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Allocation

An explicit context model is especially advantageous to model the allocation of components on hardware and software resources. Figure 2.11 depicts a system that uses replicated components to fullfil requests. In our example, server I is assumed to be slow and server II is assumed to be fast. Hence, the workload is not distributed equally, but 30% of the requests are directed to server I and 70% are directed to server II.

Figure 2.11: Component allocation.
Image Allocation

Here, we see several context influences. We have two copies of the same component allocated on different machines and, thus, in different contexts. The workload of each replicated component is different because of the distribution strategy. The processing power available to both replicated components is varying with the underlying hardware systems. However, both components are connected with an identical logical link going from the required interface of the workload balancer to the provided service of the replicated component. But again, each of these logical connections is most likely using a different physical communication channel, i.e., different network links.


next up previous contents index
Next: An Explicit Context Model Up: Context Influences Previous: Hierarchy - Vertical Composition   Contents   Index
Snowball 2007-03-16