4.2.1 A Single ASP and Multiple Services 

The first architecture that is presented is where the customer installs a proxy provided by the 

Application Service Provider on the end users host. The web browser must be configured to 

only use the proxy for requests to the ASP that provided the proxy, either by the use of a 

proxy auto config file

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 or manually configuring the browser to do this. Once the proxy is 

initialised, it retrieves a SLA for the customer from the ASP via HTTP, which configures the 

proxy to monitor specific performance and availability parameters of requests to the service 

provided by the ASP. The proxy may analyse the information gathered locally before 

sending it to the Service Provider over HTTP or may just send all the logged information 

with no analysis being done locally. The Service Provider when processes the data received 

against the customers SLA which it already has and verifies that the service is SLA 

compliant. The Service Provider can then make a report available to the customer on service 

compliance. A block diagram of this architecture is given next showing the interaction 

between the Customer and Service Provider. 

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 A proxy auto config file allows the automatic configuration of HTTP proxies so that optimal use is made of 

network resources. It supports features such automatic redirection to a secondary proxy if a primary one fails, 

load balancing between a number of proxies and the use of specific proxies for certain resources. 

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