Bfd Sessions - Dell Force10 Z9000 Configuration Manual

Field Description
My Discriminator A random number generated by the local system to identify the session.
Your Discriminator A random number generated by the remote system 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 The minimum rate at which the local system would like to send control packets to the remote system.
Interval
Required Min RX The minimum rate at which the local system would like to receive control packets from the remote system.
Interval
Required Min Echo The minimum rate at which the local system would like to receive echo packets.
RX
Authentication Type, An optional method for authenticating control packets.
Authentication
Length,
Authentication Data
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.
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BFD Sessions

BFD must be enabled on both sides of a link in order to establish a session.
The two participating systems can assume either of two roles:
Active The active system initiates the BFD session. Both systems can be active for the same session.
Passive The passive system does not initiate a session. It only responds to a request for session initialization from the
active system.
A BFD session has two modes:
Asynchronous mode In Asynchronous mode, both systems send periodic control messages at an agreed upon interval to indicate
that their session status is Up.'
Demand mode If one system requests Demand mode, the other system stops sending periodic control packets; it only
sends a response to status inquiries from the Demand mode initiator. Either system (but not both) can
request Demand mode at any time.
NOTE: Dell Networking OS supports Asynchronous mode only.
A session can have four states: Administratively Down, Down, Init, and Up.
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Bidirectional Forwarding Detection (BFD)
NOTE: Dell Networking OS does not currently support the echo function.
NOTE: Dell Networking OS does not currently support the BFD authentication function.
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.