Administrator Guide

downstream devices can execute the protection or recovery procedures they have in place to establish
alternate connectivity paths, as shown in the following illustration.
Figure 117. Uplink Failure Detection Example
If only one of the upstream interfaces in an uplink-state group goes down, a specified number of downstream
ports associated with the upstream interface are put into a Link-Down state. You can configure this number
and is calculated by the ratio of the upstream port bandwidth to the downstream port bandwidth in the same
uplink-state group. This calculation ensures that there is no traffic drops due to insufficient bandwidth on the
upstream links to the routers/switches.
By default, if all upstream interfaces in an uplink-state group go down, all downstream interfaces in the same
uplink-state group are put into a Link-Down state.
Uplink Failure Detection (UFD) 897