High availability
Figure 24 Uplink Failure Detection for switches
Failure Detection Pair
To use UFD, you must configure a Failure Detection Pair and then turn UFD on. A Failure Detection Pair consists of the following groups of ports:
•Link to Monitor (LtM)
The Link to Monitor group consists of one uplink port
•Link to Disable (LtD)
The Link to Disable group consists of one or more downlink ports
Spanning Tree Protocol with UFD
If Spanning Tree Protocol (STP) is enabled on ports in the LtM, then the switch monitors the STP state and the link status on ports in the LtM. The switch automatically disables the ports in the LtD when it detects a link failure or STP Blocking state.
When the switch determines that ports in the LtM are in STP Forwarding State, then it automatically enables the ports in the LtD, to fall back to normal operation.
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