Limitations with VoIP SLAs

  • A maximum of 80 concurrent VoIP SLAs can be scheduled in a 20 second slot.

  • A single VoIP probe takes 20 seconds to complete.

  • The default and minimum probe interval for VoIP SLA is 120 seconds.

  • SLAs scheduled in the same slot, periodically sends 1000 probe packets for 120 seconds in 20 second intervals.

  • Default 120 second probe interval is divided in to 6 slots of 20 seconds to avoid synchronization of all configured VoIP SLAs sending probes at the same time.

  • SLAs started at the same time exceeding the concurrent limit of 80 must wait for the next 20 second VoIP slot to open before moving to ‘running’ state.

  • The maximum number of VoIP SLAs supported is 80 X 6 slots = 480 SLAs.

  • SLAs exceeding 480 will continue to remain in the 'waiting for VoIP slot' until any slot is freed by stopping the running SLA.

  • To avoid high RTT, a single switch with more than 20 SLAs should not have single responder SLA.