Frame loss measurement can be deployed per forwarding class (FC) counter. The config>oam-pm>session>ethernet>lmm>enable-fc-collection command in the related oam-pm session enables frames to be counted on an FC basis, either in or out of profile. This counting method alleviates some of the ordering and interleaving issues that arise when using a single counter, but does not improve on the base protocol concerns derived from multiple paths and complex based counting.
This approach requires the operator to configure the individual FCs of interest and the profile status of the frames under the collect-lmm-fc-stats context. The command allows for the addition or removal of an individual FC by using a differential. The entire command with the wanted FC statements must be included. The system determines the new, deleted, and unchanged FCs. New FCs are allocated a counter. Deleted FCs stop counting. Unchanged FCs continue counting.
Support for per-FC collection includes SAPs, MPLS SDP bindings, and router interfaces.
The enable-fc-collection command must be coordinated between the ETH-LMM test and counting model to configure either single per SAP or MPLS SDP binding counter, or per FC counter. The command is disabled by default, and single per SAP or MPLS SDP binding counter is used.
Symmetrical QoS is required for correct collection of frame counters. The FC must match the priority of the OAM-PM ETH-LMM test. The ETH-LM PDUs must ensure that they are mapped to the correct FC on ingress and egress so that the appropriate counters are collected. Mismatches between the ETH-LMM PDUs and the collected FC cause incorrect or no data to be reported.
The show>eth-cfm>collect-lmm-fc-stats command displays the SAPs, MPLS SDP bindings, and router interfaces that are configured for per-FC collection, and whether the collection is priority aware or unaware. It also includes the base mapping of OAM-PM ETH-LMM priority to FC.