If no green tokens remain, however, then the E-bucket is checked to determine if any
yellow tokens remain. If there are yellow tokens, then the service frame is EIR-conformant,
colored yellow, and allowed in the network. If no yellow tokens are available, then the
service frame is colored red and discarded.
Figure 2.7 Enforcing a predefined bandwidth profile using the token bucket concept (Source: MEF)
Bandwidth Profile Defined by Token Bucket
Algorithm (2 rates, 3 colors)
C-Bucket E-Bucket
???Yellow???
Tokens
Overflow Overflow
Committed
Information
Rate (CIR)
Excess
Information
Rate (EIR)
Committed
Burst Size
(CBS)
Excess
Burst Size
(EBS)
???Green???
Tokens
Carrier Ethernet 65
The MEF has defined an additional capability whereby unused green tokens from
the C-bucket may be added to the E-bucket as yellow tokens when checking EIRconformance.
If this capability is enabled, more yellow service frames are allowed in
the Service Provider network.
Performance Parameters The performance parameters affect the service quality experienced
by the subscriber and consist of the following.
Availability This is still being formalized by the MEF but essentially attempts to
indicate the availability of a service at a predefined performance SLA.
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