Methods, apparatus and systems for implementing Physical Media Attachment (PMA) alignment and rapid transition from a link training mode to a data mode for next-generation high-speed Ethernet links including a 100 Gbps Ethernet link. Training frames are transmitted between first and second Ethernet interfaces on opposing ends of the link in a pair-wise manner, with a first training frame being sent from a first Ethernet interface and a second training frame being returned from the second Ethernet interface. The training frames have a length that is different that the length of Physical Media Attachment (PMA) frames, and the returned training frames include receiver readiness status indicia identifying a readiness status of a local receiver port, frame alignment offset data identifying a relative offset between a training frame and a predetermined location in a PMA frame, and countdown data. The readiness status indicia, frame alignment offset data and countdown data are employed to facilitate a rapid transition from the link training mode to the data mode.