Making Access Grid Easy

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The growth of the Access Grid videoconferencing system has been relentless. Worldwide, the AGToolkit has been downloaded tens of thousands of times. There are now over 150 large, Access-Grid-enabled conference and meeting rooms in the UK. The uptake of the system could be increased even further by overcoming Access Grid’s lack of easy accessibility. Making Access Grid easy is the aim of the PAG (Portlet Access Grid) project, which is funded by OMII-UK.

PAG is a portlet version of the Access Grid Toolkit (AGTk) client, which allows any web-based machine – even one located in a remote place or behind a restrictive firewall – to become an interface to the Access Grid. PAG overcomes the complicated Access Grid installation process by downloading and installing all of the client-side tools automatically using Java Web Start. The PAG project has also been working to remove the restrictions imposed by network firewalls and bandwidth limitations through the implementation of a TCP/IP bridge and automatic multicast/unicast detection and switching.

PAG had to break out of the ordinary portlet structure to address the challenges imposed by the Access Grid networking and service architecture. The portlet creates the web interface of the PAG Client and a signed Java applet, the VenueClient Controller, is used to communicate between the Portal Server and the PAG client, using asynchronous XML-RPC calls via AJAX. As all the communication is embedded in HTTP, PAG avoids problems with firewalls and proxy servers. This also means that the portal can be installed separately from the AG Server. The PAG model means that a service provider looks after the portal as well as the PAG portlet installation. The only worry left for the user is the meeting itself!

PAG’s benefits:

• An AG client user interface accessible entirely through a portal interface.

• Access to new bridging technology with minimal requirements for ports to be opened through firewalls.

• An improved user experience through the introduction of “client-level bridging”, which also allows for future AG network upgrades.

• An implementation of the current node services provided by the AGTk, including, but not limited to, audio and video services. These services will use the existing node service executables, and employ Java to deliver the executable packages to the client computer.

• An implementation of shared applications currently available within the AGTk, including the Shared Presentation tool and the Shared Browser.

• Access to the AGTk shared data architecture.

A PAG installation will be accessible from Summer 2008.

Martin Turner, PAG

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