructure. The realisation of the ODD model requires innovations in many different area including the areas of opportunistic communications, naming of information, direct peer-to-peer communications and reinforcement learning. This paper focuses on highlighting the usage of the ODD model in real application scenarios and the details of the architectural components.

Open Connectivity Services for future networks

This presented work gives an overview on the FP7 project — SAIL, that aims at designing architectures for the Future Networks. The conceptual developments in the work package - Open Connectivity Services (OConS) is the focus of this paper. OConS is proposing an open and flexible architecture framework for handling the connectivities in current and future networks. As exemplary studies, we applied OConS architecture framework to two scenarios: (1) the Mult-P transmission of 3GPP LTE connected with WLAN; (2) the extensions of ICN (Information Centric Networks) supporting Multi-P. They show the flexibility and the openness of OConS, and the benefits expected will be e.g. higher data rates, higher resource utilization and more reliable connectivity.

TEACHING THE INTERNET OF THINGS

Teaching the Internet of Things has become vital in engineering, but also very challenging. This is mainly due to the almost unbelievable variety of available systems, hardware and software components, and online resources. This column discusses how we, at the University of Bremen, approached this problem: with hands-on experience and concept abstraction.

Open connectivity services for the future internet

In this paper we present an Open Connectivity Services architecture, which has been conceived such as to cope with the challenges posed by the Future Internet. By relying on currently working solutions and establishing a trustworthy migration strategy, the proposed architecture provides a flexible framework that supports both legacy and enhanced connectivity mechanisms. It is able to dynamically adapt the operation of the involved mechanisms according to the particular requirements of the services and applications. This open architecture is based on three main modules (information gathering, decision taking and decision enforcement) which mimic the basic functionalities of any connectivity mechanism. By having a common way of representing current and future mechanisms, the OConS operation eases the instantiation, launch and interconnection of mechanisms by the specified orchestration procedures. A challenging flash crowd scenario is presented for validation of the architecture, where enhanced connectivity mechanisms support both cloud networking and network of information use cases.