Subscription checking and renewal

The probe periodically checks the status of and renews its subscription with the NNMi system.

Checking the subscription

The probe regularly checks whether the subscription with the NNMi server is active. The value of the HeartbeatInterval property determines the frequency (in seconds) of this check.

The default value of HeartbeatInterval is 60. Change this, if necessary, to suit your local environment. The value of the property can be in the range 1 to 299. Note that the value of this property also affects how often the probe renews the subscription (see Renewing the subscription). Take that into account when determining the value of the property that is suitable for your site. For more details, refer to Configuring a secure connection with the NNMi system.

Note: The probe will not successfully start up if the HeartbeatInterval property is not configured correctly.

Renewing the subscription

In addition to checking the subscription, the probe also renews it. The value of the HeartbeatInterval property has a role in determining the expiry time of the subscription:

Table 1. Determining the subscription expiry time

Value of HeartbeatInterval

Subscription expiry time


The probe sets the subscription expiry time to 5 minutes (300 seconds).


The probe sets the subscription expiry time to the value of HeartbeatInterval plus one minute (60 seconds).

For example, if the value of HeartbeatInterval is 270, the probe sets the subscription expiry time to:

270 + 60 = 330 seconds = 5 minutes 30 seconds

The initial subscription expiry time

The probe creates the initial subscription when it connects to the NNMi system. The expiry time of this subscription is always 5 minutes, which is the default expiry time of the NNMi system.

Failure of the subscription check

The subscription check can fail for a number of reasons, which includes:

  • The NNMi system is not running
  • The NNMi system has become unreachable as the network connection to the NNMi system has failed or is unavailable.

If the subscription check fails, the probe does one of the following:

  • Immediately shuts down
  • Attempts to reconnect to the NNMi system

The value of the RetryCount property determines which action the probe takes. When the property value is 0, the probe immediately shuts down. When the property has a positive value, the probe attempts to reconnect to the NNMi system as shown in Reconnection and backoff strategy.