CANOGA PERKINS 9145E NID Software Version 4.10 - Manual (Page 101)

Diagnostics 9145E NID Software User’s Manual
Network Performance
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ence its ARP Table to determine whether a Test Packet should be forwarded out its Net-
work Port or that of its PLPM Partner.
In the case of an Active/Passive LAG, the Active Master NID can determine whether all Test
Packets should be sent out its Network Port or that of the Passive Master NID by simply
identifying which link is active. Determining the correct Network Port to forward a Test Packet
when the LAG is in Active/Active mode is slightly more involved. The ARP Table in the Active
Master NID is queried to see if the ARP Reply for an ARP Request on a particular test instance
was received at the NID's Network Port or MPP. If the ARP Reply was received at the Network
Port, the NID concludes that the EVC for that particular test instance traverses the same link on
which the Active Master is located. If the ARP Reply was received at the NID's MPP, then the
reply must have been forwarded to the Active Master NID by the Passive Master NID. Therefore,
the EVC traverses the link on which the Passive Master is located. It is obviously very important
that the ARP Table entries be up-to-date for the above procedures to work correctly.
NOTE: It is strongly suggested that the ARP Table is cleared before PLPM testing is enabled. To
clear the ARP Table, use the procedures outlined in Section 7.7.
NOTE: When enabling PLPM, there are a few default settings that will be automatically config-
ured on both NIDs, namely: User and Network port speeds will be set to 1Gig Full-Duplex, the
MPP will be enabled, LLF will be enabled in both directions, and RMTF will be enabled on both
ports.
CAUTION: If the MPP port goes down, all communications between the two NIDs will be
lost. In that scenario, both NIDs will act as active master and will perform PM testing of all
test instances. In an Active/Passive LAG, you may lose communication with the NID
located on the passive link if the MPP port link goes down.
CAUTION: In order for PLPM to function properly, the configuration settings of the PLPM
partner NIDs need to be kept synchronized at all times.
4.6.15.3 How PLPM Works
The following figures are used to illustrate how PLPM functions.
One NID is designated as the Active Master via PLCP protocol handshaking. This NID
generates PM, CPM, and SAM test packets toward the Network and receives reflector packets
from the Network. The PLPM partner forwards any packets (management or PM/SAM/CPM)
received on the leg of the LAG that are addressed to the Active Master to the Active Master
through its MPP.
If the Active Master 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 then proceeds with testing
by sending all of its traffic over the MPP to the attached partner NID for forwarding on the other
LAG leg, thus testing proceeds normally.