A Survey of Routing Techniques for Mobile Collaborative Virtual Environment Applications <s> Discussion <s> Wireless communication systems are becoming the new enabling technology for accessing, sharing and processing data. It is easy to foresee that in the near future users will access the Internet through wireless PDA, while roaming from one place to another. Mobile ad-hoc networks (MANET) are peer-to-peer wireless networks that do not rely on the presence of a wired interconnection infrastructure. Apart from more traditional applications in the military field as well as in disaster recovery and emergency situations, MANET may represent an interesting possibility for personal communications and interaction among mobile users. We identify some possible fields of application for such wireless systems, identifying advantages and drawbacks. We also present a prototype application where MANETs are used in order to provide a distributed image processing service. <s> BIB001 </s> A Survey of Routing Techniques for Mobile Collaborative Virtual Environment Applications <s> Discussion <s> More than half a million casualties are due to traffic accidents each year. Therefore, there is a high demand for innovative technologies focused on collision warning and collision avoidance. Among such technologies, the inter-vehicle communication and the vehicle-to-road communication are considered to have extensive potential for supporting the safety systems located within a vehicle. In this paper we propose a new approach to vehicular communication. We designed a safety-oriented vehicular communication, built around the concept of mobile ad-hoc peer-to-peer (P2P) networking. The merging between ad-hoc connectivity and P2P paradigm facilitates the development of a vehicular network characterized by self-organization, fault-tolerance, scalability, shareable resources and services, cooperation, cases of interconnection and cost efficiency. These characteristics recommend the communication proposed here as an efficient method for providing safety-relevant data for safety systems installed in vehicles. <s> BIB002 </s> A Survey of Routing Techniques for Mobile Collaborative Virtual Environment Applications <s> Discussion <s> Mobile ad hoc networks (MANETs) and peer-to-peer (P2P) applications are emerging technologies based on the same paradigm: the peer-to-peer paradigm. Motivated, respectively, by the necessity of executing applications in environments with no previous infra-structure and the demand for applications that share, in a satisfying manner, files through the Internet, MANETs and P2P applications have brought onto themselves some interest from the community. As a characteristic of the distributed model which they follow, such technologies face a difficult task of routing requests in a decentralized environment. In this paper, we conducted a detailed study of a Gnutella-like application running over a mobile ad-hoc network where three different protocols were considered. The results show that each of the protocols analyzed performed well in some scenarios for some metrics yet had drawbacks in others. <s> BIB003 </s> A Survey of Routing Techniques for Mobile Collaborative Virtual Environment Applications <s> Discussion <s> Content-based publish-subscribe middleware is emerging as a promising answer to the demands of modern highly dynamic distributed computing by providing the necessary decoupling and flexibility. The majority of currently available systems implement event dispatching on top of an overlay network with a tree topology. However, they fail to provide any mechanism to maintain it in the presence of failures, thus hampering their applicability in dynamic scenarios. In this paper, we present a novel approach to reconfiguring the overlay topology by exploiting a distributed hash table. Our algorithm supports arbitrary tree topologies and deals very well with the dynamicity of network scenarios by limiting the impact of reconfigurations induced by topology changes. These results are confirmed by simulations, which validate the applicability of our approach in reconfigurable publish-subscribe middleware. Beyond publish-subscribe, the algorithm is applicable in a wide range of contexts and provides a general way to maintain an overlay network with a controlled topology in dynamic environments. <s> BIB004 </s> A Survey of Routing Techniques for Mobile Collaborative Virtual Environment Applications <s> Discussion <s> The scalability of large-scale networked virtual environments (NVEs) such as today's massively multiplayer online games (MMOGs) faces inherent limits imposed by client-server architectures. We identify an emerging research direction that applies peer-to-peer (P2P) networks in order to realize more scalable and affordable NVEs. The central issue for P2P-based NVE (P2P-NVE) systems is to correctly and efficiently maintain the topology of all participating peers by solving the neighbor discovery problem. We also propose the Voronoi-based overlay network (VON), a simple and efficient design that maintains the P2P topology in a fully-distributed, low-latency, and message-efficient manner. Simulation results show that by bounding the per-node resource consumption, VON can be fundamentally more scalable than existing methods while achieving high topology consistency and reliability <s> BIB005 </s> A Survey of Routing Techniques for Mobile Collaborative Virtual Environment Applications <s> Discussion <s> With the rapid development of Mobile Ad-hoc Networks (MANET) and Peer-to-Peer (P2P) computing, it is envisioned that building P2P multimedia sharing system over MANETs is promising. In this paper, we propose a geographic-information based distributed index structure, Geographically Hierarchical Index (GHI), based on which, we could design improved p2p algorithms especially for the multimedia sharing over MANET. <s> BIB006
There are some other studies about using structured overlay networks over MANETs using different class of routing, like geographical routing as proposed in BIB006 . The protocol design is based on Geographical Hierarchical Index (GHI) over CAN. Efforts are often made for mobile file sharing applications, which represent a target for MCVEs. For the purpose of determining their performance, the structured overlay network is undesirable for mobile ad-hoc networks because node mobility will hamper their routing efficiency, especially when dealing with application that require a user to participate in a battlefield situation or emergency preparedness scenario after an earthquake. The most common problem of the structured network is that it does not address the area of interest BIB005 . Also DHT BIB004 may suffer more overheads in the maintenance process; an unstructured network may therefore perform better. Apart the approaches mentioned above there are many other relevant mobile applications, such as PDA access to video stream, remote processing, remote controllers BIB001 , inter-vehicle communication, and vehicle-to-road communication BIB002 that have been reported in the literature. All in all, while most of the existing proposed mobile systems in the literature are greatly beneficial (and applicable) in the research academic and commercial sectors, they falter suffer from being limited to specific tasks, and their architectures are typically tightly coupled to the characteristics of their networks, and any extension or modification to adopt a new class of application is almost impossible. In some discussed solution authors state different opinions about the performance when combine peer-to-peer and MANETs. Barbosa et al BIB003 describe an interesting evaluation of ad-hoc routing protocols under Gnutella peer-to-peer network. Their simulation concludes that none of the ad-hoc routing protocols performed well under all circumstances in Gnutella network.