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Overview
Overview
This feature when enabled let QoS policies to accounts for the Ethernet frame overhead (for
example, it accounts for the IFG (inter-frame gap) and the preamble). Typically, the IFG and
preamble constitutes about 12 + 8 = 20 bytes. The overhead for Ethernet ports uses this value.
A configurable CLI command enables accounting of the frame overhead at ingress. This is a
system wide parameter and affects the behavior of the ingress meter. By default frame-based
accounting is disabled on ingress. Frame overhead is always accounted for at the egress (queue
rates and egress rate) and user has no option of disabling it.
Effects of Enabling Ingress Frame Based Accounting on Ingress Meter
Functionality
To enable system-wide consistency in configuring QoS queue and meter rate parameters, the
meters used on the system ingress might need to account for Ethernet frame overhead. ingress and
service ingress meters account for Ethernet frame overhead. A configurable CLI command can
enable or disable the frame overhead accounting. This is a system-wide parameter affecting the
behavior of all the meters in the system.
Effects of Egress Frame Based Accounting on Queue Functionality
Because of frame overhead accounting consideration, queue scheduler accounts for the Ethernet
frame overhead. The maximum egress bandwidth accounts for the Ethernet frame overhead (it
accounts for the IFG (inter-frame gap) and the preamble). Typically, the IFG and preamble
constitutes about 12 + 8 = 20 bytes. The overhead for Ethernet ports uses this value.
Accounting and Statistics
Accounting logs and statistics do not account for frame overhead.
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7210 SAS-X and 7210 SAS-R6 OS Quality of Service Guide
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