This read-only counter reports the total count of LMI frames received with errors on this interface, and for NNI, network-to-network interface, links specifically it equals the sum of lportDTEInErrorFrames and lportDCEInErrorFrames since an NNI port runs both DTE and DCE LMI roles simultaneously. An admin uses this single aggregate figure as a quick top-level health check on NNI trunks without having to add the two role-specific counters manually. For example, on an NNI port between two Cascade switches, a nonzero lportLMIInErrorFrames prompts the admin to break it down into its DTE and DCE components to see which signaling role is actually generating the errors.