Flow Control Of Noiseless Channel

For Flow control of Noiseless channels, we assume an ideal channel where no frames are lost, corrupted, or duplicated. Protocols in flow control for Noiseless channels are of following two kinds

1. Simplest Protocol

It is a very simple and easy to implement protocol. It is unidirectional protocol in which data frames are traveling only from sender to receiver.

In simplest protocol, the sender sends sequence numbers of frames without thinking about the receiver.  No concept of acknowledgment is used by receiver.

Following figure explain all

2. Stop and Wait Protocol

In stop and wait, the sender sends one frame and waits for Acknowledgement (feedback) from the receiver. When the Acknowledgement arrives, the sender sends the next frame.

So, it is a half-duplex in direction as shown in the following figure

Most important in stop and wait is that, it does not use any timer. If frame is lost after transmission then receiver has to wait for infinite amount of time.

In the same way, if ACK is lost after transmission then sender has to wait for infinite amount of time.

Note: If Speed of sender is higher than receiver then frames must be stored until their use and after consumption of frame feedback is compulsory in stop and wait.