Information About BFD Deterministic Hardware Offload
The BFD deterministic hardware offload feature allows you to define the BFD transmission timer value. Any BFD sessions below or equal to the set value are sent to hardware. In the conventional BFD design, sessions can be hosted in hardware or software. However, sessions hosted in hardware have the advantage of running at more aggressive timers and not being impacted by CPU spikes.
Currently the determination of which session is hosted in hardware or software is done on a first come first serve basis. The sessions are hosted in hardware till the hardware limit is reached and then the sessions are either hosted in software (if supported) or rejected. In addition, after stateful switchover (SSO) or on reloading, sessions which are hosted in hardware do not necessarily remain in hardware. A similar condition applies for software sessions. The number of BFD sessions that can be supported in the hardware are also limited.
The BFD deterministic hardware offload feature allows you to select the destination of sessions to either hardware or software. This feature allows sessions hosted in hardware to remain in hardware after SSO or reload.
Using this feature you can configure a global command which defines the BFD transmission timer below or equal to the sessions are hosted in hardware.
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On reaching hardware session limit, inactive BFD session do not come up when an active session is removed. |
Note |
Starting with Cisco IOS XE Release 3.13, the global command defines the BFD transmission timer below which the sessions are hosted in hardware; those equal to or above this value are hosted in the software. |