For the service mappings that were defined previously, parameter values were assigned. For 

example, 

Read Mail

 had the following performance values specified: 

Parameter 

Value 

Function 

HEADER RESPONSE TIME 

2000 

MAX 

ENTITY DOWNLOAD RATE 

2 

MIN 

Table 11: Parameters Assigned for Read Mail Service Mapping 

This states that the header response time for a request to the 

Read Mail

 service function 

should be a maximum of 2000 and entity download rate of the message body greater that 2.  

It is worth observing that these assigned parameters are appropriate for the 

Read Mail

service function but may not be appropriate for other service functions. For example, 

assigning HEADER RESPONSE TIME to the 

Send Mail

 service function may not really 

provide any useful information. This is because if the request has a large amount of data to 

transfer it will impact the time that the full request is received by the server which will in 

turn impact the time that the reply is returned to the client. However it is possible to define a 

new derived parameter that could be used for service functions that use the POST method. 

For example, it could be possible to define HEADER RESPONSE TIME AFTER 

REQUEST BODY which measures the time from when a request body stream ends and the 

time the reply header returns. Again this highlights the flexibility of the framework in that 

new derived parameters can be defined from the base parameters when needed. The list of 

base parameters is defined in Appendix F for reference. 

For the Yahoo Mail case study, the required availability and performance parameters were 

defined as follows:  

Minimum Service Availability Percentage Required  

98% 

Minimum Service Performance Percentage Required 

95% 

Table 12: Table of Required Availability and Performance for Case Study 

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