Let's say a server has 1 Gbps upload speed, and a client has 100 Mbps download speed.
Client requests data from this server and the server starts to send.
To prevent frames being lost, there should be a data rate synchronization.
In OSI model, doesn't Physical Layer do that with Bit Synchronization?
But also we have Flow Control in Data Link Layer, and as I know it's for the same reason. For data rate synchronization to prevent frames being lost.
If it works like this, according to OSI model there are 2 times synchronization. First physical layer, then data link layer and why would it work like that?
There should be a difference between Physical Layer's Bit Synchronization and Data Link Layer's Flow Control.