The design of a protocol for collaboration in a distributed repository - Nomad

Abstract

Computer Supported Cooperative Work (CSCW) is the study of how people use technology, with relation to hardware and software, to work together in shared time and space. Mobile office environments are becoming commonplace. Workers form virtual online communities on a global scale and use groupware to collaborate and complete a common goal. We tend to be mobile, yet need to be available to collaborate. This thesis investigates a protocol for our decentralized artifact control system, Nomad. Nomad enables globally dispersed members of small casually connected communities to share artifacts which are gathered on a best effort approach. The Nomad protocol takes into consideration the work habits of users and their variety of devices. The major contribution of this thesis is a simulator of the Nomad protocol, which serves as a proof-of-concept for its design. Specifically, we look at how such a protocol handles casually connected small communities. We consider high level aspects such as setting up the community, the overhead of nodes, availability, scalability and connectivity. We demonstrate scenarios that the protocol will need to handle. Furthermore, we take a broad look at CSCW, push and pull technologies, peer-to-peer technologies, and enabling technologies such as Microsoft .Net. These form the basis of the Nomad design. In addition, we suggest the integration of mobile agents, which we consider a future addition to Nomad. It was found that the protocol had to compensate for two nodes that were never online at the same time. In the case that a best effort approach is not feasible, we propose alternate approaches at the cost of overhead on a propagation node. The developed concept provided valuable insight into the problem domain, outlined the boundaries of the protocol and provided a possible solution for Nomad. The simulator proved to be a useful tool for determining outcomes from possible scenarios. The results from the simulator will feed directly into the development of Nomad.