Chapter 4: Feature Description
Ethernet Features
The following parameter is neither a profile parameter, nor specifically a rate meter parameter, but
rather, is a logical interface parameter. For more information about logical interfaces, see
•
Line Compensation – A rate meter can measure CIR and EIR at Layer 1 or Layer 2 rates. Layer 1
capacity is equal to Layer 2 capacity plus 20 additional bytes for each frame due to the
preamble and Inter Frame Gap (IFG). In most cases, the preamble and IFG equals 20 bytes, but
other values are also possible. Line compensation defines the number of bytes to be added to
each frame for purposes of CIR and EIR calculation. When Line Compensation is 20, the rate
meter operates as Layer 1. When Line Compensation is 0, the rate meter operates as Layer 2.
This parameter is very important to users that want to distinguish between Layer 1 and Layer 2
traffic. For example, 1 Gbps of traffic at Layer 1 is equal to ~760 Mbps if the frame size is
64 bytes, but ~986 Mbps if the frame size is 1500 bytes. This demonstrates that counting at
Layer 2 is not always fair in comparison to counting at Layer 1, that is, the physical level.
Rate Metering (Policing) at the Logical Interface Level
Rate metering at the logical interface level supports the following:
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Unicast rate meter
•
Multicast rate meter
•
Broadcast rate mete
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User defined Ethertype 1 rate meter
•
User defined Ethertype 2 rate meter
•
User defined Ethertype 3 rate meter
For each rate meter, the following statistics are available:
•
Green Frames (64 bits)
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Green Bytes (64 bits)
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Yellow Frames (64 bits)
•
Yellow Bytes (64 bits)
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Red Frames (64 bits)
•
Red Bytes (64 bits)
Rate Metering (Policing) at the Service Point Level
Users can define a single rate meter on each service point, up to a total number of 1024 rate
meters per network element at the service point and CoS per service point levels.
The following statistics are available for each service point rate meter:
•
Green Frames (64 bits)
•
Green Bytes (64 bits)
•
Yellow Frames (64 bits)
•
Yellow Bytes (64 bits)
•
Red Frames (64 bits)
•
Red Bytes (64 bits)
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