outage-detection total-silence

Controls the way CNA detects an outage (when all HRTT measurements for a prefix on all links cease).

outage-detection total-silence { enable | disable |
 
        tslm_threshold <min> <max> <multiplier> }
 
no outage-detection total-silence { enable | disable | tslm_threshold }
 

 

• min--minimum time interval between measurements before an outage can be declared; in milliseconds (100 through 2,147,483,647)
• max--maximum time between measurements before an outage will be declared; in milliseconds (100 through 2,147,483,647)
• multiplier--integer (1 through 10,000,000)

Must be in engine or policy configuration mode (config-engine or config-engine-policy), which requires privileged-level access.

Use once.

Global level:

• min--60000 (60 seconds)
• max--86,400,000 (24 hours)
• multiplier--100

Values within a decision policy default to the settings currently in effect at the global level.

The outage-detection total-silence command sets the parameters used by CNA to determine that a prefix has been totally silent--no UTT measurements recorded for any of your links--for an unacceptable period of time.

Each time a measurement is received for a sufficiently measured prefix, CNA will compute a deadline for the next measurement. If no measurements are received for the prefix across any of your links before the deadline arrives, CNA will declare an outage for that prefix across all links.

When an outage is declared across all links, CNA will withdraw its route assertion for the prefix, unless the prefix is user-defined (not learned from BGP). For non-BGP prefixes, CNA will take no action as a result of the outage.

The deadline is calculated as follows:

• interval = multiplier times maxIMT
• if interval < min, then interval = min
• if interval > than max, then interval = max
• deadline = interval+ time last measurement received

NOTE: The total-silence detection process runs once a minute in the background, as a backstop for prefix outages that might otherwise go undetected. There may be as much as a two-minute delay between the actual and reported times of an outage.

See the outage-detection silence command.

For more information on the outage-detection mechanisms, see Prefix Outage Control in Chapter 3: Adaptive Path Control of the CNA Adaptive Path Controller Guide.

Use the no form of the command to revert to default values for min, max and multiplier.