How can we calculate the N/W latency from local machine or External application to Azure cloud

Hi,

In our project we are calling an API that is hosted on Azure (using REST API's).  We are doing some bench marking on the performance. We wanted to know the average Network latency for connecting to the cloud. This will help us in defining the SLA's for request and response. We are able calculate the internal delays or processing time within API logic. Since the SLA can be defined based on both N/W Latency and Internal processing, please guide us on this. 

Meanwhile , we came across the below URL's. Can we consider the values from these sites for calculating Average N/W Latency.

http://www.azurespeed.com/ 

http://azurespeedtest.azurewebsites.net/

Regards,

Prem.