IP SLA Parameters

When configuring IP SLA, there are several parameters that can be used to modify the behavior of the operation. The following context sensitive help shows these parameters for use with the icmp-echo SLA feature:

R1(config-ip-sla)#icmp-echo R1(config-ip-sla-echo)#? IP SLAs Icmp Echo Configuration Commands: default Set a command to its defaults exit Exit operation configuration frequency Frequency of an operation history History and Distribution Data no Negate a command or set its defaults owner Owner of Entry request-data-size Request data size tag User defined tag threshold Operation threshold in milliseconds timeout Timeout of an operation tos Type Of Service verify-data Verify data vrf Configure IP SLAs for a VPN Routing/Forwarding instance

Some of the most commonly used parameters include:

  • frequency - indicates how often the ICMP echo request will be sent out in seconds.
  • threshold - specifies after how much time a "reaction event" takes place, such as considering a particular SLA as "down." In simpler terms, for an icmp-echo SLA, it is the amount of time that must pass without a successful ping before the SLA is considered down.
  • timeout - the amount of time an IP SLA will wait for a response from its echo request packet.

Typically, for an ICMP echo request SLA, the following should be true:

(frequency seconds ) > (timeout milliseconds ) > (threshold milliseconds )

Otherwise, it may be that the SLA will always fail, even if the link is actually up.