Egress statistics are supported for both binding-label and endpoint MPLS forwarding policies; however, egress statistics are only supported in case where the next-hops configured within these policies are of resolution type direct. The counters are attached to the NHLFE of each next hop. Counters are effectively allocated by the system at the time the instance is programmed in the data-path. Counters are maintained even if an instance is deprogrammed and values are not reset. If an instance is reprogrammed, traffic counting resumes at the point where it last stopped. Traffic counters are released and therefore traffic statistics are lost when the instance is removed from the database when the egress statistic context is deleted, or when egress statistics are disabled (egress-statistics shutdown).
No retry mechanism is available for egress statistics. The system maintains a state per next hop and per-instance about whether the allocation of statistic indexes is successful. If the system is not able to allocate all the needed indexes on a specified instance because of a lack of resources, the user should disable egress statistics on that instance, free the required number of statistics indexes, and re-enable egress statistics on the needed entry. The selection of which other construct to release statistic indexes from is beyond the scope of this document.