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MANET technology can complement other network technologies when integrated with them. This integration reduces communication and deployment costs and provides additional services for MANET. The integration of heterogeneous networks unavoidably raises significant issues. Gateways are employed to overcome the incompatibilities between different communication architectures. This paper proposes a system based on optimised link state routing (OLSR) to integrate a MANET with the wider Internet. The proposed system solves the micro-mobility issue by eliminating the process of mobile node registration with a specific gateway. Hence, no independent gateway discovery procedure is required. Instead, the proposed system optimises an OLSR routing mechanism to disseminate gateway information. The proposed system is evaluated using a network simulator to investigate its behaviour under different network settings.

In this paper we investigate the behaviour of Opportunistic Native Multicast under node churn. Previously, we have introduced an Opportunistic Native Multicast approach that facilitates native multicast where possible and which reverts to using overlay multicast when needed. Here, we are evaluating Overlay Native Multicast in a more realistic environment considering the effect of network churn and propose election algorithms to offer resilience and adaptivity required in the real world. We have developed a mechanism where the network can autonomously and deterministically elect a primary node for each multicast island. We have further investigated ways to improve the efficiency and responsiveness of the protocol by introducing a secondary node selection process. We have tested our proposed improvements using Oversim simulation. We show that Opportunistic Native Multicast can achieve success rates well above 90 percent despite realistic levels of node churn.

In order to achieve one-to-many data delivery on the internet, native multicast is used and implemented in some parts of the Internet. On the other hand, application layer multicast (ALM), which uses P2P overlays (overlay multicast, OM), can be used to create multicast trees and deliver the data at the application layer. Despite Native Multicast being more efficient than Application Layer Multicast, it is not deployed widely. A hybrid multicast protocol has been proposed that opportunistically combines overlay multicast protocols and native multicast protocols to create and maintain hybrid multicast trees. The design for hybrid multicast trees leverages the AMT multicast tunneling protocol. It is expected that this hybrid approach will improve both efficiency and availability of multicast. This paper presents a simulation model for the Oversim/Omnet++ simulation framework to evaluate the performance of the hybrid multicast approach. Our model combines both a scalable overlay and a detailed network layer model that includes routers with native multicast support.

With smartphones and other network enabled consumer devices becoming increasingly popular, the number of available services and their complexity is growing considerably. With an increasingly large and dynamic environment it is important that users have a comprehensive yet efficient mechanism to discover these services. Many existing wide-area service discovery mechanisms are centralised and do not scale to large amounts of users. Peer-to-peer networks however have been prove to scale well, and can be used to provide not just a platform on which peers can offer and use services without relying on a centralised resource, but also as a means of service discovery. There are various wide-area peer-to-peer service discovery mechanisms that allow discovery of services via their attributes, however the majority are limited to keyword matching and do not support other types of complex queries. This chapter starts with a review of complex queries and existing approaches which provide support for such queries. We illustrate the use of blind search in Distributed Hash Tables (DHTs) to provide support for all types of complex queries, such as wild-card search, range queries, and even regular expressions. Using blind search allows for processing the search query at every node within the network, supporting queries as complex as required. However due to the nature of broadcast trees search performance suffers under high churn levels; to combat this we note that data is already replicated within the network for redundancy. This can be further used to improve the success rate of blind search when under high churn. Finally, we present novel results considering churn level vs replication of data.

Native multicast deployment is relatively slow and linked with a number of issues. However, there are a number of native multicast regions. Application Layer Multicast (ALM) can be used in areas of the network where there is no native multicast available. The SAM (Scalable Adaptive Multicast) Research group within the IRTF is investigating hybrid approaches to multicast, involving native deployments were available and ALM in other regions. SAM is using a P2P overlay to connect the nodes. Here we describe a protocol and API extensions to RELOAD for constructing Scalable Adaptive Multicast (SAM) sessions using hybrid combinations of ALM, native multicast, and multicast tunnels. The Automatic Multicast Tunneling (AMT) relay and gateway elements are employed for interoperation between native regions and ALM regions.

The development of hybrid multicast simulation models is required for analyzing proposed hybrid multicast architectures such as those from the IRTF Scalable Adaptive Multicastw Research Group. However most network layer simulators don't scale to the number of nodes needed for analyzing large overlays, and most overlay simulators don't have multicast routing models needed for analyzing hybrid approaches. In this work we have extended the OverSim simulator and INET framework which run on OMNET++ to include a multi-destination multicast routing protocol (XCAST). This paper describes our implementation experience.

The feature or service interaction problem within home networks is an established topic for the FI community. Interactions between home appliances, services and their environment have been reported previously. Indeed earlier work by the authors introduced a device centric approach which detects undesirable behaviour between appliances and their effects on the environment. However this previous work did not address side-effects between components of the modelled environment. That is some appliances do not only affect the environment through their main function, but may do so also in other ways. For instance, an air conditioner cools the air as its main function, but also decreases the humidity as a side-effect. Here we extend our earlier approach to handle such side effects effectively and discuss previously unreported results.

Technology-mediated home care is attractive for older people living at home and also for their carers. It provides the information necessary to give confidence and assurance to everyone interested in the wellbeing of the older person. From a care delivery perspective, however, widespread deployment of home care technologies presents system developers with a set of challenges. These challenges arise from the issues associated with scaling from individual installations to providing a community-wide service, particularly when each installation is to be fitted to the particular but changing needs of the residents, their in-home carers and the larger healthcare community. This paper presents a home care software architecture and services that seek to address these challenges. The approach aims to generate the information needed in a timely and appropriate form to inform older residents and their carers about changing life style that may indicate a loss of well-being. It unites sensor-based services, home care policy management, resource discovery, multimodal interaction and dynamic configuration services. In this way, the approach offers the integration of a variety of home care services with adaptation to the context of use.