CANOGA PERKINS 9145E NID Software Version 4.10 - Manual (Page 102)

9145E NID Software User’s Manual Diagnostics
Network Performance
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If the Passive NID experiences a Link Loss or Remote Fault on either of its LAG Ports, it first
forwards the Link Loss to the other port via Link Loss Forwarding. It informs the Active Master of
the failure on its leg. The Active Master, which is still transmitting all PM/CPM/SAM test packets
on its Network Port, will now receive any traffic that used to come through the MPP port on its
Network Port, allowing testing to proceed normally.
If the MPP port loses link or the attached unit stops responding, the PLCP protocol will wait as
directed by the programmed timeout, become the Active Master, and start sending out PM/CPM/
SAM test packets. If the attached unit is still operational and only the MPP is down, both units
will become Active Masters.
Whenever the MPP port goes down, a flag is included in the test result to CV-EMS to indicate
that the MPP Port was not operational during the test. If both units have become Active Masters,
some of the test results may be valid. Some tests may have failed because their responses
came to the other NID. The same tests running on the other NID may be valid. CV-EMS
attempts to correlate the results using the NPA Accuracy Level flag received with the result.
Figure 4-43 Normal PM on the LAG
In Figure 4-43, both NIDs are operational and the LAG links are up. In this case, the master NID
sends all test packets from its Network Port and receives some test responses over its Network
Port and some over its MPP port, forwarded by the slave.
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