Estimating file transfer time over network?

Question

I am transferring file from one server to another. So, to estimate the time it would take to transfer some GB's of file over the network, I am pinging to that IP and taking the average time.

For ex: i ping to 172.26.26.36 I get the average round trip time to be x ms, since ping send 32 bytes of data each time. I estimate speed of network to be 2*32*8(bits)/x = y Mbps --> multiplication with 2 because its average round trip time.

So transferring 5GB of data will take 5000/y seconds

Am I correct in my method of estimating time.

If you find any mistake or any other good method please share.

Answer 1

No. Your method of estimating bandwidth is entirely incorrect. Ping can only tell you about delay. You have to send something large enough to saturate the network to get the bandwidth.

Answer 2

It could also depend on the protocol. PING is ICMP and ftp uses TCP. The delays need not the be same for both the protocols. TCP tries to adjust to network during congestion time and this means longer delays. Just send 100 MB or 500MB files using FTP and collect the stats and do estimates (one way). Or, there is a tool called iperf/jperf that can pump TCP traffic of your interest and show some bandwidth and time stats. Possibly you can try that.