6. Frame-Based Accounting

This chapter provides information to configure frame-based accounting using the CLI.

6.1. Overview

When enabled, frame-based accounting lets QoS policies account for the Ethernet frame overhead (for example, it accounts for the IFG (inter-frame gap) and the preamble). Typically, the IFG and preamble constitute about 20 bytes (12 + 8). The overhead for Ethernet ports uses this value.

6.1.1. Frame-Based Accounting

A configurable CLI command enables accounting of the frame overhead on ingress or egress. This is a system-wide parameter and affects the behavior of the ingress meter or egress rate. When disabled, the queue rates and egress-rate do not account for the Ethernet frame overhead. By default, frame-based accounting is disabled for both ingress and egress. Frame overhead is always accounted for on egress (queue rates and egress rate) and the user has no option to disable it.

Note:

  1. The egress port rate limiter (ERL) calculation is also frame based, and the user has no option to disable it; ERL can be applied on the port to shape the egress rate.
  2. Frame-based accounting for SAP-egress aggregate meters is not supported on the 7210 SAS-R6 and 7210 SAS-R12 in port scheduler mode.

6.1.2. 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. Network ingress and service ingress meters account for Ethernet frame overhead. A configurable CLI command enables or disables the frame overhead accounting. This is a system-wide command that affects the behavior of all the meters in the system.

6.1.3. Effects of Egress Frame-Based Accounting on Queue Functionality

Because of frame overhead accounting considerations, the 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 constitute about 20 bytes (12 + 8). The overhead for Ethernet ports uses this value.

6.1.4. Accounting and Statistics

Accounting records and statistics do not account for frame overhead.

6.2. Basic Configurations

To enable frame-based accounting, perform the following:

  1. Enable the frame-based-accounting command in the config>qos>frame-based-accounting context.
  2. Configure the ingress-enable command to enable frame-based accounting for ingress metering.

The following is a sample frame-based accounting configuration output.

*A:Dut-1>config>qos>frame-based-accounting# info detail 
----------------------------------------------
            no ingress-enable
 
 
*A:Dut-1>config>qos>frame-based-accounting#

6.2.1. Enabling and Disabling Frame-Based Accounting

To enable the frame-based-accounting command for ingress, use the ingress-enable command. To disable the frame-based-accounting command for ingress, use the no ingress-enable command.

CLI Syntax:
config>qos>frame-based-accounting

The following is a sample configuration output that shows the enabling of frame-based accounting.

*A:Dut-1>config>qos>frame-based-accounting# ingress-enable 
 
*A:Dut-1>config>qos>frame-based-accounting# info 
----------------------------------------------
            ingress-enable
 
 
*A:Dut-1>config>qos>frame-based-accounting#

The following is a sample output configuration that shows the disabling of frame-based-accounting:

*A:Dut-1>config>qos>frame-based-accounting# no ingress-enable 
*A:Dut-1>config>qos>frame-based-accounting#
*A:Dut-1>config>qos>frame-based-accounting# info detail 
----------------------------------------------
            no ingress-enable
 
 
*A:Dut-1>config>qos>frame-based-accounting#

6.2.1.1. Default Frame-Based Accounting Values

By default, the frame-based-accounting command is disabled for ingress.

By default, the frame-based-accounting command is disabled for egress. It is user-configurable and can be enabled or disabled.