Link OAM provides a way to monitor the health of a physical Ethernet link through:
The VLNC40/42/42B circuit packs support IEEE 802.3 Clause 57, formerly referred to as 802.3ah.
Note:
L2CP Tunneling and Link OAM are allowed simultaneously. However, the loopback cannot be operated and remote loopback capability cannot be enabled when L2CP Tunneling and Link OAM are both enabled on a port.
Link OAM uses Operations, Administration, and Maintenance Protocol Data Units (OAMPDUs) for:
During normal operation, one PDU is sent per second. Up top 10 PDUs can be sent per second, unless there is a new critical event. The absence of PDUs indicate that a failure or fault has occurred. PDUs can contain multiple Type/Length/Value (TLV).
Each port can be configured in active or passive mode. The discovery function is manadatory and is used to determine it the link partner is 802.3 OAM-capable and which features of the protocol it supports
Only active ports can initiate discovery or loopback. Discovery is initiated when link OAM is enabled on a port and the port is configured in the active mode. The port sends information PDUs. In active mode, a port can initiate discovery, respond to discovery initiated from the remote end and initiate or respond to a loopback command.
Only active ports can initiate discovery or loopback. If a port is in the passive mode, it can respond to discovery and can respond to a loopback command, but cannot initiate discovery or loopback.
A loopback is initiated at one end using the CLI. OAMPDUs are then sent to the far end, requesting that it put up a physical loopback. Once the loopback is up, a response is sent to the originating node. During the loopback, the remote node loops all traffic except for link OAMPDUs, and optionally L2CP PDUs (so that protocols such as RSTP and LACP may continue to be peered during the loopback). The local end drops all traffic coming from the remote, except for link OAMPDUs, and optionally L2CP PDUs. The loopback may be disabled at the local end using the CLI, or at the remote end by disabling the remote loopback capability, or disabling the link OAM feature.
Beginning in Release 5.1, Alcatel-Lucent 1850 TSS-5 supports generation and processing of link OAM events. Non-thresholded events include Link Fault, which can be used to generate a Remote Failure Indication for ports which support Unidirectional Transmission (1000BASE-X PTM-based optical ports).
Thresholded events are:
These events may be individually enabled or disabled, and have configurable intervals and thresholds. Non-zero events are logged at both ends.
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