We have discovered ISP devices in our environment & then there is complete site topology starting with core-router.
We have given criticality "4" to ISP & criticality "3" to our core-router.
Whenever there is disconnection from ISP side, we are not getting alarm on ISP router but we are getting alert on our core-router. While seeing events log it shows
"The VNM is unable to contact device GBUPMZRED0002R of type GnSNMPDev because all of the devices that this one is connected to are unreachable. An alarm will be generated but will be suppressed from the Alarm view."
Under VNM - Unresolved fault alarm disposition is set to "Device In Fault Domain"
Can anybody help to understand why it is happening.