OAM events

EFM OAM defines a set of events that may impact link operation. The following critical link events (as defined in 802.3ah clause 57.2.10.1) are supported:

link fault

The PHY has determined a fault has occurred in the receive direction of the local DTE.
dying gasp

An unrecoverable local failure condition has occurred.
critical event

An unspecified critical event has occurred.

These critical link events are signaled to the remote DTE by the flag field in OAM PDUs.

The 7210 SAS does not generate EFM OAM PDUs with these flags except for the dying gasp flag. However, it supports processing of these flags in EFM OAM PDUs received from the peer.