IEEE 802.3-2008 clause 37 describes the 1000BASE-X Auto-Negotiation function that allows a device to advertise the supported modes of operation to a device at the remote end of a link segment (link partner), and to detect corresponding operational modes that the link partner might be advertising. Auto-Negotiation is controlled and monitored through the PCS management registers. 2500BASE-X follows the same Auto-Negotiation function as defined in IEEE 802.3-2008 clause 37.