?– Continuity check This function allows for continuous monitoring of a path
(multiple hops) or a link between two endpoints using a periodic ???I am alive??? message
exchange.
?– Loopback This common function provides the ability to test whether a physical/
virtual circuit is operating correctly. It essentially sends and receives a set of Ethernet
frames to a remote point in the Service Provider network. If the remote location is a
physical Ethernet port/facility, then the loopback will be intrusive (i.e., will impact
regular data flow); a nonintrusive loopback can be initiated on a per-service instance
(i.e., a specific EVC) basis.
?– Alarm Indication Signal (AIS) and Remote Defect Indicator (RDI) This
provides the capability of generating only one alarm message when an issue is
TABLE 2.7 Ethernet OAM Layers, Functionality, and Standards
Layer Standards Key Functions
Service ITU Y.1731
IEEE 802.1ag
MEF Spec 7, MEF Spec 16
(E-LMI)
Discovery
Continuity check
Loopback
AIS/RDI (alarm indication signal/remote defect indicator)
Traceroute
Performance management
Connectivity ITU-T Y.1731
IEEE 802.1ag
Discovery
Continuity check
Loopback
AIS/RDI (alarm indication signal/remote defect indicator)
Traceroute
Transport/
data-link
IEEE 802.
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