Exhibit:Referring to the exhibit, at which interval will the interface be considered down if no...

The exhibit shows the configuration ofBidirectional Forwarding Detection (BFD)for OSPF on interface xe-0/0/4.0, with the following parameters:

minimum-interval: 400 milliseconds

multiplier: 5

Step-by-Step Breakdown:

BFD Liveness Detection:BFD is used to detect link failures at sub-second intervals, providing faster convergence times for routing protocols like OSPF. Theminimum-intervalis the time between BFD control packets (in milliseconds), and themultiplierindicates how many missed BFD packets trigger a failure.

Calculating Failure Detection Time:The failure detection interval is calculated as:

Failure Interval=minimum-interval×multiplier\text{Failure Interval} = \text{minimum-interval} \times \text{multiplier}Failure Interval=minimum-interval×multiplier

In this case:

400 milliseconds×5=2000 milliseconds(2seconds)400 \, \text{milliseconds} \times 5 = 2000 \, \text{milliseconds} (2 seconds)400milliseconds×5=2000milliseconds(2seconds)

Conclusion:If no BFD control packets are received within2000 milliseconds (2 seconds), the interface will be considered down, triggering OSPF to recalculate routes.

Juniper Reference:

BFD Configuration: BFD parameters such as minimum-interval and multiplier are used to fine-tune the failure detection time for faster convergence.