Specifications

Appendix C Operation, Administration and Maintenance (OAM) Installation and Operation Manual
C-6 OAM Flows LA-210 Ver. 1.5
LB reply message. The DA of the reply message is a unicast MAC address of
requesting device, learned from request message.
Continuity Check (ETH-CC)
Ethernet Continuity Check (ETH-CC) can be used to detect continuity failures
across flows between a given pair of edge service point on a flow. Continuity
failures are caused by:
• Major failures (link failure, device failure, network path failure etc)
• Minor failures (software failure, memory corruption, incorrect configuration
etc).
The ETH-CC signal is generated by one MEP. Upon receipt of the first ETH-CC
signal from a sending MEP, the receiving MEP detects continuity with sending MEP
and expects to receive further periodic ETH-CC signals. Once the receiving MEP
stops receiving periodic ETH-CC signals from sending MEP, it declares continuity
failure. The MEP that detects the continuity failure notifies the operator by
sending an alarm or a trap.
OAM Procedures
This section discusses the continuity check (CC) and the performance
measurement (PM) procedures.
Continuity Check Procedure
The loopback message and the ETH-CC messages are used for continuity check. In
case the services are defined and PM collection is enabled, they are also used to
carry PM messages. If PM collection is disabled, the messages are used for
continuity check only.
If the RX CC mode of the receiver is configured to CC-based, the continuity
detection is based on ETH-CC. If the mode is set to LB-based, the continuity
detection is based on ETH-LB. If the mode is disabled, the continuity detection is
not performed.
ETH-LB Method
The ETH-LB method includes the following elements:
• Unicast ETH-LB transmission
Unicast ETH-LB request message is transmitted by a MEP (LA-210) every
1 second. The transmitted Transaction Identifier is retained for at least
5 seconds after the unicast ETH-LB signal is transmitted. The Transaction
Identifier must be changed for every unicast ETH-LB message, and no
Transaction Identifier from the same MEP is allowed to be repeated within
1 minute.
• Unicast ETH-LB reception and reply transmission
Whenever a valid unicast ETH-LB request message is received by MEP
(LA-210), a unicast ETH-LB reply message is generated and transmitted to
the requesting MEP. Every field in the unicast ETH-LB request message is
copied to the unicast ETH-LB reply message with the following exceptions: