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• Though the token bucket algorithm has several uses, the algorithm is best understood in the context of network traffic shaping or rate limiting
• It has a bucket with a valve at the bottom. The valve is opened whenever any packet arrives.
• A token is added to the bucket every sec.
• The bucket can hold at the most b tokens.
• If a token arrives when the bucket is full, the token is discarded.
• One token permits one byte of data to be transmitted
• When a packet (network layer PDU) of n bytes arrive, n tokens are removed from the bucket, and the packet is sent to the network.
• If less than n tokens available, the packet is dropped.
• A token bucket allows bursts of up to b bytes, but over the long run output is limited to the constant rate, .

Sometimes the leaky bucket and token bucket algorithms are lumped together under the same name.

1 See also

• Leaky bucket
• Traffic shaping
• Rate limiting

• Traffic shaping and rate control
• Congestion control
• A token bucket programming exercise