Many protocols provide a flow control function in order
to eliminate the possibility of a sender overflowing the receiver's buffer.
One mechanism that implements flow control is a credit-based sliding
window algorithm. But, it relies on feedback information from the receiver
and thus, is not suited for real-time multimedia applications that need
a continuous data transfer.
Rate control is an alternative flow control mechanism
that works without feedback. Sender and receiver agree on a data rate for
a certain time period. The sender can now send up to the maximum amount
of data and as soon as a new time slot starts it has the same credit again
without any new acknowledgement from the receiver. Best suited is this
type of flow control for the transmission of continuous media where you
have a constant data rate that is known in advance.
Have a look at rate control with different data rates!