Reference Guide

Field Description
NOTE: Dell Networking OS does not currently support multi-point sessions,
Demand mode, authentication, or control plane independence; these bits are
always clear.
Detection
Multiplier
The number of packets that must be missed to declare a session down.
Length The entire length of the BFD packet.
My Discriminator A random number the local system generates to identify the session.
Your Discriminator A random number the remote system generates to identify the session.
Discriminator values are necessary to identify the session to which a control packet
belongs because there can be many sessions running on a single interface.
Desired Min TX
Interval
The minimum rate at which the local system would like to send control packets to
the remote system.
Required Min RX
Interval
The minimum rate at which the local system would like to receive control packets
from the remote system.
Required Min Echo
RX
The minimum rate at which the local system would like to receive echo packets.
NOTE: Dell Networking OS does not currently support the echo function.
Authentication
Type,
Authentication
Length,
Authentication
Data
An optional method for authenticating control packets.
NOTE: Dell Networking OS does not currently support the BFD authentication
function.
Two important parameters are calculated using the values contained in the control packet.
Transmit
interval
Transmit interval is the agreed-upon rate at which a system sends control packets.
Each system has its own transmit interval, which is the greater of the last received
remote Desired TX Interval and the local Required Min RX Interval.
Detection time Detection time is the amount of time that a system does not receive a control
packet, after which the system determines that the session has failed. Each system
has its own detection time.
• In Asynchronous mode: Detection time is the remote Detection Multiplier
multiplied by greater of the remote Desired TX Interval and the local Required
Min RX Interval.
• In Demand mode: Detection time is the local Detection Multiplier multiplied by
the greater of the local Desired Min TX and the remote Required Min RX
Interval.
BFD Sessions
To establish a session, enable BFD on both sides of a link.
The two participating systems can assume either of two roles:
Bidirectional Forwarding Detection (BFD)
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