Oam Link Monitoring Feature - Juniper JUNOSE SOFTWARE 11.2.X - LINK LAYER CONFIGURATION GUIDE 7-7-2010 Configuration Manual

JunosE 11.2.x Link Layer Configuration Guide
Related Topics

OAM Link Monitoring Feature

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a maximum value of 1000 (the default value) and a minimum value of 100. Also, you
can configure the local OAM function with a packet loss threshold, which specifies the
number of Information OAM PDUs that an interface can miss before the link between
peers is considered down. When the PDU loss threshold is exceeded, a link fault event
is triggered. The product of the PDU timer and the PDU loss threshold equals the lost-link
timer value, which is used to reset the discovery state diagram that maintains the states
of the OAM entities and determines the condition of the link based on various stored
values.
When the PDU loss threshold is exceeded, the OAM function signals a problem with the
link and the link is immediately transitioned to the down state. When the OAM association
with the peer is rediscovered after a successful discovery operation, the link transitions
to the up state.
NOTE: The operational status displayed in the output of the show commands related
to interface settings will be down if the OAM session is down owing to loss of association.
OAM Feature Overview on page 230
OAM Messages on page 226
Configuring 802.3ah OAM Link-Fault Management on page 238
Monitoring OAM Link-Fault Management Discovery Settings for an Interface on page 245
ethernet oam lfm
ethernet oam lfm mode
ethernet oam lfm pdu-lost-threshold
ethernet oam lfm pdu-transmit-interval
show ethernet oam lfm discovery
The router performs link monitoring by sending periodic Information OAM PDUs to
advertise OAM mode, configuration, and capabilities. Link monitoring uses the Event
Notification OAM PDU and sends events to the remote OAM entity when problems are
observed on the link. You can configure the OAM application to track frame and symbol
errors on the link to analyze the overall health and quality of the link. Frame errors include
frameTooLong, lengthError (runts), alignmentError, and frameCheckSequence errors.
You can monitor frame and symbol errors by setting up a monitoring period or window
and a threshold value. If the number of errors observed during the window meets or
exceeds the configured low threshold, an Event Notification PDU (in the appropriate
TLVs) is generated and sent to the peer. Alternatively, if you configure a high threshold
value on the local OAM peer, the OAM function attempts to alter the operational state
of the link whenever the high threshold value is exceeded. The monitoring of the link
continues with a new window or period as long as the operational state of the link is up.
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