Why can the transmission speed decrease?

Question

Computer networks

I copy from one PC to another 60GB archive. Between two PCs there is a gigabit switch. The first 10GB are copied to the norm (80-90mb / sec), and then the speed starts to drop to 20-60mb sec. How to find out why this is happening?

Answer 1

Usually, when copying on the transmitting machine, it is not the transfer speed that is visible, but the file reading speed. Accordingly, at first the file is read into the buffer, and only when the buffer is full will the real transfer rate be seen. On the receiving machine, the received data is also written to disk through a buffer in memory, which means that when this buffer is also full, the transfer rate will decrease to the speed of writing to the disk of the receiving machine.
The actual network transfer rate can be obtained using programs like iperf , which transfer in memory-to-memory mode without using disks.

Answer 2

Watch download by I/O

Answer 3

Measure disk speed