A network is said to be congested when the offered traffic approaches or exceeds the network capacity.
Congestion causes:
- Increased delay
- Packet loss
- Reduced throughput
Congestion Control
Open Loop Control
Prevents congestion before it occurs. Network state is not monitored. Typically implemented at transport or network layer.
Closed Loop Control
Detects and reacts to congestion.
Steps:
- Monitor network conditions
- Inform relevant nodes
- Take corrective action