To determine bandwidth to another computer, ICMP is used to ping the computer and time the responses. This generates about 12 KB of traffic. Once the speed is determined, it is not necessary to check the speed again for six hours.
Note: The request will not time out if a firewall is present blocking ICMP traffic. The request will simply be blocked.
Once bandwidth is determined, use it to throttle the transfer of files across the network when the maximum allowed bandwidth usage is specified as a percentage of available bandwidth. For example, if bandwidth throttling is set to 10 percent, the software will ping the remote computer to determine speed, then only transmit data at 10 percent of the rate that was determined.
When bandwidth throttling is set to an absolute value, such as 2 KB/sec, it is not necessary to ping the remote computer, and ICMP is not required.