Research On WebService Based Grid And An Improved Policy Of Resource State Update

Grid is a new techonogy that build on World Wide Web, it is being a newgeneration of network infrastructure. Research on Grid is becoming a new hotresearch area in the world. The goal of the Grid is to intergrate the resources in thenetwork effectively, to realize the dynamic resources sharing across organization andarea. So it's an important task for the Grid to manage the resources in the Grid. Thereare numerous resources in the Grid and the resources are dynamic, that is the state ofthe resources are changed momentarily. To use the resources effectively , the Gridresouce management system must update the state information of resourcesperiodically. The numerous state information produced by the changed state ofresources will increase the burden of the network. Some policies are taken to avoidthis, as decrease the update frequence and update when the state is changed. Thepolicy of decrease the update frequence can reduce the messages transferred in thenet by reducing the times of update. But if the update frequence is too low , theresource state information that managed by the Grid Resource Management Systemdisgree wiht the real resource state. Then the user will not use the resourceeffectively.The policy of update with data changing meant that the resource willnotify the information center when the state value is changed. There are numerousresources that change at any moment and the notifications will be flooding. In fact, ifthe changed state value doesn't affect the user who use the resource correctly, theresource need not to send out notification even its state is changed. When the changedstate exceed the range of the specificied data, the resource will send out thenotification. That is the difference with the policy of update with data changing. Wecall this policy as improved policy of resource state update. This work isdemonstrated by simulation experiment. Finally we implement the policy with OGSIspecification.