Juniper JUNOSE SOFTWARE 11.2.X - LINK LAYER CONFIGURATION GUIDE 7-7-2010 Configuration Manual page 273

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In this case, frame seconds summary events are detected during a period of 10
seconds. The configured window is valid for both high and low threshold settings.
The high and low threshold settings are reset whenever a new window, during
which errors are counted, commences.
g. Configure a low threshold value for symbol error events that causes an Errored
Symbol Period Event TLV to be sent to the OAM entity when it is exceeded. The
Errored Symbol Period Event TLV counts the number of symbol error events
that occurred during the specified period.
host1(config-if)#ethernet oam lfm link-monitor symbol-period threshold low
60
In this case, a low symbol errors threshold of 60 symbols is set. When this
threshold is exceeded, an Errored Symbol Period Event TLV in an Event
Notification OAM PDU is sent from the local OAM entity to the remote peer. This
event is generated if the symbol error count is equal to or greater than the
specified threshold for that period.
h. Configure a high threshold value for symbol errors, which when exceeded, triggers
an action.
host1(config-if)#ethernet oam lfm link-monitor symbol-period threshold low 10
In this case, a low symbol errors threshold of 10 symbols is set. When this
threshold is exceeded, the action configured on the interface using the ethernet
oam lfm high-threshold action command is taken.
i. Specify a period of time in which symbol error events are counted for both high
and low threshold settings. The time period is specified in seconds.
host1(config-if)#ethernet oam lfm link-monitor symbol-period window 10
In this case, symbol error events are counted over a period of 10 seconds. The
configured window is valid for both high and low threshold settings. The high
and low threshold settings are reset whenever a new window, during which
errors are counted, commences.
NOTE: We recommend that you do not use a multiple of the number of symbols because
the window size varies greatly, depending on the speed of the link. For example, a 10
Gigabit Ethernet link generates 10.3x10M symbols per second. If the window has a lower
bound of 1M symbols, sampling the symbol error statistic occurs every 97 microseconds.
Some of the interfaces do not support statistics for errored symbol events. If you
configure a monitor for symbol errors on such interfaces, the setting does not have any
effect.
Configure a specific action to occur when a high threshold for an error is exceeded
6.
on an Ethernet OAM interface. You can configure the OAM application to influence
the operational state of the link, when a link quality threshold is exceeded or a critical
event PDU is received from the peer, or both. If you configured the action for an OAM
Chapter 7: Configuring IEEE 802.3ah OAM Link-Fault Management
241