This counts how many times, since the last system reset, the LMI protocol on the DTE side actually declared the link down because accumulated errors, tracked in lportDTEPollErrorCounts, crossed the configured threshold, a concrete count of real outage declarations rather than just error blips. An admin treats every increment here as an actual service-affecting event worth logging in an outage report, unlike the more granular error counters which can tick without causing a declared failure. For example, lportDTEFailCounts incrementing from 2 to 3 overnight is a strong signal to check for a real customer-visible outage window around that timestamp.