Meaning
Dynamic data transmission protocol that allows multiple packets to be sent without waiting for an individual acknowledgment for each one. The sliding window size determines how many unacknowledged packets can be in flight at any given time. This technique is used in protocols like TCP to maximize the use of the available bandwidth on a network link.
Throughput Optimization
Continuous flow of data is maintained by allowing the sender to keep transmitting as long as the window is not full. The sliding window mechanism prevents the sender from idling while it waits for a response from the receiver over a long distance. This is especially useful in satellite or long haul fiber links where the round trip time is high.
By filling the pipe with data, the system achieves a much higher average throughput than a simple stop and start method.
Flow Control
Receiver manages the rate of incoming data by adjusting the size of the window it advertises to the sender. If the receiver buffer starts to fill up, it shrinks the sliding window to slow down the sender and prevent an overflow. This feedback loop ensures that the transmitter does not overwhelm the processing capacity of the destination.
Once the receiver has processed the data and freed up space, it expands the window again to resume high speed transmission.
Error Recovery
Missing or corrupted packets are identified by the gaps in the sequence numbers within the current window. The sliding window allows the system to retransmit only the specific packets that were lost, rather than the entire sequence. This selective repeat capability saves bandwidth and reduces the time needed to recover from a network glitch.
The management of sequence numbers and acknowledgments is handled automatically by the transport layer of the network stack.
