WShare: An Instant Virtual Workspace

over Wireless LAN

Faculty: Tzi-cker Chiueh

Group Members:

WShare is a novel file and application sharing system that enables a group of mobile stations without any initial security association and infrastructure support to share files and application content instantly with minimal human intervention. WShare is useful for a group of users, with 802.11 NIC-equipped laptops, who gather at a common place, such as a conference room, to have a face-to-face meeting, and need to exchange files as well as run some collaborative applications.  Instead of relying on Access Point infrastructure that might be absent or heavily-loaded, WShare automatically builds a peer-to-peer network among the mobile stations. Furthermore, WShare secures the network using a shared key that is chosen on the spot by the participants. The key is used to authenticate every member of the dynamic group, encrypt all communication, as well as verify the validity of all exchanged packets. After authentication WShare further builds up higher level networked workspace among the participants without requiring any extra inputs from the users.  The components of the virtual working space are the following -

Shared File Repository

WShare creates a transparent shared file repository to allow secure exchange of files with single drag and drop operations. Users can add or delete files from this shared file space. At any point in time, the set of files currently in the shared file space are accessible to all participating users.  Files in the shared file space are not maintained on any centralized file server, but are fully replicated on all the nodes. Moreover, upon joining the group, a new wireless node can immediately access the existing files in the repository.

OLE automation based Application Sharing

As an example of collaborative applications through relaying of UI events, the prototype currently includes a PowerPoint slide synchronizer that allows multiple PowerPoint instances on the participating laptops to display the same PowerPoint file in a synchronized fashion. WShare supports fine-grained synchronization for PowerPoint presentation at the level of individual animation steps. The slide synchronizer is based on a general OLE Automation framework, and can be easily extended to synchronize other Microsoft Office applications such as Word or Excel, or other OLE-compatible applications.

VNC-based Generic Application User-Interface Sharing

For applications that do not provide any event/control mechanism, WShare also provides a shared display mechanism in form of a broadcast-based VNC (Virtual network computing) server/viewer. This allows the group to share a specific application window among its members, and thus gives a default mechanism for any generic application sharing at user-interface level.

A prototype of WShare has already been implemented, and tested for a small number of nodes. We are in the process of deploying the system in real classroom and conference room settings. Below is a picture of a WShare used in a meeting.
 

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Last modified: 11/08/04