This read-create object indicates whether the error metric configured for this IP Reachable Address entry is internal or external to the IS-IS domain, completing the internal/external classification for all four IS-IS metric types on this reachable address. It ensures consistent handling of the error metric alongside the default, delay, and expense metrics when routers compare paths. An administrator would typically set csIsisIPRAErrMetricType to match the classification used for the other metrics on the same entry, such as internal for a locally attached network.