This read-only EthernetPortSpeed object reports the actual link speed the Ethernet Network Port negotiated with its link partner. Admins compare this against cmEthernetNetPortConfigSpeed to detect auto-negotiation mismatches, since a negotiated speed lower than expected often explains unexplained throughput shortfalls. For example, if a customer reports slower-than-purchased bandwidth, an admin would check cmEthernetNetPortNegotiatedSpeed to confirm the port actually linked at the full contracted rate rather than falling back to a lower speed.