A Survey of Routing Techniques for Mobile Collaborative Virtual Environment Applications
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paper_title: Effective replica allocation in ad hoc networks for improving data accessibility

paper_content:

The advances in computer and wireless communication technologies have led to an increasing interest in ad hoc networks which are temporarily constructed by only mobile hosts. In ad hoc networks, since mobile hosts move freely, disconnections occur frequently, and this causes frequent network division. Consequently, data accessibility in ad hoc networks is lower than that in the conventional fixed networks. We propose three replica allocation methods to improve data accessibility by replicating data items on mobile hosts. In these three methods, we take into account the access frequency from mobile hosts to each data item and the status of the network connection. We also show the results of simulation experiments regarding the performance evaluation of our proposed methods.
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paper_title: Analysing movement and world transitions in virtual reality tele-conferencing

paper_content:

In this paper we make use of automatically generated logs of user activity from 6 meetings held using the MASSIVE-1 virtual reality tele-conferencing system to determine a number of characteristics of user movement and world transition. These results are applied to a consideration of four issues for CVE system design and resource requirements: the amount of network bandwidth and computation required to handle movement within worlds; the degree of look-ahead required when moving; whether world transitions by groups of participants could benefit from special handling (e.g. some form of multicast state-transfer); and whether caching of world state would be useful in these contexts. In each case the implications are quantified for the meetings analysed.
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paper_title: MANET: possible applications with PDA in wireless imaging environment

paper_content:

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.
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paper_title: NetEffect: a network architecture for large-scale multi-user virtual worlds

paper_content:

We describe NetEffect, a highly-scalable architecture for developing, supporting and managing large, media-rich, 3D virtual worlds used by several thousand geographically dispersed users using low-end computers (PCs) and modems. NetEffect partitions a whole virtual world into communities, allocates these communities among a set of servers, and migrates clients from one server to another as clients move through the communities. It devotes special attention to minimizing the network traffic, in particular, the traftic that must go through servers. HistoryCity, a virtual world for children, has been developed on NetEffect and is currently being beta-tested for deployment in Singapore.
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paper_title: Analysing movement and world transitions in virtual reality tele-conferencing

paper_content:

In this paper we make use of automatically generated logs of user activity from 6 meetings held using the MASSIVE-1 virtual reality tele-conferencing system to determine a number of characteristics of user movement and world transition. These results are applied to a consideration of four issues for CVE system design and resource requirements: the amount of network bandwidth and computation required to handle movement within worlds; the degree of look-ahead required when moving; whether world transitions by groups of participants could benefit from special handling (e.g. some form of multicast state-transfer); and whether caching of world state would be useful in these contexts. In each case the implications are quantified for the meetings analysed.
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paper_title: A flexible architecture for Virtual Humans in Networked Collaborative Virtual Environments

paper_content:

Complex virtual human representation provides more natural interaction and communication among participants in networked virtual environments, hence it is expected to increase the sense of being together within the same virtual world. We present a flexible framework for the integration of virtual humans in networked collaborative virtual environments. A modular architecture allows flexible representation and control of the virtual humans, whether they are controlled by a physical user using all sorts of tracking and other devices, or by an intelligent control program turning them into autonomous actors. The modularity of the system allows for fairly easy extensions and integration with new techniques making it interesting also as a testbed for various domains from “classic” VR to psychological experiments. We present results in terms of functionalities, example applications and measurements of performance and network traffic with an increasing number of participants in the simulation
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paper_title: BrickNet: A Software Toolkit for Network-Based Virtual Worlds

paper_content:

Network-based virtual worlds allow multiple virtual worlds connected on a network to share information with one another. The development effort required to produce a network-based virtual world is quite large. The BrickNet toolkit simplifies this development by providing the standard facilities required by a wide range of network-based virtual worlds. It provides support for graphical, behavioral and network modeling of virtual worlds in an object-oriented fashion. BrickNet enables graphic objects to be maintained, managed, and used efficiently, and permits objects to be shared by multiple virtual worlds. In this paper, the architecture and implementation of BrickNet are described.
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paper_title: RING: a client-server system for multi-user virtual environments

paper_content:

This paper describes the client-server design, implementation and experimental results for a system that supports real-time visual interaction between a large number of users in a shared 3D virtual environment. The key feature of the system is that server-based visibility algorithms compute potential visual interactions between entities representing users in order to reduce the number of messages required to maintain consistent state among many workstations distributed across a wide-area network. When an entity changes state, update messages are sent only to workstations with entities that can potentially perceive the change—i.e., ones to which the update is visible. Initial experiments show a 40x decrease in the number of messages processed by client workstations during tests with 1024 entities interacting in a large densely occluded virtual environment.
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paper_title: NPSNET:A Network Software Architecture for LargeScale Virtual Environments

paper_content:

This paper explores the issues involved in designing and developing network software architectures for large-scale virtual environments. We present our ideas in the context of NPSNET-IV, the first 3-D virtual environment that incorporates both the IEEE 1278 distributed interactive simulation DIS application protocol and the IP multicast network protocol for multiplayer simulation over the Internet.
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paper_title: SCORE: a scalable communication protocol for large-scale virtual environments

paper_content:

This paper describes and analyzes SCORE, a scalable multicast-based communication protocol for large-scale virtual environments (LSVE) on the Internet. Today, many of these applications have to handle an increasing number of participants and deal with the difficult problem of scalability. We propose an approach at the transport layer, using multiple multicast groups and multiple agents. This approach involves the dynamic partitioning of the virtual environment into spatial areas and the association of these areas with multicast groups. It uses a method based on the theory of planar point processes to determine an appropriate cell size, so that the incoming traffic at the receiver side remains with a given probability below a sufficiently low threshold. We evaluate the performance of our scheme and show that it allows to significantly improve the participants' satisfaction while adding very low overhead.
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paper_title: VON: a scalable peer-to-peer network for virtual environments

paper_content:

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
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paper_title: A Spatial Model of Interaction in Large Virtual Environments

paper_content:

We present a spatial model of group interaction in virtual environments. The model aims to provide flexible and natural support for managing conversations among large groups gathered in virtual space. However, it can also be used to control more general interactions among other kinds of objects inhabiting such spaces. The model defines the key abstractions of object aura, nimbus, focus and adapters to control mutual levels of awareness. Furthermore, these are defined in a sufficiently general way so as to apply to any CSCW system where a spatial metric can be identified - i.e. a way of measuring position and direction. Several examples are discussed, including virtual reality and text conferencing applications. Finally, the paper provides a more formal computational architecture for the spatial model by relating it to the object oriented modelling approach for distributed systems.
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paper_title: Publish-subscribe tree maintenance over a DHT

paper_content:

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.
---
paper_title: NPSNET:A Network Software Architecture for LargeScale Virtual Environments

paper_content:

This paper explores the issues involved in designing and developing network software architectures for large-scale virtual environments. We present our ideas in the context of NPSNET-IV, the first 3-D virtual environment that incorporates both the IEEE 1278 distributed interactive simulation DIS application protocol and the IP multicast network protocol for multiplayer simulation over the Internet.
---
paper_title: SCORE: a scalable communication protocol for large-scale virtual environments

paper_content:

This paper describes and analyzes SCORE, a scalable multicast-based communication protocol for large-scale virtual environments (LSVE) on the Internet. Today, many of these applications have to handle an increasing number of participants and deal with the difficult problem of scalability. We propose an approach at the transport layer, using multiple multicast groups and multiple agents. This approach involves the dynamic partitioning of the virtual environment into spatial areas and the association of these areas with multicast groups. It uses a method based on the theory of planar point processes to determine an appropriate cell size, so that the incoming traffic at the receiver side remains with a given probability below a sufficiently low threshold. We evaluate the performance of our scheme and show that it allows to significantly improve the participants' satisfaction while adding very low overhead.
---
paper_title: VON: a scalable peer-to-peer network for virtual environments

paper_content:

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
---
paper_title: Publish-subscribe tree maintenance over a DHT

paper_content:

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.
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paper_title: Chord: A scalable peer-to-peer lookup service for internet applications

paper_content:

A fundamental problem that confronts peer-to-peer applications is to efficiently locate the node that stores a particular data item. This paper presents Chord, a distributed lookup protocol that addresses this problem. Chord provides support for just one operation: given a key, it maps the key onto a node. Data location can be easily implemented on top of Chord by associating a key with each data item, and storing the key/data item pair at the node to which the key maps. Chord adapts efficiently as nodes join and leave the system, and can answer queries even if the system is continuously changing. Results from theoretical analysis, simulations, and experiments show that Chord is scalable, with communication cost and the state maintained by each node scaling logarithmically with the number of Chord nodes.
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paper_title: Exploiting the Synergy between Peer-to-Peer and Mobile Ad Hoc Networks

paper_content:

We argue that there exists a synergy between peer-to-peer (p2p) overlay networks for the Internet and mobile ad hoc networks (MANETs) connecting mobile nodes communicating with each other via multi-hop wireless links-both share the key characteristics of self-organization and decentralization, and both need to solve the same fundamental problem, that is, how to provide connectivity in a decentralized, dynamic environment. We propose Dynamic P2P Source Routing (DPSR), a new routing protocol for MANETs that exploits the synergy between p2p and MANETs for increased scalability. By integrating Dynamic Source Routing (DSR) and a proximity-aware structured p2p overlay routing protocol, DPSR limits the number of the source routes that each node has to discover and rediscover to O(logN), while retaining all the attributes of DSR for dealing with the specifics of ad hoc networks. This is in contrast to the maximum of N source routes each node has to maintain in DSR. Thus DPSR has the potential to be more scalable than previous routing protocols for MANETs, such as DSR and AODV. ::: ::: In addition to being a network layer multi-hop routing protocol, DPSR simultaneously implements a distributed hash table (DHT) in MANETs; it implements the same functionalities as CAN, Chord, Pastry, and Tapestry, which can be exposed to the applications built on top of it via a set of common p2p APIs.
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paper_title: Performance evaluation of the mobile peer-to-peer service

paper_content:

The utilization of peer-to-peer (P2P) overlay networks on mobile ad hoc networks (MANET) introduces new services and possibilities such as content based routing and location based services (LBS). A simple layering of both networks is inefficient and does not scale well because the virtual P2P overlay network does not match the frequently changing physical network topology of the MANET. The mobile peer-to-peer (MPP) protocol stack offers a very promising concept by introducing a cross-layer communication channel between the physical network layer and the virtual P2P network layer. This reduces significantly the messaging overhead and increases the search success rate, as we can prove in this work. Therefore, we describe an implementation of the MPP protocol stack in the Network Simulator 2 (ns-2). With this implementation, we prove the significant performance improvements which can be achieved with MPP, to allow P2P networking in mobile ad hoc environments.
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paper_title: Towards reliable peer-to-peer data sharing over mobile ad hoc networks

paper_content:

This paper presents a reliable communication method for assuring stable peer-to-peer (P2P) data sharing in mobile ad hoc networks. The method for guaranteeing reliable P2P data sharing mainly tackles the problem of disconnection due to the sudden disappearance of one or more nodes involved in the active transmission route. We propose a communication mechanism which includes two schemes; a configuration scheme and a routing scheme. The configuration scheme discovers mobile devices and automatically constructs a MANET (mobile ad hoc network) using a dynamic IP addressing technique. The routing scheme allows for reliable transmission of data via mobile devices. It does this using our reconnection mechanism that finds emergency routes in instances of abrupt disconnection. We developed a reliable mobile P2P data sharing system with these two schemes. We also performed some experiments for verifying our communication method for stable transmission using our real testbed. The experiments lead us to conclude that our communication method is effective and assures reliable P2P data sharing over mobile ad hoc networks. Our reconnection mechanism affords a good ratio of successful transfers for services requested by users. In addition, our system minimizes the number of relayed transmissions using our scanning table and lookup table. This provides a good transmission performance and reliability, but our system takes a relatively long time for discovery.
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paper_title: From Pastry to CrossROAD: CROSS-layer ring overlay for ad hoc networks

paper_content:

P2P systems for mobile ad hoc networks are currently an open research area. Most of the existent solutions were thought for the wired networks, where thousands of nodes participate to the same service, while ad hoc networks are generally characterized by limited dimensions and scarce resources. In this paper, a performance evaluation of a structured P2P system (Pastry), running on a real ad hoc network, will be presented, and a new optimized solution, called CrossROAD, will be defined. CrossROAD exploits a cross-layer architecture to reduce the communication overhead introduced by Pastry and, at the same time, maintains all the basic principles of structured overlay networks.
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paper_title: Infrastructure for Distributed Applications in Ad Hoc Networks of Small Mobile Wireless Devices

paper_content:

Mobile wireless computing devices such as cellphones, pagers, per- sonal digital assistants, pocket PCs, and tablet computers are all potential plat- forms for participating in small group, wireless, many-to-many distributed appli- cations. The networking technology needed to support such applications is readily available. However, almost all existing middleware infrastructure for distributed applications was designed for central servers and wired connections. The Anhinga Infrastructure described here runs entirely on the wireless mobile devices and so does not require any central server support. The Anhinga Infrastructure provides a message broadcast ad hoc networking protocol and a distributed computing plat- form based on lightweight versions of Java, Jini Network Technology, and tuple spaces.
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paper_title: Research on Mechanism Optimization of ZRP Cache Information Processing in Mobile Ad Hoc Network

paper_content:

In the research area of mobile ad hoc network, ZRP which integrates advantages of proactive routing protocols and on-demand routing protocols has been the crucial research now. In this paper, the principle and the cache mechanism of ZRP are analyzed. In allusion to the problems of late-deletion and early-deletion in ZRP, the optimized A-ZRP which associates the routing information priority with the latest access time is proposed. It improves information store format of cache in the routing table. Finally, the simulation experiment shows that A-ZRP shows advantages to ZRP in terms of the radius of routing zone, routing overhead, delivery fraction and packet delay based on the same transmission load and node movement. In A-ZRP, the processing of path discovery is reduced, the routing overhead is decrease and the performance of the delivery fraction and the packet delay are improved. The routing protocol performance of mobile ad hoc ZRP is improved.
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paper_title: Experimental comparison of routing and middleware solutions for mobile ad hoc networks: legacy vs cross-layer approach

paper_content:

In this paper we present an experimental evaluation of a full ad hoc network architecture with particular attention to routing and middleware layers. In particular we set up a MANET prototype on which we performed a large set of experiments: in a first phase, we analyzed performances of a proactive and a reactive routing protocols in case of low mobility scenarios in small-medium scale ad hoc networks; then we studied the performances of a first prototype of an optimized p2p system for ad hoc networks (CrossROAD), based on a cross-layer interaction with a proactive routing protocol. Our analysis shows that the use of a proactive routing protocol does not negatively influence system performances, furthermore it allows the optimization of a structured p2p system on ad hoc networks, providing a complete and timely updated knowledge of the network topology. In this way, the overlay network is completely self-organizing and correctly manages network partitioning and topology changes.
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paper_title: Information services to support e-learning in ad-hoc networks

paper_content:

Mobile ad-hoc networks are a growing research topic. Much effort has been put into providing a technical basis for such networks. However, up to now, there has been very little work on how to facilitate integrated usage of the resources available in such a network. In this paper, we give an insight into our research on developing concepts to use the services of an ad-hoc net in an integrated, effective, and efficient manner. Our main focus lies on information services supporting e-learning applications.
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paper_title: MASSIVE: An Emulation Environment for Mobile Ad-Hoc Networks

paper_content:

Developing and evaluating protocols and applications for mobile ad-hoc networks requires significant organisational effort when real mobile ad-hoc networks with several mobile terminals are considered. For fine tuning and optimizing ad-hoc protocols, network simulators like the OpNet Modeller, NS2, or GloMoSim are most suitable. However, for the comprehension of the mode of operations of adhoc network mechanisms and their effects on the communication flow of applications a real-time experiment environment is more preferable. In this paper, an emulation environment for mobile ad-hoc networks is presented, which operates within existing local area networks utilizing virtual overlay structures reflecting the characteristics of mobile ad-hoc networks. Routing protocols and applications are able to communicate in real-time over emulated mobile infrastuctures using the unmodified IP protocol stack. The emulator provides an extensible interface for specifying mobility patterns in order to define and to evaluate diverse mobile scenarios. Several ad-hoc specific mobility patterns have been integrated and evaluated.
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paper_title: An Efficient DSDV Routing Protocol for Wireless Mobile Ad Hoc Networks and its Performance Comparison

paper_content:

One of the popular wireless network architectures is mobile ad hoc network (MANET) which can be deployed easily in almost any environment, without any underlying backbone and infrastructure support. In this paper, an efficient DSDV (Eff-DSDV) protocol is proposed for ad hoc networks. Eff-DSDV overcomes the problem of stale routes, and thereby improves the performance of regular DSDV. The proposed protocol has been implemented in the NCTUns Simulator and performance comparison has been made with regular DSDV and DSR protocols. The performance metrics considered are packet-delivery ratio, end-end delay, dropped packets, routing overhead, route length. It has been found after analysis that the performance of Eff-DSDV is superior to regular DSDV and sometimes better than DSR in certain cases.
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paper_title: P2P multimedia sharing over MANET

paper_content:

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.
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paper_title: A peer-to-peer approach to vehicular communication for the support of traffic safety applications

paper_content:

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.
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paper_title: VON: a scalable peer-to-peer network for virtual environments

paper_content:

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
---
paper_title: MANET: possible applications with PDA in wireless imaging environment

paper_content:

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.
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paper_title: Evaluation of ad-hoc routing protocols under a peer-to-peer application

paper_content:

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.
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paper_title: Publish-subscribe tree maintenance over a DHT

paper_content:

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.
---
paper_title: Performance evaluation of the mobile peer-to-peer service

paper_content:

The utilization of peer-to-peer (P2P) overlay networks on mobile ad hoc networks (MANET) introduces new services and possibilities such as content based routing and location based services (LBS). A simple layering of both networks is inefficient and does not scale well because the virtual P2P overlay network does not match the frequently changing physical network topology of the MANET. The mobile peer-to-peer (MPP) protocol stack offers a very promising concept by introducing a cross-layer communication channel between the physical network layer and the virtual P2P network layer. This reduces significantly the messaging overhead and increases the search success rate, as we can prove in this work. Therefore, we describe an implementation of the MPP protocol stack in the Network Simulator 2 (ns-2). With this implementation, we prove the significant performance improvements which can be achieved with MPP, to allow P2P networking in mobile ad hoc environments.
---
paper_title: Supporting mobile devices in Gnutella file sharing network with mobile agents

paper_content:

The use of peer to peer file sharing networks such as Gnutella is proliferating on the Internet, but its use is bandwidth consuming due to the broadcast nature of some peer to peer protocols. This is undesirable for mobile devices due to their bandwidth and power constraints. This paper proposes an architecture that uses mobile agents to participate in the Gnutella network on behalf of mobile devices in order to reduce the amount of traffic for the mobile device, as well as providing support for device mobility. Using real Gnutella traffic characteristics, analysis on the viability of the architecture is presented.
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paper_title: A cross-layer optimization of gnutella for mobile ad hoc networks

paper_content:

In recent years, the Internet has witnessed the introduction of many peer-to-peer systems designed to realize large-scale data sharing. These platforms exhibit interesting features like self-configuration, self-healing and complete decentralization, which make them appealing for employment in ad hoc environments as well. However, the impact of ad hoc dynamics on the performance of these protocols, and the different set of constraints which this emerging networking paradigm imposes, haven't been yet carefully evaluated. This paper investigates the performance of Gnutella, one of the most widely used peer-to-peer systems, when put through typical ad hoc conditions like node mobility, frequent network partitioning, etc.. We show that a straightforward implementation of the protocol is not satisfactory under the point of view of the produced overhead and the average overlay connectivity. Finally, we propose a cross-layer optimization of Gnutella, which enhances its performance up to the expectations and makes it more suitable to the degree of self-organization and self-healing required in ad hoc environments.
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paper_title: An integrated approach for P2P file sharing on multi-hop wireless networks

paper_content:

P2P file sharing protocol and ad hoc wireless routing protocol share many intriguing similarities even though they are motivated on totally different basis. The goal of P2P file sharing system such as KaZaa is to locate a set of servers that contain a given file and disseminate it efficiently. The key problem of an ad hoc network routing protocol is to determine which route to take to reach a given remote host. P2P file sharing application on mobile ad hoc network (MANET) has gained more momentum as shown in the research of recent years. One natural way is to implement P2P application and ad hoc routing at different layers they belong to. In this paper, we argue that instead of stacking one on the top of the other, more work needs to be done to make both P2P file sharing protocol and MANET routing protocol interact with each other. We extract the commonalities of these two and design a common query/response framework on which ad hoc network routing and P2P file sharing are integrated seamlessly. The extensive experiments show that our strategy performs better than the layered approach in terms of traffic, average delay and packet delivery ratio.
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paper_title: A Performance Evaluation of an Optimized Caching Protocol for the Mobile Gnutella based Network to Support Distributed Collaborative Virtual Environments

paper_content:

A novel caching protocol for the mobile Gnutella based network is presented and evaluated in this paper. The caching mechanism is combined with a Gnutella Ultrapeer System (GUS) to better meet the mobility requirement of collaborative virtual environments (CVEs). The contributions of this work are twofold: a) an efficient overlay formation mechanism for mobile nodes participating in a CVE; b) an optimized PONG caching technique implemented in selected nodes to control PING/PONG messages.
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paper_title: An Enhanced Gnutella for Ad-Hoc Networks

paper_content:

In recent years, Internet has witnessed the introduction of many peer-to-peer systems designed to implement large scale resource sharing. These systems exhibit interesting features like self configuration, self-healing and complete decentralization, which make the systems appealing for deployment in ad hoc environments as well. This paper enhances Gnutella with peer-node hierarchy to achieve better performance with less overhead in the ad hoc network. The proposed system introduces ultrapeer selection scheme based on the metric values and a proactive communication mechanism among ultrapeers. According to the simulation results, the proposed system gives better performance than Gnutella in terms of query success rate, query response time, and overhead.
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paper_title: Proem: a middleware platform for mobile peer-to-peer computing

paper_content:

The combination of personal mobile devices and mobile ad-hoc networks enables the creation of mobile peer-to-peer systems in which mobile peers establish peering relationships over wireless links based on proximity. In this paper, we discuss challenges of mobile peer-to-peer middleware and present the Proem mobile peer-to-peer platform.
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paper_title: A JXTA compliant framework for mobile handheld devices in ad-hoc networks

paper_content:

The availability of powerful personal computers and high bandwidth home connectivity is changing the way users cooperate and exchange information on the network. Peer to peer computing is becoming a common paradigm for many distributed applications, allowing for extensive resource sharing and direct communication among peers. Recently, the wide spreading of new wireless communication technologies and personal computing devices, enables the adoption of the P2P paradigm also in mobile environments. However, several questions arise when trying to develop such systems: existing solutions do not address all the requirements of these environments. In this paper we present a framework to develop mobile applications which exploits the P2P paradigm: it is designed to work on J2ME enabled mobile devices, interacting with each other in an ad-hoc fashion. The designed framework is also interoperable with JXTA, a well-known P2P open platform.
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paper_title: Plug-and-play application platform: towards mobile peer-to-peer

paper_content:

While peer-to-peer (P2P) has emerged as a new hot communication concept among the Internet users, mobile usage of P2P applications is still taking its first steps. This article first elaborates the evolutionary process that P2P architectures are going through. Challenges and requirements for mobile P2P are then identified, followed by a definition of a novel Plug-and-Play Application Platform (PnPAP). This platform enables dynamic selections between diverse P2P and session management protocols while preserving the best available network connectivity through Holistic Connectivity (HCon) management. On-the-fly reconfiguration and run-time parameter optimization can be done with a lightweight interpretable state machine. The concept enables flexible and seamless communications for mobile devices in P2P networks.
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paper_title: Fast Forwarding for Content-Based Networking

paper_content:

This paper presents an algorithm for content-based forwarding, an essential function in content-based networking. Unlike in traditional address-based unicast or multicast networks, where messages are given explicit destination addresses, the movement of messages through a content-based network is driven by predicates applied to the content of the messages. Forwarding in such a network amounts to evaluating the predicates stored in a router’s forwarding table in order to decide to which neighbor routers the message should be sent. We are interested in nding a forwarding algorithm that can make this decision as quickly as possible in situations where there are large numbers of predicates and high volumes of messages. We present such an algorithm and give the results of studies evaluating its performance.
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paper_title: Information services to support e-learning in ad-hoc networks

paper_content:

Mobile ad-hoc networks are a growing research topic. Much effort has been put into providing a technical basis for such networks. However, up to now, there has been very little work on how to facilitate integrated usage of the resources available in such a network. In this paper, we give an insight into our research on developing concepts to use the services of an ad-hoc net in an integrated, effective, and efficient manner. Our main focus lies on information services supporting e-learning applications.
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paper_title: SCORE: a scalable communication protocol for large-scale virtual environments

paper_content:

This paper describes and analyzes SCORE, a scalable multicast-based communication protocol for large-scale virtual environments (LSVE) on the Internet. Today, many of these applications have to handle an increasing number of participants and deal with the difficult problem of scalability. We propose an approach at the transport layer, using multiple multicast groups and multiple agents. This approach involves the dynamic partitioning of the virtual environment into spatial areas and the association of these areas with multicast groups. It uses a method based on the theory of planar point processes to determine an appropriate cell size, so that the incoming traffic at the receiver side remains with a given probability below a sufficiently low threshold. We evaluate the performance of our scheme and show that it allows to significantly improve the participants' satisfaction while adding very low overhead.
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Title: A Survey of Routing Techniques for Mobile Collaborative Virtual Environment Applications

Section 1: Introduction
Description 1: Provide an overview of mobile collaborative virtual environments (MCVEs), their applications, challenges, and the significance of routing techniques.

Section 2: Backgrounds and Related Works
Description 2: Highlight influential works related to virtual environment systems from the past 40 years and classify various desktop CVE systems.

Section 3: Client-Server-based CVE
Description 3: Discuss the main CVE systems that utilize client-server and multi-server architectures, including notable examples and their features.

Section 4: Peer-to-peer Network based CVEs
Description 4: Explore peer-to-peer CVE systems, describing their architecture, key features, and prominent examples.

Section 5: Distinctive Classifications of MCVEs
Description 5: Present a novel classification of MCVE systems based on network overlay topology, routing techniques, and types of experimental results.

Section 6: Structured Overlay Network
Description 6: Discuss structured overlay networks and their routing techniques in the context of MANETs, including relevant applications.

Section 7: Reactive Routing Scheme
Description 7: Describe various approaches employing reactive routing schemes for MANETs and their performance evaluations.

Section 8: Proactive Routing Scheme
Description 8: Explain proactive ad-hoc routing protocols and their implementations in MCVE applications.

Section 9: One Hop Routing Scheme
Description 9: Outline face-to-face collaboration systems that utilize one-hop routing schemes for improved performance.

Section 10: Discussion
Description 10: Critique the performance and applicability of various structured overlay networks over MANETs for different applications.

Section 11: Unstructured Overlay Network
Description 11: Detail unstructured overlay networks and their classifications, including centralized, decentralized, and hybrid network overlays.

Section 12: Centralized Network Overlay
Description 12: Present centralized network overlay architectures and examples of mobile file-sharing applications.

Section 13: Decentralized Network Overlay
Description 13: Discuss decentralized network overlay architectures, improvements in protocols, and relevant case studies.

Section 14: Hybrid Network Overlay
Description 14: Explain hybrid network overlay architectures, featuring a combination of centralized and decentralized schemes and their applications.

Section 15: Other Unclassified Approaches
Description 15: Describe additional schemes and protocols aimed at enhancing system performance and addressing specific challenges in MCVE applications.

Section 16: Conclusions
Description 16: Summarize the survey, outlining the key classifications and challenges in MCVE applications, and emphasize the importance of routing techniques.