ATL Telecom R1-SW Ethernet Switch - Manual (Page 175)

Configuring QoS
9-7
The following graph shows the variables.
Token Bucket
There are several implementation of policer function, and the typical implementation is the
token bucket. The token bucket contains tokens, each of which can represent a unit of bytes.
Token is filled up in the token bucket for a certain rate. When packets are arrived, the same
amount of tokens is removed from the token bucket.
The variables of policer can be substituted for the element of token bucket as follows:
y CIR : Token Rate
y CBS : Bucket Size
Information
Rate(bps)
time
Burst Size (Bytes)
CIR PIR CBS PBS
EBS
Token Bucket
Token
Bucket Size
Token Rate
Packet
The same amount of tokens is
removed from the bucket.