Configuring BFD

This section provides default BFD values and a procedure for configuring a BFD on your system.

Default BFD Parameters

Parameter	Description	Default Value
Minimum Transmit Interval	The minimum time period in milli-seconds between the transmission of BFD Control or Echo packets	250ms
Minimum Receive Interval	The minimum time period in milli-seconds in which a local BFD session expects to receive a BFD Control or Echo packet.	250ms
Detection time Multiplier	Specifies the value multiplied by the negotiated transmit rate that produces the detection time, causing the peer to transition the BFD session to the down state if a control packet is not received within the detection time interval.	4 packets
Echo Packet Miss Count	The minimum number of consecutive Echo packets that can be missed before the BFD session transitions to down.	3
Demand mode	A BFD mode of operation which assumes that the Echo function rather than Asynchronous operations will verify liveliness on the interface.	Disabled
Echo mode	A BFD feature that tests the forwarding plane by transmitting BFD Echo packets to the remote peer, with the remote peer routing the packet back to the sender via the interface in which the packet was received.	Enabled
Slow Timer	A timer parameter that overrides the Control min-rx value when the Echo feature is active.	2000ms

The following procedure describes BFD configuration on the Extreme Networks S- and K-Series devices.

Configuring BFD

Step	Task	Command(s)
1	Create a named BFD probe in global configuration mode.	probe probe-name bfd
2	Optionally, in BFD probe configuration mode, modify the BFD probe Control packet parameters: minimum transmit interval, minimum receive interval, and Control packet multiplier.	control {min-tx interval | min-rx interval | multiplier number}
3	Optionally, in BFD probe configuration mode, disable the Echo function, if you are operating in Asynchronous mode.	no echo-mode
4	Optionally, in BFD probe configuration mode, modify the Echo packet parameters, minimum transmit interval, minimum receive interval, and Echo packet miss count.	echo {min-tx interval | min-rx interval | miss-count number}
5	Optionally, in BFD probe configuration mode, enable Demand mode to disable Asynchronous operations and depend upon the Echo function for the detection of a communications failure on the remote interface.	demand-mode up-time
6	Optionally, in BFD probe configuration mode, provide a string of up to 127 characters to describe the BFD probe.	description “string”
7	Optionally, in BFD probe configuration mode, modify the BFD slow timer feature to override the Control min-rx value when Echo mode is active.	slow-timer interval
8	In BFD probe configuration mode, place the BFD probe in service.	inservice
9	In interface configuration mode, enable the default or named BFD probe for the OSPF interface configuration mode context in which it will operate.	bfd probe {default | probe-name}
10	In router configuration mode, direct OSPF to create BFD sessions for its neighbors for the specified interface or all interfaces.	bfd {all-interfaces | interface interface-name}

Refer to the S-, K-, and 7100 Series CLI Reference Guide for more information about each command.