Possible Fault Scenarios - Allied Telesis SwitchBlade x3100 Series Manual

Introduction
- "BFD Detected mis-wiring" (failing, severity as appropriate for the interface)
For detection that the system has not received BFD packets within the interval times the detection multi-
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plier. The alarm is as follows:
- "BFD Session Failed" (failing, severity as appropriate for the interface)
For detection that the remote peer is reporting (in the State field received in the remote's packets) that the
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remote BFD State is down. The alarm is as follows:
- "Remote BFD Session Failed" (failing, severity as appropriate for the interface)
The treatment of the failures reported via BFD will be subject to OAM's special debounce treatment of failures
for Ethernet interfaces:
The first raise and clear of an alarm is reported immediately (no soak).
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If a second raise and clear of an alarm on that same interface is declared before a 15 second timer expires,
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then the raise is processed immediately, but the clear will not be reported (soaked) for 10 seconds.

7.7.4 Possible Fault Scenarios

There are situations, described below, in which packets are not being exchanged between two
mal physical layer fault detection (such as LOL or LOF) does not report the failure. Once the failure has been
reported by BFD, it is treated as a physical link failure and topology features (such as RSTP) are activated to
restore network connectivity. Following are some examples where this could occur.
7.7.4.1 BFD with a DS3 Configuration
One example in which this can occur is when Network Access products are connected using DS3 facilities,
with RSTP selecting which FE port is forwarding packets. Refer to the following figure.
SBx3112
SBx3100
RSTP
GE
DS3_Connection_3112
FIGURE 7-16
7-120
Software Reference for SwitchBlade x3100 Series Switches (Network Management)
DS3 Module
1.0
2.0
DS3 Module
Network Access Products Connected using the TN-1000 (no faults)
DS3 Module
DS3
Network
DS3 Module
Possible Fault Scenarios
802.3 MACs but the nor-
SBx3112
SBx3100
1.0
RSTP
GE
2.0