Alcatel-Lucent 7750 SR OS User Manual
Page 35
IP Router Configuration
7750 SR OS Router Configuration Guide
Page 35
D Bit
The “demand mode” bit. If set, the transmitting system wishes to operate in demand
mode.
P Bit
The poll bit. If set, the transmitting system is requesting verification of
connectivity, or of a parameter change.
F Bit
The final bit. If set, the transmitting system is responding to a received BFD control
packet that had the poll (P) bit set.
Rsvd
Reserved bits. These bits must be zero on transmit and ignored on receipt.
Detect Mult
Detect time multiplier. The negotiated transmit interval, multiplied by this value,
provides the detection time for the transmitting system in asynchronous mode.
Like the IGP hello protocol mechanisms, this is analogous to the hello-multiplier in
IS-IS, which can be used to determine the hold-timer.
(hello-interval) x (hello-multiplier) = hold-timer. If a hello is not received within
the hold-timer, a failure has occurred.
Similarly in BFD: (transmit interval) x (detect multiplier) = detect-timer. If a BFD
control packet is not received from the remote system within detect-timer, a failure
has occurred.
Length
Length of the BFD control packet, in bytes.
My Discriminator
A unique, nonzero discriminator value generated by the transmitting system, used
to demultiplex multiple BFD sessions between the same pair of systems.
Your Discriminator
The discriminator received from the corresponding remote system. This field
reflects back the received value of my discriminator, or is zero if that value is
unknown.
Desired Min TX Interval
This is the minimum interval, in microseconds, that the local system would like to
use when transmitting BFD control packets.
Required Min RX
Interval
This is the minimum interval, in microseconds, between received BFD control
packets that this system is capable of supporting.
Required Min Echo RX
Interval
This is the minimum interval, in microseconds, between received BFD echo
packets that this system is capable of supporting. If this value is zero, the
transmitting system does not support the receipt of BFD echo packets.
Table 3: BFD Control Packet Field Descriptions (Continued)
Field
Description