ExtremeSwitching (EXOS)

Working example of Link-Flap in EXOS

  • 1.  Working example of Link-Flap in EXOS

    Posted 06-28-2017 12:56
    Just wondering if anyone has any working examples of EXOS link-flap. I'm trying to make sense of the documentation while at the same time introduce some realistic values. Here is what the documentation says:
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    The maximum value configurable for threshold depends on the link-flap interval value and the link scan interval. For example, if the link scan interval is 50 ms (0.0.5 seconds) (default link-scan interval on most platforms), maximum link down/up events detectable by the hardware is 20 per second. Thus the maximum number of link-flaps detectable per second is 10. If the link-flap interval is 20 seconds, the maximum configurable threshold value is 20 * 10 = 200.

    Thus, the maximum configurable value for threshold = link-flap interval (seconds) * maximum link-flaps detectable/second

    To turn on or off port link-flap detection, use the following command:

    configure ports [port_list | all] link-flap-detection [on | off]

    To set interval, threshold (maximum number of link down events), and disable time values for link-flap detection, use the following command:

    configure ports [port_list | all] link-flap-detection [{interval [interval | indefinitely]} {threshold threshold} {disable-time [disable_time | until-cleared]}]

    To add or delete actions (disabling ports, logging events, generating SNMP traps) to be taken when excessive link-flapping is detected, use the following command:

    configure ports [port_list | all] link-flap-detection action [add | delete] [{{disable-port} {log} {trap}} | all-actions]

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    Based on those figures I guess the confiugration will look something like:

    configure ports 1:1 link-flap-detection on
    configure ports 1:1 link-flap-detection interval 10 threshold 200 disable-time 15
    configure ports 1:1 link-flap-detection action log trap

    Although the 'disable-time' seems to suggest the amount of time, possibly in seconds, to disable the port if the threshold is reached, or you could use the until-cleared option. Yet there is a separate configure statement that you can set the action to disable-port, log, or trap.

    So if I just wanted link-flap to send a log and trap, but not disable the port, what would you configure?

    Perhaps the disable-time is just a period of time before any breached threshold is reset?