If the public bandwidth that you use for an Elastic Compute Service (ECS) instance in the stress testing is a fixed bandwidth, no traffic charges are incurred. If the public bandwidth supports the pay-as-you-go billing method, you are charged based on the existing traffic billing policies configured for ECS instances.
Traffic fees for the public IP addresses of ECS instances follow the following rules:
If the public bandwidth of an ECS instance is a fixed bandwidth, no traffic fee is incurred because the traffic fee is paid when the ECS instance is purchased.
If the public bandwidth supports the pay-as-you-go billing method, you are charged based on the existing traffic billing policies configured for ECS instances. If you do not want to perform the stress testing over the Internet, we recommend that you use the private IP address of the Server Load Balancer (SLB) instance associated with the ECS instance or the internal IP address of the ECS instance in the test script.