Frame-Loss Measurement

Frame-loss is measured by sending and receiving frames with frame-loss information between peer maintenance end points (MEPs).

Frame-loss ratio is defined as a percentage of the number of service frames not delivered divided by the total number of service frames during a defined time interval, where the number of service frames not delivered is the difference between the number of service frames arriving at the ingress Ethernet flow point and the number of service frames delivered at the egress Ethernet flow point in a point-to-point Ethernet connection (see the following figure).
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Frame-Loss Ratio Formula
../Graphics/EX_CFM_FrameLossRatio.svg
To support frame-loss measurement, a MEP requires the following configuration information:
  • Maintenance domain (MD) level—MD level at which the MEP exists.

  • Frame-loss measurement transmission period—time interval when frame-loss measurement frames are sent.

  • Priority—identifies the priority of the frames with frame-loss measurement information (configurable per operation).

  • Drop eligibility—frames with frame-loss measurement information are always marked as drop ineligible (not necessarily configured).

A maintenance intermediate point (MIP) is transparent to frames with frame-loss measurement information. Therefore MIPs do not require any information to support frame-loss measurement functionality.

There are two frame-loss measurement methods: