4.3.1 Additions and Modifications to Services Monitored 

The ability to make modifications to the Services that are monitored for a Customer operates 

as follows: 

1. Each time the list of services it retrieved by the proxy from the SLAVSP, it checks for 

any modification since the last retrieval. 

2. If the proxy detects a new service identified, which uniquely identified the Service to the 

Customer, a SLA for that Service is retrieved from the SLAVSP. The service list will 

contain the necessary information that allows the correct SLA to be retrieved. 

3. If the proxy detects that an update to the SLA for a Service has occurred, a new SLA for 

that service is retrieved from the SLAVSP. This is possible as each version of the SLA 

for a particular service has a unique contract identifier. 

4. If the contract identifier returned in the list of service is set to  1 for a particular service 

identifier, the service is no longer monitored. 

This architecture overcomes the inflexibility that the first architecture was prone to. What 

has been highlighted in the previous section is that a common method to describe Service 

performance and availability as perceived by the end user is necessary. Considering that the 

SLAVSP may be required to monitor multiple Services delivered by multiple ASPs for 

multiple Customers, a generic way to describe Services is of the utmost importance. 

4.4 Client Side Proxy Design and Operation 

Having now defined a flexible architecture that can support monitoring of Web delivered 

services, the design of the client side proxy that will capture the necessary data is described 

in the following section including the process of how information on a request and its 

response is captured.