Email alerts are set to trigger when received power (Rx) drops to a certain threshold, as this is the most obvious way to tell when there is a link loss event.
In order to fire send the alert, the impacted device also needs to be connected to the internet. If there is a general outage of power or the internet connection is lost along with the link between devices, this will also delay the delivery of the alert.
All alerts are relayed through Transcelestial's servers, which process the information and then display the event in our monitoring tools. While this is not a "real-time" or even "near-real-time" process, once an alert is sent successfully from Centauri devices, we usually see the event in logs and in our monitoring tools within a few seconds.
For setup of monitoring and alerts for Centauri devices in your own NOC tools, Transcelestial supports SNMP V3, and we are also working on additional network monitoring tools.