Visual of Windowing

 

Windowing Diagram

Window size of 1 = sending machine waits for an acknowledgement for each data segment it transmit before transmitting another segment.

Window size of 3 = allowed to transmit three data segments before an acknowledgement is actually received.

Types of flow control and a closer look at Windowing

 

The three types of flow control consists of:

1. buffering
2. windowing
3. congestion avoidance

A closer look at what windowing is and it's function at the transport layer

Windowing

• Windowing is the quantity of data segments (measured in bytes) that the transmitting machine is allowed to send without receiving an acknowledgement for them.
• In other words, it's the break of time in between data segments of before and after.
• Windowing is used to control the amount of outstanding, unacknowledged data segments.

Note: if hosts fails to receive all segments that it should have acknowledged, the host can improve the communication session by decreasing window size.