4.3 Architecture in Operation 

The operational description of the architecture will now be given: 

1. The customer approaches the ASP to provide a service that will be delivered via the 

Web. They negotiate an appropriate SLA for performance and availability of the service. 

2. The Service Provider makes the SLA(s) that have been defined with the Customer 

available to the SLAVSP that the customer will use monitor the service. The SLA can be 

made available via HTTP or some other mechanism for the SLAVSP to access it. 

3. The SLAVSP adds the SLA to a list of monitored services for the customer. 

4. The proxy on the client is configured to contact the SLAVSP when it starts up. It 

identifies the customer that is using the proxy to the SLAVSP and is returned a list of 

services to monitor. The DTD to describe the structure of this data is defined in 

Appendix B. 

5. Once the proxy detects that a new service requires monitoring, it automatically retrieves 

the appropriate SLA for that service and configures the proxy to log information for the 

service described in the SLA. The DTD to describe the structure of this SLA data is 

defined in Appendix A. 

6. The proxy will retrieve the list of services from the SLAVSP at a period that is 

configurable. If the proxy cannot contact the SLAVSP, it will attempt to reconnect to the 

SLAVSP at a predefined period.  

7. The proxy then retrieves a SLA for each service that was listed. 

8. The proxy analyses the SLA and is immediately configured to log information related to 

the service. 

9. Periodically the proxy will analyse the data logged for each service and determine if 

SLA compliance is achieved. The frequency and period of service usage that the analysis 

runs for is determined by parameters contained in the SLA. The data is then summarised 

and sent to the SLAVSP via HTTP. 

10. If the analysis determines that a SLA violation occurred, the proxy may notify the ASP. 

The ASP can then retrieve the data that the proxy passed to the SLAVSP and use the 

information to diagnose the service being delivered to the customer.