Users Guide

• In Step C, UFD on S1 disables the link to the server. The server then stops using the link to S1 and switches to using its link to
S2 to send traffic upstream to R1.
Figure 129. Uplink Failure Detection
How Uplink Failure Detection Works
UFD creates an association between upstream and downstream interfaces. The association of uplink and downlink interfaces is
called an uplink-state group.
An interface in an uplink-state group can be a physical interface or a port-channel (LAG) aggregation of physical interfaces.
An enabled uplink-state group tracks the state of all assigned upstream interfaces. Failure on an upstream interface results in
the automatic disabling of downstream interfaces in the uplink-state group. As a result, downstream devices can execute the
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