3Com 4210G Series Configuration Manual page 434

Congestion management provides a resource scheduling policy to arrange the forwarding
sequence of packets when congestion occurs. Congestion management is usually applied to the
outgoing traffic of a port.
Congestion avoidance monitors the usage status of network resources and is usually applied to
the outgoing traffic of a port. As congestion becomes worse, it actively reduces the amount of
traffic by dropping packets.
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