If the data flow is so heavey or have,,,?

If the data flow is so heavey or have so much load they have too pass at the same time does they all act on the single protocol or maybe they used other if yes then why?

Your question is not much clear!

However, when there is heavy data flow then some flow control mechanisms are used to handle this situation.
Flow control refers to the process of managing the rate of data from one device to another to ensure that the receiving device can handle all of the incoming data.