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● If one of the upstream interfaces in an uplink-state group goes down, either a user-configurable set of downstream ports or
all the downstream ports in the group are put in an Operationally Down state with an UFD Disabled error. The order in which
downstream ports are disabled is from the lowest numbered port to the highest.
○ If one of the upstream interfaces in an uplink-state group that was down comes up, the set of UFD-disabled downstream
ports (which were previously disabled due to this upstream port going down) is brought up and the UFD Disabled error is
cleared.
● If you disable an uplink-state group, the downstream interfaces are not disabled regardless of the state of the upstream
interfaces.
○ If an uplink-state group has no upstream interfaces assigned, you cannot disable downstream interfaces when an
upstream link goes down.
● To enable the debug messages for events related to a specified uplink-state group or all groups, use the debug uplink-
state-group [group-id] command, where the group-id is from 1 to 16.
○ To turn off debugging event messages, use the no debug uplink-state-group [group-id] command.
○ For an example of debug log message, refer to Clearing a UFD-Disabled Interface.
Configuring Uplink Failure Detection
To configure UFD, use the following commands.
1. Create an uplink-state group and enable the tracking of upstream links on the switch/router.
CONFIGURATION mode
uplink-state-group group-id
● group-id: values are from 1 to 16.
To delete an uplink-state group, use the no uplink-state-group group-id command.
2. Assign a port or port-channel to the uplink-state group as an upstream or downstream interface.
UPLINK-STATE-GROUP mode
{upstream | downstream} interface
For interface, enter one of the following interface types:
● 10 Gigabit Ethernet: enter tengigabitethernet {slot/port/subport | slot/port-range}
● For a 40-Gigabit Ethernet interface, enter the keyword fortyGigE then the slot/port information.
Where port-range and port-channel-range specify a range of ports separated by a dash (-) and/or individual ports/
port channels in any order; for example:
upstream tengigabitethernet 1/1/1-1/1/2,1/5/1,1/9/1,1/11/1-1/12/2
downstream port-channel 1-3,5
● A comma is required to separate each port and port-range entry.
To delete an interface from the group, use the no {upstream | downstream} interface command.
3. Configure the number of downstream links in the uplink-state group that will be disabled (Oper Down state) if one upstream
link in the group goes down.
UPLINK-STATE-GROUP mode
downstream disable links {number | all}
● number: specifies the number of downstream links to be brought down. The range is from 1 to 1024.
● all: brings down all downstream links in the group.
The default is no downstream links are disabled when an upstream link goes down.
NOTE:
Downstream interfaces in an uplink-state group are put into a Link-Down state with an UFD-Disabled error
message only when all upstream interfaces in the group go down.
To revert to the default setting, use the no downstream disable links command.
4. (Optional) Enable auto-recovery so that UFD-disabled downstream ports in the uplink-state group come up when a disabled
upstream port in the group comes back up.
UPLINK-STATE-GROUP mode
downstream auto-recover
Uplink Failure Detection (UFD)
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