This read-only counter reports the 5-minute peak value of inbound DE-marked (Discard Eligible, the Frame Relay equivalent of ATM's CLP) octets for the circuit, from Bulk Statistics. Since DE-marked traffic is the first to be dropped under Frame Relay congestion, a high value here relative to total inbound octets indicates the circuit is regularly sending traffic that exceeds its committed rate and relies on discard-eligible handling to burst. An engineer noticing that a customer's circuit shows cktInDEOctetsPeak consistently high would flag that the customer is habitually bursting above CIR and might need a bandwidth upgrade rather than continued reliance on best-effort DE traffic.