Traffic Shaping - Token Bucket Algorithm

The leaky bucket algorithm enforces a strict maximum traffic generation. It is often better to permit short bursts, but thereafter to constrain the traffic to some maximum.

The token bucket algorithm provides a bucket of permit tokens - before any packet may be transmitted, a token must be consumed. Tokens 'drip' into the bucket at a fixed rate; if the bucket overflows with tokens they are simply discarded (the host does not have enough traffic to transmit).

Packets are placed in an 'infinite' queue. Packets may enter the subnet whenever a token is available, else they must wait.

The token bucket algorithm enables an application to generate and transmit 'bursty' traffic (high volume, for a short period). It avoids saturating the network by only permitting a burst of traffic to continue for a limited time (until the tokens run out).