This report is the response to a request by the Committee on Space Research of the International Council for Science to prepare a roadmap on observation and integrated Earth-system science for the coming ten years.
The response of a DASMI server to an interaction request is a DASINT XML document (Fig. 3b).
The table is designed to include the method of the request (for example, GET or POST), number of bytes returned in the request, status that indicates the action taken in response of a request, protocol version used by the browser during a request, and time spent on the web access.
A document is requested again if the response of the current request is not served before a defined timeout.
When V2 receives the response of this request, it will forward the response to V1 directly.
V1 sends a request to V2, but V2 has received the response of the same request from V3.
Although prefetching reduces the response time of a requested document, it also increases the network load, as some documents will be unnecessarily prefetched (due to the imprecision in the prediction algorithm).
Moreover, a closed-form formula for calculating the average response time of a request and a unified framework to manage different levels of SLAs are provided.
In this study, we analyze the confluence of the two effects through a tractable mathematical model that enables us to establish the conditions under which prefetching reduces the average response time of a requested document.
At the same meeting, President Obama also approved the start of the airdrops in response to a request from the Iraqi government.
