Friday, August 26, 2011

A Spontaneous Ad-hoc network to Share WWW Access (Raquel Lacuesta et al.)

This is a summary of the research paper A Spontaneous Ad-hoc network to Share WWW Access, done by Raquel Lacuesta et al. I chose this paper to present in my MSc course module, Mobile Computing.

In this paper, authors have proposed a secure spontaneous ad-hoc network, based on direct p2p interaction, in order to achieve a easy, quick and secure WWW access to the users. According to them, they are the first group of researches to come up with a design and a simulation of spontaneous ad-hoc networks.

Their paper is structured as follows
  1. An introduction to spontaneous ad-hoc networks and relevant literature
  2. The model they have proposed.
  3. Auto configuration procedures used in their model.
  4. A mathematical analysis.
  5. Security related things.
  6. The protocol procedure and messages
  7. Comparison of the proposal with some caching techniques
  8. Validation of the model through simulation
  9. Summary of the work and conclusion

Introduction

A mobile ad-hoc network can be briefly defined as a group of wireless nodes collaboratively form a network, which operates without the support of a fixed infrastructure. Several applications of such networks are; data collection in sensor arrays, communication in hostile or disaster stricken environments. Main challenges present in ad-hoc networking are that those should operate independent of an access point infrastructure, where nodes are unreliable and unpredictable. Also, the network should be able to provide administrative services need to support applications despite the fact that it operate independent of a pre-configured or centralized network management infrastructure. This is different from an infrastuctured networks, where those services like address allocation, name assignment are handled by a central authority of global scale. Name resolutions, file system management, mail and web services are centrally administered. Many general applications are server-based and hence preconfigured by human administrators and network tools. But in ad-hoc networks those services cannot be centralized and preconfigured because the network population and topology is not known in advance and also unpredictability of the network causes configuration needed to be changed rapidly.

A spontaneous ad hoc network is a type of ad-hoc network which is formed in a certain time during a period of time, with no dependence on a central server and without the intervention of expert users in order to carry out a specific task. The network is built by several independent nodes and the nodes are free to enter the network as well as leave the network whenever required. An example for a spontaneous network is when a group of people get together and use wireless computing devices for some computer based collaborative task. In spontaneous networks, users do not need to identify all the participating human and devices or don't need to configure their devices in advance.

Main features of ad-hoc networks can be described as follows.
  1. Network boundaries are poorly defined
  2. The network is not planned
  3. Hosts are not preconfigured
  4. No any central servers
  5. Users are not experts
Another important thing about spontaneous networks are that the participating nodes are limited in resources and power. Caching techniques have used in this model in order to avoid the nodes being overloaded.


Spontaneous Network Proposal Description

When a device joins a network following steps must be followed
  • Device should be integrated into the network
  • Service and Resource discovery
  • Accessing the services discovered
  • Collaborative tasks
A quick creation and configuration is very important for the performance of spontaneous networks, in the model described here authors have followed a way which requires minimum human intervention when setting up the network.