• If one of the upstream interfaces in an uplink-state group goes down, either a user-configurable set of downstream ports or all thedownstream ports in the group are put in an Operationally Down state with an UFD Disabled error. The order in which downstreamports 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 linkgoes 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 DetectionTo configure UFD, use the following commands.1 Create an uplink-state group and enable the tracking of upstream links on the switch/router.CONFIGURATION modeuplink-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} interfaceFor interface, enter one of the following interface types:• 10 Gigabit Ethernet: enter tengigabitethernet {slot/port | slot/port-range}• For a 40-Gigabit Ethernet interface, enter the keyword fortyGigE then the slot/port/subport information.• For a 25-Gigabit Ethernet interface, enter the keyword twentyFiveGigE then the slot/port/subport information.• For a 50-Gigabit Ethernet interface, enter the keyword fiftyGigE then the slot/port/subport information.• For a 100-Gigabit Ethernet interface, enter the keyword hundredGigE then the slot/port/subport information.Where port-range and port-channel-range specify a range of ports separated by a dash (-) and/or individual ports/portchannels in any order; for example:upstream tengigabitethernet 1/1/1-1/1/2,1/5/1,1/9/1,1/11/1-1/12/2downstream 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 thegroup goes down.UPLINK-STATE-GROUP modedownstream 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.904 Uplink Failure Detection (UFD)
